Pulmonary arterial disease with multifocal dissecting haemorrhage in a newborn infant

Intramural haemorrhage in pulmonary arteries is very rare and usually takes the form of a dissecting aneurysm in the pulmonary trunk or a major pulmonary artery. It usually develops on the basis of cystic medial necrosis and pulmonary hypertension. We report a newborn infant with congenital heart disease in whom multifocal haemorrhage occurred in the media of elastic and muscular pulmonary arteries weakened by a structural abnormality, which, so far as we know, has not been described before. A similar, but not identical, lesion has recently been reported by van Unnik (1963, 1964).