Case report of rat true hermaphroditism: colocalization of oocytes and granulosa and sertoli cells in the germinal cord.

We describe a case of rat hermaphroditism with bilateral ovotestes. In a 7-week-old apparently male Sprague-Dawley rat, both testes were relatively small, and the right testis with a faint protrusion was somewhat round and small as compared with the left testis. Microscopically, the testes contained ovarian tissues within their tunica albugineas in conjunction with spermatogenesis in the seminiferous tubules. As bilateral changes, oocytes surrounded by granulosa-like cells were present in the seminiferous tubule-like germinal cord. Granulosa-like and Sertoli-like cells were layered together on the basal lamina, and theca interna-like cells were occasionally observed around the basal lamina. As unilateral changes, cystic dilatation of the germinal cords with eosinophilic fluid was seen in the lumen, and the theca interna-like cells appeared to be vacuolated. Immunohistochemically, the granulosa-like and Sertoli-like cells showed positive reactions for 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and vimentin, respectively. Theca interna-like cells reacted positively to both 3beta-HSD and cytochrome P-450 17alpha-hydroxylase. Ultrastructurally, the granulosa, Sertoli, and theca interna cells were also identified in the ovarian tissue. From these morphological characteristics, the male rat with bilateral ovotestes was diagnosed as true hermaphroditism.