Gonadoblastoma with proliferation resembling Sertoli cell tumor.

A gonadoblastoma containing a proliferation of the sex cord element resembling a Sertoli cell tumor was found in the dysgenetic gonad of a 19-year-old Japanese phenotypic woman whose karyotype was 46 XY. The tumor was a solid mass 9 cm in maximal dimension composed of gonadoblastoma, dysgerminoma, and a proliferative sex cord element resembling a Sertoli cell tumor. Transitions between the gonadoblastoma nests and the sertoliform element were observed. These findings suggest that the sex cord element of gonadoblastoma can progress to an independent sex cord tumor.