Extramammary Paget Disease of the Scrotum: A Contemporary Clinicopathologic Analysis of 20 Cases in the United States.

Extramammary Paget disease (EMPD) often involves apocrine gland-bearing locations including vulva and perianal area. EMPD of the scrotum is rare. Twenty patients were identified from the pathology files of 4 institutions between 2000 and 2018. Patients were 63- to 87-year-old (mean: 73 y) with a history of symptoms of between 4 months and 10 years. Two patients had a history of prostate cancer. Follow-up was available in 11 patients for a median of 71 months (range: 8 to 126 mo). Nine of 11 patients (82%) had positive margins, and 73% required reexcisions. Three patients had a focal dermal invasion, 1 of whom reportedly died of another etiology 25 months post diagnosis and 2 were disease-free at 24 and 68 months. No patient had inguinal lymphadenopathy. Two patients were alive with disease. Immunohistochemically, GATA3 and GCDFP15 were expressed in 6/6 cases, CK7 in 8/8 cases, and androgen receptor in 13/13 cases. HER2 was positive in 5/12 cases. PSA was positive in 1 patient who had a history of prostate cancer, whereas other prostate markers (NKX3.1 and prostein) were negative, and CK7 and GCDFP15 were positive, rendering primary EMPD diagnosis. Twelve other cases were negative for PSA and NKX3.1. In conclusion, EMPD of the scrotum has an insidious onset and its nonspecific symptoms can be misdiagnosed as dermatitis or fungal infection. Although localized EMPD has a favorable prognosis, the invasive disease is rare and did not predict metastasis or progression. Margins are frequently positive requiring reexcision. Occasionally, cases can be positive for PSA leading to diagnostic pitfalls.