[Epididymal sperm invasion apparently suggestive of a testicular tumor].

A 49-year-old man visited the outpatient clinic suffering from painless swelling of the left testicular content which he had recognized 1 week earlier. The lower portion of the testis or the epididymis gave rise to a thumb-head sized irregular tumor. At the exploring operation, the tumor was revealed to be the swollen epididymal tail. Epididymectomy was performed. Microscopically, the tumor was diagnosed as an epididymal granuloma invaded by many sperm, histiocytes, macrophages, neutrophil leukocytes and lymphocytes around the epididymal tubules. Eight cases of epididymal sperm invasion reported in Japan during the recent 20 years are reviewed and briefly discussed.