Significance of mild cervical cytologic atypia in a sexually transmitted disease clinic population.

While the clinical management of patients with cytologic atypia consistent with cervical intraepithelial neoplasia (CIN) is well established, the management of so-called nondyskaryotic or benign atypias is controversial. The natural history of such atypias was prospectively studied in 124 patients attending a sexually transmitted disease clinic. The benign atypias were subdivided into different categories according to the cell type involved, and the patients were followed cytologically and colposcopically without cervical biopsy until they reached one of the study end points. Benign atypias often signified the presence of CIN: 17% of the patients had a smear consistent with CIN on the first study visit, and an additional 24% had such a smear by six months of follow-up. After 30 months of follow-up, the overall cumulative rate of biopsy-confirmed CIN 2 to CIN 3 was 13.5%; it was 12.5% among those with two consecutive smears showing benign atypias. Of the ten patients who reached biopsy-confirmed CIN 2 to CIN 3, a cytologic smear consistent with CIN was obtained in less than one year of follow-up in all but one case; however, colposcopic evidence of progression was seen in only half of the ten cases, suggesting a sampling error rather than true progression in many cases. Patients with metaplastic cell atypia had a higher progression rate to biopsy-confirmed CIN 2 to CIN 3 (21%) than did those with nonmetaplastic cell atypia (3%). This study provides direct evidence of the potential significance of metaplastic atypia as a marker of CIN. We conclude that patients with mild atypia are often found to have CIN and warrant further investigation by colposcopy and biopsy.