Findings: CXR – This film was taken in the infants early neonatal life which shows vague, bubbly cystic changes at the left lung base - best seen on the lateral view. CT SCAN – This scan was obtained at approximately 4 weeks of life which reveals multiple, well-circumscribed cysts of varying size confined predominately to the left lower lobe but to a lesser degree the left upper lobe. There is an area of consolidated lung seen at the left base posteriorly.

Diagnosis:Congenital cystic adenomatoid malformation (CCAM).

Discussion: CCAM is a congenital anomaly of the terminal brochioles which results in a dysplastic, multicystic mass. These cysts usually communicate with the bronchial tree. At birth, these cysts are fluid-filled. Ultimately, communication with the airway allows for the fluid-filled mass to become air-filled. Whether fluid-filled or air-filled, the cysts become increasing larger, exert mass effect, compress mediastinal structures and lung parenchyma.

Infants less than one year old usually present with respiratory distress. Usually, the abnormality is confined to one lobe. There are three types of CCAM:

1. Type I: Single/multiple cysts > 2cm (most common).
2. Type II: Smaller cysts <2cm with mixed solid component.
3. Type III: Solitary solid mass.

Treatment: Surgical lobectomy is curative with Type I. There is increased morbidity and mortality with Type II and II because the lesions are often larger at presentation.

References:

1. Brickman H. Pediatric Radiology: The Requisites, 2nd Edition, 1998.
2. Swischuk L. Imaging of the Newborn, Infant and Young Child, 3rd Edition, 1989.