OBJECTIVE To examine the relation between invasive adenocarcinoma and its alleged precursor, cervical glandular intraepithelial neoplasia (CGIN), and to assess the management and outcome of CGIN and the validity of using the term "microinvasive adenocarcinoma." METHODS The clinical and pathological features of 121 cases of glandular neoplasia of the cervix diagnosed between the years 1990 to 1995 were examined for the following: histological diagnosis, smear records, type of treatment, the association between the precursor lesions and invasive disease, and follow up. RESULTS 27 cases were identified as low grade CGIN (L-CGIN) and 38 as high grade CGIN (H-CGIN), 10 as microinvasive adenocarcinoma (less than 5 mm in depth), and 46 as invasive adenocarcinoma. The ratio of non-invasive to invasive disease was 1.12:1. The mean age of women was 39, 43, 43, and 48 years for L-CGIN, H-CGIN, microinvasive, and invasive adenocarcinoma, respectively. L-CGIN was seen in 13% and 18% of H-CGIN and microinvasive disease, respectively. H-CGIN was seen in 100% of microinvasive and 26% of invasive adenocarcinomas. The available smears before diagnosis predicted 59% of L-CGIN, 70% of H-CIGN, 100% of microinvasive adenocarcinoma, and 32% of invasive adenocarcinomas. Treatment of 74% of L-CGIN, 52% of H-CIGN, and 10% of microinvasive adenocarcinoma was by diathermy loop excision only. The remaining cases had hysterectomy. Residual disease was found in 43%, 50%, and 33% of hysterectomies for L-CGIN, H-CGIN, and microinvasive adenocarcinoma, respectively. This is correlated with positive margins, or disease within 3 mm of margins on loop specimens. Cervical smear follow up for two to seven years revealed no recurrence of glandular lesions in any of the cases of CGIN or microinvasive adenocarcinoma. CONCLUSIONS Precursor glandular lesions tend to progress to invasive carcinoma. There is a progressive increase in age of patients from L-CGIN to invasive disease, a span of approximately 10 years. There is a high association between H-CGIN and invasive disease. In the management of such alleged precursors, it is important to ensure adequate free margins of at least 3 mm. Microinvasive adenocarcinoma appears to have an excellent prognosis if treated by hysterectomy.