Distinction between neo plastic and radiation‐induced brachial plexopathy, with emphasis on the role of EMG

results of clinical, radiologic, and electro physiologic studies are retrospectively reviewed for 55 patients with neo plastic and 35 patients with radiation-induced brachial plexopathy. The presence or absence of pain as the presenting symptom, temporal profile of the illness, presence of a discrete mass on CT of the plexus, and presence of myokymic discharges on EMG contributed significantly to the prediction of the underlying caw of the brachial plexopathy. The distribution of weakness and the results of nerve conduction studies were of no help in distinguishing neo plastic from radiation-induced brachial plexopathy.