Fig. 1.

a Maximum intensity projection FDG-PET/CT image showing linear hypermetabolic lesions involving multiple peripheral nerves, corresponding to the patient’s complex neurologic symptoms, as follows. Involvement of the mandibular branch of the left trigeminal nerve (black arrowhead) corresponded to loss of pain and temperature sensation in the left hemiface. Left brachial plexus involvement (black large arrow) corresponded to loss of pain and temperature sensation and motor weakness in the left upper extremity. Left sciatic nerve involvement (small black arrow) corresponded to motor weakness of the left lower extremity. Right sciatic nerve (small white arrow) and right femoral nerve (large white arrow) involvement corresponded to motor weakness of right lower extremity. However, the right axillary nerve (white arrowhead) lesion did not cause any symptom. b FDG-PET/CT showed a linear hypermetabolic lesion in the left brachial plexus. c FDG-PET/CT showed linear hypermetabolic lesions in both sciatic nerves. d Cervical spine T1 weighted MRI showing diffuse thickening with gadolinium enhancement of the left brachial plexus. e Pelvis MRI showing diffuse thickening with enhancement in the proximal portion of the left sciatic nerve