Left congenital cystadenoma. CT showed increased transmittance of the posterior segment of the upper lobe and the dorsal segment of the lower lobe of the left lung, with a range of about 38.5 ∗ 26.6 ∗ 42.9 mm, with multiple round areas of different sizes, with a maximum diameter of about 7.7 mm, some of the walls slightly thicker, enhancement of the cyst wall, thickened pulmonary artery blood supply, and cystic adenomatoid malformation of the lung (type II). Ultrasound revealed irregular hypoechoic pulmonary consolidation areas, pleural lines were not smooth and unclear, A-lines decreased or disappeared, and dense B-lines or B-lines fused.