To present a case of secondary neurolymphomatosis (SNL) that occurred after 11 years of remission of B-cell CNS lymphoma.

Neurolymphomatosis (NL) is a rare condition characterized by infiltration of peripheral nerves by aggressive non-Hodgkin lymphoma. Progressive painful polyneuropathy, radiculopathy or multiple mononeuropathy can be patients’ initial presenting symptom (primary NL) or signify a relapse in their disease (SNL). SNL has been previously noted to occur after a median of 1-2 years after the onset of lymphoma, usually with systemic involvement.

Case report

A 74-year-old male with a past medical history of CNS lymphoma 11 years prior presented with a four-year history of numbness, tingling, and weakness of his bilateral lower extremities. MRI and CT scans were negative. CSF analysis showed elevated protein. EMG revealed chronic active demyelinating neuropathy with axon loss. A sural nerve biopsy showed perivascular, endoneurium, sub-perineurium lymphocytic infiltrate with cytological atypia. Muscle biopsy had large lymphoid cells with atypia involving the nerve sheath. Repeat PET scan showed no evidence of relapses in the other organ systems. Patient was diagnosed with neurolymphomatosis and subsequently referred to his oncologist for additional work-up and treatment. Upon follow-up, a year later, patient had significant improvement of his neurologic condition.

Neurolymphomatosis remains a differential diagnosis in patients with a past medical history of non-Hodgkin lymphoma presenting with progressive neuropathy symptoms despite remission of greater than 10 years. Establishing a diagnosis could lead to early detection of relapse and better prognosis.