The dark side of pulmonary alveolar proteinosis.

Background: Pulmonary alveolar proteinosis (PAP) has an unpredictable clinical course. Although usually benign, an association with pulmonary fibrosis is described in literature, with troubling therapeutic and prognostic implications.

Clinical case: We report the case of a patient affected by autoimmune PAP who developed pleuro-parenchymal fibroelastosis (PPFE) after 6 years of disease and underwent bilateral lung transplantation due to end stage respiratory failure.

Conclusion: Punctual descriptions of pulmonary fibrosis in PAP are still lacking and no predictors of fibrotic evolution of PAP are known. It is necessary to ensure a strict follow up in order to promptly recognize signs of fibrotic evolution and early refer patients with evolutive disease to lung transplant center. Moreover, an extended genetic analysis by targeted next-generation sequencing could provide high-resolution information that may allow the identification of susceptible patients in a pre-fibrotic stage of disease.