Invasive Mucinous Adenocarcinoma in a Newborn With Antenatally Diagnosed Congenital Pulmonary Airway Malformation: A Case Report.

Congenital pulmonary airway malformations (CPAMs) are rare multicystic lung lesions typically diagnosed antenatally. We present a case of a term female neonate with antenatally diagnosed CPAM who required pleuro-amniotic shunting at 22 weeks of gestation. The patient was born with a right-sided pneumothorax and severe cardiorespiratory distress, necessitating extracorporeal membrane oxygenation (ECMO). Chest CT confirmed CPAM, revealing multiple cystic lesions in the right middle lobe and a significant contralateral mediastinal shift. On the second day of life, while on ECMO, the patient underwent a right middle lobectomy and an upper lobe anterior segmentectomy via a posterolateral thoracotomy. Post-surgery cardiac CT showed narrowing of the left pulmonary artery, although a perfusion study indicated normal left lung perfusion. Histopathological examination identified CPAM type 1 with invasive mucinous adenocarcinoma (IMA; stage 1: pT1b), featuring low-to-intermediate cellularity and KRAS G12D mutations. The invasive mucinous component measured at least 15 mm but did not invade the visceral pleura. After a gradual weaning process, the patient was successfully extubated and discharged home after 70 days. To our knowledge, this is the first reported case of CPAM type 1 with IMA that underwent pleuro-amniotic shunting in the second trimester.