Polypoid Basal cell carcinoma on the perianal region: a case report and review of the literature.

We report the case of an 88-year-old Japanese woman with polypoid BCC on the perianal region. The basaloid, solid aggregations of BCC were limited to the upper to middle part of the polypoid area. A review of the English and Japanese literature that excluded cases of fibroepithelioma of Pinkus found 21 total cases in which the polypoid BCC could be recognized as a variant of nodular BCC. The following points were used to categorize the lesions: 1) characteristic polypoid appearance that often mimics clinically benign or malignant adnexal neoplasms, melanocytic nevus, or malignant melanoma; 2) the peculiar favorable locations such as scalp (23.8% of the 21 cases), genital area (23.8% of the cases), and back-buttock areas (19% of the cases). These areas suggest that etiologic factors other than ultraviolet radiation exposure are involved in such cases. These characteristic locations may also be the main reason why fibroepithelioma of Pinkus type BCCs frequently manifest with a polypoid appearance, because these types of BCCs also have similar preferred sites such as the back-buttock and genital areas. Polypoid BCCs appear to affect more women than men than do nodular BCCs (7 men and 14 women). Although the polypoid BCCs have a large average size, they are not considered aggressive because the lesions are well-circumscribed and the growth patterns are non-infiltrative.