Arterial thoracic outlet syndrome secondary to hypertrophy of the anterior scalene muscle

Thoracic outlet syndrome (TOS) was first introduced in literature by Peet et al. in 1956. Since then is has been studied extensively and subcategorized into at least four closely related syndrome. Neurogenic TOS due to the compression of brachial plexus, arterial TOS in cases of compression of the subclavian artery, venous TOS in cases of compression of the subclavian vein, and non-specific type of TOS. Neurogenic TOS is by far the most common consisting of 95% of the cases, followed by venous and lastly arterial. Arterial TOS comprises ~1% of all TOS cases, they are caused largely by presence of cervical rib and/or anomalies of first rib. Here we describe arterial TOS caused by hypertrophy of the anterior scalene muscle in a 65-year-old male. Patient underwent successful open surgical repair with Dacron interposition graft. Postoperative course was unremarkable. Patient was discharged home on POD 2.