A rare clinical case of diagnosis and treatment of metastases of Merkel carcinoma in the right inguinal lymph nodes without an identified primary focus

Introduction. Merkel’s carcinoma is a neuroendocrine malignant epithelial skin tumor, rapidly progressive, prone to local recurrence and metastasis to regional lymph nodes and internal organs. The etiology and pathogenesis of Merkel’s carcinoma are still an insufficiently studied issue. Because of its rare occurrence, only single observations of Merkel’s carcinoma metastasis without an identified primary focus, most often with regional lymph node involvement, have been described in the world literature.Clinical case. This article presents a clinical case of metastatic lesion of inguinal lymph nodes with microinvasion into femoral artery in Merkel’s carcinoma without identified primary focus. After a comprehensive examination and onco-consilium the patient underwent surgical treatment in the scope of cytoreductive excision of the inguinal lymph node conglomerate on the right side and artery prosthesis with an autovenous graft. According to the routine postoperative pathomorphologic and immunohistochemical studies, the diagnosis of Merkel’s carcinoma metastasis was finally confirmed.Conclusion. Identification and description of such clinical cases are practically significant and can serve for formation of certain algorithms for treatment of Merkel’s carcinoma both with local manifestations and in progressive forms. Patients with Merkel’s carcinoma should be discussed in oncological consiliums, as treatment may include surgical stage, including biopsy of sentinel lymph nodes, adjuvant radiotherapy, chemotherapy and immunotherapy in case of tumor dissemination.