Crazy paving pattern caused by pulmonary alveolar proteinosis: CT findings and the pathologic basis.

OBJECTIVE: To explore CT findings and pathologic basis of crazy paving pattern caused by pulmonary alveolar proteinosis.

METHODS: Twenty-four patients who were diagnosed pathologically as pulmonary alveolar proteinosis by transbronchial lung biopsy and bronchoalveolar lavage fluid from June 2006 to May 2012 were included in this retrospective study. All patients underwent a 64-slice CT of the lungs.

RESULTS: CT findings: crazy paving pattern was observed on CT imaging of all 24 patients. In 23 patients, crazy paving pattern displayed strip-shaped opacities with smooth edges, and there was a clear boundary between the pathological and normal lung tissues. The reticular opacities were connected with peripheral blood vessels and the branches were formed, and their diameters decreased slightly. Microscopically, hemangiectasis were seen in 17 patients.

CONCLUSION: Crazy paving pattern caused by pulmonary alveolar proteinosis displayed clear edges, and smooth reticular opacities, most of which were due to hemangiectasis of interlobular, interacinar and interalveolar septa. These findings of CT are helpful for the specific diagnosis of pulmonary alveolar proteinosis.