Inflammatory atypia. An apparent link with subsequent cervical intraepithelial neoplasia explained by cytologic underreading.

A review of 5,752 cervical smears done on college students at a medium-sized midwestern university in a 24-month period showed 496 cytologic diagnoses of inflammatory atypia and 132 of dysplasia (cervical intraepithelial neoplasia: CIN). Further retrospective review of a nonselected cohort (178 cases) of the 496 patients with inflammatory atypia showed that their subsequent cytologic smears were more likely to show CIN than could be explained by chance alone. Only ten cases accounted for this difference, and a case-controlled blind review of the original cytologic smears of these ten patients resulted in the reclassification to CIN (mild dysplasia) of seven who had subsequently "progressed" from inflammatory atypia to dysplasia. Only one control smear was reclassified. In this population, underreading of a small number of cervical smears explained a strong statistical apparent correlation between inflammatory atypia and the subsequent development of CIN.