Case 6- Arie Perry; This previously healthy 33 year old woman presented with acute onset severe stabbing and burning pain from her left elbow to her fingertips. Her symptoms then progressed into left upper extremity weakness with numbness in the dorsum of her left arm. Her symptoms were intermittent and random. She also experienced a deep aching feeling in her left forearm and into her lateral chest. Associated symptoms included skin hypersensitivity, agitated by clothing and hot water. Her past medical history was unremarkable and there was no relevant family history. Physical exam revealed motor strength measurement scores of 2-3 in left shoulder abduction and elbow flexion, 3-4 in elbow extension, and 1 in her intrinsic hand muscles. Sensation was reduced in a left C8-T2 distribution. There were no cutaneous stigmata of neurofibromatosis. MR imaging (see below) revealed a 2-3 cm contrast enhancing mass involving the lower trunk of the left brachial plexus. PET CT study did not show any hypermetabolic activity suggesting a benign nerve sheath tumor. EMG/NCV study showed denervation in the left lower and to a lesser extent middle trunk muscles. The patient was taken to surgery for diagnosis and therapy. Intra-operatively, a discrete appearing mass was identified expanding the T1 nerve root and proximal brachial plexus. The tumor was internally debulked away from surrounding functioning nerve fibers. The patient had an uneventful post-operative course and is currently considering further therapeutic options.