Solitary plasmacytoma presenting as an intramedullary mass of the cervical cord

Extramedullary plasmacytomas originating in the spinal cord are extremely rare lesions. We report a 52-year-old man presenting with progressive tetraparesis. Spinal magnetic resonance imaging (MRI) showed an ill-defined contrast-enhancing intramedullary mass at the C5-6 level. After a biopsy was taken, pathology including immunohistochemistry revealed plasmacytoma. Complete workup for multiple myeloma was negative. The patient was treated with intravenous chemotherapy followed by radiotherapy and corticosteroids without any improvement of the clinical symptoms or decreased tumor size on the follow-up MRIs. The most common spinal manifestation of plasmocytoma is involvement of the vertebral bodies leading to extradural compression of the cord. Only rarely plasmocytoma manifests itself as a primarily dural lesion leading to an intradural cord compression. This report describes the extremely rare manifestation of plasmocytoma of the spinal cord itself that therefore should be considered in the differential diagnosis of spinal cord mass lesions.