Intradural extramedullary cervical metastasis from Merkel cell carcinoma: a case report and literature review

BACKGROUND: Merkel cell carcinoma (MCC) is a rare aggressive primary skin carcinoma with an incidence of 44 cases per 100,000. The natural course of MCC often results in rapid growth and early metastasis. On the other hand, the spinal cord is rarely affected and frequently features the end stage of the disease. The aim of this paper was to clarify the management of patients with spine metastasis from a skin lesion and showed a case-based update. CASE PRESENTATION: A 73-year-old female was admitted to the Neurosurgical Department in December 2021 for a sudden right hemiparesis with bladder dysfunction and a history of cutaneous Merkel cell carcinoma. A magnetic resonance imaging (MRI) of the central nervous system (CNS) showed an intradural-extramedullary right-sided C6–C7 tumor with mass effect and edema of the cervical cord. The patient underwent a C6–C7 laminectomy with microsurgical total resection of the intradural extramedullary lesion. The neuropathological examination identified a metastasis from Merkel cell carcinoma. Nowadays, evidence for spinal metastasis from malignities skin cancer is generally lacking, probably because they are extremely rare. The exact time of life expectancy is controversial, and some clinicians use a cutoff of 3 months to determine whether surgical intervention should be offered, while others advocate at least 6 months of life expectancy. CONCLUSIONS: To the best of our knowledge, we showed the first case of solitary intradural extramedullary cervical spine metastasis from MCC. We recommend to consider metastasis of MCC in the differential diagnosis of spinal metastasis.