Autoimmune pulmonary alveolar proteinosis presenting as localized multifocal GGOs: A case report

Pulmonary alveolar proteinosis (PAP) is a rare disease, which is characterized by the alveolar accumulation of surfactant. A crazy-paving appearance on chest thin-section computed tomography (TSCT) is a characteristic feature of this disease. We report an unusual case of PAP, which presented as multiple localized ground glass opacites (GGOs) on TSCT in an 80-year-old female. As one of these lesions at the apex of the right lung increased in size, it was suspected to be a pulmonary adenocarcinoma. However, the others became smaller during the follow-up period. Right upper lobectomy was performed, and PAP was histologically diagnosed. In cases exhibiting multiple localized GGOs, PAP should be considered, even if GGOs with a crazy-paving-like appearance are distributed in a lobular rather than diffuse manner.