A Rare Case of Pulmonary Ossification Findings That Rapidly Progressed and Improved During the Course of <scp>COVID</scp> ‐19 Pneumonia

An 88-year-old man with a history of myocardial infarction, non-valvular atrial fibrillation and hypothyroidism was admitted to our hospital with a diagnosis of coronavirus disease. On admission, he had hypoxemia, with peripheral blood oxygen saturation at 95% on 5 L of oxygen via face mask ventilation. Chest computed tomography (CT) showed bronchial wall thickening and emphysema in both lungs, ground-glass opacities and high-attenuation areas in the bilateral lower lungs. After hospitalization and treatment, hypoxemia improved; however, chest CT showed marked progression of the high-attenuation areas, suggestive of pulmonary ossification (PO) in both lower lungs. The patient was transferred to a rehabilitation hospital; however, hypoxemia had improved at the time of discharge and chest CT showed marked improvement in the findings suggestive of PO.