Fig. 4

a Light microscopic examination of the tumor shows a diffuse pattern of large polygonal cells with abundant eosinophilic cytoplasm, round nuclei, and prominent nucleoli. No definite Reinke crystals were identified. There is no evidence of tumor necrosis, nuclear pleomorphism, increase mitosis, or vascular invasion. b The Ki67 proliferative index is low with 1–2%. c The tumor cells are diffusely positive for inhibin. d The tumor cells are diffusely positive for vimentin. e The tumor cells are diffusely positive for calretinin. f The tumor cells are focally positive for Mart-1. The spermatic cord shows benign adrenal rest and Leydig cell hyperplasia. The diagnosis was consistent with benign LCT