Rhabdomyomatosis of the newborn lung unassociated with other malformations

Aims: To describe a case of rhabdomyomatosis of the lung unassociated with other external or visceral malformations in a newborn infant. Methods and results: A 26 weeks' gestation newborn male with no relevant medical or family history presented a well‐circumscribed solid area in the posterior mediastinum occupying the upper lobe of the right lung. The possibility of neuroblastoma or an extralobar pulmonary sequestration were excluded after laboratory and arteriographic studies. No visceral anomalies were found. At the age of 9 months the patient underwent a partial lobectomy, and he is free of disease 39 months after surgery. Histological examination demonstrated the presence of numerous bundles of striated fibres arranged haphazardly in the pulmonary interstitium in a background of a type‐II congenital cystic adenomatoid malformation‐like morphology of the resected lung. Conclusion: The presence of striated muscle fibres in the lung not necessarily represents a lethal congenital malformation. As this case shows, rhabdomyomatosis of the lung can affect a single pulmonary lobe, and resection of the affected lung parenchyma may be curative. It is important for pathologists to be aware of this entity, although it is exceptional, and to include it in the differential diagnosis of pulmonary masses in the newborn lung.