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In‐transit recurrence of Merkel cell carcinoma associated with Bowen's disease: The first reported case successfully treated by avelumab
Author(s) -
Kiyohara Takahiro,
Shijimaya Takako,
Miyamoto Mari,
Nagano Naoko,
Nakamaru Sei,
Makimura Kaoru,
Tanimura Hirotsugu
Publication year - 2019
Publication title -
the journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 65
eISSN - 1346-8138
pISSN - 0385-2407
DOI - 10.1111/1346-8138.14829
Subject(s) - merkel cell , merkel cell carcinoma , pathology , nodule (geology) , cytokeratin , medicine , lymph node , carcinoma , biology , immunohistochemistry , paleontology
A 65‐year‐old Japanese man presented with a dome‐shaped nodule, the base of which was contiguous with a dull brown plaque, on the left leg. After local excision of the cutaneous lesion and left inguinal lymph node dissection, several dermal and subcutaneous nodules developed successively on the left lower extremity. Hematoxylin–eosin staining of the primary cutaneous lesion demonstrated uniform neoplastic cells arranged in a trabecular pattern extending from the dermis to subcutis. Mitotic figures were abundant. Although the overlying epidermis was substantially intact, the Merkel cells had invaded the epidermis, resulting in Pautrier‐like microabscesses. The hyperplastic epidermis adjacent to the nodule consisted of abnormally growing atypical keratinocytes. The enlarged left inguinal lymph node and successive secondary nodules contained Merkel cells similar to those in the primary nodule. Immunohistochemically, most tumor cells were positive for CAM 5.2, synaptophysin, chromogranin A, CD 56 and vimentin. The tumor cells in the left inguinal lymph node were positive for CAM 5.2, synaptophysin and cytokeratin 20 but negative for CM 2B4, and less than 1% of the cells expressed programmed cell death ligand 1. The patient was treated with avelumab, which showed significant efficacy against the in‐transit recurrence. Two months later, all nodules had disappeared completely. We describe a case of in‐transit recurrence of Merkel cell carcinoma that was associated histologically with Bowen's disease and was successfully treated with avelumab. Although accumulation of additional cases is needed, avelumab therapy may be a useful treatment for in‐transit recurrence of Merkel cell carcinoma.