The immunohistochemical discrimination of endometrioid adenocarcinomas.

Carcinomas of endometrioid histology frequently arise in the endometrium, ovary, and endocervix and involve the pelvic tissues in women. Adenocarcinomas of psuedoendometrioid morphology developing in the colon also frequently involve the ovary. The authors retrospectively examined 97 adenocarcinomas from the uterus, cervix, ovary, and colon to ascertain whether the site of origin could be determined by using a battery of antibodies with the immunoperoxidase method on formalin-fixed tissue. This study was restricted to tumors with endometrioid morphology. There were 27 endometrial, 16 ovarian, 23 endocervical adenocarcinomas, and 31 psuedoendometrioid colonic adenocarcinomas. The battery of antibodies included vimentin (V), monoclonal carcinoembryonic antigen (mCEA), and monoclonal CEA D-14. V-positive cells were defined by the presence of a crisp paranuclear band of staining, and CEA-positive cells showed irregular or diffuse cytoplasmic staining. V diffusely decorated 22 of 27 (81.4%) of endometrial tumors, 3 of 23 (13%) of endocervical tumors, (rare, focal staining), diffusely stained 5 of 16 (31.3%) of ovarian tumors, and was rare and focal in 2 of 31 (6.4%) of colon tumors. Both CEA antibodies were negative for cytoplasmic staining in both endometrial and ovarian tumors, but decorated from 65.2% (CEA D-14) to 95.6% (monoclonal CEA) of endocervical tumors and from 83.8% (CEA D14) to 90.3% (mCEA) of colonic tumors. The authors conclude that endometrioid adenocarcinomas developing in endometrium and ovary are most often strongly V positive and CEA negative, which greatly aids in distinguishing them from endometrioid or pseudoendometrioid tumors arising in endocervix and colon, which are only rarely, and very focally V and CEA positive. The antibodies do not allow for discrimination between endocervical and colonic tumors. CEA D-14 offered no immunodiagnostic superiority over mCEA. These results support the use of immunohistochemistry is assisting in the distinction of endometrial from endocervical primary sites in curettage specimens and in metastatic sites.