EXCESSIVE ANTERIORISATION OF THE SUPERIOR VENA-CAVA ASSOCIATED WITH AN AZYGOS LOBE

A wide variety of congenital vascular anomalies of the superior medias tinum exist. Being clinically silent, most of these anomalies are dete cted incidentally on plain radiographs or CT scans where they could be mistaken for mediastinal masses. Familiarity with these anomalies is very important for correct interpretation and avoidance of confusion. We present a case of a mediastinal mass detected accidentally on plain radiography which on further radiological investigation was found to be an unreported normal variant of the superior vena cava (SVC), CT sc ans of the thorax and superior vena cavograms showed excessive anterio risation of the SVC in the presence of an azygos lobe. After reviewing the literature and the embryology of the SVC and azygos lobe, we post ulate that the variation in the location of the SVC was possibly due t o the presence of the azygos lobe.