ANEURYSMS of the trunk and of the primary branches of the pulmonary artery are a rare entity. According to recent reviews on large numbers of cases,1 etiologic factors, in order of frequency, are congenital defects, syphilis, arteriosclerosis, rheumatic fever, bacterial endocarditis or endoarteritis and trauma.
Aneurysms of the smaller branches of the pulmonary arteries are found frequently in tuberculous cavities and occasionally in other chronic infectious cavities of the lungs.2 In such cases, however, they are small, rarely reaching a size above a few millimeters in diameter. Larger intrapulmonary aneurysms, associated either with an intrinsic disease or with a congenital defect of the arterial wall, are rare.
Syphilis has occasionally been found to tbe the etiologic factor in large aneurysms.3 Congenital defects, such as patent ductus arteriosus and patent interatrial or interventricular septum, are occasionally accompanied with pronounced ectasia of the pulmonary artery and its branches, and