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Merkel cell carcinoma arising in association with cutaneous T‐cell lymphoma: A potential diagnostic pitfall
Author(s) -
Zoumberos Nicholas A.,
McMullen Emily,
Wang Lisha,
Wang Xiaoming,
Harms Kelly L.,
Tejasvi Trilokraj,
Chan May P.,
Fullen Douglas R.,
Hristov Alexandra C.,
Harms Paul W.
Publication year - 2019
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.13404
Subject(s) - mycosis fungoides , merkel cell carcinoma , merkel cell , medicine , pathology , lymphoma , population , biopsy , merkel cell polyomavirus , peripheral t cell lymphoma , skin biopsy , dermatology , carcinoma , t cell , immunology , immune system , environmental health
Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous neuroendocrine carcinoma with increased prevalence in patients with immunosuppression or B‐cell neoplasms. To the best of our knowledge, an association with cutaneous T‐cell lymphoma (CTCL) has not been previously described. In this report, we present two cases of MCC arising in the setting of CTCL. The first case was a female during her 70s with previously diagnosed stage IVA1 Sezary syndrome. Biopsy of a scaly patch showed two distinct abnormal cell populations. The first population consisted of hyperchromatic dermal and epidermotropic lymphocytes, expressing CD3 and CD4 with diminished CD7. The second population consisted of intraepidermal clusters of larger atypical cells that expressed synaptophysin, neurofilament, CK20, and Merkel cell polyomavirus transcript. The combination of findings was consistent with intraepidermal MCC in a background of CTCL. Excision showed residual intraepidermal MCC without dermal involvement. The second case was a male during his 50s with a longstanding history of mycosis fungoides, who presented with a new lesion on his right thigh. Biopsy and excision showed dermal MCC without secondary involvement by CTCL. Our cases show that MCC may rarely occur in the setting of T‐cell lymphoma, and that intraepidermal MCC may mimic epidermotropic T‐cells.