Definition, Association with Malignancy, Biologic Behavior, and Treatment of Ectopic Extramammary Paget's Disease: A Review of the Literature.

Extramammary Paget's disease (EMPD) is a rare neoplasm that affects apocrine gland-bearing skin. Patients usually present with a long-standing, unilateral, ill-defined, erythematous, crusted patch or plaque. In certain cases, this disease can be associated with internal malignancy. EMPD arising in anatomic areas devoid of apocrine glands is exceedingly rare and is termed (E-EMPD). We discuss the classification, origin, and management of E-EMPD. We reviewed the literature and herein discuss the reported cases of true E-EMPD. Forty-five cases of E-EMPD disease were identified in the literature. The etiology and pathophysiology are largely unknown. Based on there only being one reported case of lymph node metastasis and associated underlying malignancy identified, compared to EMPD, ectopic lesions appear to be less aggressive. Various treatment options have been reported, with surgical removal being the preferred method of treatment. E-EMPD is a rare neoplasm that manifests in areas without apocrine glands. With adequate formal data unavailable, the authors recommend that a diagnosis of E-EMPD warrants a focused malignancy screening. Surgical excision is the most common first-line treatment. Further research is needed regarding the etiology, biologic behavior, and treatment of E-EMPD.