Intraoperative monitoring of an unusual brachial plexus tumor

This case illustrates the importance of intraoperative monitoring of neuronal function to help separate tumor tissue from neural tissue in a 54-year-old patient with left shoulder pain resulting from a desmoid tumor. Preoperative nerve conduction and electromyographic studies showed a lesion in the lateral cord of the brachial plexus, which was found to be intimately involved with the tumor mass and was splayed into a very thin effaced sheet of neural tissue. Stimulation of the tumor/nerve tissue mass proximal to the lesion was impossible due to the invasion of the brachial plexus by the tumor. The technique that was adapted for this unusual presentation was to stimulate the tumor/nerve tissue mass itself and record compound muscle action potentials distally. With the technique described, a subtotal resection of an aggressive fibromatosis enmeshed in the proximal brachial plexus was possible, and excellent relief of pain symptoms and retention of functional capabilities of the involved extremity were achieve.