Primary intramedullary spinal cord lymphoma is rare, comprising less than 1% of CNS lymphoma. Prior case series showed a median delay in diagnosis of 8 months. 87% of cases were B-cell in origin, and 57% cases had lower spinal cord involvement. 

A 70-year-old man presented with neck pain, bilateral lower extremity numbness and weakness. MRI demonstrated two enhancing lesions (C2, pontomedullary junction). His symptoms resolved on Dexamethasone, but recurred with steroid taper. Serum and CSF were negative for autoimmune, neoplastic, and paraneoplastic etiology. Three months later, PET scan revealed a persistent hypermetabolic lesion in the cervical cord. Repeat large volume LP had negative cytology/flow cytometry. Two weeks later, he was re-admitted with recurrent weakness and hypoxia. MRI showed a longitudinal enhancing lesion in the cervical cord. Given the location, lack of constitutional symptoms, and two negative cytology results, a biopsy was not pursued. Within 48 hours, the patient became quadriplegic requiring intubation. Biopsy 19 days later confirmed Diffuse Large B-Cell Lymphoma. He was emergently started on radiation with no symptom improvement.

Primary intramedullary spinal cord lymphoma is an uncommon etiology of myelopathy and a rare presentation of CNS lymphoma, particularly in the cervical cord. Delay in diagnosis is common, but in this case, resulted in full quadriplegia. CSF cytology can be diagnostic, and while addition of flow cytometry enhances specificity, steroids may decrease sensitivity. Newer CSF testing such as micro-RNA and antithrombin III levels may be useful, yet availability of testing is limited and biopsy remains the gold standard. While the cervical cord is understandably a risky surgical target, a negative autoimmune workup and an enhancing expansile mass with PET positivity merit prompt consideration of malignancy and biopsy.