Two cases of perianal basal cell carcinoma were reported. Less than 100 cases have been so far described. The first case was a pigmented tumour, in the second an erosive erythematous plaque somewhat similar to Paget's disease. Basal cell carcinoma of the anal margin is about 15-fold less common than squamous cell carcinoma. The tumour is often ulcerated, sometimes infiltrative but metastasis never occurs.
Histopathological findings are often close to what is observed in cloacogenic carcinoma.
Surgical resection of the lesion is the best treatment but electrontherapy permitted lesion healing in one of our cases. Grossly, the masses were nodular, fungiform or ulcerated. Histologically, pleomorphic tumor cells mixed together giving a feature somewhat like either carcinomatoid or sarcomatoid, with a predominance of one kind of the malignant cells. Histopathologic observation supported the idea that this tumor developed from the melanocytes and nevus cells located at the basal layer of the epithelium. Immunohistochemistry proved that melanocytes originated from the neural crest.