Neurolymphomatosis diagnosed by (18)F-FDG PET-CT.

Neurolymphomatosis is defined as infiltration of the nervous system by hematological malignancy and is difficult to diagnose. We report a case of a 57-year-old man, treated for small B-cell non-Hodgkin lymphoma, presenting with sensorimotor impairment of the lower limbs, which started 6 years after diagnosis. He was treated with chemotherapy, after which, the symptoms disappeared. After 7 months, he developed sensorimotor impairment of both upper limbs. MRI of the brachial plexus showed no abnormalities. F-FDG PET-CT showed increased uptake at the brachial plexus and nerves, suggesting neurolymphomatosis. Confirmatory biopsy revealed conversion of the malignancy to diffuse large B-cell lymphoma.