Idiopathic Azygos Phlebectasia Simulating Mediastinal Tumor

The roentgen appearance of the normal azygos vein was first described by Ottonello in 1932. It casts an ovoid or almond-shaped shadow in the right tracheobronchial angle, seen to best advantage on frontal laminagrams of the chest. The width of the normal azygos vein in adults has been reported not to exceed 6 mm. (Fleischner and Udis). Dilatation of the azygos vein has been described under various pathologic circumstances, including right-sided heart failure, portal venous hypertension, obstruction of the superior or inferior vena cava, and absence of the inferior vena cava. Particularly in the latter case, the azygos and hemiazygos venous systems may serve as important collateral channels for return of blood to the right side of the heart. It is our purpose to record the case of a healthy 19-year-old white male who was rejected from military service because a routine induction chest roentgenogram revealed a “mediastinal tumor” (Fig. 1). At a subsequent exploratory thoracotomy, a huge azygos vein was found. Since this patient did not present any of the previously described conditions which could account for such dilatation, we rather reluctantly were forced to a diagnosis of “idiopathic azygos phlebectasia,” realizing that a peculiar venous obstruction in the portal system or elsewhere in the abdomen had not been entirely excluded. Case Report L. P., a 19-year-old white male, had always been in excellent health. On induction into military service in January 1960, a routine chest roentgenogram showed a “right mediastinal mass,” and he was therefore rejected. He was admitted to Montefiore. Hospital on Feb. 22, completely asymptomatic. His past history revealed only a tonsillectomy in childhood. The entire physical examination was within normal limits. The roentgenographic work-up consisted first of films of the chest in frontal, oblique, and lateral projections, with a barium swallow to outline the esophagus. There was no abnormal esophageal indentation, and the possibility of a right-sided aortic arch, or a double aortic arch, was thus excluded. Subsequent laminagrams (Fig. 2) clearly demonstrated an ovoid soft-tissue density in the right tracheobronchial angle, without calcification in or about the lesion. There was no evidence of bronchial compression. For further evaluation, an intravenous angiocardiographic study was performed on Feb. 24. A spheroid radiolucent defect, measuring almost 3 cm. in diameter, was noted in the lower portion of the superior vena cava, on its posterior aspect (Figs. 4 and 5). There was no reflux of opaque medium into this soft-tissue structure. Although we were aware of the possibility of an azygos phlebectasia, the findings were erroneously interpreted as representing an extrinsic indentation on the superior vena cava, probably due to enlarged lymph nodes. Consideration was given to sarcoidosis, lymphoma, tuberculous or non-specific lymphadenitis, and a bronchogenous cyst.