Distinction between endometrial and endocervical adenocarcinoma: an immunohistochemical study.

We investigated the possibility of distinguishing between primary endometrial and endocervical adenocarcinomas by using a panel of immunohistochemical stains, which included vimentin (VIM), carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), and cytokeratins 7 and 20 (CK7 and CK20). Twenty-nine endocervical adenocarcinomas (CCAs) and 30 endometrial adenocarcinomas (EMCAs) including cases with overlapping histologic features (CCAs with endometrioid differentiation [15/29] and EMCAs with mucinous differentiation [16/30]) were evaluated. Most EMCAs (29/30, 97%) were VIM positive, whereas only 2/29 (7%) CCAs were VIM positive. The great majority of EMCAs (28/30) and all 29 CCAs were CK7 positive, whereas all 30 EMCAs and 27/29 CCAs were negative for CK20. CEA positivity was more common in CCAs (18/29, 62%) than in EMCAs (8/30, 27%). EMA positivity was present in all 30 EMCAs and in 26 of 29 (90%) CCAs. We conclude that VIM and CEA are useful immunohistochemical markers in distinguishing EMCAs and CCAs, but CK7, CK20, and EMA are not useful in this distinction.