A case of pulmonary alveolar proteinosis misdiagnosed as COVID-19 pneumonia.

A 48-year-old female patient with complaints of shortness of breath and coughing had bilateral diffuse infiltration in her chest X-ray and diffuse ground-glass opacities in her chest computed tomography. Despite her polymerase chain reaction test being negative, she was treated 10 days for coronavirus disease 2019 (COVID-19) pneumonia due to her radiological images and clinical hypoxia. As there was no improvement in her symptoms, she was administered fiberoptic bronchoscopy and she was diagnosed with pulmonary alveolar proteinosis (PAP).