Two month-old girl presented with respiratory distress. CT scan shows multiple large cysts (>2cm) involving the lower lobe of left lung. The cysts are air-filled, expand the lower lobe, cause mediastinal shift and hypoplasia of right lung. The condition was complicated by spontaneous pneumothorax for which intercostal drain was inserted. Lobectomy was performed.

CCAM consists of a multicystic intralobar mass of disorganized lung tissue, derived primarily from bronchioles. It can involve an entire lobe. Lower lobes are most often involved, but any lobe can be affected. The treatment of choice is excision of the affected lobe.

CCAMs are often classified into 3 types which have different histology, gross pathologic findings, radiographic appearance and prognosis.
Radiological differential diagnosis: Congenital diaphragmatic hernia, congenital lobar emphysema, localized persistent pulmonary interstitial emphysema and pneumatocele.

Reference: Webb & Higgins. Thoracic imaging, Pulmonary and cardiovascular radiology. Lippincott Williams & Wilkins 2005.

Credit: Dr Ahmed Haroun