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Medical Science Monitor Basic Research


A Spontaneous Regression of an Isolated Lymph Node Metastasis from a Primary Unknown Merkel Cell Carcinoma in a Patient with an Idiopathic Hyper-Eosinophilic Syndrome

Unusual clinical course

Raffaele Longo, Oana Balasanu, Mathilde Chastenet de Castaing, Eric Chatelain, Mohammed Yacoubi, Marco Campitiello, Nathalie Marcon, Francesca Plastino

France Division of Medical Oncology, Centre Hospitalier Régional (CHR) Metz-Thionville, Ars-Laquenexy, France

Am J Case Rep 2018; 19:1437-1440

DOI: 10.12659/AJCR.911840

Available online: 2018-12-04

Published: 2018-12-04


BACKGROUND: Merkel cell carcinoma (MCC) is a rare, aggressive primary cutaneous neuroendocrine tumor frequently associated with Merkel cell polyomavirus infection. Despite its aggressiveness, a few reports of spontaneous MCC regression have been described in the literature, most of them following incisional biopsy supporting a hypothetical role of surgery-induced inflammation in the process of regression.
CASE REPORT: We report a case of 69-year-old Caucasian male who was followed for an idiopathic hyper-eosinophilic syndrome. A positron emission tomography (PET) scan documented a hyper-metabolic, left, inguinal adenopathy, histologically corresponding to a metastasis of a poorly differentiated neuroendocrine carcinoma. This lesion spontaneously regressed at clinical examination and radiological imaging. After its excisional dissection, histology was negative. Five months later, a nearby adenopathy reappeared. The patient underwent another excisional biopsy. Histology and immunohistochemistry were compatible with a lymph node metastasis of a MCC. As the patient refused radical surgery, a regional radiotherapy was performed. As of a follow-up at 10 months, he was alive and free of tumor recurrence. The hyper-eosinophilic syndrome was stable; however, the serum levels of chromogranin-A were inexplicably elevated in the absence of any tumor evidence at the PET scan.
CONCLUSIONS: The particularity of this case relies on the rarity of MCC complete spontaneous regression in a patient without a primary tumor and with a synchronous, idiopathic hyper-eosinophilic syndrome.

Keywords: Carcinoma, Merkel Cell, Neoplasm Regression, Spontaneous, Polyomavirus