Post-mortem Histopathologic Findings of Vital Organs in Critically Ill Patients with COVID-19.

Background: The scientific evidence concerning pathogenesis and immunopathology of the coronavirus disease 2019 (COVID-19) is rapidly evolving in the literature. To evaluate the different tissues obtained by biopsy and autopsy from five patients who expired from severe COVID-19 in our medical center.

Methods: This retrospective study reviewed five patients with severe COVID-19, confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and imaging, to determine the potential correlations between histologic findings with patient outcome.

Results: Diffuse alveolar damage (DAD) and micro-thrombosis were the most common histologic finding in the lung tissues (4 of 5 cases), and immunohistochemical (IHC) findings (3 of 4 cases) suggested perivascular aggregation and diffuse infiltration of alveolar walls by CD4+ and CD8+ T lymphocytes. Two of five cases had mild predominantly perivascular lymphocytic infiltration, single cell myocardial necrosis and variable interstitial edema in myocardial samples. Hypertrophic cardiac myocytes, representing hypertensive cardiomyopathy was seen in one patient and CD4+ and CD8+ T lymphocytes were detected on IHC in two cases. In renal samples, acute tubular necrosis was observed in 3 of 5 cases, while chronic tubulointerstitial nephritis, crescent formation and small vessel fibrin thrombi were observed in 1 of 5 samples. Sinusoidal dilation, mild to moderate chronic portal inflammation and mild mixed macro- and micro-vesicular steatosis were detected in all liver samples.

Conclusion: Our observations suggest that clinical pathology findings on autopsy tissue samples could shed more light on the pathogenesis, and consequently the management, of patients with severe COVID-19.