Neurolymphomatosis associated with muscle and cerebral involvement caused by natural killer cell lymphoma: a case report and review of literature.

We report a biopsy-proven case of neurolymphomatosis (NL) presenting with sensory motor axonal polyneuropathy, polymyositis, and cerebral involvement. Ours is the second reported case of NL caused by natural killer-cell lymphoma defined by morphology and immunophenotyping. For 3 months, the patient developed stocking-glove distribution of hypesthesia, subacute progressive weakness and mental deterioration. EMG showed severe sensorimotor mixed axonal-demyelinating polyradiculoneuropathy. Lumbar puncture revealed mildly high protein level with normal glucose and cell count. Sural nerve biopsy demonstrated lymphomatous axonal neuropathy and muscle biopsy was indicative of lymphomatous polymyositis. Brain MRI revealed multiple white matter lesions, consistent either with progressive multifocal leukoencephalopathy or cerebral lymphoma. Bone marrow biopsy showed neoplastic infiltrates. The patient died of multiple organ failure prior to initiation of chemotherapy.