Acquired air-filled lung cysts in childhood: pathogenesis of cysts of diverse etiologies; nuances of management
Background Air-filled pulmonary parenchymal cysts (pneumatoceles/PCs) – a pathological condition – involving the lung parenchyma may be congenital or acquired. In children, acquired cases are often caused by staphylococcal pneumonias, but other etiologies may also cause PCs and lead to diagnostic confusion.
Objectives The aim of this study was to examine the natural history and clinicopathologic features of noncongenital, nonstaphylococcal PCs in children.
Patients and methods Four children with nonstaphylococcal PCs were included in this study. A full history, clinical examination, relevant radiological and pathological findings, surgical intervention where relevant, and follow-up were analyzed.
Results The cases described represent acquired PCs: one occurred after infarction following cardiac surgery, another was a subpleural pulmonary bleb of inflammatory origin, and the remaining two were post-traumatic pseudocysts. The inflammatory-process bleb and the postinfarction cysts presented with pneumothorax. The postinfarction and post-traumatic PCs responded to observation. The pulmonary bleb was excised.
Conclusion Our understanding of the clinicopathologic features and pathogenesis of many types of acquired PCs is incomplete. We propose that PC formation has a basis in destruction of the distal airways of the lung. Damaged tissue may act as a valve, and cause air-trapping, which leads to PC formation. Cysts arising after infarction or after trauma usually resolve on observation. Subpleural blebs may require excision because of nonresolution and recurrence of pneumothorax.