Atypical cervical cytology. Colposcopic follow-up using the Bethesda System

Patients with a cytologic diagnosis of either atypical squamous cells of undetermined significance (squamous ACUS) (191), atypical squamous cells suggestive of papillomavirus (ACPV) (79), low grade squamous intraepithelial lesion (LSIL) (184) or atypical glandular cells of undetermined significance (glandular ACUS) (30) obtained over an 18-month period were evaluated colposcopically at the National Naval Medical Center. The diagnosis of squamous atypia rendered using the Bethesda System was reduced when compared to the diagnosis of atypia rendered using traditional cytologic terms (1.9% versus 7.2%). Results from colposcopic evaluations of patients with squamous ACUS demonstrated similar rates of underlying dysplasia as in studies using older terminology (low grade dysplasia in 14% and high grade in 6% of the referrals). Colposcopic evaluation of patients with a referral diagnosis of squamous ACPV demonstrated rates of underlying low grade dysplasia double that of the diagnosis of squamous ACUS but half that of a diagnosis of LSIL (25% versus 14%, and 48%, respectively). Colposcopic evaluation of glandular ACUS rendered a diagnosis of high grade dysplasia more than three times (20%) as often as of squamous ACUS (6%). While the Bethesda System reduces inconsistencies in the diagnosis of atypical cytologic changes, a separate category (ACUS) appears to be useful in identifying underlying, unsuspected low grade dysplasias in our laboratory. In addition, glandular atypias herald a significant rate of underlying high grade dysplasias and warrant immediate colposcopic investigation.