Mixed germ cell-sex cord stromal tumor. A gonadal tumor distinct from gonadoblastoma.

A mixed germ cell-sex cord stromal tumor and a gonadoblastoma were examined by light and electron microscopy. The mixed germ cell-sex cord stromal tumor occurred in a normal adult male, father of two children, whereas the gonadoblastoma arose in a dysgenetic gonad of a phenotypic female. The light-microscopic appearance of the gonadoblastoma was distinctive for its organoid arrangement of sex cord cells and germ cells and its pattern of secondary alterations resultings in mulberry areas of hyalinization and calcification. The ultrastructural features of the sex cord stromal cells were similar in both lesions; however, the germ cells of the mixed germ cell-sex cord stromal tumor were distinctive for the presence of true intercellular bridges. This finding suggested primary spermatogenic differentiation. It was concluded that the mixed germ cell-sex cord stromal tumor was clinically and pathologically distinct from the more widely recognized gonadoblastoma.