[Verrucous carcinoma of the anal margin. The importance of adequate biopsy technique].

Buschke-Löwenstein tumor (verrucous carcinoma, giant condylomata) of the anal margin is a locally invasive, destructively growing carcinoma that does not metastasize. The lesions are rare despite the increased incidence of anal condylomata and anal carcinomas. Authors report a case of a 63-year-old woman suffering from verrucous carcinoma (Buschke-Löwenstein tumor) of the anal margin. The tumor invaded the rectal sphincter and extended beyond the muscle, infiltrating the lower abdomen. Infiltration of the perivesical soft tissue caused bilateral hydronephros. Because both under- and overdiagnosis of anal cancer and precancer may lead to inappropriate treatment, it is important to perform adequate sampling for histology. Non-representative superficial biopsies may result underdiagnosis of the disease.