Case history on Epstein-Barr Virus-associated smooth muscle tumor (EBV-SMT) of cranio-cervical junction in an immunocompetent patient.

Epstein-Barr virus-associated smooth muscle tumor (EBV-SMT) is a rare mesenchymal tumor that almost exclusively occurs in immunocompromised hosts. Here, we report a 75-year-old Taiwanese woman without definite immune-deficient history presenting with progressive occipital neuralgia, low cranial nerve deficits (CN9-12) and cervical (C1-C5) radiculopathy. Magnetic resonance imaging revealed a 4.5*4.0*6.7 cm infiltrating mass occupying posterior skull base and C1-C2 vertebra and C1-5 epidural extension with bone destruction and vertebral artery (VA) encasement. There was also a synchronous 2.7 cm tonsillar tumor. A two-stage operation for cranio-cervical tumor excision and stabilization was performed. Tumor was confirmed directly arising from VA intraoperatively. Pathology reported a spindle cell neoplasm and the diagnosis of EBV-SMT was confirmed by EBER (EBV-encoded small RNA) in situ hybridization. An immune survey and reconstruction should be conducted for patient with EBV-SMT. A near-total resection of tumor may be beneficial for local control, however, the role of surgical resection in treating CNS EBV-SMT remains to be determined.