Retrospective analysis of non-correlating cervical smears and colposcopically directed biopsies

The purpose of this study is to evaluate the cause of discrepancies between non-correlating cytologic and histologic cervical samples. The biopsy results of 433 women examined colposcopically were compared to their referral cervical smears (RS). There was a discrepancy between the RS and the subsequent biopsy in 120 women (28%). One hundred of these 120 RS were available for review; and in each case, a reason for the discrepancy was established and classified as RS overcall, RS undercall, RS sampling error, or biopsy sampling error. Fifty-one discrepant RS were overcalled. They were reported initially as condyloma (19), mild dysplasia (22), and moderate dysplasia (10). One RS was undercalled. Nine RS were not diagnostic of the biopsy-proven lesion due to smear sampling error. The discrepancies in the remaining 39 cases were due to biopsy sampling error. Twenty-one of these 39 cases had additional biopsies or smears that confirmed the presence of condyloma/dysplasia, and 18 had negative follow-up. In summary, discrepancies were a result of pathologists' interpretative error, predominantly overcalls, in 52% of non-correlating cases, and smear or biopsy sampling error in the remaining 48%.