Congenital cystic adenomatoid malformation presenting as repeated pneumonia in a young adult.

Computed tomography (CT) of an 18-year-old man with a history of repeated episodes of pneumonia demonstrated consolidation containing multiple cysts in the right lower lobe. Additional CT angiography and thin-section CT of the lesion revealed neither a supplying systemic artery nor an abnormal bronchus. Lobectomy was performed, and histological examination showed many cysts resembling enlarged bronchioles, diagnosed as congenital cystic adenomatoid malformation.