An Atypical Presentation of Congenital Pulmonary Airway Malformation (CPAM): A Rare Case with Antenatal Ultrasound Findings and Review of Literature

BACKGROUND Congenital pulmonary airway malformation (CPAM) is a relatively rare congenital anomaly with a wide spectrum of ultrasound features depending on the specific variety of CPAM. Antenatal ultrasound is a valuable, safe, nonionizing, cost-effective, widely available and easily reproducible imaging tool and is indispensable in the diagnosis of CPAM. In this paper, we aimed to report an atypical imaging presentation of CPAM type II in the second trimester, extensively involving all lobes of the left lung. CASE REPORT A 25-year-old G1P0A0 woman with a gestational age of around 22 weeks was referred for an anomaly scan. The antenatal ultrasound scan showed a single, live, intrauterine foetus corresponding to a gestational age of around 22 weeks and 4 days. There were multiple, anechoic structures noted within the pulmonary tissue in the left hemithorax, each measuring around 3 to 4 mm in diameter. The lesion was extending from the left lower lobe up to the apical (apicoposterior) segment of the left upper lobe. The ultrasound diagnosis of congenital pulmonary airway malformation type II was made. After explaining the condition and the poor prognosis to the patient, an informed consent was obtained after she opted for medical termination of pregnancy. CONCLUSIONS Congenital pulmonary airway malformation (CPAM) is an uncommon foetal anomaly with a very wide range of ultrasound appearances depending on the specific type of CPAM. CPAM also has a wide spectrum of differential diagnoses and a variable prognosis. Antenatal ultrasound should always be the primary mode of diagnosis in CPAM.