MRI examination of the brain showed bilateral ventral pontine lesions extending into the middle cerebellar peduncles, ventrolateral midbrain and cerebral peduncles as well as bilateral cortical frontal lobe lesions. Also present were intrinsic mixed intensity DWI/ADC lesions of undetermined etiology and extensive subcortical and periventricular white matter hyperintensities. CT angiography of her head and neck showed large vessel intracranial vasculopathy involving the bilateral MCA branches. Conventional angiogram, however, did not show any evidence of angiographic vasculitis. MRI spectroscopy was non-diagnostic. MRI of the neuroaxis showed a small focus of linear non-enhancing hyperintense lesion at the level of C3. EMG demonstrated severe generalized sensory-motor polyneuropathy with severe axonal loss. EEG showed mild to moderate diffuse slowing. CSF evaluation was negative, HCV viral load was undetectable, connective tissue markers (Anti-dsDNA, Anti-SCL70, Anti-CENTR, Anti-RNP, Anti-Smith, Anti-SSA/SSB, ANCA) were negative and the remaining serology was significant for elevated ESR, CRP, low C4 complements, positive anti-AQP4 antibodies titers (1:2560) and positive myelin basic protein. Brain biopsy showed perivascular lymphocytic inflammation, confirming vasculitis. Our patient completed courses of high dose steroids, IVIG and Rituximab with mild improvement in motor strength.

Although an atypical feature of NMO, cryoglobulinemia with production of anti-AQP4 antibodies may, in part, contribute to development of a demyelinating process.