Progression to fibrosing diffuse alveolar damage in a series of 30 minimally invasive autopsies with COVID‐19 pneumonia in Wuhan, China

Abstract

Aims Coronavirus Disease 2019 (COVID‐19) caused by Severe Acute Respiratory Syndrome Coronavirus ‐2 (SARS‐CoV‐2) infection has been deemed as a global pandemic by World Health Organization. While diffuse alveolar damage (DAD) is recognized to be the primary manifestation COVID‐19 pneumonia, there has been little emphasis on the progression to the fibrosing phase of DAD. This topic is of great interest due to growing concerns regarding the potential long‐term complications in prolonged survivors. Methods Here we report a detailed histopathologic study of thirty autopsy cases with COVID‐19 virus infection, based on minimally invasive autopsies performed between February to March, 2020. Results The mean age was 69 years, with twenty (67%) males and 10 (33%) females and frequent (70.0%) underlying comorbidities. The duration of illness ranged from 16 to 82 (median=42) days. Histologically, the most common manifestation was diffuse alveolar damage (DAD) in 28 (93.3%) cases which showed predominantly acute (32%), organizing (25%), and/or fibrosing (43%) patterns. Patients with fibrosing DAD were one decade younger (p=0.034) and they had a longer duration of illness (p=0.033), hospitalization (p=0.037) and mechanical ventilation (p=0.014) compared to those with acute DAD. Patients with organizing DAD had a longer duration of illness (p=0.032) and hospitalization (p=0.023) compared to those with acute DAD. Conclusions COVID‐19 pneumonia patients who develop DAD can progress to the fibrosing pattern. While we observed fibrosing DAD in fatal cases, whether surviving patients are at risk for developing pulmonary fibrosis and the frequency of this complication will require further clinical and radiologic follow‐up studies.