Vessels that encapsulate tumour clusters vascular pattern in hepatocellular carcinoma

Vessels that encapsulate tumor clusters (VETC) is a distinct histologic vascular pattern with a novel mechanism of metastasis. First described in human cancers in 2004, its prevalence and prognostic significance in hepatocellular carcinoma (HCC) has only been appreciated in the past decade with a rapidly increasing body of literature. A robust biomarker of aggressive disease, VETC pattern is easy to recognize but relies on histologic examination of tumor tissue for its diagnosis. Radiological recognition of VETC pattern is an area of active research and is becoming increasingly accurate. As a prognostic marker, VETC has consistently proven to be an independent predictor of disease recurrence and overall survival in HCC patients undergoing resection and liver transplantation. It can also provide treatment guidance by predicting response to other therapies such as transarterial chemoembolization and sorafenib. Without prospective randomized controlled trials or routine evaluation of VETC in clinical practice, there are currently no firm treatment recommendations for VETC-positive tumors, although some perspectives are provided in this review based on the latest knowledge of their pathogenesis – a complex interplay between tumor angiogenesis and the immune microenvironment. Nevertheless, VETC has great potential as a promising future biomarker which takes HCC one step closer as a target for precision medicine.