Fluorothymidine PET/CT in neurolymphomatosis.

Neurolymphomatosis, a rare extranodal lymphoma, may involve the cranial nerves, peripheral nerves, spinal nerve roots, or nerve plexus. F-FDG PET/CT however shows increased FDG uptake in the nerves but is not specific for malignancy. We report a patient with neurolymphomatosis who underwent F-FDG PET/CT and F-fluorothymidine PET/CT where both the scans showed increased tracer uptake in the right sciatic nerve, proven later as neurolymphomatosis on nerve biopsy. Furthermore, the F-FDG avid mediastinal lymph nodes did not show F-fluorothymidine avidity, suggesting an inflammatory etiology.