Teaching NeuroImages: diagnostic utility of FDG-PET in neurolymphomatosis.

A 70-year-old woman with a history of non-Hodgkin lymphoma presented with left-sided facial pain. MRI of the face, orbit, and neck was negative (figure). A week later, she developed hypesthesia in a V3 distribution. Repeat MRI was again nondiagnostic but FDG-PET showed increased uptake along the left V3 branch of the trigeminal nerve, as well as in the parotid gland. Biopsy of the left parotid confirmed recurrent lymphoma.