Answer: D

Histological Description: Affecting part of the testis there are non-necrotizing granulomas filling seminiferous tubules. Granulomas are composed of epithelioid histiocytes, giant cells admixed with lymphocytes and plasma cells. Chronic inflammatory cells including eosinophils and plasma cells infiltrate interstitium. The surrounding seminiferous tubules show active spermatogenesis.

Discussion: Idiopathic granulomatous orchitis is of unknown etiology. It is a benign inflammatory condition that can be bilateral and lead to loss of spermatogenesis in involved testes even if orchiectomy avoided. In infectious processes, necrotizing and/or non-necrotizing granulomatous inflammation composed of epithelioid histiocytes and multinucleated giant cells mainly involving the testicular interstitium. Infectious processes involving the testis also always start in the epididymis. The same interstitial distribution is also seen in sarcoidosis, yet non-necrotizing granulomas are seen. Germ cell neoplasia in situ (GCNIS) can also be associated with a granulomatous reaction. Intratubular epithelioid histiocytes, fewer giant cells are associated with GCNIS. GCNIS cells are enlarged, atypical germ cells residing within seminiferous tubules as isolated cells or a single row along a usually thickened basement membrane. GCNIS cells have clear cytoplasm, irregular nuclear contours, coarse chromatin, and enlarged single or multiple nucleoli. Some GCNIS cells have mummified pyknotic enlarged hyperchromatic nuclei. Seminiferous tubules containing GCNIS usually lack active spermatogenesis and contain mostly Sertoli cells. GCNIS cells can be highlighted by immunohistochemistry for PLAP and OCT4. Typically GCNIS with a granulomatous reaction is accompanied by invasive seminoma with a granulomatous reaction.