Antenatal Ultrasonographic Diagnosis and Longitudinal Monitoring of Congenital Pulmonary Airway Malformation with Spontaneous Third-Trimester Resolution: A Case Report

Abstract

Background: Congenital pulmonary airway malformation (CPAM) is one of the most common congenital cystic lung lesions diagnosed during the antenatal period. Prenatal ultrasonography plays a central role in its detection, characterization, assessment of lesion size and morphology, and longitudinal monitoring. Serial imaging is particularly important for evaluating lesion progression or regression and identifying associated complications such as mediastinal shift, hydrops fetalis, and impaired fetal growth.                        Case Report: A 38-year-old pregnant woman underwent routine second-trimester anomaly screening with high-resolution obstetric ultrasonography. Multiple well-defined cystic lesions were identified within the fetal lung, with sonographic features consistent with CPAM. Serial ultrasonographic examinations were subsequently performed throughout pregnancy to assess the lesion's morphology and size, fetal growth, amniotic fluid volume, and development of associated complications. During follow-up, progressive reduction in the size and conspicuity of the cystic lesions was observed, with near-complete spontaneous resolution during the third trimester. No significant mediastinal shift, hydrops fetalis, or other adverse sonographic features developed during the follow-up period. Conclusion: This case highlights the value of serial prenatal ultrasonography in the diagnosis and longitudinal assessment of CPAM. Recognition of spontaneous regression during pregnancy may help avoid unnecessary intervention in appropriately selected cases. Careful assessment of lesion characteristics, fetal well-being, and potential complications, combined with structured serial ultrasound follow-up, can support individualized antenatal management and appropriate perinatal planning. BJusg. vol. 26, no. 2, December 2025, Page: 93-100