Inaccuracy of cytologic diagnosis in high grade squamous intraepithelial lesions (CIN 3).

Through a retrospective review of records, this study attempted to determine whether a correlation between cytology and histology would change with time in one laboratory. The study encompassed a geographic area of Scotland with a female population of 175,500 served by one colposcopy clinic, at Ninewells Hospital and Medical School, Dundee. The subjects were referred to the Nine-wells colposcopy clinic between January 1, 1985, and December 31, 1990. The results showed many women with high grade squamous intraepithelial lesions (SILs) (CIN 3) and cytology revealing abnormalities milder than severe dyskaryosis, for an average of 71.9% over the six years of the study. The referral of women for colposcopic assessment if they have persistent smears showing mild dyskaryosis suggestive of low grade SILs seems to be worthwhile.