Histopathology of livers in patients with congenital portosystemic shunts (Abernethy malformation): a case series of 22 patients.

Congenital portosystemic shunt (CPSS) is a congenital anomaly resulting in partial or complete diversion of the portal blood into the systemic circulation. The literature on the histological changes in livers of patients with CPSS is limited. Liver histology of 22 consecutive patients managed in our institution between 2001 and 2016 was reviewed. Twenty-one patients were children at the time of diagnosis. Thirty-two specimens were available and consisted of three explant livers and 29 biopsy samples from 19 patients. Sixteen samples were from wedge biopsies taken at the time of shunt closure. Thirteen were from core needle biopsies taken during clinical work-up. A variable proportion of portal tracts contained prominent thin-walled channels (PTWCs) and arterio-biliary dyads. The proportion of portal tracts containing triads, arterio-biliary dyads and biliary monads varied considerably in the different samples. Dilated inlet venules, increase in the number of portal arteries or the presence of portal arteries of increased size, deposition of copper-associated protein, sinusoidal dilatation, capillarization and intralobular individual arteries were present. Physiological nuclear vacuolation of periportal hepatocytes was absent in most samples from our paediatric patients. Presence of PTWCs, arterial-biliary dyads, increased arterial profiles in portal tracts and lobule and lack of the physiological periportal vacuolated hepatocytes in children are the most characteristic histological changes of CPSS in the liver periphery.