Fig. 5

Complementary examinations (PA Chest X-ray, CT-scan, light microscopy and transmission electron microscopy) from case 2. A PA chest radiograph shows ground-glass opacification of bilateral perihilar region and the peripheral middle third of the right hemithorax. B Abdominal contrast-enhanced CT showing a short stenosis of the proximal transverse colon with mild involvement of the pericolic fat and proximal dilation of the ascending colon and small intestine (white arrow). C-D Haematoxylin and eosin staining of the surgical specimen. C Mucosal necrosis, haemorrhage, and submucosal oedema were observed (×40). D Transmural ulcer showed abundant granulation tissue, chronic inflammation, fibrosis, and steatonecrosis, findings consistent with intestinal ischaemia (×200). E Electron micrograph of the surgical specimen showing virus particles (red circle) in an oedematous, damaged endothelial cell. F Low-power high-resolution electron micrograph with markedly oedematous endothelial cells and pericytes, congested capillaries with red blood cells and platelets, endothelial cell containing enlarged nuclei and active nucleoli. All these features are a reflection of endothelial cell stress, damage, and reactive changes