Congenital segmental overinflation: Beware the hidden congenital pulmonary airway malformation

Congenital segmental overinflation (CSO) is frequently managed non-operatively. We observed some children with CSO developing symptoms and requiring resection. Here we aim to report indications for surgery and subsequent histological classification of children undergoing resection for radiologically suspected CSO.

Patients who had resection for a congenital lung malformation (CLM) between 2009 and 2026 were identified. Retrospective data collected included patient characteristics, radiological findings, symptom status and histological findings. Data were analysed for patients with radiological findings suggesting CSO and compared with those with congenital lobar overinflation (CLO).

Of 143 patients who underwent resection for CLM, 16 had CLO and 7 had CSO. Four patients with CSO were initially managed conservatively but developed infection in the overinflated segment and were subsequently managed surgically. One had a repeat CT prior to resection which demonstrated some small cysts in addition to the overinflated area which had not been evident on earlier CT. The remaining asymptomatic three had resections due to parental preference. Histology demonstrated CPAM features in six of the CSO cases and emphysema/inflammation in one. By comparison, 15 of the CLO specimens were histologically overinflated and one was CPAM (p = 0.0005, Fisher's exact). Most CSO specimens were excised from the lower lobe.

Although frequently managed conservatively, radiologically diagnosed CSO may develop infection within the overinflated segment. When resected, CPAM histology is commonly found. This information may be helpful when counselling parents of children with CSO, which should align with counselling for CPAM.