Anomalous subaortic left brachiocephalic vein: Prevalence and associated anomalies

Introduction: Thoracic venous anomalies are very rare with an estimated prevalence of 0.7% in the general population. One of the rarest such anomaly is a subaortic course of the left brachiocephalic vein (LBV) commonly associated with congenital cardiac or aortic arch anomalies. Material and Methods: We retrospectively analyzed chest computed tomography scans of 710 participants and found incidentally two cases of anomalous subaortic course of the LBV in two females. Results: The observed prevalence of subaortic LBV is 0.28% (2/710 cases). Isolated subaortic LBV without any associated cardiac or aortic arch anomaly was observed in a female patient. Rare bilateral ectopic origin of bronchial arteries from corresponding subclavian arteries was also noted in this patient. In another female patient, right aortic arch anomaly was associated with subaortic LBV. The right-sided aortic arch had an aberrant retroesophageal left subclavian artery arising from a Kommerell's diverticulum as the last branch. Discussion and Conclusion: Extensive literature search has yielded only 15 cases of isolated anomalous subaortic LBV in subjects without any cardiac and aortic arch anomaly. Although this condition is asymptomatic, its presence, when detected, should alert the clinician to the possible presence of associated congenital cardiac and aortic arch anomalies. Accurate knowledge of these rare anomalies will enhance the diagnostic accuracy and proper interpretation of radiological images. Such thorough knowledge will avoid interpreting the anomalous vein as an enlarged lymph node, enlarged left superior intercostal vein, and reduce the chances of surgical complications.