The Stromal and Myogenic Sarcomas of the Uterus

Abstract

Stromal sarcomas of the uterus generally originate as homologous tumors from endometrial stromal cells with fixed potentialities. They may be composed of one type of cell or of several types, or rarely they may consist only of endometrial granulocytes. From the same source but with a more favorable prognosis is endolymphatic stromatosis, which arises primarily in the myometrium but does not diffusely invade it, as the stromal sarcoma does. By contrast, heterologous malignant mesenchymal mixed tumors of the endometrium originate from Müllerian epithelium derived from the mesoderm, and are therefore pluripotential. In this group we find rhabdomyosarcomas and chondroblastomas which have a very poor prognosis. The myogenic sarcomas are three times more common, and arise from smooth muscle cells of the myometrium or its blood vessels. The degree of nuclear pleomorphism may vary considerably, from normal to giant cell types, and may differentiate also as clear-cell myoblasts. They portend a somewhat more favorable prognosis than the stromal sarcomas.