Collateral circulation caused by end-stage hepatic alveolar echinococcosis.

BACKGROUND: Hepatic alveolar echinococcosis (HAE), as a benign parasitic disease with malignant infiltrative activity, grows slowly in the liver, allowing sufficient time for collateral vessels to emerge in the process of vascular occlusion. METHODS: The portal vein (PV), hepatic vein and hepatic artery were observed by enhanced CT and the inferior vena cava (IVC) by angiography, respectively. Analysis of the anatomical characteristics of the collateral vessels helped to look into the pattern and characteristics of vascular collateralization caused by this specific etiology. RESULTS: 33, 5, 12 and 1 patients were included in the formation of collateral vessels in PV, hepatic vein, IVC and hepatic artery, respectively. PV collateral vessels were divided into two categories according to different pathways: type I: portal -portal venous pathway (13 cases) and type II: type I incorporates a portal-systemic circulation pathway (20 cases). Hepatic vein (HV) collateral vessels fell into short hepatic veins. The patients with IVC collateral presented with both vertebral and lumbar venous varices. Hepatic artery collateral vessels emanating from the celiac trunk maintains blood supply to the healthy side of the liver. CONCLUSIONS: Due to its special biological nature, HAE exhibited unique collateral vessels that were rarely seen in other diseases. An in-depth study would be of great help to improve our understanding related to the process of collateral vessel formation due to intrahepatic lesions and its comorbidity, in addition to providing new ideas for the surgical treatment of end-stage HAE.