Cystic adenomatoid malformation in children: CT histopathological correlation

This study was performed to assess the accuracy of computed tomography (CT) in classifying the various types of cystic adenomatoid malformation (CAM) of the lung, as described by Stocker et al., taking histopathology as the gold standard.

We retrospectively reviewed six cases of histologically proven CAM. Chest radiography, chest CT and histopathology results were available for all patients. The CT images were reviewed blinded to the histological findings, and attention was paid to the number and size of cysts so as to classify the lesions into the three groups described by Stocker et al. The classification of lesions based on the CT images was then correlated to the histopathological findings.

Areas with small-sized cysts (<2 cm) were detected by CT in two patients (33.3%), areas with large cysts (>2 cm) were seen in three cases (50%) whereas in the remaining case, the diagnosis was mixed type I and type II CAM. In one patient with type I CAM, an area of low-density consolidation around the cysts was interpreted as CAM in a context of pulmonary sequestration. The CT classification based on Stocker et al.'s categories was in agreement with the histopathological findings in four cases, whereas in the remaining two cases, the lesions were classed as type I or II on CT and as mixed (type I and II) lesions at histopathology. In one case, the CT classification was correct, but the histopathology revealed the coexistence of pulmonary sequestration.

In our study, there was concordance between CT and histopathology in 66.7% of cases, whereas in 33.3% histopathology revealed areas with mixed grade lesions. CT proved to be accurate in identifying and characterising CAM and provided important information on lesion site and extension.