Abstract
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has become a global pandemic. Many survivors of serious COVID-19 pneumonia have long-term residual pulmonary disease. However, there is little documentation of the histopathological characteristics of lung sequelae post-COVID-19 and effective treatments. We present two Japanese cases of lung sequelae post-COVID-19. The patients were histopathologically diagnosed with organizing pneumonia (OP) or OP with fibrosis and no diffuse alveolar damage on video-assisted thoracoscopic surgery. Case 1, who had been diagnosed with OP, was successfully treated with corticosteroid and other immunosuppressive agents over a 6-month period. Although case 2, who had been diagnosed with OP with fibrosis, had a partial and unsatisfactory response to immunosuppressive agents, the patient responded to antifibrotic treatment including nintedanib.