Background: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has varied clinical and radiographic manifestations. Severe initial viral infection, cytokine release, opportunistic infection and post-viral inflammation may all contribute to progressive symptoms and severe lung injury. Acute fibrinous and organizing pneumonitis (AFOP), a rare pattern of acute lung injury characterized by intra-alveolar fibrin ball, has so far been reported associated with infections, connective tissue diseases, drugs and toxins, hematologic malignancy, altered immune status and inhalation injury.

Case presentation: The authors report a case of 26-year-old man with severe COVID-19 pneumonia that clinical and radiographic imaging worsened after episode of cytokine storm. The diagnosis of AFOP was confirmed by transbronchial biopsy, and the patient was successfully treated with high-dose corticosteroids.

Conclusions: AFOP can be found in severe COVID-19 patients especially when clinical deterioration occurs later in disease course. Clinical suspicion is needed for prompt diagnosis and treatment. High-dose corticosteroid is an effective medication.

Keywords: SARS-CoV-2; COVID-19; Acute fibrinous organizing pneumonia; Respiratory failure;
Viral pneumonia; Case report; Acute lung injury