Extramammary Paget’s Disease
Extramammary Paget’s disease is a rare cutaneous adenocarcinoma that occurs in elderly women more often than in men and is located in the vulva, scrotum, axilla, or the perianal area. Various histochemical studies suggest sweat gland etiology of the disease.
Extramammary Paget disease (EMPD) is morphologically and histologically identical to mammary Paget disease of the nipple. It involves the genital and perianal skin, and other cutaneous sites rich in apocrine glands.
EMPD may evolve from two different sites. EMPD most often arises as a primary cutaneous adenocarcinoma. The epidermis is infiltrated with tumor cells showing glandular differentiation. These cancer cells originate from apocrine gland ducts or from keratinocytic stem cells.
The disease may be associated with an underlying adenocarcinoma or carcinoma of the rectum, and 26% of affected patients ultimately die either from the disease itself or from an associated internal malignancy. The location of the underlying internal malignancy is closely related to the location of the cutaneous disease; that is, a perianal location is associated with adenocarcinoma of the digestive system and a penile location is associated with genitourinary malignancy. Extramammary Paget’s disease should be viewed as a cutaneous malignancy that aides in the diagnosis of internal adenocarcinoma.