Confluence of pulmonary veins simulating a pulmonary mass.

Confluence of the pulmonary veins commonly appears on the frontal view of the chest and generally is easily recognized as such. On plain film tomography, computerized tomography, and pulmonary angiography, the anatomy of convergence of pulmonary veins prior to common entry into the left atrium is clearly displayed. In this report, attention is called to the occasional appearance of confluence of the pulmonary veins on the lateral view of the chest as a clearly circumscribed round opacity mimicking a lung or mediastinal mass.