Further evaluation and hospital course

Repeat chest xray, CT scan of the chest, and chest ultrasound revealed a homogeneous mass in the left upper and anterior hemithorax, filling most of the hemithorax and compressing the mediastinum to the right. The right lung was normal.

The clinical diagnosis was a fluid-filled congenital pulmonary malformation that was not connected to the lung airway system and which compressed the remainder of the left lung, preventing ventilation.

A left upper lobectomy was carried out, allowing the atelectatic left lower lobe to expand. The postoperative course was uneventful and the pathologic diagnosis was Polyalveolar Lobe, a congential lung malformation that does not communicate with the lung airway system.