The purpose of the present study was to compare histology outcomes of cytological atypical squamous cells of undetermined significance (ASCUS) to the histology outcomes of cytological low-grade squamous intraepithelial lesion (LSIL). Cases with a cytology diagnosis of ASCUS and LSIL that had correlative histology obtained within 3 mo of the cervico-vaginal smear were accrued from the files of the Cytology and Histology Departments of Mercy Hospital Medical Center (Des Moines, IA). All of the cytology cases were examined by a cytotechnologist, a cytopathologist, and the histopathologist who signed out the biopsy material. The laboratory's benign: ASCUS: LSIL: HSIL + ratio was 94.0%: 3.8%: 1.5%: 0.7% for the time period of this analysis; its ASCUS:SIL proportion was 1.76. Histology correlations to 249 ASCUS cases showed 45 (18%) CIN2s (cervical intraepithelial neoplasm 2) or CIN3s, 134 (54%) CIN1s, and 70 (28%) nonneoplastic biopsies. Ten of 24 (42%) ASCUS cases that showed histological CIN3 and seven of 21 (33%) ASCUS cases that showed histological CIN2 contained atypical immature squamous metaplastic cells, while the remainder showed squamous cells with mature, superficial/intermediate-type cytoplasm. Histology correlations to 576 LSIL cases showed 96 (17%) CIN2s or CIN3s, 397 (69%) CIN1s, and 83 (14%) nonneoplastic biopsies. One hundred forty-six (59%) ASCUS and 424 (74%) LSILs had histological koilocytosis with nuclear atypia (KA); the sole histological finding of KA was seen among 76 (30.5%) ASCUS and 146 (25.3%) LSIL cases. The majority of cytological ASCUS and LSIL cases selected by clinicians for biopsy have histological CIN and a substantial minority show CIN2 and CIN3, which, in the case of ASCUS, is frequently associated with atypical immature squamous metaplastic cells. There is a high prevalence of histological KA among ASCUS and LSIL cases. Diagn. Cytopathol. 21:292-295, 1999.
Copyright 1999 Wiley-Liss, Inc.