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This is the most common benign soft tissue tumor of adults. They are sometimes multiple and usually painless and asymptomatic. Malignant transformation is virtually never seen. Angiolipoma is a common variant which has a proliferation of small vessels scattered throughout the fat. Unlike common lipomas, these tumors are usually painful.


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INCIDENCE Most common benign soft tissue tumor in adults
1/1000 of general population
AGE RANGE-MEDIAN 40-60 years
Slightly greater in M



Multiple spindle cell lipomas and dermatofibrosarcoma protuberans within a single patient: Evidence for a common neoplastic process of interstitial dendritic cells?

Harvell JD.

Department of Pathology, Stanford University Medical Center.

J Am Acad Dermatol 2003 Jan;48(1):82-5 Abstract quote

This case report describes a 48-year-old man with multiple spindle cell lipomas of the neck and a dermatofibrosarcoma protuberans (DFSP) with fibrosarcomatous transformation of the chest. The presence of familial and nonfamilial multiple spindle cell lipomas within a single patient is a rare event, with only two reports in the current literature.

This case represents the first report of multiple spindle cell lipomas occurring in association with a DFSP. It is of particular interest in that both spindle cell lipoma and DFSP represent, at least in part, neoplastic proliferations of CD34(+) spindled cells. The exact nature and differentiation of these spindled cells remains controversial, but prior studies have suggested that they could represent neoplastic interstitial dendritic cells.

The association of DFSP and spindle cell lipoma within this single patient suggests that these two tumors (and their histologic variants) may well be linked, conceptually, as neoplastic proliferations of CD34(+) interstitial dendritic cells.


Characteristic chromosomal abnormalities for lipoma Translocations involving 12q13-15
Interstitial deletions of 13q
Rearrangements involving 6p21-23


Intraosseous lipoma. A clinical, radiologic, and pathologic study of 5 cases.

Division of Surgical Pathology, Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555-0588, USA.

Ann Diagn Pathol. 2007 Oct;11(5):320-5. Epub 2007 Aug 17. Abstract quote

Intraosseous lipoma is an uncommon tumor of bone with indistinct radiologic features that makes it diagnostically challenging to radiologists and pathologists. There is a need to familiarize these physicians with the radiographic and pathologic features of this lesion for the correct diagnosis.

We described the radiologic and pathologic features of intraosseous lipoma in 5 women. In 4 patients, the tumors occurred in long bones, whereas in the fifth patient, the skull was involved. Patients' age ranged from 50 to 63 years. Plain radiographs of the long bones revealed well-circumscribed benign-appearing osteolytic lesions with sclerotic margins, whereas in the skull, a poorly defined lytic aggressive-looking lesion was observed. In the long bones, the lesions showed remodeling of the affected bone with matrix calcification, simulating bone infarcts.

Microscopically, mature adipose tissue with fat necrosis, absence of hematopoietic elements, and dystrophic calcification corresponding to the calcified matrix seen on the plain radiographs were seen. The osteolytic skull lesion had large caliber thin-walled vasculature with occasional fibrin thrombi mimicking intramuscular hemangiomas of soft tissue.

On plain radiographs, an intraosseous lipoma is usually seen as a rather benign-appearing osteolytic bone lesion with well-defined margins and a heavily calcified/ossified dense matrix. Plain radiographs alone cannot establish the diagnosis of intraosseous lipoma as it mimics several other benign and malignant bone lesions. Intraosseous lipoma often contains calcified necrotic fat with little mature adipose tissue and characteristically induces expansion/remodeling of the affected bone.

Intracortical lipoma of the femur.

Yamamoto T, Marui T, Akisue T, Hitora T, Nagira K, Ohta R, Yoshiya S, Kurosaka M.

Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Chuo-ku, Japan.

Am J Surg Pathol 2002 Jun;26(6):804-8 Abstract quote

The authors report on a rare case of intracortical lipoma of the right femur in a 74-year-old woman. Magnetic resonance imaging and computed tomography of the femur demonstrated an intracortical lesion in the lateral diaphysis. No medullary involvement by the lesion was noted. Both imaging methods revealed the presence of fat in the lesion.

Histologically, the tumor consisted of a large area of mature adipose tissues, admixed with foci of fat necrosis, calcification, and myxoid degeneration. Total excision of the tumor was curative.

This is the second reported case of intracortical lipoma.


Multiple painful lipomas or lipomatosis which arise in adult

Usually occurs in middle aged women
Usually obese

Rare familial occurrence

Long-standing pain relief of adiposis dolorosa (Dercum's disease) after intravenous infusion of lidocaine.

Juhlin L

J Am Acad Dermatol 1986 Aug;15(2 Pt 2):383-5 Abstract quote

A 60-year-old woman with adiposis dolorosa for 20 years was treated with repeated intravenous infusions of lidocaine.

Partial relief of pain in the legs was obtained after 1.3 gm. A dose of 5.2 gm lidocaine given for 4 days was needed for complete pain relief. The effect lasted for 3 weeks, and then the pain gradually returned. The patient has now been given two additional treatments with complete pain relief for 2 months.

The mechanism of the effect remains unknown.

Adiposis dolorosa (Dercum's disease): liposuction as an effective form of treatment.

DeFranzo AJ, Hall JH Jr, Herring SM.

Department of Surgery, Bowman Gray School of Medicine.

Plast Reconstr Surg 1990 Feb;85(2):289-92 Abstract quote

The clinical picture of adiposis dolorosa makes a lasting impression on the examining physician. The patient is typically an obese, asthenic woman who appears to have a low pain threshold. She has an unusual distribution of fatty tumors, and her complaint of pain in these tumors seems out of proportion to the physical findings. Alcoholism, emotional instability, and depression are common, and narcotic pain medicine is frequently requested. The patient is easily dismissed as a malingerer after a brief examination.

However, liposuctioning of the painful fatty tumors appears to be both practical and effective. While adiposis dolorosa is an unusual disease, it is one that plastic surgeons can recognize and treat.

Fat-cell heat production, adipose tissue fatty acids, lipoprotein lipase activity and plasma lipoproteins in adiposis dolorosa.

Fagher B, Monti M, Nilsson-Ehle P, Akesson B.

Department of Internal Medicine, University Hospital of Lund, Sweden.

Clin Sci (Lond) 1991 Dec;81(6):793-8 Abstract quote

1. Gluteal adipose tissue was examined in 13 patients with generalized adiposis dolorosa, a clinical condition characterized by painful adiposity with a chronic intractable course. The total metabolic activity of fat cells, isolated by collagenase and suspended in Krebs-Ringer bicarbonate buffer with glucose and insulin, was assessed by the measurement of heat production at 37 degrees C using microcalorimetry.

2. Fat cells were markedly enlarged; their metabolic activity expressed in terms of microW/g, but not in pW/cell, was significantly decreased when compared with both lean and weight-matched non-painful subjects. Both mean values were, however, significantly higher than in grossly obese subjects with similar mean cell size. Heat production as expressed per g of tissue, but not per cell, was inversely correlated with body mass index. One additional patient had unilateral disease, and fat cells from the painful side had a lower heat production than cells from the unaffected side.

3. The fatty acid composition of adipose tissue, as determined by g.c., revealed a significantly increased proportion of monounsaturated (18:1 and 16:1) at the expense of saturated (14:0 and 18:0) fatty acids compared with healthy control subjects. The activity of adipose tissue lipoprotein lipase was slightly, but not significantly, decreased.

4. It is concluded that a metabolic pathogenetic factor cannot be ruled out in adiposis dolorosa. As the results do not explain the nature of the diffuse pain, further studies need to be performed.

Hormonal and metabolic study of a case of adiposis dolorosa (Dercum's disease).

Pimenta WP, Paula FJ, Dick-de-Paula I, Piccinato CE, Monteiro CM, Brandao-Neto J, Kettelhut IC, Foss MC.

Departamento de Clinica Medica, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Botucatu, SP, Brasil.

Braz J Med Biol Res 1992;25(9):889-93 Abstract quote

A case of a 43-year-old nonobese woman with adiposis dolorosa (Dercum's disease) is reported.

Muscle glucose uptake and oxidation before and after ingestion of 75 g of glucose were similar to control group values, although a greater insulin release (16,578 vs 6,242 +/- 1,136 microU/3 h) occurred simultaneously. In vitro studies of abdominal normal and painful subcutaneous adipose tissue of the patient revealed lower responsiveness to norepinephrine and lack of response to the antilipolytic effect of insulin in the painful adipose tissue (0.98 vs 1.43 microM FFA/10(6) cells at 5.0 microM of norepinephrine). The disease was not correlated with the HLA system and there were no alterations in hormonal secretion at the pituitary, adrenal, gonadal, and thyroid levels.

These findings indicate the presence of peripheral insulin resistance in this patient with adiposis dolorosa.

Adiposis dolorosa (Dercum's disease): 10-year follow-up.

Brodovsky S, Westreich M, Leibowitz A, Schwartz Y.

Department of Plastic Surgery, Assaf HaRofeh Medical Center, Tzrifin, Israel.

Ann Plast Surg 1994 Dec;33(6):664-8 Abstract quote

Adiposis dolorosa is a disease characterized by painful, subcutaneous fatty tumors. This disorder usually occurs in obese, postmenopausal women and is associated with weakness and mental disturbances such as depression, confusion, lethargy, and dementia. The cause is unknown, and there is no specific treatment. Pain may be relieved by steroids, intravenous lidocaine, or analgesics. Surgical treatment consists of excision or liposuction of the painful masses.

We present two cases of adiposis dolorosa in men, with a follow-up of more than 10 years.

Liposuction in Dercum's disease: impact on haemostatic factors associated with cardiovascular disease and insulin sensitivity.

Berntorp E, Berntorp K, Brorson H, Frick K.

Department of Coagulation Disorders, University of Lund, Malmo University Hospital, Sweden.

J Intern Med 1998 Mar;243(3):197-201 Abstract quote

OBJECTIVE: To study the impact of adipose tissue removal by liposuction on factors associated with increased risk of cardiovascular atherosclerotic disease within the coagulation and fibrinolytic system and glucose metabolism.

DESIGN, SETTING AND SUBJECTS: Liposuction was performed in 53 patients with Dercum's disease. The levels of fibrinogen, von Willebrand factor antigen (VWF:Ag) and plasminogen activator inhibitor type 1 activity (PAI-1) were measured preoperatively, and 2 weeks, 4 weeks and 3 months postoperatively. In a subsample of 10 patients, insulin sensitivity was determined before and 2-4 weeks after surgery using the 2-h euglycaemic hyperinsulinaemic clamp technique. The study was performed as a single-centre study.

MAIN OUTCOME MEASURE: Fibrinogen, PAI-1 and VWF:Ag levels, and glucose uptake before and after removal of adipose tissue.

RESULTS: Weight reduction was sustained throughout the follow-up period with a mean decrease from 90.7 to 86.6 kg (P < 0.0001). There was a slight increase in levels of coagulation factors 2 and 4 weeks postoperatively, probably in reaction to the surgical trauma. After 3 months the values had returned to preoperative levels except for PAI-1, which still showed a slight increase (P < 0.05). In the subsample of 10 patients, glucose uptake was improved (P < 0.05) from a short-term perspective after surgery.

CONCLUSION: Surgical removal of adipose tissue, without change in lifestyle, does not seem to improve the levels of coagulation and fibrinolytic factors associated with cardiovascular atherosclerotic disease, whereas glucose takeup may be facilitated and insulin sensitivity increases from a short-term perspective.

Treatment of pain in adiposis dolorosa (Dercum's disease) with intravenous lidocaine: a case report with a 10-year follow-up.

Devillers AC, Oranje AP.

Clin Exp Dermatol 1999 May;24(3):240-1

Familial occurrence of adiposis dolorosa.

Campen R, Mankin H, Louis DN, Hirano M, Maccollin M.

Department of Dermatology, Massachusetts General Hospital, Boston, MA, USA

J Am Acad Dermatol 2001 Jan;44(1):132-6 Abstract quote

Adiposis dolorosa is a rare condition characterized by multiple painful lipomas.

We describe two typically affected siblings who were found to have at least 5 affected first-degree relatives in two generations. Manifestations were remarkably variable, ranging from complete disability to solitary asymptomatic tumors. Review of histopathologic findings did not reveal any features that might distinguish the tumors from common sporadic lipomas. Mutational analysis excluded the 8344 A to G mitochondrial mutation seen in other patients with multiple lipomas.

Adiposis dolorosa may be an extreme manifestation of the more common condition of familial multiple lipomas. Further work is needed to define the genetic basis of these conditions.

Spindle Cell Lipoma of the Oral Cavity.

Billings SD, Henley JD, Summerlin DJ, Vakili S, Tomich CE.

From the *Department of Pathology and Laboratory Medicine, and daggerDepartment of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana; double daggerDepartment of Oral Pathology, Indiana University School of Dentistry, Indianapolis, Indiana; section signDermatopathology Laboratory, Indianapolis, Indiana, and paragraph signRichard L. Roudebush VA Medical Center, Indianapolis, Indiana.

Am J Dermatopathol. 2006 Feb;28(1):28-31. Abstract quote  

Spindle cell lipoma is typically seen in the neck/trunk region of middle-aged and older men. Rare cases of oral spindle cell lipoma have been reported. An entity described as myxoid lipoma of the oral cavity has rarely been reported but appears to be more properly classified as spindle cell lipoma.

We describe the largest series yet of oral spindle cell lipoma involving the tongue (4), buccal mucosa (1), floor of mouth (1), and lip (1). The patients (3M; 4F) ranged from 31 to 88 years old. All presented with mass lesions. All were circumscribed and composed of mature adipocytes admixed with bland spindled cells. In two cases the adipocytes appeared atrophic, imparting a pseudo-lipoblastic appearance. No true lipoblasts were seen and none had the characteristic vasculature of a myxoid liposarcoma or the characteristic hyperchromatic cells of well-differentiated liposarcoma. The stromal background of all cases contained characteristic wiry collagen and myxoid ground substance. The myxoid ground substance was prominent in four cases.

Immunohistochemical stains for CD34 highlighted the bland spindle cells in all cases. The combination of the histologic features and the immunoreactivity for CD34 confirmed the diagnosis.

Spindle cell lipoma should be considered in the differential diagnosis of oral cavity mesenchymal tumors.

Oral spindle cell lipoma

Nasser Said-Al-Naief, DDS, MS
Fazlur R. Zahurullah, MD
James J. Sciubba, DMD, PhD

From the Department of Pathology, the University of Alabama at Birmingham; the Department of Otolaryngology, Rockford Health System, Rockford, IL; and the Department of Otolaryngology Head and Neck Surgery, Division of Dental & Oral Medicine, Johns Hopkins University, Baltimore, MD.

Ann Diagn Pathol 5: 207-215, 2001. Abstract quote

Lipoma is an uncommon benign, oral, soft-tissue neoplasm commonly found on the buccal mucosa. It is predominantly composed of mature fat with or without other mesenchymal tissue elements, showing a variety of histologic subtypes, one of which is the rare “spindle cell variant” with only nine previously reported cases in the English literature.

In this report, we review clinical and histomorphologic data of 164 cases of oral lipomas retrieved from the files of Long Island Jewish Medical Center, Department of Dental Medicine (New Hyde Park, NY). Of these, only two cases were diagnosed as the spindle cell variant, further confirming the rarity of this histologic subtype. A review of oral lipoma with particular reference to the spindle cell variant is also presented.

Subconjunctival Herniated Orbital Fat: A Benign Adipocytic Lesion That may Mimic Pleomorphic Lipoma and Atypical Lipomatous Tumor.

*Emory Eye Center double daggerDepartment of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA daggerDepartment of Ophthalmology, Ruprecht-Karls-University, Heidelberg, Germany.


Am J Surg Pathol. 2007 Feb;31(2):193-198. Abstract quote

Prolapse of subconjunctival intraconal orbital fat is a rare cause of an intraorbital mass lesion. Over the past several years, we have seen a number of cases in which this prolapsed fat was confused pathologically with a neoplasm of adipocytic lineage, specifically pleomorphic lipoma and atypical lipomatous neoplasm (well-differentiated liposarcoma).

We report the clinical, histopathologic, and immunohistochemical findings in 21 specimens from 17 patients, all of whom presented with prolapsed intraconal orbital fat. All specimens were routinely examined and processed for light microscopy. Immunohistochemistry for CD34, CD68, S100 protein, vimentin, alpha-smooth muscle actin, and Ki-67, and Giemsa, Masson trichrome, and alcian blue histochemical stains were performed.

Clinical and follow-up information was extracted from a chart review. The mean age (+/-SD) of the patients was 65.6+/-11.9 years (range: 41 to 85 y); 2 were women and 15 were men. Subconjunctival prolapsed orbital fat was localized in the superotemporal quadrant or lateral canthus around the rectus muscle below the lacrimal gland. The lesions were unilateral in 10 and bilateral in 7 patients. No recurrence was clinically evident over a mean (+/-SD) follow-up time of 2.5+/-3.2 years (range: 1 mo to 13.5 y).

Histopathologically, all specimens showed an admixture of mature fat, fibrous septae lacking hyperchromatic cells, adipocytes with intranuclear vacuoles (Lochkern cells), multinucleated giant cells with a wreathlike configuration of normochromatic nuclei (floret cells), and varying numbers of histiocytes, lymphocytes, plasma cells, and mast cells. "Control" sections of normal orbital fat showed occasional Lochkern cells but lacked floret cells.

By immunohistochemistry, the floret cells expressed only CD34 and vimentin, whereas the Lochkern cells expressed CD34, S100 protein, and vimentin.

We conclude that subconjunctival herniated orbital fat commonly contains multinucleated floretlike giant cells, fibrous septae, and Lochkern cells, features that may result in diagnostic confusion with pleomorphic lipoma and atypical lipomatous neoplasms. Importantly, specific diagnostic features, such as aggregates of bland spindled cells associated with wiry collagen, as seen in pleomorphic lipoma, and enlarged hyperchromatic cells within fibrous septae, as in atypical lipomatous neoplasms, are entirely absent in herniated orbital fat. Multinucleated floret cells present in prolapsed orbital fat likely represent a reactive phenomenon, as they are not present in normal orbital fat.

Intradermal spindle cell/pleomorphic lipoma of the vulva: case report and review of the literature

Jorge S. Reis-Filho
Fernanda Milanezi
Maria F. Soares
José Fillus-Neto
Fernando C. Schmitt

J Cutan Pathol 2002;29:59 Abstract quote

Background: Spindle cell/pleomorphic lipoma (SC/PL) is a benign adipose tissue tumor that usually affects the subcutaneous tissues of shoulders, backs, and neck region of middle-aged male patients. Histologically, it is characterized by the presence of primitive CD34-positive spindle cells arranged in short fascicles, bizarre floret-like multinucleated giant cells, mature adipocytes, and a small number of lipoblasts. Recently, an intradermal subset has been described, which mainly affects female patients and presents a wider antomical distribution when compared to the classical variant of SC/PL.

Methods: We report a case of intradermal SC/PL affecting the labium majus of a 56-year-old female patient.

Results: The histological examination disclosed the typical histological features, however the lesion showed poorly demarcated and infiltrative borders, as well as involvement of dermal nerves. The immunohistochemical analysis according to streptovidin-biotin-peroxidase technique showed immunoreactivity for CD34 and vimentin in the spindle cells, as well as S100 protein and vimentin in the adipocytic cells.

Conclusions: To the best of our knowledge, this is the first case of intradermal SC/PL affecting the vulvar region. Care must be taken not to misdiagnosis this rare tumor as well-differentiated liposarcoma, cellular angiofibroma, solitary fibrous tumor, and cutaneous neurofibroma.


General Circumscribed collection of mature adipose tissue
Cutaneous Apocrine Cystic Adenolipoma.

Antunez P, Santos-Briz A, Munoz E, Fernandez M, de Unamuno P, Bullon A.

From the *Departamento de Anatomia Patologica, Hospital Universitario de Salamanca, Salamanca, Spain;
daggerDepartamento de Biologia Celular y Patologia, Universidad de Salamanca, Salamanca, Spain; and double daggerClinica San Marcos and section signServicio de Dermatologia Hospital Universitario de Salamanca, Salamanca, Spain.
Am J Dermatopathol. 2005 Jun;27(3):240-242. Abstract quote  

Adenolipoma is a rare microscopic variant of cutaneous lipoma composed of large lobules of mature adipocytic tissue admixed with eccrine ducts and glands.

We report a new case of cutaneous adenolipoma, and the first showing an apocrine cystic glandular component. This lesion may not be a specific entity, and could represent entrapment of epithelial structures within a lipoma.

Cellular angiolipoma.

Hunt SJ, Santa Cruz DJ, Barr RJ.

Department of Pathology, St. John's Mercy Medical Center, St. Louis, MO 63141-8221.

Am J Surg Pathol 1990 Jan;14(1):75-81 Abstract quote

Three examples of cellular angiolipoma are presented.

They occurred as part of multiple, occasionally painful, subcutaneous nodules on the extremities and trunk of healthy men. There was no familial tendency. Grossly, the cellular angiolipomas were small lesions, approximately 1 cm.

Histologically, dense cellular angiomatous tissue comprised more than 95% of the lesions. Much of this component contained prominent spindle cells. Lesser degrees of involvement in the other subcutaneous nodules illustrated the continuum of histology between cellular angiolipomas and more typical angiolipomas. The differential diagnosis of cellular angiolipomas includes spindle cell lipoma, Kaposi's sarcoma, and other vascular tumors.

The most important distinguishing features are encapsulation, intravascular fibrin thrombi, septation, association with other more typical angiolipomas, and occurrence in healthy individuals.

Two cases of angiomyxolipoma (vascular myxolipoma) of subcutaneous tissue.

Lee HW, Lee DK, Lee MW, Choi JH, Moon KC, Koh JK.

Department of Dermatology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Korea.
J Cutan Pathol. 2005 May;32(5):379-82. Abstract quote  

Angiomyxolipoma (vascular myxolipoma) is a recently described rare variant of lipoma, four cases of which have been reported to date.

Microscopically, the lesion consists of adipose tissue without lipoblasts, extensive myxoid areas, and numerous blood vessels. The main differential diagnosis of this lesion is myxoid liposarcoma, and other adipocytic lesions such as myxolipoma, myxoid spindle cell lipoma should be included.

We report two cases of angiomyxolipoma located in the subcutaneous tissue of the forearm and the wrist.
Angiomyxolipoma (vascular myxolipoma) of subcutaneous tissue.

Tardio JC,
Martin-Fragueiro LM.

Department of Pathology, Hospital El Escorial, Madrid, Spain.
Am J Dermatopathol. 2004 Jun;26(3):222-4. Abstract quote  

Three cases of angiomyxolipoma (vascular myxolipoma) have been published to date.

We report an angiomyxolipoma located in the subcutaneous tissue of the scalp. Histologically, it consisted of an admixture of paucicellular myxoid areas and mature fat tissue, both containing numerous dilated blood vessels with hyalinized thin walls. The cells in the myxoid areas expressed CD34.

This lesion requires differential diagnosis with other benign fat tissue tumors, especially myxoid spindle cell lipoma, superficial angiomyxoma, myxoid liposarcoma, and low-grade myxofibrosarcoma.

The Morphologic Spectrum of Hibernoma A Clinicopathologic Study of 170 Cases

Mary A. Furlong, M.D.; Julie C. Fanburg–Smith, M.D.; Markku Miettinen, M.D. From the Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, DC, U.S.A.

Am J Surg Pathol 2001;25:809-814 Abstract quote

Hibernoma, an uncommon tumor of brown fat, has been described only in a few case reports and small series. The authors reviewed 170 cases of hibernoma and evaluated the morphologic features and the behavior of this tumor. The records from the Soft Tissue Registry of the Armed Forces Institute of Pathology from 1970 were searched for cases coded as ``hibernoma.'' Clinical information and available slides from 170 hibernomas were reviewed.

Immunohistochemical staining for S-100 and CD34 was performed on select cases. Follow-up information was obtained from the patients' medical records, the patients' physicians, and the patients themselves. Of 170 patients with hibernoma, 99 were men and 71 were women. The tumor occurred most commonly in adults, with a mean age of 38.0 years (age range, 2–75 years). Nine tumors occurred in pediatric patients. The most common anatomic locations included the thigh (n = 50), shoulder (n = 20), back (n = 17), neck (n = 16), chest (n = 11), arm (n = 11), and abdominal cavity/retroperitoneum (n = 10). The average duration of the tumor was 30.6 months. Tumor size ranged from 1 to 24 cm with an average dimension of 9.3 cm.

All tumors were composed partly or principally of coarsely multivacuolated fat cells with small, central nuclei and no atypia. Four morphologic variants of hibernoma were identified: typical, myxoid, spindle cell, and lipoma-like. ``Typical'' hibernoma (n = 140) included eosinophilic cell, pale cell, and mixed cell types based on the tinctorial quality of the hibernoma cells. The myxoid variant (n = 14) contained a loose basophilic matrix. Spindle cell hibernoma (n = 4) had features of spindle cell lipoma and hibernoma; all occurred in the neck or scalp. The lipoma-like variant (n = 12) contained only scattered hibernoma cells. Immunohistochemically, 17 of 20 cases (85%) were positive for S-100 protein. Only one hibernoma of 20, a spindle cell variant, was positive for CD34, whereas other hibernoma variants were negative. Follow-up was obtained for 66 cases (39%) over a mean period of 7.7 years (range, 6 months–28 years). None of the patients with follow-up had a recurrence or metastasis, including eight with intramuscular tumors. No patient died of disease.

Hibernoma is a tumor found most often in adults and most commonly in the thigh, with several morphologic variants. It is a benign tumor that does not recur with complete excision. Hibernomas should not be confused with atypical lipomas or well-differentiated liposarcoma.


Lele SM, Chundru S, Chaljub G, Adegboyega P, Haque AK.

Departments of Pathology (Drs Lele, Chundru, Adegboyega, and Haque) and Radiology (Dr Chaljub), University of Texas Medical Branch at Galveston, Galveston, Tex. Dr Lele is now at the Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington.

Arch Pathol Lab Med 2002 Aug;126(8):975-978 Abstract quote

Hibernomas are rare neoplasms composed of brown adipose tissue. The behavior of these neoplasms has been described as uniformly benign in humans. The only recurrence cited in the English literature involved a sarcoma with hibernoma-like features, which was reported in abstract form.

We present 2 cases of hibernoma, one that continued to grow following partial excision and another at an unusual site (anterior abdominal wall). Both of these tumors overexpressed p53 protein by immunohistochemistry, which was a novel finding. A review of the literature highlights recent advances that may help confirm the diagnosis and explain the biology of these rare tumors.


Myelolipoma associated with adrenal ganglioneuroma.

Merchant SH, Herman CM, Amin MB, Ro JY, Troncoso P.

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

Arch Pathol Lab Med 2002 Jun;126(6):736-7 Abstract quote

Adrenal myelolipomas are rare, benign mesenchymal tumors composed of mature adipose tissue and hematopoietic cells in varying proportions. Although the majority of cases occur as isolated adrenal lesions, myelolipomas have been described in association with various adrenal pathologic conditions. These conditions include enzyme deficiencies and hyperplastic and neoplastic lesions of the adrenal cortex, with perhaps endocrine dysfunction as a common feature. Ganglioneuroma is a benign tumor of the sympathetic nervous system that rarely produces symptoms of endocrine dysfunction.

We report an unusual case of myelolipoma associated with ganglioneuroma of the adrenal medulla. The histogenesis of myelolipoma remains speculative. However, the close proximity to adrenal cortical cells within the stroma of ganglioneuroma suggests that the hormonal microenvironment may have played a role in the development of the myelolipoma.

Histopathologic changes after intralesional application of phosphatidylcholine for lipoma reduction: report of a case.

Department of Dermatology, Medical University of Graz, Austria.


Am J Dermatopathol. 2006 Aug;28(4):331-3
Abstract quote

Phosphatidylcholine, a lecithin extracted from soy beans, is able to lower serum cholesterol to some extent. When applied intralesionally within fat tissues, it is supposed to act as a "fat burner" and reduce undesired fat deposits.

We applied intralesionally phosphatidylcholine within a lipoma of a young patient. To evaluate the volume of the lipoma sonographic imaging was performed before treatment and one month after the third application. Only a partial reduction of the lipoma could be achieved, and increased echographic density could be observed after the third intralesional application of phosphatidylcholine. Surgical excision was performed.

Histologic examination showed focal fibrosis, inflammatory reaction with granulomatous features, and presence of pseudomembranous degeneration of fat tissue.

Off-label intralesional use of phosphatidylcholine as "fat burner" for the reduction of aesthetically disturbing lipomas should be considered only on a case-to-case basis after careful consideration of possible undesired effects similar to those described in our patient.
Cancer 1981;47:126-133

Pleomorphic lipoma. Case reports and review of the literature.

Digregorio F, Barr RJ, Fretzin DF.

Department of Pathology, Humana Hospital-Michael Reese, Chicago, Illinois 60616-3390.

J Dermatol Surg Oncol 1992 Mar;18(3):197-202 Abstract quote

Two patients are reported with pleomorphic lipoma, a benign subcutaneous fatty tumor showing atypia in which histologic diagnosis may be difficult. The tumors are well circumscribed lesions, most commonly occurring in the neck and shoulder of middle aged men. An important histologic criteria is the presence of floret-like multinucleated giant cells embedded in a myxoid stroma.

Pleomorphic lipoma may be confused with several malignant soft-tissue neoplasms, including myxoid malignant fibrous histiocytoma and variants of liposarcoma. It is important to establish the correct diagnosis to avoid unnecessary radical surgery.

Sclerotic (fibroma-like) lipoma: a distinctive lipoma variant with a predilection for the distal extremities.

Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.

Am J Dermatopathol. 2006 Aug;28(4):308-16 Abstract quote

This report details the clinicopathologic and immunohistochemical findings identified in 21 cases of a fibrosclerotic variant of lipoma from acral sites that is frequently misdiagnosed as a fibromatous (nonlipogenic) process.

The study includes 12 males and 9 females; aged 7 to 72 (mean and median, 39). The patients presented with solitary, mostly asymptomatic, masses that ranged from 0.6 to 2.2 (median, 1.2; mean, 1.3) cm and involved fingers (n=17), hands or wrists (n=3), and toes (n=1).

Microscopically, the lesions were well-circumscribed nodules that showed very low to moderately low cellularity and consisted of cytologically bland spindled and stellate-shaped cells and a minor component of randomly dispersed adipocytes embedded in a collagenous to myxocollagenous stroma. Eight tumors were "fibroma-like" owing to their paucity of spindled cells, dense fibrosclerotic stroma, and inconspicuous vasculature. One tumor showed features of spindle cell/pleomorphic lipoma, whereas another demonstrated a vague onion skin-like arrangement of collagen reminiscent of sclerotic (storiform) fibroma. In all cases, the mitotic activity was negligible. Nonlipogenic tumor cells were immunoreactive for CD99 (6 of 6 cases), CD34 (6 of 8), S-100 protein (4 of 7), and smooth muscle actin (2 of 6). Follow-up data on 8 patients (range, 1 to 20 years; median, 9.5 years) revealed no recurrence in 6, but indicated the possibility of persistent tumor in the remaining 2 individuals after simple excision. Despite histological overlap in 1 case with the sclerotic fibroma, no patient displayed definitive clinical features of Cowden syndrome.

Our study indicates that fibrosclerotic lipomas demonstrate a broader histological scope than what was initially described.
Am J Dermatopathol 1995;17:529-533
Intradermal spindle cell/pleomorphic lipoma

Histopathology 1995;27:533-540
Am J Dermatopathol 2001;22:496-502

20 cases
20-85 years, median 42 years
14/20 females
Sites: Head/neck, shoulder upper back, lower limbs, trunk, upper limbs

Usually <2.5 cm

Unencapsulated with poorly defined infiltrative margins, intradermal tumors, with occasional extension into subcutaneous tissue

Variable portions of uniform short cells with scant to moderate amounts of eosinophilic poorly demarcated cytoplasm, small fusiform nuclei with vesicular chromatin, and indistinct nucleoli

Mixed with pleomorphic cells with bizarre spindle cells and floret type giant cells

May have prominent myxoid component

Positive for CD34, negative for S100

Fibrous Spindle Cell Lipoma Report of A New Variant

Carlos Diaz-Cascajo, etal.

Am J Dermatopathology 2001;23:112-115 Abstract quote

Spindle cell lipoma is a benign tumor characterized by mature fatty tissue alternating with short fascicles of small spindle cells in a stroma that varies from fibrous to myxoid. The variable proportion of these elements among different examples of the neoplasm confers to spindle cell lipoma a variable microscopic appearance that can make the diagnosis difficult. Furthermore, in some instances, spindle cell lipoma may resemble liposarcoma, hemangiopericytoma, neurilemmoma, and other neoplasms representing a histopathologic pitfall.

We report on two cases of spindle cell lipoma with abundant fibrous stroma reminiscence of fibroma and fibrolipoma. The name fibrous spindle lipoma is proposed for this tumor.


Special stains  
J Cutan Pathol 1996;23:546-550
Positive in spindle cell lipomas

Leptin and Leptin Receptor mRNA are Widely Expressed in Tumors of Adipocytic Differentiation

Andre M. Oliveira, M.D., Antonio G. Nascimento, M.D. and Ricardo V. Lloyd, M.D., Ph.D.

Department of Laboratory Medicine and Pathology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota Correspondence: Address reprint requests to: Ricardo V. Lloyd, M.D., Ph.D., Department of Laboratory Medicine and Pathology, Mayo Clinic

Mod Pathol 2001;14:549-555 Abstract quote

Adipose tissue is the principal source of leptin, a cytokine-like peptide with many biologic functions. Leptin binds to the leptin receptor, present in the hypothalamus and in many other tissues, and modulates energy balance and maintenance of body weight. The expression of leptin and leptin receptor in tumors of adipocytic differentiation has not been previously examined. Because normal adipose tissue is the principal source of leptin and expresses leptin receptor, we hypothesized that tumors of adipose tissue differentiation may also express leptin and/or the long functional form of the leptin receptor (OB-Rb).

Leptin and OB-Rb were analyzed by immunohistochemistry, in situ hybridization, RT-PCR, and western blotting in 21 lipomas, 2 hibernomas, and 16 liposarcomas.

Immunostaining and in situ hybridization showed leptin and OB-Rb mRNA expression in all cases of lipomas, hibernomas, and liposarcomas, including dedifferentiated and pleomorphic liposarcomas. RT-PCR analysis showed leptin and OB-Rb mRNA in both lipomas (n = 5) and liposarcomas (n = 5). Western blotting identified the 16 kDa leptin protein in a lipoma and a liposarcoma. No important difference in the expression of leptin and OB-Rb mRNA was found between lipomas and liposarcomas, although the level of leptin protein was higher in a lipoma than a liposarcoma by western blotting.

These results show for the first time that leptin and OB-Rb mRNA are expressed in lipomas, hibernomas, and liposarcomas. The presence of leptin and its receptor may provide new insights into the pathobiology of these tumors.



Hyperplasia of the subcutaneous adipose tissue is the primary histopathologic abnormality in lipedematous scalp.

Scheufler O, Kania NM, Heinrichs CM, Exner K.


Am J Dermatopathol. 2003 Jun;25(3):248-52. Abstract quote

A 51-year-old white woman presented with thickening of the scalp located at the vertex and left lateral occiput without hair abnormalities or alopecia. Skin biopsies of the thickened scalp showed thickening of the subcutaneous tissue with proliferation of mature subcutaneous fat cells but no signs of inflammation or hair abnormalities. During 2.5 years of follow-up, scalp thickening progressed over the entire hair-bearing scalp and persisted without signs of further progression at 3.5 year follow-up.

Lipedematous scalp is an extremely rare diagnosis. It is defined by a thickening of the subcutaneous layer of the scalp and can be distinguished from lipedematous alopecia, in which subcutaneous thickening is associated with diffuse alopecia and shortening of scalp hairs. A total of seven cases of lipedematous alopecia and two cases of lipedematous scalp have been reported.

We report the third case of lipedematous scalp in a 51-year-old white woman associated with early symptoms of meningitis. Additional features described in the literature include pruritus, pain, and paresthesia of the scalp as well as associated medical problems such as hyperelasticity of skin and laxity of joints, renal failure, and diabetes mellitus.

This sporadic disorder is predominantly located at the vertex and occiput. The etiology and pathogenesis of lipedematous scalp and alopecia remain unclear. The treatment is symptomatic.


The chief differential is with cases of pleomorphic lipomas of the skin

If lipoblasts are present in an otherwise typical pleomorphic lipoma of the skin, superficial, favor a diagnosis of pleomorphic lipoma


Prognostic Factors Benign
Recurrence 1-2% in cases of intradermal spindle cell/pleomorphic lipomas
Treatment Simple 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. Fourth Edition. Mosby 2001.

Commonly Used Terms

Lipocyte or adipocyte-Individual fat cells.

Soft Tissue Tumors

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