Desmoid tumour of the thoracic outlet: an unusual cause of thoracic outlet syndrome.

Desmoid tumour is an unusual and aggressive tumour associated with a high recurrence rate. A 35-year-old man presented with recurrent debilitating left arm pain 2 years after undergoing bilateral transaxillary first rib resection for thoracic outlet syndrome. Nerve conduction studies demonstrated impairment of nerve conduction in the left arm. Magnetic resonance imaging of the brachial plexus demonstrated a mass at the apex of the left hemithorax involving the lower cord of the brachial plexus. Subsequent percutaneous needle biopsies failed to provided a definitive diagnosis. A cervicothoracic approach as described by Dartevelle was used to resect the lesion. Histologic and ultrastructural studies confirmed the diagnosis of a desmoid tumour. This report describes the atypical presentation of this unusual tumour and the application of the novel Dartevelle approach to secure its complete excision.