Twenty-three cases of cervical intraepithelial glandular neoplasia (CIGN)--a term encompassing adenocarcinoma in situ and glandular dysplasia of the uterine cervix--were studied histologically, histochemically for mucins (neutral mucins, sialomucins and sulfomucins), and immunohistochemically for the affinity of four lectins (WGA, PNA, RCA, UEA). For comparison, six cases of cervical invasive adenocarcinoma and ten cases of cervices without tumor were similarly studied. Criteria for histologic grading of CIGN into three degrees were proposed according to the hyperchromasia and the stratification of nuclei, number of mitoses, and amount of intracellular mucin. Two different types of CIGN were distinguished according to their histological aspect and their mucin pattern: CIGN type A, where the mucin pattern was qualitatively similar to that of normal endocervical mucosa, i.e., neutral mucins, sulfomucins and sialomucins; and CIGN type B, where the glandular cells resembled small intestinal goblet cells and the mucins consisted of neutral mucins and sialomucins with the absence of sulfomucins. Nine cases of CIGN were of type A, 2 of type B, and 12 of both type A and B. Differences in lectin binding existed between normal columnar cells, CIGN, and invasive adenocarcinomas, as well as between CIGN of type A and B. The intensity of the positive immunochemical reaction varied, as well as the type of binded lectin and its localization in the cell. There was a great heterogeneity in the same histologic group from one case to another, and even in the same case from one cell to another.