Mixed germ cell-sex cord stromal tumor with heterologous structures.

A mixed germ cell-sex cord stromal tumor developed in the right ovary of a 4-year-old girl. The patient's cells contained sex chromatin and the karyotype was 46,XX. Clinically, she exhibited mild isosexual pseudopuberty. Some of the tumor cells showed differentiation to Sertoli cells, whereas others had characteristics of germ cells. The neoplasm was composed of solid cords consisting of a mixture of the two tumor cell types and surrounded by a delicate connective-tissue network. In one small area, the tumor contained heterologous development in the form of glands and cysts lined by columnar mucinous epithelium containing numerous goblet cells and occasional argyrophilic neuroendocrine cells. Normal ovarian tissue was present at the periphery of the tumor. Electron microscopic study confirmed the presence of both Sertoli-like and germ cell-type cells. Immunohistochemical studies demonstrated vimentin positivity in both cell types (with preference for the Sertoli-like cells) and cytokeratin positivity in the Sertoli-like cells. The patient was symptom free 4 years after right oophorectomy, radiotherapy, and chemotherapy.