Malignant mixed tumor of the vagina probably arising in mesonephric rests

An exceedingly rare tumor arising in the upper lateral vagina is described histologically, histochemically, and ultrastructurally. It is compared to the lesion reported by Okagaki et al. which is considered to represent the same type of tumor. Comparison with synovial sarcomas indicates that the lesion is similar, but the reasons why it should not be so classified are discussed. Evidence is presented for the origin of these tumors in mesonephric rests (Gartner's duct).