Congenital lung cysts

Ch'in and Tang first described cystic adenomatoid malformation (CAM) as a distinct entity in 1949. CAM is a developmental hamartomatous abnormality of the lung with adenomatoid proliferation of cysts resembling bronchioles. CAM represents approximately 25% of all congenital lung lesion. CAM is believed to result from focal arrest in fetal lung development before the seventh week of gestation secondary to a variety of pulmonary insults. CAM is subdivided into 3 major types.


Type I

Type II

Type III


Multiple large cysts or single large cyst

Multiple, evenly spaced cysts not over 1.2 cm

Multiple small cysts less than 0.5 cm


Air or fluid




Smooth muscle and connective tissue

Terminal bronchioles

Adenomatoid hyperplasia or bronchial

B. Symptoms
Progressive respiratory distress in a newborn infant
Tachypnea, subcostal retraction, cyanosis

CT findings