DISCORDANCE BETWEEN CYTOLOGIC AND HISTOLOGIC REPORTS IN CERVICAL INTRAEPITHELIAL NEOPLASIA - RESULTS OF A ONE-YEAR AUDIT

In order to investigate the factors contributing to cases in which the cytology and histology reports of cervical intraepithelial neoplasia (GIN) differ, we assessed the impact of careful review of the biopsy a nd its corresponding cervical smear. In a one-year audit of all cervic al biopsies we found that 28.8% of biopsy-smear pairs disagreed by at least two grades of CIN. Following review the mismatch rate fell by 47 %, mainly due to a drop in the number of cases in which the smear show ed less severe CIN than did the biopsy. The proportion of cases in whi ch the cytologic impression of CIN was greater than the histologic was changed little. The fall in the mismatch rate was seen after review o f the smears, while a similar review of the histology did not alter th e-rate of mismatch. Neither the presence of koilocytotic changes on ei ther cytology, histology or both, nor the size of the biopsy (punch vs . cone/hysterectomy) influenced the occurrence of such discrepancies. A similar review io of :the smears and biopsies of matching cases of C IN revealed no significant changes. This suggests particular difficult ies of interpretation in the mismatching cases. In those cases with pe rsistent mismatch an additional element of sampling error must be assu med to be the main cause even though all smears were considered of ade quate quality.