Primary pulmonary alveolar proteinosis: computed tomography features at diagnosis

Pulmonary alveolar proteinosis (PAP) is characterized by an abnormal accumulation of periodic acid-schiff-positive lipoproteinaceous material in the alveoli. Early diagnosis allows setting up of therapeutic lung lavages, which reduces the need for oxygen supplementation and weight gain. To provide a description of radiological features by CT at the onset of primary PAP in children. The clinical and radiological data of 24 patients, including 16 boys and 8 girls (median age: 12 months), diagnosed with a primary form of PAP between April 1992 and May 2012 in a tertiary referral hospital, were retrospectively reviewed. CT images were examined for the presence of alveolar and interstitial elementary lesions. Correlation between clinical and radiological findings was assessed. The types of elementary lesions detected were: ground-glass opacities (n = 24), intralobular lines (n = 24), thickened interlobular septa (n = 22), thickened fissures (n = 21), airspace consolidation (n = 16), hyperinflation (n = 16), cystic lesions (n = 2) and micronodules (n = 1). A crazy-paving pattern was found in 92% of cases. Consolidation and hyperinflation were especially detected in younger children (median age, 8 months, P < 0.01). A density dependent gradient was found. The distribution of the lesions was symmetrical. There was no correlation between radiological and clinical data of severity of the disease. CT findings are suggestive of diagnosis of PAP in immunocompetent children with chronic respiratory failure. (orig.)