Case Study #2

February 2017

A 32 year old male, non-drinker and non-smoker, complains of heaviness in his lower abdominal region. This has been noted for two months and he doesn't recall any trauma to the region. Upon examination, a 3-cm firm mass is found in the right scrotum. No lymphadenopathy is seen, and a scrotal ultrasound confirms the presence of a solid testicular mass. A radical orchiectomy is performed and histology is below. What is the diagnosis?

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H&E

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Tumor shows a diffuse pattern interrupted by fibrous septa with lymphocytic infiltrate. Seminiferous tubules are visible on the right.

H&E

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At a higher magnification, tumor cells show clear cytoplasm with round polygonal nuclei and large nucleoli.

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Neoplastic cells are negative for inhibin, but inhibin positivity are seen in Sertoli cells as well as in the Leydig cells shown on the right.

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Tumor cells show strong diffuse positivity for PLAP suggesting the neoplasm is of germ cell origin.

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Tumor cells show strong diffuse nuclear positivity for SALL4 further confirming the neoplasm is of germ cell origin.

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Neoplastic cell nuclei are negative for embryonal carcinoma marker SOX-2.

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The tumor cells do not express CD30, making embryonal carcinoma less likely.

Alpha-Fetoprotein

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Alpha-fetoprotein is not expressed in the tumor cells, reducing the likelihood of the tumor being a yolk sac tumor.

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Neoplastic cells show strong diffuse nuclear positivity, suggesting possibly either a seminoma or a embryonal carcinoma.

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Tumor cells are positive for CD117.

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Neoplastic cells show strong diffuse nuclear positivity, further suggesting seminoma.