Paraneoplastic isolated myelopathy: clinical course and neuroimaging clues.

OBJECTIVE: To report the clinical phenotype and outcome of isolated paraneoplastic myelopathy.
METHODS: We systematically reviewed clinical, serologic, and MRI data for 31 patients (20 female) who presented with an isolated myelopathy and coexisting cancer: carcinoma (lung, 9; breast, 7; kidney, 2; thyroid, 2; ovary/endometrium, 2), melanoma (2), or other cancer (3), or a paraneoplastic autoantibody with strong cancer association (amphiphysin-immunoglobulin G [IgG], 9; collapsin response-mediator protein 5-IgG, 9; Purkinje-cell cytoplasmic autoantibody type 1, 2; antineuronal nuclear autoantibody [ANNA]-1, 1; ANNA-3, 1).
RESULTS: Of 31 patients who presented with a progressive myelopathy, symptom onset was subacute in 16 (52%). The median age was 62 years. CSF abnormalities included elevated protein (>45 mg/dL), 22; pleocytosis, 15; excess oligoclonal bands (normal <4), 7. MRI cord abnormalities identified in 20 patients were longitudinally extensive (>3 vertebral segments), 14; symmetric tract or gray matter-specific signal abnormality, 15 (enhancing in 13). Myelopathy preceded cancer diagnosis in 18 patients (median interval 12 months; range 2-44). After myelopathy onset, 26 patients underwent oncologic treatment, immunosuppressive treatment (median delay to commencing immunotherapy 9.5 months [range 1-54]), or both; only 8 improved (31%). At last neurologic evaluation (median interval after onset 17 months; range 1-165 months), 16 patients (52%) were wheelchair-dependent (median time from onset to wheelchair 9 months [range 1-21]). Ten patients died after a median of 38 months from symptom onset (range 7-152).
CONCLUSION: Symmetric, longitudinally extensive tract or gray matter-specific changes on spinal MRI should raise suspicion for a paraneoplastic myelopathy. Resulting disability is often severe. Only a minority of patients improve with treatment.