HPV-driven anal neoplasia: review and recent developments.

A host of human papillomavirus (HPV)-associated squamous and glandular lesions may be identified in the anal canal in men and women. Given their relative rarity, familiarity with the morphological spectrum associated with HPV-driven anal neoplasia is important for proper identification and diagnosis. In this article, we review the classification and basic histopathological features of HPV-related squamous intraepithelial and invasive lesions as well as associated pitfalls. In addition, we provide an update on recently described HPV-driven, non-squamous tumours. As our experience with these lesions evolves, we expect the histological spectrum to further expand, particularly as it relates to non-squamous HPV-driven neoplasia.