Malignant hepatic vascular tumors in adults: Characteristics, diagnostic difficulties and current management

Abstract

Malignant vascular tumors of the liver include rare primary hepatic mesenchymal tumors developed in the background of a normal liver parenchyma. Most of them are detected incidentally by the increased use of performing imaging techniques. Their diagnosis is challenging, involving clinical and imaging criteria, with final confirmation by histology and immunohistochemistry. Surgery represents the mainstay of treatment. Liver transplantation (LT) has improved substantially the prognosis of hepatic epithelioid hemangioendothelioma (HEHE), with 5-year patient survival rates of up to 81%, based on the European Liver Intestine Transplantation Association-European Liver Transplant Registry study. Unfortunately, the results of surgery and LT are dismal in cases of hepatic angiosarcoma (HAS). Due to the disappointing results of very short survival periods of approximately 6-7 mo after LT, because of tumor recurrence and rapid progression of the disease, HAS is considered an absolute contraindication to LT. Recurrences after surgical resection are high in cases of HEHE and invariably present in cases of HAS. The discovery of reliable prognostic markers and the elaboration of prognostic scores following LT are needed to provide the best therapeutic choice for each patient. Studies on a few patients have demonstrated the stabilization of the disease in a proportion of patients with hepatic vascular tumors using novel targeted antiangiogenic agents, cytokines or immunotherapy. These new approaches, alone or in combination with other therapeutic modalities, such as surgery and classical chemotherapy, need further investigation to assess their role in prolonging patient survival. Personalized therapeutic algorithms according to the histopathological features, behavior, molecular biology and genetics of the tumors should be elaborated in the near future for the management of patients diagnosed with primary malignant vascular tumors of the liver.

Keywords: Hepatic malignant vascular tumors; Hepatic small vessel neoplasia; Hepatic perivascular epithelioid cell tumor; Hepatic hemangiopericytoma; Hepatic epithelioid hemangioendothelioma; Kaposi sarcoma; Hepatic angiosarcoma; Diagnostic; Prognostic; Treatment

Core tip: Primary malignant vascular tumors of the liver are rare mesenchymal tumors, most commonly detected incidentally using modern imaging techniques. They have variable clinical and imaging features, histology, immunohistochemistry, and molecular findings; therefore, their diagnosis may be difficult. Surgery represents the mainstay of treatment. Hepatic angiosarcoma has a dismal outcome and represents a contraindication for liver transplantation. Development of novel antiangiogenic and other molecular targeted treatments are needed to improve the patient outcome. This paper provides an overview of this group of tumors based on the most recent literature data, encompassing modern information regarding diagnostic challenges, prognostic factors and perspective therapeutic approaches.