AUTHOR=Rao Shijia , Wang Alun , Liu Wei , Yin Hongling , Li Ji , Tsang Lemuel Shui-Lun , Wu Yuhui , Shi Wei 

TITLE=Mammary Paget Disease With Melanocytic Proliferation Mimicking Malignant Melanoma in situ: A Case Report

JOURNAL=Frontiers in Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.839954

DOI=10.3389/fmed.2022.839954

ISSN=2296-858X

ABSTRACT=Several cases of pigmented mammary Paget disease (PMPD) mimicking cutaneous malignant melanoma have been reported. In these cases, the tumor cells are colonized by melanocytes, indicated by the presence of a population of melanocytes staining for HMB-45 and S100. Here, we report a case of mammary Paget disease (MPD) which was misdiagnosed as melanoma in-situ due to the interpretation of the staining of melanocytic markers of S-100, Melan-A, and HMB-45. The tumor cells strongly expressed CK7 and GATA3, and a dual labeling showed negative PHH3 labeling for the melanocytes. Pathologists need to be aware of the caveat of colonization of melanocytes in Paget disease.