Smears diagnosed as ASCUS: Interobserver variation and follow-up

The purpose of this study was to apply atypical squamous cells of undetermi ned significance (ASCUS) criteria from the Bethesda System for Reporting Ce rvical/Vaginal Cytologic Diagnoses (TBS) to the rescreen of cases previousl y diagnosed as ASCUS, to compare initial and rescreen diagnoses, and to ana lyze agreement with follow-up (cytology or histology). Two cytotechnologist s (S.B. and M.J.M.) and one cytopathology fellow (M.A.) rescreened 632 cerv icovaginal specimens diagnosed as ASCUS between June 1. 1992-December 31, 1 995. Age and LMP were provided. Rescreen diagnoses were categorized as with in normal limits (WNL). ASCUS, low-grade squamous intraepithelial lesions ( LSIL), high-grade squamous intraepithelial lesions (HSIL), or caret. noma ( CA). Complete agreement was found in 200 specimens (32%): 31 (15%) WNL; 91 (45%) ASCUS: 77 (38.5%) SIL; and one (0.50%) CA. Follow-up revealed no abno rmality in 67% of the cases reclassified as WNL, 49% of the cases reclassif ied as ASCUS. and 48% of the cases reclassified as squamous intraepithelial lesions (SIL). SIL was found in 29% of cases reclassified as WNL, 29% of s pecimens rediagnosed as ASCUS, and 34% of cases reclassified as SIL. Partia l agreement was,found in 391 specimens (62%). In 41 specimens (6%), rescree ners it-ere in complete disagreement, and follow-up revealed 9/41 (22%) SIL or worse: 21/41 (51%) WNL; and 4/41 (10%) inconclusive. Applying establish ed criteria. 14% (91/632) of cases diagnosed as ASCUS resulted in complete agreement, and 30% (190/632) resulted in partial agreement. Follow-up of ca ses initially diagnosed as ASCUS revealed SIL or CA in 30% of cases. ASCUS is a significant diagnosis warranting careful patient follow-up. (C) 2001 W iley-Liss, Inc.