[Radiological findings in initial pulmonary alveolar proteinosis detected in the post-treatment course of nocardiosis].

Chest CT detected a small localized ground glass opacity in the right upper lung in a 52-year-old woman being treated for nocardiosis. A PAS-stain positive material and elevated surfactant level were confirmed in bronchoalveolar lavage fluid, then a diagnosis of pulmonary alveolar proteinosis was established. In early pulmonary alveolar proteinosis with focal opacity, HRCT can demonstrate the substantial findings of alveolar proteinosis such as a crazy-paving appearance or geographic distribution. We should note that alveolar proteinosis in the early stage is easily overlooked and, in addition, nocardiosis might overlap with alveolar proteinosis.