Chronic demyelinating polyneuropathy preceding T-cell lymphoma: differentiation between primary neurolymphomatosis and paraneoplastic neuropathy.

A 49-year-old man presented with progressive asymmetric weakness and pain. Electrodiagnostic tests and nerve biopsy suggested chronic demyelinating polyneuropathy refractory to immune-modulating therapy. The patient's symptoms were aggravated, and he was finally diagnosed with T-cell lymphoma based on the findings of the second 18F-2 fluoro-2-deoxy-glucose positron emission tomography/CT performed 16 months after symptom onset. The patient received intravenous chemotherapy, but died 2 months later because of lymphoma progression. A clinical suspicion of neurolymphomatosis and early diagnosis are important for proper management.