COLPOSCOPIC APPEARANCE OF ANAL SQUAMOUS INTRAEPITHELIAL LESIONS - RELATIONSHIP TO HISTOPATHOLOGY

PURPOSE: The incidence of anal cancer is increased in men with a histo ry of anal receptive intercourse. Analogous to cervical cancer, whose precursor is cervical high-grade squamous intraepithelial lesion (HSIL ), anal cancer may be preceded by anal HSIL. Although not yet proven, detection, follow-up, and treatment of HSIL may prevent development of anal cancer. Cervical colposcopic methodology was used to describe an al lesions and to determine if HSIL could be distinguished from low-gr ade squamous intraepithelial lesion (LSIL). METHODS: The colposcopic c haracteristics of 385 biopsied anal lesions were described and correla ted with results of histopathology in a cohort of 121 human immunodefi ciency virus-positive and 31 human immunodeficiency-negative homosexua l/bisexual men with anal lesions followed as part of a longitudinal st udy of anal squamous intraepithelial lesions. Color, contour, surface, and vascular patterns of anal lesions were analysed and correlated wi th histologic diagnosis. RESULTS: Sixty-seven percent of biopsies show ed LSIL and 26 percent showed HSIL. The positive predictive value for anal HSIL in lesions with characteristics typical of cervical LSIL was 7.7 percent (95 percent confidence interval, 1.8-14), whereas the pos itive predictive value for anal HSIL in lesions with characteristics t ypical of cervical HSIL was 49 percent (95 percent confidence interval , 40-58). CONCLUSIONS: The colposcopic appearance of different grades of anal squamous intraepithelial lesions was similar to those describe d for the cervix. Incorporation of colposcopy into assessment of anal disease could aid in distinguishing anal LSIL from HSIL.