Demyelinating Neuropathy Due to Intravascular Large B-cell Lymphoma.

We herein report the case of a 67-year-old man who presented with the acute onset of limb weakness. Brain magnetic resonance imaging revealed multiple abnormal-signal-intensity lesions. Steroids were administered, and the patient initially responded. Nerve conduction testing findings were consistent with demyelinating polyneuropathy. A sural nerve biopsy specimen revealed fascicles with extensive onion-bulb formation. Although skin and sural nerve biopsies showed no atypical cellular infiltration, the histopathological diagnosis of intravascular large B-cell lymphoma was obtained by a brain biopsy. The neuropathy in this patient may be attributed to a demyelinating process independent of ischemic damage by lymphoma.