Primary neurolymphomatosis with MAG antibody: a case report.

Neurolymphomatosis (NL) is a rare neurologic manifestation of non-Hodgkin lymphoma (NHL) with poor prognosis. Investigations including MRI, PET/CT, nerve biopsy and cerebrospinal fluid (CSF) analysis can aid the diagnosis of NL. In this study, we presented a case of NL with co-existing myelin-associated glycoprotein (MAG) antibody. The patient first presented with symptoms of peripheral neuropathy involving multiple cranial nerves and cauda equina, and later developed obstructive hydrocephalus and deep matter lesions. He also had persistently positive MAG antibody, but did not develop electrophysiologically proven neuropathy and monoclonal immunoglobulin. The final brain biopsy confirmed diffuse large B cell lymphoma.