Teratoma of the Testis

Background

The teratoma is a germ cell neoplasm of the testis. These tumors encompass a broad range of tumors ranging from mature teratomas to immature teratomas. The histologic hallmark is a mixture of multiple tissue types derived from embryologically diverse source such as epithelium and mesenchyme such as smooth muscle and cartilage.

OUTLINE

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Histopathological Features and Variants

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DISEASE ASSOCIATIONS CHARACTERIZATION

NEPHROBLASTOMA

Nephroblastoma Arising in a Germ Cell Tumor of Testicular Origin.

Emerson RE, Ulbright TM, Zhang S, Foster RS, Eble JN, Cheng L.

Departments of *Pathology and Laboratory Medicine and daggerUrology, Indiana University School of Medicine, Indianapolis, IN.

Am J Surg Pathol. 2004 May;28(5):687-692. Abstract quote

We report a nephroblastoma arising in a germ cell tumor of testicular origin occurring in a 22-year-old man. Orchiectomy demonstrated a malignant mixed germ cell tumor composed of mature and immature teratoma with nephroblastoma and rhabdomyosarcoma. Following chemotherapy, the patient developed supraclavicular and retroperitoneal lymphadenopathy.

Excision demonstrated metastatic teratoma at both sites. No recurrence was noted with 21 months of additional follow-up. Using tissue microdissection and loss of heterozygosity analysis, we investigated the clonality of the mature teratoma, immature teratoma, nephroblastoma, and rhabdomyosarcoma components of the primary tumor and of the metastatic mature teratoma at the two separate distant sites. Nine microsatellite polymorphic makers were used to examine the pattern of allelic loss in both primary and metastatic tumors. Loss of heterozygosity was found in 4 DNA loci, and the same pattern of allelic loss was demonstrated at all 4 loci in all of the different components of the primary tumor and the metastatic mature teratomas, supporting the germ cell tumor origin of the nephroblastoma component.

Loss of heterozygosity on chromosome 17p13 (TP53) was detected in metastatic mature teratoma, but not in the primary tumor. Loss of heterozygosity was observed at 11p13, the locus of WT1 inactivation in patients genetically predisposed to nephroblastoma, and this loss may be an important genetic mechanism in nephroblastomatous differentiation of germ cell tumors.

These data support a common clonal origin for nephroblastoma and the other germ cell tumor components.

HISTOLOGICAL TYPES CHARACTERIZATION

General

VARIANTS

CARCINOID TUMOR

Neuroendocrine Carcinomas (Carcinoid Tumor) of the Testis
A Clinicopathologic and Immunohistochemical Study of Ten Cases

Adriana Reyes, MD,1 Cesar A. Moran, MD,1 Saul Suster, MD,2 Michal Michal, MD,3 and Hugo Dominguez, MD
Am J Clin Pathol 2003;120:182-187 Abstract quote

We studied 10 cases of primary pure testicular neuroendocrine carcinoma. Patients were between 16 and 48 years old and had testicular swelling with pain or a painless testicular mass and no history of neuroendocrine carcinoma or other malignant neoplasm. All underwent orchiectomy.

The tumors were low (n = 9) and intermediate (n = 1) grades with a variegated histologic appearance characterized by a nesting pattern, cords of neoplastic cells with rosettes, or sheets of neoplastic cells. Mitotic activity was lacking in 9 cases. In 1 case, mitotic figures ranged from 7 to 8 per 10 high-power fields, and cellular atypia and comedo-like necrosis were present.

Immunohisto-chemical studies using a keratin cocktail, chromogranin, synaptophysin, epidermal growth factor, p53, placental-like alkaline phosphatase, and CD117 (c-kit) were performed in all cases. Keratin, chromogranin, and synaptophysin were positive in all tumors. Clinical follow-up information was obtained for 6 patients (range, 12-60 months): 5 with low-grade tumors were alive 24 to 60 months after diagnosis; 1 with an intermediate-grade tumor died of tumor 12 months after initial diagnosis.

The behavior of these tumors, while in the testicular region, correlates well with the histologic grade. We propose replacing the term testicular carcinoid with neuroendocrine carcinoma, which better reflects the nature of these neoplasms.

DERMOID CYST

Dermoid Cyst of the Testis A Study of Five Postpubertal Cases, Including a Pilomatrixoma-Like Variant, With Evidence Supporting Its Separate Classification From Mature Testicular Teratoma

Thomas M. Ulbright, M.D.; John R. Srigley, M.D.

Am J Surg Pathol 2001;25:788-793 Abstract quote

It is controversial if the rare dermoid cyst of the testis should be classified as a variant of mature teratoma or separately. The spectrum of findings is also ill defined, as is the relationship of dermoid cyst to intratubular germ cell neoplasia of the unclassified type (IGCNU).

This study therefore reports the findings in five testicular dermoid cysts that occurred in five patients, 17�42 years of age, who presented with testicular masses. Four lesions consisted of a keratin-filled cyst with a thickened wall, whereas one had islands of ``shadow'' squamous epithelial cells with superimposed calcification and ossification (pilomatrixoma-like variant). Hair was identified grossly in two cases.

On microscopic examination, four tumors had hair follicles with sebaceous glands showing a typical, cutaneous-type orientation to an epidermal surface, although no hair shafts were present in two. In addition, the fibrous wall contained smooth muscle bundles (all tumors) and eccrine or apocrine sweat glands (4 tumors). In some cases there were also glands lined by ciliated epithelium (4 tumors, including the pilomatrixoma-like variant), intestinal mucosa (1 tumor), and bone (2 tumors). There was no cytologic atypia or apparent mitotic activity, and no case had IGCNU in the seminiferous tubules.

All patients were clinical stage I and were treated by orchiectomy without adjuvant therapy. All were well on follow-up from 1.5 to 9.5 years later.

This study supports that dermoid cyst may have noncutaneous teratomatous elements and that an important criterion for its diagnosis is the absence of IGCNU. It also supports that it should be categorized separately from mature testicular teratoma because of the malignant nature of the latter in postpubertal patients. These observations suggest that there are at least two pathways for testicular teratomas in postpubertal patients: the more common being through IGCNU by differentiation from an invasive malignant germ cell tumor and the less common one, taken by dermoid cyst, by direct transformation from a nonmalignant germ cell.

Henry JB. Clinical Diagnosis and Management by Laboratory Methods. Twentieth Edition. WB Saunders. 2001.
Rosai J. Ackerman's Surgical Pathology. Eight Edition. Mosby 1996.
Sternberg S. Diagnostic Surgical Pathology. Third Edition. Lipincott Williams and Wilkins 1999.
Robbins Pathologic Basis of Disease. Sixth Edition. WB Saunders 1999.
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. 5th Edition. McGraw-Hill. 1999.
Weiss SW and Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors. Fourth Edition. Mosby 2001.

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Last Updated 5/18/2004

Disease Associations
Histopathological Features and Variants
Commonly Used Terms
Internet Links

HISTOLOGICAL TYPES	CHARACTERIZATION
General
VARIANTS
CARCINOID TUMOR
Neuroendocrine Carcinomas (Carcinoid Tumor) of the Testis A Clinicopathologic and Immunohistochemical Study of Ten Cases Adriana Reyes, MD,1 Cesar A. Moran, MD,1 Saul Suster, MD,2 Michal Michal, MD,3 and Hugo Dominguez, MD	Am J Clin Pathol 2003;120:182-187 Abstract quote We studied 10 cases of primary pure testicular neuroendocrine carcinoma. Patients were between 16 and 48 years old and had testicular swelling with pain or a painless testicular mass and no history of neuroendocrine carcinoma or other malignant neoplasm. All underwent orchiectomy. The tumors were low (n = 9) and intermediate (n = 1) grades with a variegated histologic appearance characterized by a nesting pattern, cords of neoplastic cells with rosettes, or sheets of neoplastic cells. Mitotic activity was lacking in 9 cases. In 1 case, mitotic figures ranged from 7 to 8 per 10 high-power fields, and cellular atypia and comedo-like necrosis were present. Immunohisto-chemical studies using a keratin cocktail, chromogranin, synaptophysin, epidermal growth factor, p53, placental-like alkaline phosphatase, and CD117 (c-kit) were performed in all cases. Keratin, chromogranin, and synaptophysin were positive in all tumors. Clinical follow-up information was obtained for 6 patients (range, 12-60 months): 5 with low-grade tumors were alive 24 to 60 months after diagnosis; 1 with an intermediate-grade tumor died of tumor 12 months after initial diagnosis. The behavior of these tumors, while in the testicular region, correlates well with the histologic grade. We propose replacing the term testicular carcinoid with neuroendocrine carcinoma, which better reflects the nature of these neoplasms.
DERMOID CYST
Dermoid Cyst of the Testis A Study of Five Postpubertal Cases, Including a Pilomatrixoma-Like Variant, With Evidence Supporting Its Separate Classification From Mature Testicular Teratoma Thomas M. Ulbright, M.D.; John R. Srigley, M.D.	Am J Surg Pathol 2001;25:788-793 Abstract quote It is controversial if the rare dermoid cyst of the testis should be classified as a variant of mature teratoma or separately. The spectrum of findings is also ill defined, as is the relationship of dermoid cyst to intratubular germ cell neoplasia of the unclassified type (IGCNU). This study therefore reports the findings in five testicular dermoid cysts that occurred in five patients, 17�42 years of age, who presented with testicular masses. Four lesions consisted of a keratin-filled cyst with a thickened wall, whereas one had islands of ``shadow'' squamous epithelial cells with superimposed calcification and ossification (pilomatrixoma-like variant). Hair was identified grossly in two cases. On microscopic examination, four tumors had hair follicles with sebaceous glands showing a typical, cutaneous-type orientation to an epidermal surface, although no hair shafts were present in two. In addition, the fibrous wall contained smooth muscle bundles (all tumors) and eccrine or apocrine sweat glands (4 tumors). In some cases there were also glands lined by ciliated epithelium (4 tumors, including the pilomatrixoma-like variant), intestinal mucosa (1 tumor), and bone (2 tumors). There was no cytologic atypia or apparent mitotic activity, and no case had IGCNU in the seminiferous tubules. All patients were clinical stage I and were treated by orchiectomy without adjuvant therapy. All were well on follow-up from 1.5 to 9.5 years later. This study supports that dermoid cyst may have noncutaneous teratomatous elements and that an important criterion for its diagnosis is the absence of IGCNU. It also supports that it should be categorized separately from mature testicular teratoma because of the malignant nature of the latter in postpubertal patients. These observations suggest that there are at least two pathways for testicular teratomas in postpubertal patients: the more common being through IGCNU by differentiation from an invasive malignant germ cell tumor and the less common one, taken by dermoid cyst, by direct transformation from a nonmalignant germ cell.