Atypia in cervical cytology as a risk factor for intraepithelial neoplasia.

All Papanicolaou smears obtained during the years 1977 to 1982 were reported by a descriptive cytologic interpretation instead of a numerical report. All smears showing "atypia" were reviewed and found to fall into one of three categories: inflammatory atypia, squamous atypia, and endocervical atypia. Patients with the latter two categories and those with persistent inflammatory atypia after specific therapy underwent colposcopy and directed biopsies if indicated. Colposcopically directed biopsies revealed that 29% of patients with atypical Papanicolaou smears had underlying cervical intraepithelial neoplasia. There was no statistically significant difference in the incidence of underlying cervical intraepithelial neoplasia among patients in each of the three categories of atypia. Of those with intraepithelial neoplasia, 35% had lesions of greater severity than grade 1 cervical intraepithelial neoplasia. We conclude that all patients with squamous, endocervical, and persistent inflammatory atypia on Papanicolaou smear should undergo colposcopic evaluation to rule out intraepithelial neoplasia.