Home Translating Report News Physicians Diseases Body Sites Lab tests Search
Home Diseases and Health Information


Dermatofibroma is a common soft tissue tumor. It is also known as a fibrous histiocytoma. It is a benign tumor although deep seated tumors, that is, tumors that grow deeply into the fat underlying the skin do have the potential for aggressive growth and local recurrence. For the pathologist, there is sometimes a diagnostic problem distinguishing atypical and cellular variants of this tumor and its malignant mimic, dermatofibrosarcoma protuberans (DFSP). Using the immunohistochemical stain for CD34 has greatly aided in this distinction. DFSPs are typically CD34 positive while dermatofibroma is negative.

Under the microscope, these tumors are composed of spindle cells arranged in a storiform or haphazardly intersecting fascicles, characteristically entrapping collagen fibers. Occasional tumors may extend into the fat with a root-like configuration. The epidermis overlying the tumor is usually separated by a thin Grenz zone. The epidermis may be hyperplastic and frequently may show accentuation of basal melanin cytoplasmic pigment. In addition, there may be secondary follicular induction caused by the dermatofibroma which at times may mimic a basal cell carcinoma. Numerous histologic variants have been described.

Atypical (Pseudosarcomatous)
With Osteoclastic-like giant cells
Cholesterotic associated with hyperlipoproteinemia
With smooth muscle
With granular cells
With Monster cells

Recently, there have been reports of cases which have metastasized. These tumors involved the dermis and subcutaneous fat but appeared well-delineated though unencapsulated. They ranged in size from 1-3 cm. They all shared features of a cellular or aneurysmal/atypical dermatofibroma. Mitoses ranged from 6-11/10 hpf with frequent tumor necrosis. There was a history of frequent local recurrences and these recurrences and metastases showed similar histologic features to the original tumor. The pathologist finding these characteristics in a dermatofibroma needs to alert the treating physician of the importance of complete excision and careful clinical followup.

Disease Associations  
Laboratory/Radiologic/Other Diagnostic Testing  
Gross Appearance and Clinical Variants  
Histopathological Features and Variants  
Special Stains/
Electron Microscopy
Differential Diagnosis  
Commonly Used Terms  
Internet Links  


Multiple eruptive dermatofibromas in a patient with HIV infection: case report and literature review

JeanKanitakis, ElisabethCarbonnel, SergioDelmonte, Jean-MarcLivrozet, MichelFaure and AlainClaudy

J Cutan Pathol 2000;27 (1), 54-56 Abstract quote

Multiple eruptive dermatofibromas have been reported in the setting of autoimmune diseases treated with immunosuppressive drugs and more recently in the course of human immunodeficiency virus (HIV) infection.

We report herein the ninth case of multiple eruptive dermatofibromas associated with HIV infection. The relevant literature is reviewed and the differences of these lesions from “ordinary” dermatofibromas are discussed.

Melanocytic lesions associated with dermatofibromas: a spectrum of lesions ranging from junctional nevus to malignant melanoma in situ.

King R, Googe PB, Page RN, Mihm MC.

[1] 1Knoxville Dermatopathology Laboratory, Knoxville, TN, USA [2] 2Department of Pathology, University of Tennessee, Knoxville, TN, USA.

Mod Pathol. 2005 Aug;18(8):1043-7. Abstract quote  

Dermatofibromas are common lesions that are often associated with epidermal hyperplasia and basal layer hyperpigmentation. A single case of lentiginous melanocytic hyperplasia overlying a dermatofibroma has been reported, however, nevi and melanoma have to the best of our knowledge, not been previously reported.

We present 14 cases of melanocytic lesions associated with dermatofibromas. The clinical data and hematoxylin- and eosin- stained sections were obtained and formalin-fixed, paraffin-embedded tissue was immunostained with antibodies against S-100, Mart-1, Factor XIIIa, and CD117. There were nine females and five males ranging in age from 30 to 64 years and anatomic sites included back (five), arm (six), flank (two), and leg (one). The clinical diagnosis ranged from dermatofibroma to desmoplastic melanoma.

Histologically, the melanocytic lesions included junctional, compound, and dermal nevi, and malignant melanoma in situ. In four cases the dermal component appeared to merge with the dermatofibroma. In the case of the melanoma in situ, the dermatofibroma abutted the epidermis. Immunohistochemically, the melanocytic lesions were S-100/ Mart-1+, FXIIIa-, and the dermatofibromas were S-100/Mart-1-, FXIIIa+. Melanocytic neoplasia may appear in association with dermatofibromas. The fibrohistiocytic proliferation may be misinterpreted as a spindle or pleomorphic melanocytic process.

Awareness of this association will aid in the correct diagnosis, and immunohistochemical studies will help in the differentiation of these two cell populations.



Proliferation and Differentiation of the Keratinocytes in Hyperplastic Epidermis Overlying Dermatofibroma Immunohistochemical Characterization

Kwang-Ho Han, etal.

Am J Dermatopathol 2001;23:90-98 Abstract quote

Epidermal changes overlying dermatofibromas (DFs) have been described as ranging from psoriasiform simple hyperplasia to basaloid hyperplasia sometimes morphologically indistinguishable from superficial basal cell carcinoma (BCC).

To characterize epidermal hyperplasia overlying DFs and to determine its association with the disease process, we examined 30 cases of DF showing hyperplastic epidermis.

We used nine immunohistochemical markers associated with keratinocyte proliferation or differentiation. In DFs, the dermal metallothionein (MT) expression and immunophenotypic changes with regard to epidermal differentiation varied depending on the stage of lesional evolution of the DFs.

Immunostaining for epidermal growth factor receptor (EGFR), MT, and keratin 6 (K6) increased in simple hyperplastic epidermis (SHE) overlying DFs (n = 11), whereas it gradually diminished in basaloid hyperplastic epidermis (BHE) overlying DFs (n = 19). In SHE, there was a significant increase in K14 expression. Among 19 BHE cases, 12 showed premature expression of involucrin and delayed appearance of K1 along with aberrant expression of K14. Conversely, the remaining 7 BHE cases showed a pattern of involucrin and K1 similar to that of normal skin coinciding with decreased or absent dermal MT expression. Loricrin and filaggrin expression in all DFs was the same as that of normal skin. Based on the sparse positivity of Ki-67 in the hyperplastic epidermis overlying DFs, we found that the biologic ability of BHE and SHE was not apparent in the hyperproliferative state observed in psoriasis and BCC.

These results suggest that the dermal fibrohistiocytic process may trigger the induction of SHE overlying DFs by an unknown mechanism and then mediate both the abnormal keratinocyte differentiation and the transformation of SHE to BHE through the evolution of the dermal lesions.


Dermatofibroma is a clonal proliferative disease

Tse-ChingChen, Tseng-tongKuo and Heng-LeongChan

J Cutan Pathol 2001;27 (1), 36-39 Abstract quote

Benign fibrous histiocytoma of the skin or dermatofibroma (DF) has been regarded as a fibrohistiocytic tumor. Whether DF is a neoplastic growth or a reactive process has not been settled.

Since a neoplastic process is clonal in nature, clonal analysis of DF was conducted to see if DF is a clonal disease.

Fresh specimens of 13 DFs and 2 hypertrophic scars obtained from female patients were studied. The adjacent nonlesional skin tissues served as controls. The clonal analysis was based on the methylation pattern of the polymorphic X-chromosome linked androgen-receptor gene (HUMARA). Eight DFs and 1 hypertrophic scar were heterozygous at the androgen receptor gene and could be analyzed. All 8 informative DFs showed a significant reduction in one of the allelic bands compared with the corresponding bands of the nonlesional tissue after Hha I digestion.

Therefore, DF is a clonal proliferative disease. In contrast, 1 hypertrophic scar showed a polyclonal pattern of X-chromosome inactivation. We conclude that DF is a clonal disease favoring a neoplastic process.

Clonal analysis of cutaneous fibrous histiocytoma (dermatofibroma).

Hui P, J Glusac E, Sinard JH, Perkins AS.

Department of Pathology, Yale University School of Medicine, New Haven, CT, USA Department of Dermatology, Yale University School of Medicine, New Haven, CT, USA.


J Cutan Pathol 2002 Aug;29(7):385-9 Abstract quote

BACKGROUND: Dermatofibroma (DF) or cutaneous fibrous histiocytoma is a common benign fibrohistiocytic lesion involving the dermis and subcutis. Histologically, it is subclassified into fibroblastic and histiocytoid forms. Its histogenesis is controversial. While often referred to as a neoplastic process, definite evidence of neoplasia in DF has been lacking. Alternatively, some authorities have suggested that DF is a fibrosing inflammatory process. Diagnostically, the most important question faced is the distinction from dermatofibrosarcoma protuberans (DFSP). Misdiagnosis can occur, as the early phase of DFSP can simulate DF, particularly the deep and cellular forms of DF.

METHODS: To address this issue, and to investigate whether DF is in fact a neoplasm, we evaluated 31 examples of DF of various histological types in female patients and assessed clonality by analyzing X-chromosome inactivation as indicated by the methylation status of the androgen receptor gene (HUMARA). Representative cases of DFSP were analyzed for comparison.

RESULTS: Among the selected 31 cases of DF, 24 cases provided intact DNA and informative polymorphism at the AR alleles, including one case of recurrent deep fibrous histiocytoma. Among these 24 cases, randomly inactivated AR alleles were observed in 17 cases including a deep, recurrent fibroblastic DF. A non-random inactivation at AR alleles was observed in seven cases, of which six cases showed either typical histiocytoid form of DF (four cases) or mixed cell types with predominant histiocytoid cell type (two cases). One fibroblastic DF also showed a monoclonal pattern. HUMARA analysis of DFSP revealed non-random inactivation of polymorphic AR alleles.

CONCLUSIONS: These findings suggest that DF is a heterogeneous process. Monoclonal genotype was found in DFs with histiocytoid or mixed type with predominant histiocytoid features, suggesting that histiocytoid cells probably represent the neoplastic component. The fibroblastic form of DF may represent a reactive fibroblastic proliferation. Alternatively, it may represent a true neoplasm whose neoplastic cell type has been obscured by prominent reactive fibroblastic component.


Dermatofibroma: upregulation of syndecan-1 expression in mesenchymal tissue.

Sellheyer K, Smoller BR.

The Jefferson Center for Dermatopathology, Department of Pathology, Thomas Jefferson University, Philadelphia, PA, USA.

Am J Dermatopathol. 2003 Oct;25(5):392-8. Abstract quote  

Cell surface proteoglycans play a prominent role in tissue remodeling and homeostasis. Syndecans, their most prominent members, act by binding to growth factors and interstitial matrix molecules. They, thereby, modulate the effect of the primary ligand-receptor interaction at the cell membrane by increasing the affinity of cell-ligand interactions. Additionally, they influence the strength of cell-cell and cell-matrix interactions.

Syndecan-1 is the prototypical member of this family of proteins. Under physiological conditions, its expression is restricted to the epidermis, the outer root sheath of the anagen hair follicle, and the sweat gland epithelium. The dermal compartment-with the exception of the follicular papilla of the anagen hair follicle-physiologically does not express syndecan-1. Dermatofibromas are mesenchymal lesions, which often exhibit hyperplastic changes in the overlying epidermis. In analogy to the hair follicle, they, thereby, can be used as a model for studying epithelial-mesenchymal interactions. In the current study, we examined dermatofibromas immunohistochemically for syndecan-1 expression.

We report immunoreactivity for syndecan-1 in dermatofibromas, which correlates mainly with the deposition of intercellular matrix material. Syndecan-1 is also noted in the stroma surrounding areas of basaloid hyperplasia overlying dermatofibromas and may be important in the pathogenesis of this inductive phenomenon. In analogy to the follicular papilla of the anagen hair follicle, the staining pattern for syndecan-1 in dermatofibromas indicates that this cell surface protein is produced by stromal cells and most likely serves an essential function in the growth of these common mesenchymal cutaneous lesions.


Different dermoscopic faces of dermatofibromas.

Ege University, Medical Faculty, Department of Dermatology, 35100, Bornova, Izmir, Turkey.

J Am Acad Dermatol. 2007 Sep;57(3):401-6. Abstract quote

BACKGROUND: Central white scarlike patch and a delicate pigment network at the periphery is the typical appearance of dermatofibromas on dermoscopy.

OBJECTIVE: We aimed to analyze the different dermoscopic appearances of dermatofibromas.

METHODS: Fifty-two dermatofibromas with dermoscopic features different from the classic type, which were detected between May 2003 and July 2005, were evaluated.

RESULTS: Globules in the scarlike area (38.5%), linear/irregular crypts (26.9%), lentigo-like reticular pigmentation (23%), homogeneous blue-gray pigmentation (5.9%), and erythematous homogeneous area surrounding the white patch (3.8%) were the patterns observed. In addition, dermoscopic features of an atrophic variant of dermatofibroma are described, which was seen in one lesion (1.9%).


CONCLUSION: Dermatofibromas have various dermoscopic features. Among them, "linear, irregular crypts" is not unusual and is described in this study. Homogeneous bluish pigmentation on dermoscopy may be a possible clue for the diagnosis of hemosiderotic variants of dermatofibromas.

Benign Fibrous Histiocytoma (Dermatofibroma) of the Face: Clinicopathologic and Immunohistochemical Study of 34 Cases Associated with an Aggressive Clinical Course

Thomas Mentzel, M.D.; Heinz Kutzner, M.D.; Arno Rütten, M.D.; Heino Hügel, M.D.

Department of Dermatohistopathology, Friedrichshafen, Germany.

Am J Dermatopathol 2001;23:419-426 Abstract quote

Thirty-four cases of fibrous histiocytoma (dermatofibroma) arising on the face are reported.

These neoplasms occurred frequently in females (24 female, 10 male) and showed a broad age range (12 to 85 years; mean: 43.6 years, median: 41 years). The neoplasms originated on the forehead (nine cases), the cheek (eight cases), the eyebrow (four cases), the temporal region (three cases), the nose (two cases), and the ear (one case); in seven cases the location face was given only. Five of 27 cases with follow-up information (median: 5 years) recurred locally; in one case four recurrences were excised within 8 years. The majority of cases extended into the subcutis and deep soft tissue including striated muscle (50% of cases).

Histologically, only the minority of cases was composed entirely of histiocytoid and spindle-shaped tumor cells arranged in a storiform growth pattern. In many cases cellular fascicles and bundles of spindle-shaped tumor cells were noted in addition to classical morphological features of fibrous histiocytoma. A moderate mitotic rate (mean: 2.97 mitoses in 10 HPFs) was observed, and in few cases increased atypia was evident. Frank tumor necrosis and/or vascular invasion were not identified. Immunohistochemical studies revealed Factor XIIIa positivity in 13 out of 17, focal CD68 positivity in 6 out of 10, and alpha-smooth muscle actin positivity in 16 out of 19 cases tested.

These lesions should be distinguished from dermatofibrosarcoma protuberans, including its fibrosarcomatous variant, leiomyosarcoma, and low-grade myofibroblastic sarcoma. Cases of fibrous histiocytoma of the face have to be excised with wider margins in comparison with examples of classical fibrous histiocytoma occurring on the extremities because of diffuse infiltration, involvement of deeper structures, and an increased rate of local recurrences.



Aneurysmal fibrous histiocytoma of the skin. A histological, immunohistochemical, and ultrastructural study.

Yang P, Hirose T, Hasegawa T, Seki K, Hizawa K.

First Department of Pathology, University of Tokushima School of Medicine, Japan.

Am J Dermatopathol 1995 Apr;17(2):179-84 Abstract quote

We present two cases of aneurysmal fibrous histiocytoma of the skin on the lower extremities of a 41-year-old man and a 23-year-old woman.

Both the tumors appeared clinically as cutaneous nodules with a recent history of rapid growth and showed microscopically a unique formation of blood-filled tissue spaces and a storiform proliferation of histiocyte-like and fibroblast-like cells in a capillary-rich stroma. Such clinical and histologic features fit the original description of this entity. Immunohistochemically the tumor cells of both cases were immunoreactive for factor XIIIa, Mac 387, and vimentin and gave negative results for factor VIII-related antigen, desmin, actin, and S-100 protein. Ultrastructurally the tumors were composed mainly of siderosome-containing histiocyte-like cells, fibroblast-like cells, and intermediate cells and lacked prominent proliferation of endothelial cells. Thus, the ultrastructural findings agreed with the immunophenotypes expressed by the tumor cells, supporting the fibrohistiocytic origin of this lesion.

In view of the recent rapid growth, the presence of hemorrhagic pseudocysts, the extravasation of erythrocytes, and the high vascularity of the present tumors, we emphasize the importance of distinguishing this lesion from angiomatoid fibrous histiocytoma and cutaneous malignancies of mesenchymal origin.


Solid and cystic tumor with intense inflammatory cell infiltrate surrounding the tumor resembling a dermal lymph node
Spindled and round cells with eosinophilic cytoplasm at center of tumor with cystic spaces filled with blood, occasionally thrombosed
Circumscribed in 75% of cases
Mitotic figures rare

Occasional cases may have >5MF/10 hpf and pleomorphism may be moderate

The Value of Immunohistochemistry in Atypical Cutaneous Fibrous Histiocytoma.

Wilk M, Zelger BG, Nilles M, Zelger B.

*Dermatohistological Private Laboratory Nurnberg, Germany; daggerDepartment of Pathology, University of Innsbruck, Innsbruck, Austria; Dagger;Dermatohistological Private Laboratory Giessen, Germany; and section signDepartment of Dermatology, University of Innsbruck, Innsbruck, Austria.

Am J Dermatopathol. 2004 Oct;26(5):367-371. Abstract quote  

Atypical cutaneous fibrous histiocytoma is a rare variant of dermatofibroma/fibrous histiocytoma characterized by striking atypia, thus resembling atypical fibroxanthoma.

We studied 9 examples of ACFH histopathologically and immunohistochemically to investigate the nature of these atypical cells.

Histology revealed ill-defined skin nodules, which were polypoid in 6 cases. A minority of mononuclear and giant cells (< 5%) revealed striking pleomorphism and showed large nuclei with prominent nucleoli. Immunohistologically, the atypical cells expressed vimentin, but were negative for S-100 protein, the keratin marker MNF116, alpha smooth muscle actin, CD34, factor XIIIa, and monocyte/macrophage markers Ki-M1p, KP1 (CD68), and MAC387. Positivity for MiB1 was very modest (< 1%) and limited to small- and medium-sized, inconspicuous cells. Multinucleate giant cells proved to be heterogenous, on one hand cells with differentiation toward macrophages with positivity for Ki-M1p and KP1, on the other toward fibroblasts positive for vimentin only.

These immuno-histochemical results for differentiation markers in atypical cutaneous fibrous histiocytoma are similar to our previous findings and data in atypical fibroxanthoma; MiB1 helps to separate these entities from each other as the latter shows a very high proportion of proliferative atypical cells corresponding to the numerous mitoses seen in routine sections.

Atypical Fibrous Histiocytoma of the Skin Clinicopathologic Analysis of 59 Cases With Evidence of Infrequent Metastasis

Steven Kaddu, M.D. ; Máirín E. McMenamin, M.B. , M.R.C.P.I. , M.R.C.Path. ; Christopher D. M. Fletcher, M.D. , F.R.C.Path.

From the Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, U.S.A. Dr. Kaddu is currently affiliated with the Department of Dermatology, University of Graz, Graz, Austria.

Am J Surg Pathol 2002;26:35-46 Abstract quote

Atypical fibrous histiocytoma is an uncommon, poorly documented variant of cutaneous fibrous histiocytoma.

We studied 59 cases of atypical fibrous histiocytoma to better characterize the clinicopathologic spectrum. There were 33 males and 26 females (median age 38 years; range 5–79 years) with solitary lesions arising on lower (25 cases) and upper (17 cases) extremities, trunk (6 cases), head and neck (4 cases), and vulva (1 case); anatomic location was not stated in six cases. Lesions measured 0.4–8 cm in diameter (median 1.5 cm) and clinically were nodules (40 cases), polypoid tumors (18 cases), or a slightly elevated plaque (1 case).

Histologically, the lesions were primarily dermal with superficial involvement of the subcutis in one third of the cases. Salient features included a proliferation of pleomorphic, plump, spindle, and/or polyhedral cells with mainly large, hyperchromatic, irregular, or bizarre nuclei, set in a background of classic features of fibrous histiocytoma, including spindle cell areas showing a storiform pattern and entrapped thickened, hyaline collagen bundles, especially at the periphery. Multinucleated giant cells, often with bizarre nuclei and foamy, sometimes hemosiderin-rich, cytoplasm were also variably present. The degree of pleomorphism varied from only focal and minimal (14 cases) or moderate (24 cases) to marked (21 cases). Mitotic activity was observed in 55 lesions, and the number of mitotic figures ranged from 1 to 15 per 10 high power fields. Atypical mitoses were noted in 20 lesions. Furthermore, some cases of atypical fibrous histiocytoma displayed other worrisome features less often observed in ordinary FH, including unusually large size (diameter >2 cm, 8 cases), involvement of the superficial subcutis (19 cases), and geographic necrosis (7 cases).

Immunohistochemical studies performed in 42 cases showed only focal smooth muscle actin (10 cases) and CD34 (4 cases) positivity, whereas CD68, S-100 protein, desmin, pan-keratin, and epithelial membrane antigen were negative. Clinical follow-up data available in 21 patients (mean duration of follow-up 50.6 months, median 43 months) revealed local recurrences in three patients (one repeated); two patients developed distant metastases, one of whom died after 96 months. These two cases were not histologically distinct from the group as a whole.

We conclude that atypical fibrous histiocytoma has a broader clinicopathologic spectrum than previously realized. Lesions with floridly atypical features represent potential pitfalls for overinterpretation as pleomorphic sarcoma, which would appear to be inappropriate in most cases. Provided that atypical fibrous histiocytoma is treated by complete excision, a benign outcome is to be expected in most cases. However, similar to the cellular and aneurysmal variants of fibrous histiocytoma, atypical fibrous histiocytoma shows a higher tendency to recur locally than ordinary fibrous histiocytoma and may rarely metastasize.


Cellular benign fibrous histiocytoma. Clinicopathologic analysis of 74 cases of a distinctive variant of cutaneous fibrous histiocytoma with frequent recurrence.

Calonje E, Mentzel T, Fletcher CD.

Department of Histopathology, St Thomas's Hospital (U.M.D.S.), London, England.

Am J Surg Pathol 1994 Jul;18(7):668-76 Abstract quote

We report seventy-four cases of a distinctive variant of cutaneous fibrous histiocytoma, which is often mistaken histologically for sarcoma and which carries a high local recurrence rate.

These tumors appeared most commonly in young or middle-aged adults, with a predominance in men (male/female ratio 1.9:1). Anatomic distribution was wide, with cases occurring mainly in the upper limb/limb girdle (34%), lower limb/limb girdle (27%), and head and neck region (20%). Most lesions had been present for only a few months, and their sizes ranged from 0.5 cm to 2.5 cm in maximum diameter. Twelve (26%) of 46 cases with follow-up (mean duration 3 years) recurred locally, in one case twice. Distinctive histologic features were a commonly fascicular growth pattern, predominance of eosinophilic spindle cells with tapering nuclei, a moderate mitotic rate (mean three per 10 high-power fields), and frequent extension into the subcutaneous fat (33% of cases). In addition, all cases showed at least focal cytologic polymorphism (inflammatory cells, foam cells, giant cells), and 58% showed associated epidermal alterations in common with usual cutaneous fibrous histiocytomas. Nine cases (12%) showed foci of central necrosis. Immunohistochemical studies (ABC method) found only vimentin and very focal smooth muscle actin positivity. Tests for CD34, desmin, S-100, keratin, and Factor XIIIa were negative in all cases.

These lesions should be distinguished from dermatofibrosarcoma protuberans and leiomyosarcoma, with which many of these cases were initially confused.

Benign fibrous histiocytoma with indeterminate cells and eosinophils: collision, differentiation, or involution?

Solis E, Moreno A, Rodriguez-Enriquez B, Sanchez-Vizcaino JS, Haro V, Aguilar M, O'Valle F, del Moral RG.

Department of Pathology, Infanta Margarita Hospital, Cabra, Cordoba, Spain.
Am J Dermatopathol. 2004 Jun;26(3):237-41. Abstract quote  

This report describes the clinicopathologic, immunohistochemical, and ultrastructural features of a benign fibrous histiocytoma of 3 years' duration situated on the posterior right arm of a 17-year-old woman.

To our knowledge, this is the first published description of an association between the histologic features of benign fibrous histiocytoma with proliferating dermal dendrocytes and solid clusters of indeterminate cells and inflammatory infiltrate containing numerous eosinophils. Cell type identification was confirmed by immunohistochemical demonstration of positivity of indeterminate cells for CD1a and S-100 protein, by absence of Birbeck granules in electron microscopy study, and by positivity of fibroblast-like cells for factor XIIIa and negativity for CD34. Mitosis or cytologically atypical cells were absent.

The MIB1-measured proliferative index of the tumor cells was less than 5% in spindle cells and approximately 15% in indeterminate cells.

Possible pathogenic pathways are discussed that could account for divergent differentiation or a combination of neoplasms of different lineages.

Combined dermatofibroma: co-existence of two or more variant patterns in a single lesion.

Zelger BG, Sidoroff A, Zelger B.

Departments of Pathology, Dermatology, University of Innsbruck, Austria.

Histopathology 2000 Jun;36(6):529-39 Abstract quote

AIMS: Based on a series of 25 cases, we define and characterize combined dermatofibroma, a tumour comprising two or more variant patterns of dermatofibroma in a single lesion.

METHOD AND RESULTS: Dermatofibroma may present with a wide variety of architectural, cellular or stromal peculiarities. Architectural peculiarities include deep penetration, atrophy, collarette formation, fascicular to plexiform architecture, massive haemorrhage, prominent haemangiopericytoma-like vascularity and palisading; cellular peculiarities the presence of epithelioid cells, clear cells, granular cells, prominent myofibroblastic differentiation and atypical giant cells ('monster cells'); or stromal peculiarities such as prominent sclerosis, mucin, haemosiderin and cholesterotic deposits. In combined dermatofibromas two or more of these features are seen in complex or inhomogenous combination such as the silhouette of a deep penetrating dermatofibroma with an 'ordinary' storiform pattern in the upper and granular cell differentiation in the lower part of the lesion; or a dermatofibroma with ordinary features in the upper, prominent sclerosis in the middle and clear cells in the lower portion of the lesion; or the characteristic epidermal collarette and cells of epithelial cell histiocytoma with a plexiform ('neurothekeoma-like') architecture surrounded by a myxoid stroma with spindle-shaped to stellate cells. Clinically, these lesions preferentially occur on the lower extremities of young to middle-aged females, frequently with the diagnosis of a fibrohistiocytic lesion. Apart from one recurrence follow-up was uneventful in all other cases. Immunohistochemically, lesions are consistently positive with KiM1p, variably positive for factor XIIIa, smooth muscle specific actin and with KP1 (CD68), NK1C3 and E9.

CONCLUSION: Recognition of combined dermatofibroma allows the histopathologist to apply a confident benign label to unusual lesions which might otherwise elude diagnosis, or tempt description of 'new' entities and to avoid a misdiagnosis of malignancy.

Benign subcutaneous and deep fibrous histiocytomas Bounded by fibrous capsule, usually single nodules
Fibroblastic in appearance with variable cellularity
MF<5 10 hpf
Giant cells and foamy cells unusual
Stellate foci of necrosis occasionally
Staghorn vascular pattern may be present
Deep "Benign" Fibrous Histiocytoma: Clinicopathologic Analysis of 69 Cases of a Rare Tumor Indicating Occasional Metastatic Potential.

Department of Pathology, Brigham and Womenʼs Hospital and Harvard Medical School, Boston, MA.


Am J Surg Pathol. 2008 March 32(3); 354-362. Abstract quote

Benign fibrous histiocytoma (FH) is one of the most common mesenchymal neoplasms of the skin. Several histologic variants of cutaneous FH have been described, some of which also have distinct clinical features including a propensity for local recurrence.

Deep benign FH is an uncommon and poorly recognized clinical subtype that arises in subcutaneous or deep soft tissue. Only a single small series of these neoplasms has been published, and their clinical behavior is not well characterized.

In this study, we report the clinicopathologic features of 69 deep FH retrieved from our consultation files. The patients included 41 males and 28 females, ranging in age from 6 to 84 years (median, 37 y). The most common anatomic location was the extremities (58%); the remainder arose on the head and neck (22%), trunk (11%), and in the deep soft tissue of the retroperitoneum, mediastinum, or pelvis (9%). All lesions arising in nonvisceral soft tissue were subcutaneous. The tumors ranged from 0.5 to 25 cm in size (median, 3.0 cm) and were well circumscribed grossly and microscopically. All tumors were composed of bland ovoid to spindle cells arranged in a storiform pattern with admixed lymphocytes. Multinucleate giant cells, osteoclastic giant cells, and/or foam cells were present in 59% of cases, whereas the other 41% were cytologically monomorphic, often resembling cellular FH. Other common findings included a hemangiopericytomalike vascular pattern (42%) and stromal hyalinization (39%). Four cases were classified as atypical deep FH due to the presence of scattered markedly pleomorphic spindle cells within an otherwise histologically typical lesion. The median mitotic rate was 3/10 HPF; 10 cases (14%) had >10 mitoses/10 HPF. Necrosis (2 cases) and lymphovascular invasion (1 case) were rare. Immunohistochemistry revealed expression of CD34 in 20/50 cases (40%), smooth muscle actin in 15/40 (38%), and focal desmin in 1/12 (8%). Of the 37 patients for whom clinical follow-up was available (median, 40 mo), 8 (22%) had a local recurrence; in all 8 cases, the tumor had been marginally or incompletely excised. Metastases occurred in 2 patients (5%), both of whom ultimately died of disease; however, this number is likely exaggerated due to consultation bias. The metastasizing tumors were large (6 and 9 cm) and 1 had tumor necrosis but they were otherwise histologically identical to the nonmetastasizing lesions.

In summary, deep FH has many histologic features in common with cutaneous cellular FH; however, it usually has a more diffusely storiform pattern than the latter, is well circumscribed, and may have striking hemangiopericytomalike vessels. Similar to the cellular, aneurysmal, and atypical variants of FH, deep FH recurs in approximately 20% of cases and may rarely metastasize.
Dermatomyofibroma: clinicopathologic and immunohistochemical analysis of 56 cases and reappraisal of a rare and distinct cutaneous neoplasm.

Dermatopathologie Bodensee, Friedrichshafen, Germany.

Am J Dermatopathol. 2009 Feb;31(1):44-9. Abstract quote

Dermatomyofibroma represents a rare and distinct benign cutaneous mesenchymal neoplasm of fibroblastic/myofibroblastic differentiation.

A series of 56 cases of dermatomyofibroma has been analyzed to further characterize the clinicopathologic spectrum of this entity. Forty patients were female and 8 were male (gender was unknown in 8 cases). Patients' age ranged from 3 to 51 years (mean 30.8 years, median 30 years). Interestingly, 6 patients were younger than 16 years, and in this age group, 3 male and 3 female patients, respectively, were noted. The shoulder (13 cases) was the anatomic site most commonly affected, followed by the upper arm (7 cases), the neck (6 cases), the thigh (6 cases), the chest wall (4 cases), the back (3 cases), the axillary fold (2 cases), the abdominal wall (2 cases), and 1 case each was seen on the forearm, the buttock, and the popliteal fossa (exact anatomic location was unknown in 10 cases). One patient presented with 2 lesions arising simultaneously on both shoulders.

Histologically, an ill-defined, plaque-like dermal neoplasm of varying cellularity was seen in all cases, composed of bland spindle-shaped tumor cells often oriented parallel to the overlying epidermis. An infiltration of superficial part of the subcutis was seen in 23 cases, and in 6 cases, deeper parts of the subcutis were involved by often perpendicular growing bands of neoplastic cells.

Immunohistochemically, tumor cells in 11 of 48 cases tested stained positively for alpha-smooth muscle actin, and a focal expression of this marker was noted in 20 cases. In addition, a focal expression of CD34 was seen in 10 of 45 cases tested. Follow-up information was available in 38 cases (range from 3 to 156 months, median 34 months), and despite marginal or incomplete excision in 17 cases, none of the cases recurred.

Dermatomyofibroma represents a benign fibroblastic/myofibroblastic dermal neoplasm.

Haemorrhagic dermatomyofibroma (plaque-like dermal fibromatosis): clinicopathological and immunohistochemical analysis of three cases resembling plaque-stage Kaposi's sarcoma.

Mentzel T, Kutzner H.

Dermatopathologisches Gemeinschaftslabor, Friedrichshafen, Germany.

Histopathology. 2003 Jun;42(6):594-8 Abstract quote

AIMS: Dermatomyofibroma (plaque-like dermal fibromatosis) represents a distinct clinicopathological entity in the spectrum of cutaneous mesenchymal neoplasms showing a myofibroblastic line of differentiation. These benign neoplasms occur frequently, but not exclusively, in young women, and the shoulder girdle as well as the upper trunk are common locations. Histologically, dermatomyofibroma is characterized by a plaque-like proliferation of cytologically bland spindle-shaped tumour cells containing an ill-defined, pale eosinophilic cytoplasm and elongated, neuroid nuclei. Neoplastic cells are arranged in bundles and fascicles orientated parallel to the skin surface, adnexal structures are spared and elastic fibres are increased and fragmented. Immunohistochemically, tumour cells express vimentin and variably muscle actin and alpha-smooth muscle actin, but are negative for desmin, CD34, S100, and epithelial markers. The main differential diagnosis includes hypertrophic scar, dermatofibroma (fibrous histiocytoma), pilar leiomyoma, neurofibroma, adult myofibromatosis, extra-abdominal fibromatosis and plaque-stage dermatofibrosarcoma protuberans.

METHODS AND RESULTS: We report three cases of dermatofibroma arising in male patients aged 31, 36, and 47 years on the thigh, chest wall and back, respectively. All lesions were completely excised and no local recurrence has been reported. Histologically, the neoplasms showed classical features of dermatomyofibroma; however, in addition abundant extravasated erythrocytes, scattered inflammatory cells, numerous capillaries, and sieve- and slit-like spaces, features resembling plaque-stage Kaposi's sarcoma, were noted. In none of the cases did spindled tumour cells stain positively for CD34, and HHV8 was not detected by polymerase chain reaction.

CONCLUSIONS: The reported cases widen the clinicopathological spectrum of dermatomyofibroma and emphasize plaque-stage Kaposi's sarcoma as an additional differential diagnosis.


Aneurysmal and haemangiopericytoma-like fibrous histiocytoma.

Zelger BW, Zelger BG, Steiner H, Ofner D.

Department of Dermatology, University of Innsbruck, Austria.

J Clin Pathol 1996 Apr;49(4):313-8 Abstract quote

METHODS: Thirty three cases of AFH were studied by using routine histology and immunohistochemistry for factor XIIIa, the "cell activity marker" E9 (anti-metallothionein), NK1C3 (CD57), smooth muscle actin (SMA), factor VIII, ulex europaeus agglutinin, JC70A (CD31), and QBEND10 (CD34). The time dependent variation in histopathological features was evaluated by statistical methods (Pearson chi 2, likelihood ratio chi 2).

RESULTS: Of the AFHs, 29 of 33 occurred on the extremities of adults (age range 30 to 50 years), six of which were associated with rapid growth, probably caused by trauma, and pain. Twenty one lesions were thought to be vascular and/or melanocytic lesions, including two melanomas, because of a bluish-black and/or cystic appearance. Histologically, large areas of haemorrhage, up to 50% of the tumour bulk, lacking an endothelial lining were seen in otherwise typical fibrous histiocytomas. Five cases resembled nodular stages of Kaposi's sarcoma. Variable haemosiderin deposition in histiocytes (18/33) and giant cells (11/33) was suggestive of haemosiderotic histiocytoma. A haemangiopericytoma-like pattern was seen in five otherwise indistinguishable cases. On immunohistochemistry, variable reactivity was seen for factor XIIIa (18/30), with E9 (18/30), NK1C3 (19/30), and for SMA (14/30), but labelling for vascular markers was not detected. Early lesions without iron deposition were factor XIIIa positive; late lesions with iron deposition were factor XIIIa negative. Labelling for SMA correlated with prominent sclerosis.

CONCLUSION: AFHs, including a haemangiopericytoma-like variant, have a characteristic time dependent histological and immunophenotypic profile, clearly different from nodular type Kaposi's sarcoma.


Giant dermatofibroma with monster cells.

Goodman WT, Bang RH, Padilla RS.

Division of Dermatopathology (W.T.G.); Department of Dermatology, Johns Hopkins University, Baltimore, Maryland; and Department of Dermatology (R.H.B., R.S.P.), University of New Mexico, Albuquerque, New Mexico.

Am J Dermatopathol 2002 Feb;24(1):36-8 Abstract quote

We report a case of a 64-year-old woman with a giant dermatofibroma on her back with the unusual histologic feature of monster cells. The firm, exophytic, 3-cm nodule had purple and yellow components with surface telangiectasia.

Histologic examination demonstrated characteristic findings of a dermatofibroma, including rete ridge flattening and bridging; a stroma containing scattered, large, round, eosinophilic collagen bundles; and a polymorphous dermal infiltrate of spindle and xanthomatous cells with scattered siderophages. Some xanthomatous cells demonstrated features consistent with monster cells, including huge bizarre nuclei and one or more nucleoli. Immunohistochemical staining for factor XIIIa was positive. A diagnosis of giant dermatofibroma with monster cells (DFMC) was made.

Giant dermatofibromas are rare, with monster cells being an uncommon finding in dermatofibroma. To our knowledge, this is the first report of DFMC.


Most <30 years
F favored
2/3 upper extremity
Superficial subcutaneous tissue to lower dermis but may extend into skeletal muscle
1-3 cm

Ray-like extensions into the fat
Bundles of fibroblasts and clusters of histiocytic/giant cells

May be arranged as nodules which may become confluent with numerous giant cells
Or may have radiating arms of fibrous tissue extending into surrounding tissue

Hemorrhage common
MF rare


Dermatofibroma with osteoclast-like giant cells.

Kutchemeshgi M, Barr RJ, Henderson CD.

Department of Dermatology, University of California, Irvine.

Am J Dermatopathol 1992 Oct;14(5):397-401 Abstract quote

Dermatofibroma (DF), or cutaneous fibrous histiocytoma, is a common cutaneous tumor with many variants that may arise from alterations in the morphology and composition of its various components. One type that has not received much attention is DF with osteoclast-like giant cells. Two cases of this rare tumor are described. The importance of this tumor lies in the possible histologic confusion with a variety of benign and malignant neoplasms, including giant cell tumor of tendon sheath, giant cell tumor of bone, and giant cell reparative granuloma.


Sclerotic fibroma-like change in various neoplastic and inflammatory skin lesions: is sclerotic fibroma a distinct entity?

High WA, Stewart D, Essary LR, Kageyama NP, Hoang MP, Cockerell CJ.

Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
J Cutan Pathol. 2004 May;31(5):373-8. Abstract quote

Sclerotic fibroma was first described in association with Cowden's disease by Weary et al. in 1972. In 1989, Rapini and Golitz detailed 11 cases of solitary sclerotic fibroma (SFS) in the absence of Cowden's disease, suggesting the term SFS of the skin. Classic histological features include hypocellular, hyalinized bands of collagen sharply demarcated from the surrounding skin. Numerous authors have described sclerotic fibroma-like changes in other entities including melanocytic nevi, dermatofibromas, lipomas, tendon sheath fibromas, giant cell collagenomas, neurofibromas, angiofibromas, erythema elevatum diutinum, and folliculitis.

Dissension has arisen, with some dermatopathologists asserting that sclerotic fibroma is just an evolutionary end-point of a previous lesion. Others contend that SFS is a distinct lesion and cite recurrent cases and/or proliferation marker studies to corroborate this view.

We detail the histopathological findings of lesions consistent with the classic description of SFS and compare these to sclerotic changes observed in an intradermal nevus, blue nevus, erythema elevatum diutinum, neurofollicular hamartoma, angiofibroma, neurofibroma, accessory nipple, and dermatofibromas.

Sclerotic fibroma-like change may be seen in a variety of lesions and may represent a common reaction pattern in the skin.

Dermatofibroma with sclerotic areas resembling a sclerotic fibroma of the skin.

Sohn IB, Hwang SM, Lee SH, Choi EH, Ahn SK.

Department of Dermatology, Yonsei University Wonju College of Medicine, 162 Ilsan-Dong, Wonju, Kangwon-Do, South Korea.

J Cutan Pathol 2002 Jan;29(1):44-7 Abstract quote

BACKGROUND: Dermatofibromas are common benign tumors that occur as single or multiple nodules on the extremities in adults. Sclerotic fibroma of the skin (SFS) is a benign tumor characterized histopathologically by a well-demarcated, non-encapsulated dermal nodule composed of hypocellular, sclerotic collagen bundles with prominent clefts. The pathogenesis of these two conditions is still in dispute.

METHODS: We present a case of dermatofibroma with sclerotic areas resembling a sclerotic fibroma of the skin and a review of the literature.

RESULTS: The tumor showed a well-demarcated dermal, fibrocollagenous tumor with three different histopathological features. One-fourth of the lesion was consistent with dermatofibroma. Another area adjacent to dermatofibroma revealed hyalinized eosinophilic collagen bundles arranged in the characteristic interwoven pattern with prominent clefts, as is described in sclerotic fibroma of the skin. One-half of the lesion between the dermatofibroma and sclerotic fibroma showed transitional changes from dermatofibroma to sclerotic fibroma.

CONCLUSION: According to these findings, the possibility that sclerotic fibroma is an ancient or degenerated stage of dermatofibroma cannot be completely ruled out, but some authors still consider that dermatofibroma and sclerotic fibroma of the skin are completely different neoplasms.

Sebaceous Hyperplasia Overlying a Dermatofibroma.

Davis TT, Calilao G, Fretzin D.

*Department of Dermatology, University of Illinois Hospital, University of Illinois, Chicago, Illinois daggerDepartment of Pathology, University of Illinois Hospital, University of Illinois, Chicago, Illinois.

Am J Dermatopathol. 2006 Apr;28(2):155-157. Abstract quote  

Epithelial changes overlying dermatofibromas are well recognized. The presence of sebaceous differentiation overlying a dermatofibroma is unusual.

We report two patients with sebaceous hyperplasia overlying a dermatofibroma and discuss possible mechanisms for induction of the epithelium and adnexa by the mesenchyme in a dermatofibroma.

Sebaceous hyperplasia: a clue to the diagnosis of dermatofibroma.

Fuciarelli K, Cohen PR.

Department of Dermatology, University of Texas-Houston Medical School, USA.

J Am Acad Dermatol 2001 Jan;44(1):94-5 Abstract quote

We describe a man with an indurated lesion on his upper back that showed a dermatofibroma with overlying sebaceous hyperplasia. Characteristic dermal features of a dermatofibroma may be sparse or absent in a lesional specimen that has been submitted subsequent to a superficial shave biopsy.

Hyperplasia of sebaceous glands in a nonfacial lesion is a histologic feature that should prompt the search for a dermatofibroma in the underlying dermis.


Special stains  
Immunoperoxidase Positive for Factor XIIIa
Negative for CD34
Evaluation of CD10 and procollagen 1 expression in atypical fibroxanthoma and dermatofibroma.

Department of Pathology, University of California at San Francisco, San Francisco, CA 94115, USA.


Am J Surg Pathol. 2008 Aug;32(8):1111-22. Abstract quote

Atypical fibroxanthoma (AFX) (dermal pleomorphic sarcoma) remains a somewhat controversial entity. Some authors have averred that AFX is a fiction, suggesting that such lesions merely represent misclassified examples of spindled squamous cell carcinoma. In addition, the immunoperoxidase confirmation of AFX has been less than straightforward and has historically been approached as a diagnosis of exclusion because of the lack of sensitivity and specificity of available "positive" reagents.

Procollagen 1 (PC1) and CD10 represent recently developed immunoperoxidase reagents that have been forwarded as useful in this setting, and we sought to characterize our experience, both to confirm the utility of these antibodies and to compare them.

Our investigation included 3 separate data sets. Group 1 consisted of a retrospective review of 98 consecutive cases in which PC1 was used in the evaluation of dermatopathology specimens in routine practice during a 13-month interval. Group 2 consisted of a direct comparison of 11 AFX, 11 dermatofibroma (DF), and 7 epithelioid dermatofibroma (EDF) using the CD10 reagent on cases identified by database search. Group 3 consisted of a retrospective review of 47 cases in which CD10 was used in routine practice during a 10-month interval. Group 1 included 47 AFX, 13 carcinomas, and 6 melanomas. PC1 expression was observed in 45 of 47 AFX (96%), with a strong reaction in 78% of cases. Among a comparison group of carcinomas, 13 of 13 displayed strong keratin immunopositivity and 11 of 13 (85%) lacked PC1 expression whereas 2 showed focal weak labeling. Six of six melanomas exhibited avid S100 expression and none labeled with PC1. In group 2, strong CD10 immunoreactivity was present in 11 of 11 AFX. Similarly, 11 of 11 DFs were also positive. In contrast, 6 of 7 cases of EDF lacked CD10 expression. Group 3 included 38 AFX and 9 miscellaneous spindle cell proliferations. Of the 38 AFX, 37 (97%) labeled with CD10 and in 34 (92%) the reaction was strong. PC1 immunostaining was also completed in 34 of 38 AFX from group 3 and 27 (79%) cases showed positive labeling. Our results confirm that both PC1 and CD10 can be used as positive markers of AFX.

We believe that CD10 and PC1 immunostaining can be used as a useful adjunct to supplement the diagnosis of AFX, within the context of an immunoperoxidase panel. Not surprisingly, CD10 expression is also common in DF, a benign analog of AFX, with the exception of its epithelioid variant. In direct head-to-head comparison, our experience indicates that the staining of AFX with CD10 is more avid than that observed with PC1. Lastly, out data includes over 80 examples of AFX, <5% of which showed keratin labeling. Given a general lack of keratin expression, it seems unlikely that AFX merely represents poorly differentiated squamous carcinoma.
A study of CD117 expression in dermatofibrosarcoma protuberans and cellular dermatofibroma.

Department of Pathology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada.


J Cutan Pathol. 2007 Nov;34(11):857-60. Abstract quote

Background: Dermatofibrosarcoma protuberans (DFSP) is a relatively uncommon spindle cell tumor of the skin. It is locally aggressive and can be a therapeutic challenge. There are case reports of partial response of DFSP to the tyrosine kinase inhibitor STI571 (Imatinib), despite the reported negativity of the tumor cells for CD117. At least one publication reported focal CD117 positivity of DFSP cells, and we would like to clarify the issue. Cellular dermatofibroma (CDF) can mimic DFSP, but typical cases are easily differentiated from DFSP by their staining pattern for CD34 and factor 13a. We also report our experience with CD117 staining of typical CDFs.

Methods: Thirty-seven cases of clear-cut DFSP and 13 cases of clear-cut CDF were retrieved from the archives of Sunnybrook Health Sciences Center between 2000 and 2005.

Results: All DFSPs were CD34 (+), factor 13a (-) and CD117 (-). All CDFs were factor 13a (+), CD34 (-) and CD117 (-).

Conclusions: Our study on a relatively large number of cases confirms the negativity of DFSP and CDF for CD117. Therefore, if adjuvant therapy is attempted with drugs such as STI571 (Imatinib), the eligibility of patients should not be based on immunohistochemical assessment of CD117 expression.
Expression of CD163 in dermatofibroma, cellular fibrous histiocytoma, and dermatofibrosarcoma protuberans: comparison with CD68, CD34, and Factor XIIIa.

Sachdev R, Sundram U.

Department of Pathology, Stanford University Medical Center, Stanford, CA, USA.

J Cutan Pathol. 2006 May;33(5):353-60. Abstract quote  

Background: Distinction between cellular fibrous histiocytomas (FHs) with a deep component and dermatofibrosarcoma protuberans (DFSPs) can pose diagnostic problems. While CD68, CD34, and Factor XIIIa are helpful in distinguishing between these entities, none are diagnostically absolute. Recent work with CD163, a hemoglobin scavenger receptor, has demonstrated that this marker has high specificity for monocytes, macrophages, and histiocytes. Our goal is to evaluate the utility of CD163 in the diagnosis of dermatofibromas (DFs), cellular FHs, and DFSPs.

Methods: Sixty cases including 19 DFs, 23 cellular FHs with a deep component, and 18 DFSPs were tested with antibodies against CD163, CD68, CD34, and Factor XIIIa. Results: CD163 was expressed in 17/19 (89%) DFs, 23/23 (100%) cellular FHs, and 3/18 (17%) DFSPs. CD68 was positive in 8/19 (42%) DFs, 19/23 (83%) cellular FHs, and 1/16 (6%) DFSPs. CD34 was expressed in 1/19 (5%) DFs, 5/23 (22%) cellular FHs, and 100% of DFSPs. Factor XIIIa labeled 4/19 (21%) DFs, 11/23 (48%) cellular FHs, and 0/17 cases of DFSPs.

Conclusions: CD163 expression is helpful in distinguishing between cellular FHs and DFSPs and will be useful in a panel of antibodies when these entities are in the differential diagnosis.
Cyclooxygenase-2 expression in dermatofibroma and dermatofibrosarcoma protuberans.

Department of Plastic and Reconstructive Surgery, Rabin Medical Center, Beilinson Campus, Petah Tiqwa, Israel.


J Cutan Pathol. 2008 Jun;35(6):532-5. Abstract quote

BACKGROUND: Dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP) occasionally resemble each other histologically but differ in histogenesis and biological behavior. This study sought to determine if these lesions can be differentiated by the quantity or quality of expression of cyclooxygenase-2 (COX-2), an enzyme associated with both reactive and neoplastic processes.

PATIENTS AND METHODS: Formalin-fixed and paraffin-embedded samples from 20 DFs and 20 DFSPs were stained immunohistochemically with antibodies directed against COX-2. Staining was evaluated semiquantitatively for percentage and intensity using a three-tiered system. DFs were graded and analyzed by cellularity. Findings within the tumors were compared with fibrocyte staining in adjacent tissue. The results were analyzed.

RESULTS: Nineteen DFs (95%) and 15 DFSPs (75%) were immunopositive for COX-2; this difference was not statistically significant. Highly cellular DFs showed more widespread (p = 0.0039; r = 0.614) and more intense (p = 0.0586; r = 0.429) staining than less cellular DFs and more prominent staining in adjacent fibroblasts (p = 0.044; r = 0.608).

CONCLUSIONS: COX-2 immunostaining does not distinguish DFs from DFSPs. However, the enzyme is expressed more widely and more intensely in more cellular, possibly younger, DFs. The prominent expression of COX-2 in DFSP may have clinical implications for treatment with COX-2 inhibitors in tumors that are not amenable to surgery.

Expression of desmin and smooth muscle Myosin heavy chain in dermatofibromas.

Bruecks AK, Trotter MJ.

Department of Pathology and Laboratory Medicine, Calgary Laboratory Services, University of Calgary, Calgary, Alberta

Arch Pathol Lab Med 2002 Oct;126(10):1179-83 Abstract quote

Background.-The histopathologic features of dermatofibroma vary remarkably, and this diversity may occasionally cause problems in differentiating between benign and malignant mesenchymal lesions, including smooth muscle neoplasms. Immunohistochemical stains are sometimes necessary to clarify the histogenesis of a lesion.

Objective.-To evaluate dermatofibromas for expression of desmin and smooth muscle myosin heavy chain (SM-MHC) antigens, which are commonly used as evidence of smooth muscle differentiation.

Methods.-We studied 100 consecutive cases of dermatofibroma using hematoxylin-eosin-stained sections and immunoperoxidase staining with antibodies against desmin, SM-MHC, and smooth muscle actin.

Results.-We found focal positivity for desmin in 9 cases, and in 2 of these cases, at least 10% of lesional cells showed strong expression. We found focal staining for SM-MHC in 10 cases, and in 2 of these cases, at least 10% of the lesional cells were positive. Regions positive for desmin and/or SM-MHC did not show definite histologic features of myogenous differentiation on hematoxylin-eosin-stained sections. All dermatofibromas expressing desmin and SM-MHC were also strongly positive for smooth muscle actin.

Conclusions.-About 10% of dermatofibromas show focal expression of desmin and SM-MHC, and this expression may be present in up to 10% to 15% of lesional cells. Thus, in dermal spindle cell lesions, focal expression of these muscle antigens, like that of smooth muscle actin, is not diagnostic of a smooth muscle tumor.

Differential expression of HMGA1 and HMGA2 in dermatofibroma and dermatofibrosarcoma protuberans: potential diagnostic applications, and comparison with histologic findings, CD34, and factor XIIIa immunoreactivity.

Li N, McNiff J, Hui P, Manfioletti G, Tallini G.

Department of Pathology, Yale University School of Medicine, New Haven, CT 06504-8900, USA.
Am J Dermatopathol. 2004 Aug;26(4):267-72. Abstract quote  

The histologic distinction of dermatofibrosarcoma protuberans (DFSP) and dermatofibroma (DF) may be difficult, especially in the case of DF extending into the subcutaneous fat (deep DF). CD34 and Factor XIIIa staining is commonly used in separating DF from DFSP, but is not always helpful. HMGA1 and HMGA2 genes, members of the high mobility group protein family genes, encode proteins that act as architectural transcription factors and are frequently dysregulated in a variety of benign or locally aggressive mesenchymal tumors.

In this study, we evaluated the immunoreactivity of HMGA1 and HMGA2 in a series of DF and DFSP to determine the possible utility for these markers in the differential diagnosis of these two entities. Immunohistochemical stains were performed on paraffin-embedded tissues from 22 cases of DF, including 14 cases of deep DF and 14 cases of DFSP, using antibodies against HMGA1 and HMGA2. CD34 and Factor XIIIa immunoreactivity was also evaluated in these lesions and compared with the results of HMGA immunostaining. Immunopositivity for both HMGA1 and HMGA2 was seen in 21of 22 (96%) DFs, but in only 3 (21%) and 1 (7%) of 14 DFSPs, respectively.

While 100% of DFSP stained for CD34, 36% of DF also labeled for CD34. The immunoreactivity of HMGA1 and HMGA2 in DF was generally strong and diffuse, in contrast to weak and focal staining seen in DFSP. The proportion of cases with positive immunoreactivity for both markers was significantly higher in DF and in deep DF than in DFSP (P < 0.001).

We conclude that HMGA1 and HMGA2 expression can be used to distinguish DF from DFSP with a degree of accuracy that is fully equivalent to that of Factor XIIIa and CD34.
Immunohistochemical expression of matrix metalloproteinases 1, 2, 9, and 14 in dermatofibrosarcoma protuberans and common fibrous histiocytoma (dermatofibroma).

Weinrach DM, Wang KL, Wiley EL, Laskin WB.

Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Ill, USA.
Arch Pathol Lab Med. 2004 Oct;128(10):1136-41. Abstract quote  

CONTEXT: Common fibrous histiocytoma (cFH) or dermatofibroma and dermatofibrosarcoma protuberans (DFSP) are 2 spindle cell mesenchymal tumors that are distinguished in part by their microscopic growth patterns and clinically by the greater propensity for DFSP to recur. Matrix metalloproteinases (MMPs) potentially play a role in modulating the growth patterns of cFH and DFSP by remodeling the extracellular matrix.

OBJECTIVE: To evaluate the immunohistochemical (IHC) expression of MMP-1, MMP-2, MMP-9, and MMP-14 in DFSP and cFH, because (1) MMP-1, MMP-2, MMP-9, and MMP-14 are synthesized by dermal fibroblasts, the major constituent of DFSP and cFH; and (2) platelet-derived growth factor B, which is overexpressed in most examples of DFSP because of t(17;22), activates ets-1, a transcription factor that regulates molecules associated with tumor invasion and metastasis, including MMP-1, MMP-3, and MMP-9.

DESIGN: Immunohistochemical studies were performed on archived, formalin-fixed, paraffin-embedded tissue of DFSP (n = 48) and cFH (n = 47).

Results.-Significant IHC expression (>10% of tumor cells) in cFH included MMP-14 (27 [59%] of 46 tumors positive), MMP-2 (21 [47%] of 45 tumors positive), MMP-9 (9 [20%] of 45 tumors positive), and MMP-1 (6 [13%] of 46 tumors positive). No DFSPs showed significant IHC expression of any of the MMPs evaluated. However, anti- MMP-2 highlighted a rich microvascular element within deep tumor tissue present in 81% of DFSPs with a prominent subcutaneous component.

CONCLUSION: Our IHC results indicate that MMP-1 and MMP-9 are not up-regulated in DFSP. Convincing expression of MMP-14 in cFH suggests that this MMP may affect the growth pattern of the lesion, perhaps by activating MMP-2 expression in tumor cells. In DFSP, MMP-2 may play a role in tumor angiogenesis.
Stromelysin 3 expression: A useful marker for the differential diagnosis dermatofibroma versus dermatofibrosarcoma protuberans

Bernard Cribier, MD, PhD
Gérald Noacco, MD
Bernard Peltre
Edouard Grosshans, MD

Strasbourg, France

J Am Acad Dermatol 2002;46:408-13 Abstract quote

Background: Stromelysin 3 (ST3) is a member of the metalloproteinase family, which is expressed in tissue remodeling processes such as scarring, embryogenesis, or tumoral invasion. Although the prognosis of breast cancers and extracutaneous squamous cell carcinomas is correlated with the level of expression of ST3, this staining has not yet found a routine application in dermatopathology.

Objective: Our purpose was to study by immunohistochemistry the expression of ST3 in dermatofibromas and dermatofibrosarcoma protuberans (DFP).

Methods: We selected 40 cases of dermatofibromas, 40 histologically typical DFPs, and 10 giant dermatofibromas. Immunohistochemistry was carried out by means of the LSAB method, with monoclonal anti-ST3 antibody (provided by MC Rio, IGBMC Strasbourg). A semiquantitative scale (0-3) was used to evaluate the level of ST3 expression.

Results: Positively stained cells were observed in all cases of dermatofibromas (100%), including the 10 giant cases, but never in DFP (0%). The staining was intense (class 2 or 3) in 39 of the 50 dermatofibromas. The CD34 staining used as a control proved to be less efficient; 6 DFP were CD34 negative, whereas some of the dermatofibromas showed a marginal CD34 positivity.

Conclusion: Our results are consistent with those obtained by in situ hybridization in previous studies of smaller series of fibrous tumors. The study of ST3 expression in fibrous tumors of the skin shows that this immunostaining could be a useful tool in the purpose of differentiating DFP from giant or invasive dermatofibromas. Although ST3 is a “negative” marker for DFP and therefore does not demonstrate the margins of the neoplasm, it is more reliable than CD34 staining in differentiating this tumor from a dermatofibroma.


Anti-cytokeratin 20 staining of Merkel cells helps differentiate basaloid proliferations overlying dermatofibromas from basal cell carcinoma.

Mahmoodi M, Asad H, Salim S, Kantor G, Minimo C.

Department of Pathology, Drexel University College of Medicine, Philadelphia, PA, USA
J Cutan Pathol. 2005 Aug;32(7):491-5. Abstract quote  

Background: Basaloid epidermal proliferations (BEP), morphologically resembling basal cell carcinoma (BCC), have been described overlying dermatofibromas. Distinguishing the two is important because of non-aggressiveness of BEP and local aggressiveness of BCC. The aim of this study is to determine whether CK20 antibody staining for Merkel cells can be used as an adjunct method to differentiate BEP from BCC.

Methods: Ten cases of BEP overlying dermatofibromas were selected. Ten cases of BCC were used as control. The two groups were stained with CK20 antibody. Numerical density of CK20 stained Merkel cells in peri-lesional epidermis, BEP and BCC was determined by examining 300 cells at 400X in two separate areas by three independent pathologists. To determine statistical significance, the results were compared using t-test method.

Results: Density of Merkel cells in peri-lesional epidermis was 0.2-0.3%. No merkel cells were detected in the BCC. BEP overlying dermatofibromas showed an obvious increase in CK 20 stained Merkel cells. The difference was statistically significant (P < 0.02)

Conclusions: We report a significant increase in CK20 stained Merkel cells in BEP overlying dermatofibromas as compared to BCC. CK20 antibody staining for Merkel cells can be used as an adjunct method to differentiate BEP overlying dermatofibromas from BCC.
Medallion-like dermal dendrocyte hamartoma: a new clinically and histopathologically distinct lesion.

Rodriguez-Jurado R, Palacios C, Duran-McKinster C, Mercadillo P, Orozco-Covarrubias L, Saez-de-Ocariz Mdel M, Ruiz-Maldonado R.

Department of Pathology, National Institute of Pediatrics, Mexico.

J Am Acad Dermatol. 2004 Sep;51(3):359-63. Abstract quote  

Dermal dendrocyte hamartomas are extremely rare; only two examples have been described with clinical features different from our cases and with incomplete immunohistochemical characterization.

We report three female patients presenting a medallion-shaped, well-defined, slightly atrophic and asymptomatic congenital lesion. All 3 patients showed a fusiform-cell proliferation. Immunohistochemistry was positive for CD34, factor XIIIa, and fascin. Electronmicroscopy showed typical features of dermal dendrocytes.

We believe that the lesions described represent a new, clinically and histopathologically distinct lesion originating in dermal dendrocytes. We propose to name it medallion-like dermal dendrocyte hamartoma.

Histiocytoma cutis: a tumour of dermal dendrocytes (dermal dendrocytoma).

Cerio R, Spaull J, Jones EW.

Institute of Dermatology, United Medical School of Guy's Hospital, London, U.K.

Br J Dermatol 1989 Feb;120(2):197-206 Abstract quote

The histogenesis of histiocytoma (dermatofibroma) was investigated using new antibodies that demonstrate factor XIIIa (FXIIIa) positive cells and the monocyte macrophage cell series (MAC 387), in formalin fixed tissue.

The distribution of S100 protein, vimentin and Ulex europaeus agglutinin I (UEA-I) were also studied. The antibody against FXIIIa labelled the normal dermal population of fixed connective tissue cells (dermal dendrocytes) emphasizing their dendritic processes; cells that are widely distributed, but are most numerous in the papillary dermis. In contrast, the antibody, MAC 387 against monocyte derived macrophages, did not label this cell population. In 30 histiocytomas, intense labelling for FXIIIa was found peripherally, but labelling was rather weaker in cells situated centrally. Only a few cells labelled for S100 protein and with the monoclonal antibody MAC 387, but vimentin positivity was universal. UEA-I labelled only vessels in histiocytomas. However, FXIIIa labelling was negative in 16 dermatofibrosarcomas, three keloids and several other fibroproliferative lesions. These contrasting results with FXIIIa labelling have practical implications for diagnosis of benign and malignant spindle cell tumours of the skin.

We conclude that histiocytomas (dermal dendrocytomas) take their origin from dermal fixed connective tissue cells, (dermal dendrocytes), but other spindle cell tumours may differ in histogenesis.

CD34-Reactive Myxoid Dermal Dendrocytoma.

Ohata C, Kawahara K.

Department of Dermatology, Toyonaka Municipal Hospital (C.O.) and Department of Pathology, Osaka National Hospital (K.K.), Osaka, Japan.


Am J Dermatopathol 2002 Feb;24(1):50-3 Abstract quote

Normal skin is composed in part of cells that express CD34. These include periadnexal spindle cells, vascular endothelial cells, and interstitial dendritic cells.

We report on a tumor composed mainly of CD34-reactive spindle cells. A 66-year-old Japanese woman presented with a skin-colored, dome-shaped, cutaneous papule on her left palm that was 7 mm in diameter and had developed within the preceding 3 months. Light microscopic examination showed a well-circumscribed polypoid tumor consisting of spindle-shaped cells and thin collagen fibers arranged loosely in a fascicular pattern within a myxoid matrix. Immunohistochemically, most of the tumor cells stained strongly for CD34, but did not stain with antibodies to S-100 protein, smooth muscle actin, desmin, neuron-specific enolase, epithelial membrane antigen, or factor XIIIa. Staining for vimentin and CD68 was positive.

We believe this lesion to be a CD34-reactive myxoid dermal dendrocytoma of a type that has not been described previously.


Epithelioid cell histiocytoma - histogenetic and kinetics analysis of dermal microvascular unit dendritic cell subpopulations.

Silverman JS, Glusac EJ.

Southside Hospital, Department of Pathology, Bay Shore, NY, USA and Departments of Pathology and Dermatopathology, Yale University School of Medicine, New Haven, CT, USA.

J Cutan Pathol. 2003 Aug;30(7):415-22. Abstract quote

BACKGROUND: Epithelioid cell histiocytoma (ECH), also known as epithelioid fibrous histiocytoma, is a peculiar dermal tumor, which can mimic melanocytic, vascular, epithelial, or other histiocytic lesions. Thought to arise from dermal dendrocytes, most ECH contain approximately 50% FXIIIa+ histiocytic dendrocytes, but not all lesional cells express FXIIIa. A putative fibroblastic component has not been characterized.

METHODS: We analyzed the differentiation and cell kinetics of dermal microvascular unit cells in 12 previously reported ECH using antibodies to FXIIIa, CD68 (KP1), CD34, CD117, CD31, smooth muscle actin, collagen type 1 aminopropeptide, and MIB-1, using single and double immunostains.

RESULTS: In ECH, many variably sized CD34/CD31+ tumor vessels with actin+ myopericytes were surrounded by epithelioid-to-dendritic cells of three types. About 5-80% were dendritic histiocytes that expressed FXIIIa but not CD31 or KP1. Fibroblasts, in some cases showing mild nuclear pleomorphism, were usually collagen type 1+, but CD34 and actin- in 11/12 cases. One 'early' ECH had 40% CD34+ epithelioid cells, admixed with 50% FXIIIa+ histiocytes. Most ECH had about 2-20% KP1+, CD117+ mast cells. Mast cell numbers increased with FXIIIa+ histiocyte numbers and the intensity of FXIIIa expression. MIB-1/FXIIIa double-labeling showed only rare cycling histiocytes, with numerous cycling fibroblasts and endothelial cells.

CONCLUSIONS: Our findings support the impression that ECH is a vascular fibrous histiocytoma. The constituent cells appear to arise from the activation of resident microvascular CD34+ dermal fibroblasts and the accumulation of FXIIIa+ dendritic stromal assembly histiocytes. The CD34+ cells appear to differentiate toward collagenous fibrocytes in association with histiocytes and mast cells in forming collagenous stroma and vessels. ECH is a tumor composed of all requisite cell types consistent with the origin from the dermal microvascular unit.

Epithelioid cell histiocytoma. A report of 10 cases including a new cellular variant.

Glusac EJ, Barr RJ, Everett MA, Pitha J, Santa Cruz DJ.

Department of Dermatology, University of California, Irvine.

Am J Surg Pathol 1994 Jun;18(6):583-90 Abstract quote

Epithelioid cell histiocytoma is a recently recognized lesion that is considered to be a variant of cutaneous fibrous histiocytoma (dermatofibroma).

Ten cases are presented, including their light microscopic, immunohistochemical, and ultrastructural features. Eight of the cases are similar to those previously reported, presenting as elevated nodules arising on the extremities and composed of epithelioid histiocytes with overlying epidermal effacement.

Two of the cases were composed of cells with the same morphologic and immunohistochemical characteristics as typical epithelioid cell histiocytoma, including factor XIIIa positivity, but these arose in the reticular dermis and exhibited prominent cellularity.

Cutaneous changes in fibrous hamartoma of infancy.

Department of Pathology, University of British Columbia, British Columbia, Canada.


J Cutan Pathol. 2007 Jan;34(1):39-43. Abstract quote

Background: Fibrous hamartoma of infancy (FHI) is a fast growing soft tissue tumor that usually arises in the first 2 years of life. The histology of the lesion has been well described. Few studies, however, have looked at changes in the overlying skin and its appendages.

Methods: A database search performed at British Columbia Children's Hospital yielded 15 cases of unequivocal FHI occurring in 12 patients (three were recurrences). Of these, we were able to retrieve 13. Five of 13 cases had sections including epidermis. These slides were reviewed with specific emphasis on skin adnexae.

Results: Of the cases with excised epidermis in continuity with the lesion, 5/5 had eccrine changes, including hyperplasia, duct dilatation, intraluminal papillary formations, and squamous syringometaplasia. One case showed epidermal basaloid follicular hyperplasia.

Conclusions: This study shows that eccrine changes are frequently seen in cases of FHI when overlying skin is sampled. This may be a useful clue to consider this diagnosis, especially when the biopsy is superficial.

Giant cell collagenoma: a benign dermal tumor with distinctive multinucleate cells.

Rudolph P, Schubert C, Harms D, Parwaresch R.

Department of Pathology and Lymph Node Registry at the German Association of Pathologists, University of Kiel, Buchholz, Germany.

Am J Surg Pathol 1998 May;22(5):557-63 Abstract quote

We present five cases of a hitherto unreported cutaneous neoplasm.

The tumors appeared as solitary slow-growing flesh-colored nodules arising in young and middle-aged adults. They were located on the trunk, the upper extremities, and the face, and did not recur after complete excision.

Clinically, they were diagnosed as dermal nevus, Spitz's nevus, fibroma, or neurofibroma. Histology revealed polypoid flat-dome-shaped lesions with a sharply demarcated matrix consisting of coarse hyalinized collagen bundles arranged in a prominent storiform pattern and separated by mucin-containing clefts. Despite a low overall cellularity, the tumors contained numerous, occasionally bizarre-shaped, multinucleate giant cells with crowded vesicular nuclei and a pale staining foamy cytoplasm, as well as plump fibroblastlike cells with analogous nuclear morphology. Atypical nuclei or mitotic figures were not observed. The cells were strongly positive for vimentin but negative for cytokeratin, smooth muscle actin, desmin, S-100 protein, CD34, factor XIIIa, and the macrophage markers KP1, Mac 387, and Ki-M1p, suggesting a fibroblastic origin.

Based on the overall architecture, we conclude that these tumors probably represent a distinctive variant of solitary circumscribed storiform collagenoma (sclerotic fibroma) and propose the designation of giant cell collagenoma.

Giant cell collagenoma: case report and review of the literature.

Brito H, Pereira EM, Reis-Filho JS, Maeda SA.

Salomao e Zoppi Associated Pathologist, Sao Paulo, Brazil.

J Cutan Pathol 2002 Jan;29(1):48-51 Abstract quote

BACKGROUND: Giant cell collagenoma (GCC) is a recently described cutaneous fibrous neoplasm that usually affects young to middle-aged adults. Despite its similar histological appearance with circumscribed storiform collagenoma, no association of GCC with Cowden's syndrome has been described so far. To the best of our knowledge only five cases of this rare fibrous tumor have been reported so far.

METHODS: We report a case of a 79-year-old male patient presenting with a slow growing flesh-colored dome-shaped lesion in his left forearm, with a clinical diagnosis of fibroma. No stigma of Cowden's syndrome was depicted.

RESULTS: The histological analysis showed a symmetrical and well-circumscribed flat-dome-shaped lesion covered by an atrophic overlying epidermis. The neoplasm was composed of hyalinized collagen bundles disposed in a whorled storiform pattern. Admixed with the collagen matrix, there were two distinct cell populations, one composed by spindle-shaped mononuclear cells, and the other composed by bizarre multinucleated giant cells. Immunohistochemical analysis showed positivity for vimentin and actin HHF35 in the mononucleated. The multinucleated cells only immunoexpressed vimentin.

CONCLUSION: GCC is an unusual cutaneous fibrous tumor that should be differentiated from circumscribed storiform collagenoma, pleomorphic fibroma, regressive forms of dermatofibroma, and solitary myofibroma based on its histological features.


Indeterminate Fibrohistiocytic Lesions of the Skin Is There a Spectrum Between Dermatofibroma and Dermatofibrosarcoma Protuberans?

Marcelo G. Horenstein, M.D.; Victor G. Prieto, M.D., Ph.D.; J. Dean Nuckols, M.D., Ph.D.; James L. Burchette, MT(ASCP), QIHC; Christopher R. Shea, M.D.

From the Departments of Pathology (M.G.H., V.G.P., J.D.N., J.L.B., C.R.S.) and Medicine (Dermatology; V.G.P., C.R.S.), Duke University Medical Center, Durham, North Carolina; and the Department of Pathology (M.G.H.), University of South Alabama Medical Center, Mobile, Alabama

Am J Surg Pathol 2000;24:996-1003 Abstract quote

Routine histology and immunohistochemistry can usually distinguish dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP). DF generally expresses factor XIIIa whereas DFSP generally expresses CD34.

The authors report 10 cutaneous fibrohistiocytic lesions combining clinical, histologic, and immunohistochemical features of both DF and DFSP. The lesions had an average size of 1.2 cm (range, 0.4–2.7 cm), and occurred on the trunk (n = 6), extremities (n = 3), and face (n = 1) of four men and six women (average age, 30.6 yrs; age range, 15–50 yrs). Eight lesions exhibited acanthosis and densely cellular fascicles with focal storiform areas. All had keloidal collagen, infiltrated the subcutis in a honeycomb pattern, and had low mitotic counts (0 to 4 mitoses per square millimeter). All were diffusely immunoreactive for factor XIIIa (30%–60% of the neoplastic cells) as well as CD34 (20%–70%).

This series raises the possibility of a biologic spectrum between DF and DFSP; however, double-immunolabeling studies showed no notable coexpression of factor XIIIa and CD34 by individual cells, suggesting coexistence of two different cellular populations. After an average follow up of 22.3 months (range, 10–46 mos) in six cases, a single recurrence was documented. The ambiguous histologic features and the potential for local recurrence suggest that performing a complete excision may be prudent in these diagnostically indeterminate lesions.


Subungual pleomorphic fibroma.

Hsieh YJ, Lin YC, Wu YH, Su HY, Billings SD, Hood AF.

Department of Dermatology, Mackay Memorial Hospital, Taipei, Taiwan, Department of Pathology, Indiana University, Indianapolis, IN, and Department of Dermatology, Eastern Virginia Medical School, Norfolk, VA, USA.
J Cutan Pathol. 2003 Oct;30(9):569-71 Abstract quote.  

BACKGROUND: Pleomorphic fibroma is a benign fibroblastic tumor characterized by pleomorphic, hyperchromatic cells or giant multinucleated cells embedded in a collagenous stroma. These cytologic features may lead to an incorrect diagnosis of malignancy. Most cases reported in the literature are located on trunk or extremities; the presentation as a subungual mass is rare.

METHODS: We report an unusual case of a subungual pleomorphic fibroma in 66-year-old woman. Clinical information was obtained. Histologic examination and immunohistochemical studies were performed.

RESULTS: A 66-year-old woman presented with a longstanding (40 years), subungual mass that deformed the nail of the left middle finger. Microscopic examination revealed a paucicellular tumor composed of hyperchromatic spindled, pleomorphic, floret-like giant cells embedded in haphazardly arranged collagen bundles in the dermis. No mitotic figures were seen. The tumor cells were vimentin-positive but did not stain with antibodies to S-100, cytokeratin, smooth muscle actin, factor XIIIa or CD34 negative. The diagnosis of a pleomorphic fibroma was made. Follow-up shows no evidence of tumor, 36 months after excision.

CONCLUSION: Pleomorphic fibroma of the subungual region is an unusual cutaneous tumor with histologic features that may cause confusion with true sarcomas. This is only the second case reported of a subungual pleomorphic fibroma. Pleomorphic fibroma should be considered in the differential diagnosis of pleomorphic subungual tumors.
Sporadic sclerotic fibroma of the oral soft tissues.

Alawi F, Freedman PD.

Department of Dermatology, Section of Dermatopathology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA.
Am J Dermatopathol. 2004 Jun;26(3):182-7. Abstract quote  

Sclerotic fibroma (SF) is an uncommon, benign fibrous neoplasm that may present either as a sporadic, small, solitary cutaneous mass, in otherwise healthy individuals, or as solitary or multiple, discrete skin nodules in patients with Cowden syndrome. Oral SF has been reported in patients with Cowden syndrome; however we now report the first documented series of sporadic SF originating within the oral mucosa.

We describe 5 cases of SF arising in 3 women and 2 men with an age range of 43 to 66 years. The buccal mucosa was the site of involvement in 4 patients and the lower lip in 1 patient. Microscopically, each of the tumors was characterized by an unencapsulated, well-circumscribed, hypocellular submucosal nodule that was sharply demarcated from the surrounding tissues. The neoplasms were primarily composed of thick collagen bundles that were occasionally arranged in a storiform pattern. Prominent clefts separated many of the collagen bundles. In all cases, spindle and stellate-shaped cells containing fusiform or stellate-shaped nuclei and inconspicuous nucleoli were found scattered throughout the lesion. Occasional stellate-shaped, multinucleated cells were also seen. Many of the cells also exhibited long dendritic cytoplasmic processes. The tumor cells strongly expressed CD34 and vimentin, and occasionally factor XIIIa, but were negative for markers of myofibroblastic, neural or melanocytic differentiation.

These findings confirm that oral SF represents a unique entity and should be differentiated from more commonly occurring benign fibrous lesions of the oral soft tissues.
Solitary sclerotic fibroma of skin: a possible link with pleomorphic fibroma with immunophenotypic expression for O13 (CD99) and CD34

Muhammad N. Mahmood, Mohamed E. Salama, Marsha Chaffins, Adrian H. Ormsby, Chan K. Ma, Michael D. Linden and Min W. Lee

J Cutan Pathol 2003;30:631-636 Abstract quote

Background: Solitary sclerotic fibroma (SF) presents as a well circumscribed dermal nodule, composed of sparse spindle cells with alternating wavy collagen fibers arranged in a storiform pattern. The histogenesis and nature of this histologically distinct lesion are uncertain. Whether this peculiar tumor represents a true hamartoma or a degenerating end of various fibrous lesions such as pleomorphic fibroma (PF), dermatofibroma, or angiofibroma is still controversial. High proliferating index of spindle cells in SF argues against the possibility of being a degenerating end product of another lesion.

Methods: We studied morphological features and immunoprofile of eight SFs, in comparison with four PFs, one collagenized dermatofibroma, two angiofibromas, and two periungual fibromas. Immunostains for CD34, CD31, O13 (CD99), Factor XIIIa, S-100, CD68 (KP-1), and MIB-1 were carried out using a labeled streptavidin-biotin method with DAKO-automated immunostainer. Paraffin blocks of two SFs were reprocessed for electron microscopic studies. Clinical data of all patients with SF were also reviewed.

Results: Spindle cells and pleomorphic cells in SF and PF showed diffuse immunoreactivity for CD34 and O13 but were negative for CD31, S-100, and CD68. Spindle cells in one dermatofibroma and one angiofibroma were positive for Factor XIIIa. Proliferating index (MIB-1) was very low in all cases of SF, contradicting some previous reports.

Conclusions: SF is a fibrotic lesion with cells positive for CD34 and O13. It shares a common immunoprofile with PF but is distinct from dermatofibroma and other common spindle cell lesions of skin. O13 expression in SF has not been previously described.


Benign subcutaneous and deep fibrous histiocytomas
May recur but do not metastasize
Plexiform fibrous histiocytoma
1/3 cases with local recurrence
Angiomatoid FH
15% with local recurrence
Plexiform fibrous histiocytoma
Angiomatoid FH
Rare with 1-2% reported to regional lymph nodes and distant mets

Metastasizing cellular dermatofibroma. A report of two cases.

Colome-Grimmer MI, Evans HL.

Department of Pathology, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.

Am J Surg Pathol 1996 Nov;20(11):1361-7 Abstract quote

Two cases of metastasizing cellular dermatofibroma (cutaneous fibrous histiocytoma) are presented.

The first patient, an 18-year-old man, had a nodule excised from his right upper thigh. He developed three local recurrences at 1.5, 2, and 2.5 years and metastasis to inguinal lymph nodes. He underwent lung segmentectomies for metastases 1.5 and 4 years later and was alive with no evidence of tumor at latest follow-up, which was 15 months after the last surgery. The second patient, a 33-year-old man, had a nodule removed from his right posterior neck. The tumor recurred 3 months later and was reexcised. Right cervical lymph node metastases were excised at 7 and 8 years. A year later, a right cervical lymph node dissection yielded one positive node of 35, and multiple metastases were excised from the right lung. The patient was alive with lung metastases 6 years later, which was the latest follow-up. Grossly, both tumors were single 2 cm nonulcerated dermal-subcutaneous nodules.

Histologically, they were characteristic of cellular dermatofibroma; they were composed of plump to spindled "fibrohistiocytic" cells arranged in a storiform pattern and had areas of hemorrhage, hemosiderin, and infiltration between dermal collagen bundles peripherally. Recurrences and metastases were histologically similar except that lung metastases were cystic. The alternative diagnosis of angiomatoid malignant fibrous histiocytoma was considered for these two cases but was excluded because the tumors were partly dermal, had a well-defined storiform pattern, and lacked large blood lakes, multinodularity, a fibrous pseudocapsule, and surrounding chronic inflammation.

We conclude that dermatofibromas can rarely metastasize. Risk factors for metastasis may include relatively large size, high cellularity, and local recurrence. Judging from these two cases, metastasizing dermatofibromas behave in an indolent manner.

Treatment Excision
Cases occurring on the face or with atypical histological features may require wider excision

Macpherson and Pincus. Clinical Diagnosis and Management by Laboratory Methods. Twentyfirst Edition. WB Saunders. 2006.
Rosai J. Ackerman's Surgical Pathology. Ninth Edition. Mosby 2004.
Sternberg S. Diagnostic Surgical Pathology. Fourth Edition. Lipincott Williams and Wilkins 2004.
Robbins Pathologic Basis of Disease. Seventh Edition. WB Saunders 2005.
DeMay RM. The Art and Science of Cytopathology. Volume 1 and 2. ASCP Press. 1996.
Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
Fitzpatrick's Dermatology in General Medicine. 6th Edition. McGraw-Hill. 2003.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fifth Edition. Mosby Elesevier 2008

Commonly Used Terms

Touton type giant cells-These multinucleated cells form a wreath-like appearance and are frequently present.

Basic Principles of Disease
Learn the basic disease classifications of cancers, infections, and inflammation

Commonly Used Terms
This is a glossary of terms often found in a pathology report.

Diagnostic Process
Learn how a pathologist makes a diagnosis using a microscope

Surgical Pathology Report
Examine an actual biopsy report to understand what each section means

Special Stains
Understand the tools the pathologist utilizes to aid in the diagnosis

How Accurate is My Report?
Pathologists actively oversee every area of the laboratory to ensure your report is accurate

Got Path?
Recent teaching cases and lectures presented in conferences

Internet Links

Last Updated January 30, 2009

Send mail to The Doctor's Doctor with questions or comments about this web site.
Read the Medical Disclaimer.

Copyright © The Doctor's Doctor