Morphopathology of the lesions induced by SARS-CoV-2 infection in the lungs

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection spread rapidly from China around the world, causing the worst pandemic since the beginning of the 21st century. Although the disease named coronavirus disease 2019 (COVID-19) has multiple organ symptoms, the main pathological lesions occur in the lung, causing respiratory failure, pulmonary embolism, secondary bacterial pneumonia and pulmonary fibrosis. Despite the best efforts of researchers, the pathogenesis of SARS-CoV-2-induced cellular and tissue damage in organs and systems is poorly understood. Therefore, in our study, we aimed to highlight the pulmonary lesions and their extent, which could explain the complex symptomatology presented by patients who died with acute respiratory distress syndrome (ARDS). The study was performed on a number of 36 patients diagnosed with COVID-19 who died under legally suspicious conditions, requiring autopsy within the Romanian Forensic Medicine Institutes. All patients presented a local inflammatory reaction of pneumonic type, with exudative and proliferative phenomena, with intra-alveolar and interstitial inflammatory infiltrates formed by lymphocytes, macrophages and neutrophilic granulocytes, with congested or ruptured blood vessels with intra-alveolar or interstitial hemorrhages, with multiple thrombosis, with proliferation of local fibroblasts transformed into myofibroblasts and presence of granulation tissue that remodeled the entire lung parenchyma.