Immature ovarian teratoma with mature peritoneal metastatic deposits showing glial, epithelial, and endometrioid differentiation: a case report and review of the literature.

A patient with multiple peritoneal metastases showing mature (grade 0) glial, epithelial, and endometriotic differentiation occurring 20 years after removal of a grade 1 immature ovarian teratoma is reported. Although previous cases of endometriosis occurring in association with gliomatosis peritonei and a case of epithelial differentiation in metastases from an immature ovarian teratoma have previously been reported, this case would appear to be unique. Attention is drawn to similar, well-differentiated, metastases occurring in testicular teratomas.