Epithelioid Hemangioendothelioma (EHE) is a rare cancer that belongs to the group of cancers called sarcomas. EHE is a vascular sarcoma. This means it originates in the cells that line the inside of blood vessels. ‘Epithelioid’ refers to the elongated shape of the cells when seen under the microscope. The estimated incidence of this rare tumor is less than 1 per million people. However, recent scientific advances and successful efforts in raising awareness have drastically improved the correct diagnosis of EHE. It might be more common than had been estimated in the past. EHE appears more frequently in females than in males, and can be found in all ages but seems to be more prevalent in young adults. Most common locations of EHE are lungs, liver and bones. But it also found in soft tissue, skin, blood vessels and many other organs of the body.
As is the case with many other cancers, EHE is caused by a genetic malfunction, a specific chromosomal rearrangement or translocation (swapping of genetic material) called the ‘WC Fusion.’ This discovery was made by dedicated scientists studying the molecular biology of EHE. This genetic malfunction is found in 90% of EHE patients.The translocation creates a new ‘fusion gene,' which in turn generates a new fusion protein that is highly likely to be responsible for the abnormal endothelial growth seen in EHE. The WC Fusion is specific to EHE and as a result can be considered ‘disease-defining’ for EHE. There is a much rarer phenotype of EHE with YAP1-TFE3 fusions, but similar morphologic features. This unique to EHE (disease -defining) genetic makeup is currently being studied by Dr. Brian Rubin at Cleveland Clinic as an opportunity for development of a targeted therapy for EHE.
The prognosis or outlook for each person is unique, and depends on many different factors. They include EHE location, the extent of the disease, and the individual biological behavior of this disease. EHE can be indolent (slow growing) and may be characterized by slow tumor growth and mild symptoms. Some patients have no symptoms for years. Rarely, EHE tumors can even go into spontaneous regression. EHE tumors may also grow rapidly, spread or exhibit destructive behavior, even after long periods of dormancy. In short, EHE is unpredictable. Therefore, routine surveillance scans are often done to start treatment for growing tumors. Only a cancer sarcoma specialist familiar with EHE can advise about your individual prognosis and risks.
This is not a question that is easily answered. Hopefully, from the information we have shared, it is will be clear that each patient with EHE has their own unique disease behavior. If you have been diagnosed with EHE, the most important thing you can do is to make sure that your medical team has EHE experience or has contacted specialists with EHE experience. These specialists, together with your own medical team, will be able to give advice and provide the best treatment plan for your specific circumstances. Please connect with our Patient and Support Services Team who can provide information that will help guide you to the right specialists and treatment.