Anogenital malignancies and pre-malignancies.

Anogenital pre-malignancies and malignancies are frequently encountered. Aetiopathogenetically, human papillomavirus (HPV) infection plays a critical role. However, there is a variable degree of association of HPV infection with the development of anogenital malignancies. In this context, the high level of clinically unapparent HPV infection should be considered. Therefore, the question arises if the association with HPV is always causative. Besides HPV, pre-existent lichen sclerosus is also an important aetiopathologic factor in the development of anogenital malignancies. Common anogenital pre-malignancies comprise Bowen's disease (BD), Bowenoid papulosis (BP) and erythroplasia of Queyrat (EQ). From a clinical point of view, these are clearly different entities, but from a histopathological point of view, BD, BP and EQ are indistinguishable. They all represent forms of squamous intraepithelial neoplasia (IN). Intraepithelial neoplasia (IN) is not only restricted to squamous variants, but also includes non-squamous IN, Paget's disease (PD) and melanoma in situ. The risk of developing anogenital (pre)malignancies or other tumours is higher in immunocompromised and immunodeficient patients, in particular those suffering from human immunodeficiency virus (HIV) infection. Such risk factors will affect treatment and follow-up modalities. Regarding prophylactic measures, a relatively recent but very important development is the availability of HPV vaccination on a large scale. Momentarily, the effects of such vaccination, on a population-based scale, are not yet clear but will become apparent in the near future. Management of anogenital pre-malignancies and malignancies should be tailor-made and may be organized in a multidisciplinary fashion.