Congenital cystic adenomatoid malformation of the lung: CT-pathologic correlation

The purpose of this study was to correlate CT findings of congenital cystic adenomatoid malformation (CCAM) of the lung with pathologic findings.

CT scans of CCAM from 21 consecutive patients were analyzed retrospectively by two chest radiologists who achieved consensus. Pathologic findings were assessed by an experienced pulmonary pathologist. Preoperative CT findings were correlated with pathologic findings.

Areas with small cysts (< 2 cm in diameter) were seen on CT scans in 19 (90%) of 21 patients, whereas areas with a large cyst (> 2 cm in diameter) were observed in 18 patients (86%). Areas of consolidation (n = 9; 43%) with heterogeneous attenuation on enhanced scans and areas of low attenuation (lower than normal lung) around cystic lesions (n = 6; 29%) were also seen on CT scans. The diameter of the largest cyst seen on CT scans in each patient ranged from 1.0 to 8.0 cm (median, 4.5 cm). Cysts that CT showed to be filled with air, fluid, or both correlated completely with the pathologic findings. Areas of consolidation corresponded histologically to areas of glandular or bronchiolar structures with or without areas of endogenous lipoid or organizing pneumonia or mucus plugs. Areas of low attenuation corresponded to areas of microcysts blended with normal lung parenchyma.

CT scans show the variable internal characteristics of CCAM and can suggest the underlying pathology of such lesions.