Leiomyoblastoma of the epididymis in a child.

A case of leiomyoblastoma of the epididymis in a 3-year-old boy is presented. Left high inguinal orchiectomy was performed. Light and electron microscopic examinations revealed a 3.5 X 2.3 X 1.5 cm. tumor continuous with the tail of the epididymis. The lesion proved to be a leiomyoblastoma of the epididymis. Leiomyoblastoma is a form of leiomyoma mainly composed of immature smooth muscle cells. The absence of keratin, epithelial membrane antigen and negative results by alcian blue stain indicated that there were no adenomatoid elements in the tumor.