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S‐100 protein and SOX10 ‐positive breast carcinoma mimicking metastatic melanoma
Author(s) -
Newman John,
Brahmbhatt Meera,
Stoff Benjamin K.,
Martinez Anthony P.
Publication year - 2020
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.13822
Subject(s) - medicine , immunohistochemistry , pathology , melanoma , axilla , mammaglobin , biopsy , breast carcinoma , sentinel lymph node , gata3 , breast cancer , cancer , cancer research , biology , biochemistry , transcription factor , gene
We present a case detailing a 70‐year‐old female with a history of triple‐negative breast carcinoma (TNBC) of the left breast and contralateral stage pT2a nodular melanoma of the right upper arm who underwent sentinel lymph node biopsy of the right axilla demonstrating a metastatic epithelioid tumor that was strongly positive for S‐100 protein and SOX10. The tumor cells were negative for HMB‐45 and Melan‐A and positive for CK7 and other breast markers (GCDFP15, mammaglobin, and GATA3). While concerning for metastatic melanoma based on clinical history and initial immunohistochemistry, tumor morphology and subsequent immunohistochemistry was supportive of metastatic breast adenocarcinoma. This case demonstrates a rare but perilous diagnostic pitfall of triple‐negative breast carcinomas that strongly and diffusely express S‐100 protein and SOX10 mimicking melanoma.