Unusual case of thoracic outlet syndrome caused by a neurilemmoma in the pectoralis minor space.

A 34-year-old man presented with a 5-year history of paraesthesia of the right palm and the right middle and ring fingers. This paraesthesia was exacerbated by elevation of the right arm. A tumour was palpable in the subclavicular fossa. As magnetic resonance imaging (MRI) indicated a neurogenic tumour originating from the brachial plexus, a diagnosis of thoracic outlet syndrome caused by a neurilemmoma in the pectoralis minor space was made. Pathological examination showed the tumour to be a benign neurilemmoma. There have been only three previous case reports of neurilemmomas as causes of thoracic outlet syndrome worldwide, and this is the first report of a neurilemmoma originating from the lateral fascicles of the brachial plexus in the pectoralis minor space causing thoracic outlet syndrome.