Abstract
Aim: Novel coronavirus pneumonia ( COVID-19) have emerged as major global health threats since December, 2019. Up to now, the histopathology of critical patient with COVID-19 remains largely undisclosed. Methods: We here performed lung organ dissection, and described the pathological changes of one COVID-19 critical patient by HE staining, immunohistochemistry and special staining including Masson staining, PAS staining and silver methenamin staining. Results: The whole lung tissue displayed diffuse congestive appearance or partly haemorrhagic necrosis on gross examination. The haemorrhagic necrosis was prominently present in outer edge of the right lobe of the right lung. The cut surfaces of the lung displayed severe congestive and haemorrhagic changes. The main pathological lung changes showed bronchiolitis and alveolitis with proliferation, atrophy, desquamation and squamous metaplasia of epithelial cells. Massive pulmonary interstitial fibrosis, and partly hyaline degeneration, variable degrees of hemorrhagic pulmonary infarction. Small vessels hyperplasia, vessel wall thickening, lumen stenosis, occlusion and microthrombosis formation. Focal monocytes, lymphocytes and plasma cells infiltrating into pulmonary interstitium. Atrophy, vacuolar degeneration, proliferation, desquamation and squamous metaplasia in alveolar epithelial cells. Alveolar cavity congestion was prominent, and contained mucus, edema fluid, desquamated epithelial cells, and inflammatory cells. We can also found several multinucleate giant cells and intracytoplasmic viral inclusion bodies. Masson staining indicated massive pulmonary interstitial fibrosis. Immunohistochemistry results showed positive for immunity cells including CD3, CD4, CD8, CD20, CD79a, CD5, CD38 and CD68. Conclusion: We show clinical pathology of critical patient with COVID-19, which might provide a deep insight of the pathogenesis and the severity of this disease.