Buckling of the innominate artery simulating a right apical lung mass.

A tortuous retroflexed innominate artery can simulate a right apical mass. Four cases are presented to illustrate the four fairly distinct appearances which can result. When the innominate artery buckles posteriorly and laterally, it occasionally impresses deeply into the lung and becomes almost completely surrounded by air. The artery will then look like a pulmonary mass on frontal radiographs. The lower margin of the mass is always more crisply defined than the upper margin, and the appearance on the lateral film is fairly characteristic. Aortography is recommended when the radiographic picture is equivocal. In a survey of 200 randomly selected patients over 50 years old, only one had an innominate artery that presented as an apparent pulmonary mass.