Testis & paratestis

• Neoplasm composed of primitive appearing granulosa cells growing in solid and follicular patterns
• Most common neoplasm of the testis during the first 6 months; almost all tumors are seen in first decade of life (J Cancer Res Clin Oncol 2020;146:2829)
• No malignant cases reported

• Juvenile granulosa cell tumor (JGCT) is a rare neoplasm with a wide morphologic spectrum
• Solid and reticular patterns may pose diagnostic challenges but the lobular appearance and follicular differentiation are characteristic
• Immunostains aid in diagnosis with positive expression of SF1, calretinin, vimentin and inhibin and negative expression of alpha fetoprotein (AFP)

• Rare tumors that account for < 0.5% of all sex cord stromal tumors
• Afflicts patients from 30 weeks gestational age to 10 years old, with 90% occurring in patients ≤ 6 months of age (Am J Surg Pathol 2015;39:1159)
• Association with cryptorchoid testis or dysgenetic gonads (Drash syndrome) (Semin Diagn Pathol 2014;31:323, J Cancer Res Clin Oncol 2020;146:2829)
• Chromosomal abnormality linked to the Y chromosome is found in 20% of the cases (Am J Surg Pathol 1994;18:316)
• Can also occur rarely in undescended testes and dysgenetic gonads

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• Favorable prognosis, with no documented metastasis or relapses
• Lymphovascular invasion has been documented in only 2 cases and involvement of rete testis in 4 cases (Am J Surg Pathol 2015;39:1159)

• Tumors measure 0.5 - 5 cm (mean: 2 cm; median: 1.5 cm)
• Well circumscribed and yellow-orange or tan-white on cut surface
• Can have a solid (33% cases) or cystic component (67% cases) or both (Am J Surg Pathol 2015;39:1159)
• Watery to mucoid cystic fluid

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• Solid, nodular or follicular patterns are the most common and sometimes alternate
• Follicles vary from large and round / oval to small and irregular containing basophilic or eosinophilic secretion (mucicarmine+)
• In solid or nodular areas, the cells grow in sheets or irregular clusters
• Cells have moderate to large amounts of pale to eosinophilic cytoplasm, round to oval hyperchromatic nuclei, some of which contain nucleoli
• Mitoses are common, in contrast to adult granulosa cell tumor
• Extensive hyalinization (forming nodules) and prominent myxoid background may be seen
• Call-Exner bodies are uncommon
• Apoptosis, entrapped seminiferous tubules, rete testis involvement and lymphovascular invasion could be seen in rare cases (Am J Surg Pathol 2015;39:1159)

Contributed by Vikas Mehta, M.D.

• Association with abnormal karyotypes, including mosaics such as 45, X/47, XXY or 45X/46, X.r(Y) have been seen (Pediatr Dev Pathol 2016;19:471)

A 5 month old boy presented with a left testicular mass. An ultrasound of the testis showed a variably solid cystic mass with internal septations. An image from the resection specimen is shown above. Which of the following features will point toward the diagnosis of juvenile granulosa cell tumor?

1. Presence of intracellular or extracellular eosinophilic hyaline globules, basement membrane material and Schiller-Duval bodies
2. Round nests and cords composed of germ cells, small sex cord cells and globoid deposits of hyaline basement membrane material
3. Variable morphologic patterns with biphasic epithelioid and spindle cell components
4. Variable sized true follicles lined by bland appearing, oval, round cells arranged in single or multiple layers with outer layers resembling theca cells

D. Variable sized true follicles lined by bland appearing, oval, round cells arranged in single or multiple layers with outer layers resembling theca cells. Answer A is incorrect because the features described are found in yolk sac tumors. Answer C is incorrect because variable morphologic patterns with biphasic epithelioid and spindle cell components are found in a subset of sertoli cell tumors, NOS. Answer B is incorrect because the features described are found in gonadoblastoma.

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Reference: Juvenile granulosa cell tumor

Which of the following choices represents the immunoprofile of juvenile granulosa cell tumor of testis?

1. Desmin+, MyoD1+, myogenin+
2. Glypican3+, SALL4+, OCT3/4+
3. S100+, SMA+, SF1+
4. SF1+, FOXL2+, inhibin+

D. SF1+, FOXL2+, inhibin+. Answer B is incorrect because glypican3+, SALL4+, OCT3/4+ can be seen in immature teratoma. Answer C is incorrect because the features listed are consistent with gonadal stromal tumor, myoid. Answer A is incorrect because the features listed are consistent with rhabdomyosarcoma.

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Reference: Juvenile granulosa cell tumor