[A CASE OF AN AROMATASE-PRODUCING SERTOLI CELL TUMOR PRESENTING WITH GYNECOMASTIA].

A 64-year-old man had complained of a left scrotal mass and gynecomastia since June 2012. A left testicular tumor was suspected and the patient was referred to our department in December 2013. He presented with bilateral gynecomastia and a painless left scrotal mass that was firm, smooth surfaced, and the size of large hen's egg. Levels of markers of testicular germ cell tumors were all within normal range. Endocrinological examination revealed a marked elevation in serum estradiol (E2) level. The patient underwent high inguinal orchiectomy in December 2013.The pathological diagnosis was a Sertoli cell tumor of the left testis. Immunohistochemistry revealed the expression of aromatase synthesis; we speculated that this E2 production by the tumor caused the gynecomastia.Serum E2 level normalized after the orchiectomy. Owing to the diagnosis of malignancy, retroperitoneal lymph node dissection was performed in January 2014. No lymph node metastasis was found in the specimen. The gynecomastia improved gradually, and the patient has been free of disease since the surgery.