Congenital Cystic Adenomatoid Malformation (CCAM)

2 Month old male baby came with shortness of breath. CT scanogram shows large cystic lesion in the right upper zone. Axial and coronal CT lung window shows large cyst in the right upper lobe with septa within s/o Typer I congenital cystic adenomatoid malformation.

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
3. Type III: Solitary solid mass. (Multiple microcysts of 2-6 mm).

The differential diagnosis includes congenital lobar emphysema and bronchial atresia.

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.