The value of high-resolution anoscopy in the diagnosis of anal cancer precursor lesions in hiv-positive patients

context: anal cancer, although a still rare disease, is being observed in ascending rates among some population segments known to be at risk for the development of the disease. human papillomavirus (hpv) infection, immunodepression and anal intercourse are some factors associated with the development of the malignancy. its similarities to cervical cancer have led to many studies aiming to establish guidelines for detecting and treating precursor lesions of anal cancer, with the goal of prevention. high-resolution anoscopy is routinely used for the diagnosis of anal cancer precursor lesions in many centers but the medical literature is still deficient concerning the role of this diagnostic modality. objectives: to evaluate diagnostic validation and precision measures of high-resolution anoscopy in comparison to histopathological results of anal biopsies performed in hiv-positive patients treated at the tropical medicine foundation of amazonas, am, brazil. to observe any possible association between some risk factors for the development of anal cancer and the presence of anal squamous intraepithelial lesions. methods: a hundred and twenty-eight hiv-positive patients were submitted to anal canal cytological sampling for the detection of hpv infection by a pcr based method. high-resolution anoscopy was then performed after topical application of acetic acid 3% in the anal canal for 2 minutes. eventual acetowhite lesions that were detected were recorded in respect to location, and classified by their tinctorial pattern, distribution aspect, relief, surface and vascular pattern. biopsies of acetowhite lesions were performed under local anesthesia and the specimens sent to histopathological analysis. the patients were interviewed for the presence of anal cancer risk factors. results: the prevalences of anal hpv infection and of anal squamous intraepithelial lesions in the studied population were, respectively, 79% and 39.1%. high-resolution anoscopy showed sensibility of 9