We present a 21-year-old homosexual male with no pathological history of interest, who was referred to the gastroenterology department for "anal pruritus of 9 months' duration resistant to the usual treatment". During this time, his doctor had prescribed local treatment with various corticoid creams and hygienic-dietary measures without improvement. Anal examination revealed the presence of a pigmented lesion with slightly verrucous borders in the posterior perianal region. Rectal examination and anuscopy were normal.

A skin biopsy was performed and histology revealed the presence of hyperkeratosis and parakeratosis with altered cell maturation, affecting the entire thickness of the dermis. This was compatible with bowenoid papillomatosis (anal intraepithelial neoplasia grade 1). Antibodies to human immunodeficiency virus (HIV) were negative and other immunodeficiencies were ruled out.

