Minimal deviation adenocarcinoma of the uterine cervix ("adenoma malignum"). An immunohistochemical comparison with microglandular endocervical hyperplasia and conventional endocervical adenocarcinoma.

In an effort to obtain objective information that would be useful in separating minimal deviation adenocarcinoma (MDA) or "adenoma malignum" of the endocervix from benign endocervical glandular proliferations, four cases of MDA were studied immunocytochemically, and compared with seven cases of microglandular endocervical hyperplasia (MEH) and six cases of conventional endocervical adenocarcinoma (ACA). Monoclonal antibodies to carcinoembryonic antigen (CEA) and blood group isoantigens A, B, and H (BGI) were used in these analyses. All MDA and ACA were CEA-positive, whereas none of the cases of MEH stained for the presence of this substance. Six of seven examples of MEH expressed appropriate BGI; the remaining case failed to stain for blood group substances. In contrast, six of ten cases of malignant endocervical glandular tumors manifested "inappropriate" expression of BGI, based on the patients' known blood types. These data suggest that immunostains for CEA may be helpful in the diagnostic separation of MDA and MEH. The close biochemical similarity between CEA and BGI is postulated as an explanation for "inappropriate" expression of blood group antigens by malignant endocervical lesions.