Ultrastructure of Papillary Serous Carcinoma of the Endometrium

Abstract

Three cases of papillary serous carcinoma of the endometrium (PSCE) were studied by transmission electron microscopy, and the ultrastructural findings compared with those in classical endometrioid carcinoma of the endometrium (CECE) and papillary serous carcinoma of the ovary (PSCO). PSCE possesses many ultrastructural features in common with CECE and PSCO, as well as with clear cell carcinoma of the endometrium, emphasizing the close relationship existing among these different tumors of Mullerian origin. The only useful ultrastructural distinguishing features beween serous and endometrioid carcinomas of similar histologic grade are more numerous secretory granules in the former and prominent paranuclear microfilaments and tonofilaments in the latter. Despite its lack of ultrastructural distinctiveness, the clinical behavior of PSCE justifies its consideration as a unique clinicopathologic entity.