Pulmonary interstitial glycogenosis: an unrecognized etiology of persistent pulmonary hypertension of the newborn in congenital heart disease?

Background: Pulmonary interstitial glycogenosis (PIG) arises from a developmental disorder of the pulmonary mesenchyme and presents clinically with reversible neonatal respiratory distress and/or persistent pulmonary hypertension of the newborn (PPHN).
Objective: We report two cases of PIG in patients with congenital heart disease (CHD) and evidence of PPHN.
Results: Both cases demonstrated the hallmark PIG histologic finding of diffuse, uniform interstitial thickening due to the presence of immature interstitial cells containing abundant cytoplasmic glycogen.
Conclusions: We report the second and third patients with PIG associated with CHD. Because histologic examination is required to establish the diagnosis, we speculate that PIG, although rare, may be underrecognized in neonates presenting with PPHN in the setting of CHD.