The case of an apical tumour in the thorax, which presented with upper extremity symptoms, is reported. Surgery was performed and a diagnosis was established of a neurogenic mediastinal tumour, a schwannoma, compressing the T1 nerve root. This case illustrates the need for the thoracic surgeon to consider a brachial plexus or upper thoracic nerve root tumour when evaluating a patient with neurological upper extremity symptoms. Adequate preoperative evaluation is essential in such cases to enable the thoracic surgeon to select the best surgical approach, sometimes aided by a neurosurgical team. Emphasis is placed on the difficulties faced by the surgeon when exposing a tumour complicated by its localization in the superior mediastinum and which is anatomically linked with delicate nerve fascicles.