Gonadoblastoma: ultrastructural evidence for testicular origin

A gonadoblastoma arising in the dysgenetic gonad of a virilized 17-year-old Caucasian with a female phenotype and with a 45,X0/46, X-ring-Y genotype was studied by light microscopic histochemistry, electron microscopy, and ultrastructural histochemistry. The gonadoblastoma was composed of nests of cells containg large germ cells and small "granulosa-Sertoli-like cells," and stromal tissue containing "Leydig-like cells." The germ cells were identical to those found in normal fetal gonads and in germ cell tumors. Charcot-Böttcher crystalloids present in the "granulosa-Sertoli-like cells" strongly suggest that they are, in fact, Sertoli cells. Multilayered basal laminae located in the periphery of the tumor nests and in "hyaline bodies" were identical to those surrounding the seminiferous tubules of the adult testis. The "Leydig-like cells" present in the stroma contained occasional dense bodies and crystalloids which characterize the Leydig cells of the fetal testis. Delta 5-3 beta hydroxysteroid dehydrogenase activity was demonstrated in the periphery of lipid droplets and lysosome-like dense bodies of the Leydig cells, and in some Sertoli cells. The findings support the theory that gonadoblastoma arises in a dysgenetic testis rather than in a dysgenetic ovary.