Extramammary Paget's disease is a rare cutaneous adenocarcinoma, usually of epidermal origin and glandular differentiation and frequently associated with an underlying adnexal carcinoma and perhaps with underlying internal malignancy. One hundred ninety-seven cases of extramammary Paget's disease (196 cases reported in the English literature from 1962 to 1982 and one case of my own) are reviewed. It remains a rare cutaneous malignancy that occurs primarily in elderly people. It is seen more frequently in women than in men and occurs predominantly in vulvar and perianal locations. Twenty-six percent of patients with this disease will ultimately die of it or an associated internal malignancy. Twenty-four percent of patients with the disease have an associated underlying cutaneous adnexal adenocarcinoma. These patients have a higher mortality rate--46%--than patients with extramammary Paget's disease without underlying cutaneous adnexal adenocarcinoma. Twelve percent of patients with extramammary Paget's disease have an associated concurrent underlying internal malignancy. The location of the underlying internal malignancy appears to be closely related to the location of the extramammary Paget's disease--i.e., a perianal location is associated with adenocarcinoma of the digestive system, a penile-scrotal-groin location with genitourinary malignancy, etc. A directed internal malignancy search may be of benefit in patients who are diagnosed as having extramammary Paget's disease.