Pathologically Confirmed Subcutaneous Fat and Lymphovascular Invasion of a Hypopigmented Area in Extramammary Paget Disease

Extramammary Paget disease (EMPD) is a rare adenocarcinoma that usually occurs in areas of the body that are rich in apocrine sweat glands. Great depth of tumor invasion is a well-known risk factor for worse prognosis. Paget cells usually are limited to the epidermis, whereas invasive EMPD, which infiltrates the dermis, is relatively rare. It is even rarer for the tumor to spread beyond the dermis. Only 3.1% of patients with EMPD of the penis and scrotum have exhibited infiltration of the subcutaneous fat layer. We report a case of a 62-year-old male with EMPD that invaded the subcutaneous fat layer. He presented with a several-year history of a slowly expanding erythematous plaque with the hypopigmented area on the left penoscrotum. One month before presentation, the patient had undergone punch biopsy at another hospital and diagnosed with EMPD. He had no personal history of urogenital cancers. The patient was treated with Mohs micrographic surgery, and negative margins were achieved after four stages. The histopathologic findings revealed Paget cells scattered throughout the epidermis. At the hypopigmented area, Paget cells extended to the subcutaneous fat layer with lymphovascular invasion. There was no evidence of recurrence at seven months postoperatively. Herein, we describe a case of hypopigmented EMPD that infiltrated the subcutaneous layer, which rarely has been reported in Korea.