UNUSUAL CASE OF PULMONARY ARTERIOVENOUS FISTULA CONCEALED BY THE CARDIAC SILHOUETTE ON CHEST ROENTGENOGRAM.

A large pulmonary arteriovenous fistula was discovered in a patient with long-standing cyanosis, clubbing and dyspnea, with no other cardiovascular signs or symptoms and a normal chest roentgenogram at the time of cardiac catheterization and pulmonary angiography. The fistula was overshadowed by the cardiac silhouette. Surgical resection was successful. Although rarely undetected on the chest roentgenogram, this potentially lethal malformation should be considered in the differential diagnosis of cyanosis unaccompanied by other cardiovascular signs or symptoms.