| Respiratory system: Lung | |
| 1. | Alveoli: Damaged or atypical enlarged pneumocytes with large nuclei, type II pneumocyte hyperplasia, diffuse alveolar damage (DAD), focal sloughing, hyaline membrane formation, intra-alveolar haemorrhage, intra-alveolar neutrophil infiltration, amphophilic granular cytoplasm and prominent nucleoli characteristic of viral cytopathic-like changes. Vessels: Oedematous and congested vessels, plug formation, fibrinoid necrosis of the small vasculature, hyaline thrombi in microvessels. Significant deposits of complements—C5b-9 (membrane attack complex), C4d, and mannose binding lectin (MBL)-associated serine protease (MASP)-2, in the microvasculature. Cellular components: Presence of syncytial giant cells, focal infiltration of immune and inflammatory (lymphocytes and monocytes) and increased stromal cells. Ultrastructural changes: Viral particles in bronchial mucosal epithelia and type II alveolar epithelia.
| Tian et al, Barton et al, Xu et al, Luo et al, Yao, Magroet al, Bradley et al |
| Urinary system: Kidney | |
| 2. | Glomerulus: Ischaemic changes, podocyte vacuolation, focal segmental glomerulosclerosis, accumulation of plasma in Bowman’s space. Renal tubules: Loss of brush border in proximal tubule, non-isometric vacuolar degeneration, and necrosis, oedematous epithelial cells. Vessels: Erythrocyte aggregates obstructing the lumen of capillaries without platelet or fibrinoid material with occasional hemosiderin granules and pigmented casts, hyalinosis of arteriole, arteriosclerosis of medium sized arteries, fibrin thrombus, shrinkage of capillary loops in glomeruli. Ultrastructural changes: Clusters of viral particles with distinctive spikes in the tubular epithelium and podocytes.
| Yao et al, Su et al, Tietäväinen et al, Grimes et al, Bradley et al |
| Gastrointestinal system | |
| 3. | Liver: Focal macrovesicular steatosis, nuclear glycogen accumulation in hepatocytes, dense atypical small lymphocytes in portal tracts. Regenerative nodules and thick fibrous bands, mild zone 3 sinusoidal dilatation, mild lobular lymphocytic infiltration. Patchy hepatic necrosis in the periportal and centrilobular areas. Hepatic cell degeneration and focal necrosis, biliary plugs in the small bile duct. Oesophagus: Occasional lymphocytic infiltration in the oesophageal squamous epithelium. Stomach: Partial epithelial degeneration, necrosis and shedding of the gastric mucosa. Dilatation and congestion of small blood vessels and oedema of lamina propria and submucosa with infiltration of immune cells (as lymphocytes, monocytes and plasma cells). Intestine: Stenosis of the small intestine and segmental dilatation. Numerous infiltrating plasma cells and lymphocytes with interstitial oedema in the lamina propria. Pancreas: Degeneration of the cells of islets.
| Tian et al, Yao et al, Liu et al,
Xiao et al |
| Cardiovascular system | |
| 4. | Foci of lymphocytic inflammation. Acute myocyte necrosis. Presence of inflammatory cells and apoptotic bodies. Ultrastructural observation: Viral inclusion bodies in vascular endothelial cells. Immunohistochemistry: Presence of CD61+ megakaryocytes in purpuric papulovesicular.
| Tian et al, Bradley et al, Wichmann et al, Tavazzi et al, Yao et al, Varga et al, Fox et al, Gianotti et al, Kolivras et al, Varga et al |
| Reproductive system | |
| 5. | Thickened basement membrane with peritubular fibrosis and vascular congestion. Leucocyte infiltration. Extensive germ cell destruction. TUNEL assay: Increased apoptotic spermatogonic cells.
| Jian Xu et al, Chen et al |
| Nervous system | |
| 6. | Acute hypoxic ischaemic injury, hyperaemia, oedema and neuronal degeneration. CT, MRI: Ischaemia and/or haemorrhage, and enhanced cortical/subcortical grey matter and fibre tracts. SARS-CoV-2 RNA was detected in the brain tissue and cerebrospinal fluid in some patients.
| Solomon et al, Mahammedi et al, Moriguchi et al |
| Histopathogical findings (skin) | |
| 7. | Vessels: Perivascular inflammatory cells, intraluminal thrombi. Epidermis: Parakeratosis, acanthosis, dyskeratotic keratinocytes, necrotic keratinocytes, acantholytic clefts, lymphocyte satellitosis and pseudoherpetic. Immunohistochemistry: ACE-2 positivity in basal layer of cells in hair follicle, sebaceous glands, smooth muscle cells.
| Hamming et al, Gianotti et al,
Kolivras et al |