Aneurysm of patent ductus arteriosus in an adult case: findings of cardiac catheterization, angiography, and pathology.

A 42-year-old male was admitted to our hospital for evaluation of a left precordial continuous murmur. Results of catheterization revealed a step-up of oxygen content in the pulmonary arteries and the calculated left-to-right shunt flow was 40% of the pulmonary arterial flow. Furthermore, aortography unexpectedly revealed an aneurysm of the patent ductus arteriosus. During surgery, the aneurysm was discovered to arise from the frontal wall of the ductus arteriosus, and histological observation showed focal necrosis and mucoid degeneration of the media of the aneurysmal wall in contrast to a thickened intimal fibroelastosis of the adjacent ductal wall. This is presumed to be the first adult case of patent ductal aneurysm ever reported in which antemortem diagnosis and surgical treatment were successfully conducted. Our case may suggest that the fragility of the ductal wall following the structural change in an incomplete closing process is considered as a potential pathogenesis of ductal aneurysm formation.