Perianal extramammary Paget's disease.

Perianal extramammary Paget's disease is a rare disorder of unknown aetiology and is frequently associated with malignancy. Since Sir James Paget's original description, extramammary Paget's disease has been surrounded by controversy, speculation and much interest on the part of surgeons, pathologists and dermatologists. This case report draws attention to this rare condition, which should be considered in the differential diagnosis of perianal disorders. The physician must maintain a high index of suspicion, especially in cases with characteristic lesions unresponsive to conventional dermatological therapy. The importance of awareness of the condition is stressed and the diagnosis and treatment are commented upon. Treatment and prognosis depend on the presence of an underlying invasive carcinoma. An adequate initial evaluation and long-term follow up are necessary to identify recurrence and development of other malignancies.