Thoracic Outlet Syndrome With Vascular Thrombus

Image description
Coronal MR angiogram (image 1) of the upper chest and coronal CT (image 2) show thrombus (arrow) within the left subclavian vein.

Teaching point
Thoracic outlet syndrome encompasses venous, arterial, and neurogenic forms caused by compression of the neurovascular bundle at the thoracic outlet. Predisposing factors include congenital anomalies such as a cervical rib or elongated transverse process, acquired narrowing from clavicular or first-rib abnormalities, and dynamic compression related to posture or repetitive overhead activity. In the venous form, chronic compression of the subclavian vein leads to endothelial injury and stasis, predisposing to thrombosis.

Diagnosis added by author
Thoracic Outlet Syndrome With Vascular Thrombus

Image description
Frontal chest radiograph (Image 1) shows a curvilinear vascular structure along the right cardiac border consistent with a scimitar vein (arrow) and a relatively small right hemithorax. Coronal CT maximum intensity projection (image 2) demonstrates partial anomalous right pulmonary venous return, with the scimitar vein draining into the inferior vena cava.

Teaching point
Scimitar syndrome is a form of partial anomalous pulmonary venous return in which right pulmonary veins drain into the inferior vena cava. Right lung hypoplasia results in a small right hemithorax, and the anomalous descending vein produces the characteristic curvilinear “scimitar” appearance on chest radiographs. CT delineates the anomalous venous course and confirms systemic venous drainage.