Histology of a type 1 congenital pulmonary airway malformation (CPAM)

Histology specimen from a congenital pulmonary airway malformation (CPAM) type 1, showing the large cystic component lined by columnar, ciliated epithelium. The wall of the cyst resembles pre-acinar airways. Frequent openings in the cyst wall extend into the adjacent acinar structures. The wall contains smooth muscle but not cartilage.