Liver Transplantation for Hemangioendothelioma

Epithelioid hemangioendothelioma is a rare vascular endothelial cell-derived tumor that occurs in one in a million cases, and one of the most common organs affected is the liver. Clinically, it can range from benign to aggressive. Due to its rarity, clinical management has not been standardized. For this reason, diagnosis is difficult, and it is often confused with other liver tumors. The prognosis is better than that of other liver malignancies. Laboratory findings are nonspecific, and tumor markers may also be elevated but are nonspecific. Imaging methods, particularly computed tomography and magnetic resonance imaging, are used. For a definitive diagnosis, a biopsy and immunohistochemical staining must be performed to demonstrate the staining of various endothelial cell antigens. Here, it is important to determine the hemangioma and sarcoma patterns with the help of genetic markers, as this will closely affect the course of the disease. Treatment is divided into two main categories: surgical and non-surgical. If possible, surgical treatment is the first recommended curative option. Surgical treatment includes liver resection and liver transplantation. Liver resection may be preferred in unilobar and unifocal dis-ease. However, liver transplantation may be more appropriate in patients with late diagnosis and multilobar and multifocal disease at the time of diagnosis. Extrahepatic metastasis is not considered a contraindication for curative surgery. Lung metastasis is the most common type of metastasis. The success rates of both surgical methods are similar, but it should be noted that studies have shown that patients who undergo resection are in earlier stages of the disease, while those who undergo transplantation are in later and more advanced stages. Being over 60 years of age, Asian ethnicity, male gender, tumors larger than 10 centimeters, symptomatic disease, and involvement of serosal surfaces in the body are poor prognostic factors. The success rate after transplantation is over 90% in the first year, while the 5-year results are around 80%. The presence of macrovascular invasion reduces the 5-year survival rate by half. The rate of complications after transplantation is also around 20%. Non-surgical treatments include chemotherapy, radiotherapy, immunotherapy, radiofrequency ablation, hormone therapy, chemoembolization, radioembolization, and arterial embolization. These treatments are more commonly used as a bridge to surgical treatment rather than as a curative first step. With chemotherapy alone, the 5-year survival rate is below 30%. Due to the vascular origin of the tumor, commonly used chemotherapeutic agents include anti-VEGF agents and interferon alpha-2B. It has been observed that this rate is much lower when no treatment is administered. New studies will also help to better understand tumor biology and improve neo- and adjuvant treatment protocols.

Keywords: Epithelioid hemangioendothelioma, hepatectomy, liver transplantation, transplant oncology