Novel application of cryobiopsy in the diagnosis of pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disease diagnosed pathologically by the build up of surfactant in the alveolar spaces. Establishing a diagnosis usually requires invasive procedures such as bronchoalveolar lavage and forceps biopsy to obtain tissue specimens. Infrequently, surgery is required when histopathological results from other modalities are equivocal. Cryobiopsy has emerged as a novel technique for obtaining lung tissues in pulmonary diseases. Recently, cryobiopsy has been used to diagnose diffuse parenchymal lung disease, but it has rarely been used for the diagnosis of PAP. Here, we describe a 54‐year‐old male businessman presenting with intermittent coughing with yellowish sputum and dyspnoea upon exertion for half a year. Tissues from forceps biopsy fail to yield a specific diagnosis, whereas those from cryobiopsy confirm the diagnosis of PAP. Cryobiopsy offers several diagnostic advantages compared to conventional techniques and appears to be a potential diagnostic tool for diagnosing PAP.