Distinct histopathological features of post-COVID-19 cholangiopathy

Background: Cholangiopathy has been described in survivors of severe COVID-19, presenting significant clinical parallels to the pre-pandemic condition of secondary sclerosing cholangitis in critically ill patients (SSC-CIP). Aim: Herein, we examined the liver histopathology of individuals with persistent cholestasis following severe COVID-19. Methods: Post-COVID-19 cholestasis liver samples were subjected to routine staining techniques and cytokeratin 7 immunostaining, and the portal and parenchymal changes were semi-quantitatively analyzed. Results: All ten patients, five men, median age 56, interquartile range (IQR) 51–60, requiring mechanical ventilation. The median and IQR liver enzyme concentrations proximal to biopsy were in IU/L: ALP, 605 (390–1,105); GGT, 925 (776–2,169); ALT, 92 (86–110); AST, 90 (68–108); and bilirubin, 3 (1–6) mg/dL. Imaging revealed intrahepatic bile duct anomalies and biliary casts. Biopsies were performed at a median of 203 (150–249) days after molecular confirmation of infection. Portal and periportal fibrosis, moderate-to-severe ductular proliferation, and bile duct dystrophy were found in all patients, while hepatocyte biliary metaplasia was observed in all tested cases. Mild-to-severe parenchymal cholestasis and bile plugs were observed in nine and six cases. Mild swelling of the arteriolar endothelial cells was observed in five patients. A thrombus in a small portal vein branch and mild periductal fibrosis were observed in one case each. One patient developed multiple small biliary infarctions. Ductopenia was not observed in any patient. Conclusions: The alterations were similar to those observed in SSC-CIP; however, pronounced swelling of endothelial cells, necrosis of the vessel walls, and thrombosis in small vessels were notable.