Radiologically suspected COVID-19-associated organizing pneumonia responding well to corticosteroids: A report of two cases and a review of the literature.

Organizing pneumonia (OP) is a type of diffuse interstitial lung disease, which may be induced in the context of several clinical conditions, such as drug reactions, infections, autoimmune diseases and cancer. Coronavirus disease 2019 (COVID-19)-associated OP has been reported as a late-stage consequence of the infection or a histological form of COVID-19-associated pneumonia. Autopsies and postmortem lung biopsies have demonstrated that the majority of patients with COVID-19-associated pneumonia develop secondary OP, and COVID-19-associated pneumonia and OP have common radiological features. The diagnosis of COVID-19-associated OP should be suspected in patients with severe acute respiratory syndrome coronavirus 2 infection who exhibit clinical deterioration despite optimal care, or who have aggravating symptoms following an initial recovery. The use of corticosteroids is a typical treatment for OP. However, to date, at least to the best of our knowledge, there are a few reports regarding the role of corticosteroids in COVID-19-associated pneumonia; thus, the optimal time for administration, the dose and treatment duration have not yet been determined. The present study presents two cases of patients with COVID-19, who exhibited clinical deterioration following the initial phase of infection and with radiological characteristics of OP who received corticosteroids and had a favorable outcome. The early diagnosis of COVID-19-associated OP may lead to targeted treatment, decreased requirements for ventilatory support and an improved survival rate.