Venous thoracic outlet syndrome: When exercising may be discouraged.

Thoracic outlet syndrome results from neurovascular compression at the thoracic outlet. Clinical presentation varies according to the predominantly compressed structure, determining its subtype: neurogenic, venous, or arterial. The neurogenic subtype is the most common, affecting 90% of patients, while the vascular subtype is rarely found in practice. We present two case reports of young patients with upper extremity deep vein thrombosis in the setting of venous thoracic outlet syndrome: one due to an anatomic variant, the second an effort thrombosis due to repeated upper arm exercise. These reports depict uncommon clinical scenarios, which imply significant morbidity if not identified and timely treated.