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

Abstract

Patient: Male, 69Final Diagnosis: Spontaneous regression of a Lymph node metastasisSymptoms: Hypereosinophilia • inguinal massMedication: —Clinical Procedure: —Specialty: OncologyObjective:Unusual clinical courseBackground: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.

Bone marrow metastatic neuroendocrine carcinoma with unknown primary site: A case report and review of the literature

“…With regard to NENs, SR of the tumor has been reported in Merkel cell carcinoma (MCC), bile duct NET, and both lung and gastric large-cell NECs[ 23 - 26 ]. Longo et al [ 27 ] reported a case of inguinal lymphadenopathy histologically corresponding to MCC. The lesion later spontaneously regressed and histopathological examination showed negative results.…”

Spontaneous Regression of Merkel Cell Carcinoma: Case Report

“…International Medical Case Reports Journal 2021:14 714 metastatic lymph nodes and after withdrawal of immunosuppression. 24,25 We have reviewed and summarized published literature on complete spontaneous regression from 2017 onwards (added to 34 cases reviewed by Guiote et al in 2017) 26 (Table 1). Now over 50 cases of spontaneous regression of MCC have been published, mostly in elderly women.…”

Cytokeratin-20 negative nodal Merkel cell carcinoma with regressed primary: a potential pitfall in interpretation of nodal metastasis

“…al in 1986 [6], with around 60 additional cases reported since then [7][8][9][10][11][12]. Spontaneous regression could explain the reported cases of MCC involving lymph nodes without a primary skin tumor [13][14][15][16][17]. Nodal MCC of unknown primary (NMCUP) can be misinterpreted on histological examination as metastasis from other neuroendocrine carcinomas such as small cell carcinoma.…”