This rare malformation is known as Abernethy type 1b, occurring in females who may present with congenital heart disease.

This patient was diagnosed with ASD, VSD and cor triatriatum in childhood and these required surgical correction. Her congenital extrahepatic portosystemic shunt was not recognized until this acute presentation as she has no features of hepatic encephalopathy. Her portal vein connects to the IVC bypassing the liver; the liver is exclusively supplied by the hepatic artery. 

Hepatic angiogram demonstrated large hepatic arteries, but no active hemorrhage or vascular malformations. There were no hepatic tumors. Hemorrhage was presumably related to the enlarged blood vessels. The subcapsular hematoma resolved following percutaneous drainage and laparoscopic washout by the liver surgeon.

NB. Practical point: include vasculature in your systematic review. Vascular anomalies and diseases are frequently overlooked!