In 1874, Sir James Paget first described Paget disease of the nipple, also known as mammary Paget disease. In 1889, extramammary Paget disease (EMPD) of the scrotum and penis was identified. Although mammary and extramammary Paget disease are both characterized by epidermal Paget cells and share a similar clinical presentation, their uniqueness lies in anatomical location and histogenesis. EMPD presents as an erythematous plaque on apocrine gland bearing areas (i.e. vulva, perineum, perianal region, scrotum, and penis) in older men and women. It can be a focal, multifocal, or an ectopic process. Immunohistochemical staining allows for differentiation between primary and secondary EMPD in addition to the many other disease entities that clinically resemble this malignancy. When diagnosing a patient with EMPD, a full history and physical should be performed given the possibility of an underlying malignancy. Surgical excision currently is first line therapy and the prognosis is often favorable. Recent advances within the field have examined the expression of chemokine receptors within tumors, which may be applicable in determining prognosis. This review addresses the history, epidemiology, pathogenesis, clinical presentation, histopathology, differential diagnosis, diagnosis, management, and new observations with respect to extramammary Paget disease.
Introduction
Sir James Paget first described mammary Paget disease (MPD) in 1874 [1]. Paget noted a patient with a chronic eczematous disease on the skin of the nipple and areola that was associated with an intraductal carcinoma of the underlying mammary gland. MPD is a rare disease that corresponds to 1-4.3% of all breast cancers and is often associated with intraductal, in situ, or invasive neoplasms [2]. It typically affects postmenopausal women after the sixthdecade of life, but can be seen in adolescent and elderly patients [3]. Involvement of the male breast is rarely reported. Patients with Paget disease frequently present with an insidious eczematoid, lichenified, moist, or crusted plaque beginning on the nipple and extending to the areola and surrounding skin [2].