May 2013—Anal-rectal cytology has been used to evaluate HPV-related lesions of the anal canal, particularly in high-risk populations. Because anal cancer is uncommon in the general population, there is no utility in surveillance cytologic assessment on a population-wide scale (as with the Pap test for cervical disease). However, in certain populations, such as men who have sex with men (MSM) and HIV-positive men and women, the risk for anal cancer is higher and approaches the risk of cervical cancer reported in unscreened populations of women. Thus, given that anal cancer shares an HPV-related etiology with cervical cancer and involves a similar squamous mucosal site, anal cytology has been recommended as a method of screening for the prevention of anal cancer through the detection of precancerous lesions (anal intraepithelial neoplasia, AIN). Although the Bethesda terminology, criteria, and guidelines for anal cytology specimens parallel those for cervical cytology, degenerative cellular changes, extensive keratinization, and contaminating fecal material frequently make it more difficult to evaluate these specimens than to evaluate cervical specimens. Because there are limited data on the interobserver agreement of anal cytology (as compared with cervical cytology), Teresa M. Darragh, MD, et al., investigate interrater agreement of anal cytology as well as the relationship between biomarkers and anal cytologic interpretations (Cancer Cytopathol. 2013;121[2]:72–78).