Background : High-resolution anoscopy is a useful screening tool for anal intraepithelial neoplasia although reputedly challenging for interpretation of suspected lesions.
Objective : The purpose of this study was to identify straightforward descriptive criteria predictive of the histological grade of suspected lesions visualized during high-resolution anoscopy.
Patients and Methods : This prospective study was conducted from November 2010 through March 2012. All consecutive patients who underwent biopsies for at least one suspicious lesion of anal intraepithelial neoplasia during a high resolution anoscopy were included. The characteristics of the anal lesions (limits, relief, staining with acetic acid and lugol, aspect of epithelium, and vascularization) detected during high-resolution anoscopy performed by senior proctologists were compared with histology.
Results : 168 suspicious anal lesions were biopsied and analyzed in 103 patients (68% men, mean age [±SD] 49.8 years [±9]). 57.3% had HIV positive status. According to histology, 41.6% of the lesions were high grade, 34.6% low-grade, and 23.8% had no-dysplasia including 11.9% normal samples. Lesions with irregular epithelium (or irregular vascularization) were 2 times more likely to be high-grade lesions than those with a regular epithelium (or regular vascularization). 41.4% of high-grade lesions had a flat surface (vs. 17.2% for low-grade). The rates of acid acetic induced whitening were 91.4% and 94.8% for high grade and low-grade lesions, respectively (vs. 70% for non-dysplasic samples). 62.9% of high-grade lesions did not stain under Lugol’s solution (vs. 31% of low-grade). The positive predictive value of the combination of these simple morphological criteria was 68.6%.
Conclusions : Several simple morphological criteria significantly associated with high-grade anal intraepithelial neoplasia are found less often in low-grade lesions. Combining morphological criteria provides a satisfactory positive predictive value for guiding high-resolution anoscopy biopsies.