Basal Cell Carcinoma of the Anal Margin

Definition

Basal cell carcinoma of the anal margin is a malignant epithelial neoplasm. It consists of basaloid cells, and on microscopic examination, it is similar to conventional basal cell carcinoma of the skin (Gibson and Ahmed 2001).

The etiology of this tumor is unknown, but there is neither an evidence for a role of infection by HPV nor a role of ultraviolet radiation, unlike other basal cell carcinoma occurring in the sun-exposed skin. Some patients have a history of radiotherapy in the pelvic area. For some authors, the occurrence of this tumor could be favored by chronic skin irritation or a local trauma.

Clinical Features

Patients present with a perianal ulcerated tumor and complain of itching or local irritation. Some physicians sometimes initially misdiagnose these cancers as inflammatory or infectious skin lesions. Some patients have multiple basal cell carcinomas at other anatomic sites and the diagnosis of basal cell carcinoma of the anal margin should prompt an...