A case of extramammary Paget’s disease of the anus associated with an apocrine gland carcinoma is described. Concepts regarding the aetiology of these mucin producing cells with their characteristic histological appearance, are outlined. Diagnosis is by biopsy and histochemical studies. Successful treatment, as in Paget’s disease of the breast, depends on early diagnosis and radical surgery. The importance of considering an underlying neoplastic lesion in any chronic eczematous lesion of the perianal skin is stressed.