Abnormal Muscularization of Intra-acinar Pulmonary Arteries in Two Cases Presenting as Sudden Infant Death.

Abnormal muscularization of acinar arteries is the hallmark of persistent pulmonary hypertension of newborn (PPHN), an uncommon disease with high rate of morbidity and mortality. PPHN presents with signs of respiratory distress immediately following birth. We herein report 2 cases presenting as a witnessed sudden unexpected death in the late neonatal period, preceded by respiratory deterioration and in whom the presence of abnormal muscularization of the acinar pulmonary arteries was reminiscent of PPHN. The significance of this report is twofold: to increase the awareness among pediatricians and pathologists of this feature that can present in some cases of Sudden Unexpected Death in Infancy/Sudden Infant Death Syndrome, and to highlight the importance of performing a thorough autopsy in order to identify the abnormality.