Atypical endometrioid cystadenofibroma with Meigs' syndrome: ultrastructure and S-phase fraction.

A case of an ovarian endometrioid cystadenofibroma with epithelial atypia and Meigs' syndrome is described. The patient had a large pleural effusion that resolved rapidly after extirpation of the tumor. The S-phase fraction, measured by in vitro incorporation of tritiated thymidine, was extremely low, suggesting that this unusual tumor has a limited growth potential despite its atypical features. Ultrastructurally, the epithelial component has few features described in other ovarian endometrioid tumors. The cells have deeply clefted nuclei and numerous secondary cytolysosomes, features more commonly seen in Brenner tumors; the morphologic similarities may reflect a low epithelial turnover rate. Despite a review of the literature and an analysis of the case, the authors were unable to determine the pathogenetic mechanism of Meigs' syndrome.