Solitary Cervical Plasmacytoma Presenting as Acute Quadriparesis Following a Recent Cerebral Infarct: A Case Report

Solitary plasmacytoma of bone (SPB) is a rare plasma-cell neoplasm that can cause acute neurological compromise, especially when involving the cervical spine. We report a 59-year-old male with a recent right hemispheric hemorrhagic infarct who developed rapidly progressive quadriparesis and urinary retention 15 days later. Neurological examination showed spastic quadriparesis with a C5 sensory level. MRI and CT revealed a pathological C4-C5 wedge compression fracture with cord compression. Emergency anterior C4-C5 corpectomy with fusion was performed. Intraoperative tissue culture grew Staphylococcus aureus and was treated with vancomycin. Histopathology confirmed a kappa-restricted plasma-cell neoplasm. Bone marrow biopsy showed less than 10% plasma cells, and PET-CT excluded systemic disease, confirming SPB. The patient subsequently received definitive radiotherapy (43.2 Gy in 24 fractions) and physiotherapy, resulting in partial motor recovery. This case highlights that new or worsening neurological deficits in post-stroke patients should prompt urgent spinal imaging to exclude compressive lesions. Early surgical decompression combined with radiotherapy and rehabilitation can preserve function and improve outcomes.