Neurolymphomatosis on F-18 FDG PET/CT and MRI Findings: A Case Report.

Neurolymphomatosis is a rare manifestation of malignant lymphoma. A 74-year-old man, in complete remission from diffuse large B cell lymphoma, presented with a loss of pain and temperature sensation in the left hemiface and left upper extremity, and motor weakness in the left upper and both lower extremities. Cerebrospinal fluid analysis and brain magnetic resonance imaging (MRI) findings were negative. Combined fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) revealed multiple linear hypermetabolic lesions along the mandibular branch of the left trigeminal nerve, left brachial plexus, right axillary nerve, right suprarenal plexus, right adrenal gland, right femoral nerve, and both sciatic nerves, which corresponded to the patient's complex neurologic symptoms. C-spine and pelvic MRI revealed diffuse thickening with enhancement in the left brachial plexus and in the proximal portion of the left sciatic nerve, but negative findings for other sites identified by FDG-PET/CT. These findings suggest that FDG-PET/CT can detect peripheral nerve infiltration by malignant lymphoma earlier than MRI. Thus, if a patient with a history of lymphoma presents with neurologic symptoms, FDG-PET/CT should be performed to evaluate neurolymphomatosis.