Human papillomavirus-related squamous cell carcinoma of the anal canal with papillary features

Figure 1 Biopsy of anal mass showing a squamous cell carcinoma with prominent papillary features (HE, × 100).

Figure 2 Higher power view of the papillary structures and associated anal intraepithelial neoplasia 3 (carcinoma-situ) (HE, × 200).

Figure 3 p-16 immunohistochemical stain showing strong and diffuse positive reaction of the tumor cells (× 100).

Figure 4 In-situ hybridization for high risk types of human papillomavirus showing a strong and diffuse reaction of the epithelial tumor cells (× 200).