A Rare Case Of Pigmented Mammary Paget Disease

En Hyung Kim,1,2,* Wonnam Kim,3,* Ji Yeoun Lee1,2 1Department of Dermatology, College of Medicine, Chungbuk National University, Cheongju, Chungbuk, South Korea; 2Department of Dermatology, Chungbuk National University Hospital, Cheongju, Chungbuk, South Korea; 3Division of Pharmacology, School of Korean Medicine, Pusan National University, Yangsan, Republic of Korea*These authors contributed equally to this workCorrespondence: Ji Yeoun Lee, Department of Dermatology, College of Medicine, Chungbuk National University, Chungdae-ro 1, Seowon-Gu, Cheongju, Chungbuk, 28644, South Korea, Tel +82-43-269-6385, Fax +82-43-266-1698, Email [email protected]: Pigmented mammary Paget disease is a rare clinicopathologic variant of mammary Paget disease, which can mimic melanoma. We report a patient who visited the dermatology department complaining of asymptomatic brown-black plaque localized on the left nipple that had been present for 1 year. Histopathology showed large neoplastic epithelial cells with enlarged nuclei and pale cytoplasm, some harboring granular brown melanin pigment. Immunohistochemical studies showed that the intraepidermal pagetoid cells were positive for CK7, ER, and Her2, while mostly lacking immunoreactivity for CK5, SOX10, and HMB45, supporting a diagnosis of MPD. Therefore, physicians should be aware of this rare entity when diagnosing patients with pigmented lesions on the breast area.Keywords: Mammary Paget Disease, malignant melanoma, hyperpigmentation, breast adenocarcinoma