Distinction between endocervical and endometrial adenocarcinoma with immunoperoxidase staining of carcinoembryonic antigen in routine histological tissue specimens.

The differential diagnosis of endocervical and endometrial adenocarcinomas can be improved by the demonstration of carcinoembryonic antigen (CEA) in tissue by means of immunoperoxidase staining. Tissue from 131 (80%) of 163 patients with endocervical adenocarcinoma but only 11 (8%) of 137 patients with endometrial adenocarcinoma was CEA-positive. The commonest exceptions were endocervical mesonephroid adenocarcinomas (which were CEA-negative) and endometrial adenosquamous carcinomas (which were CEA-positive). After exclusion of these on simple morphological criteria, 86 of 107 endocervical adenocarcinomas (80%) were CEA-positive, and all 122 endometrial adenocarcinomas were CEA-negative. The remarkable difference in the expression of CEA between endocervical and endometrial adenocarcinomas suggests a novel application of immunohistochemistry in routine clinical practice.