CPAM Type 2


Figure 1. CPAM Type 2

This right lower lobe was resected from a 4-day-old male infant. The cut surface shows an ill-defined malformation composed of grey and reddish parenchyma (right) and normal homogeneous red parenchyma (left). Small cysts up to 3 mm in diameter are scattered throughout the malformation.

A large airway courses through the malformation, and cross sections of airways can be seen in the normal lung. Similar cross sections are absent in the malformation away from the large bronchus.

Outline the malformation.

Find 3 bronchovascular bundles in the normal portion of the lobe.

At the same time, this patient also had a resection of the posterior segment of the right upper lobe for a similar malformation.

Figure 2. Type 2 CPAM

This lesion has smaller cystic spaces than the type 1 CPAM. The architecture is distorted by irregularly-shaped, bronchiole-like structures lined by ciliated, columnar to cuboid epithelium. A smooth muscle layer underlies the epithelium in the larger cysts. Intervening more distal air spaces are dilated and lined by flat epithelium. Large vessels are diminished in number.

Figure 3. High-Power of Interstitium

There may be loose interstitium between cystic spaces. Here, capillaries are sparse and do not always make contact with the epithelial lining, which is composed of cuboid, ciliated and non-ciliated cells.

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Normal bronchovascular bundle