Epithelioid Hemangioendothelioma - Cause, Symptoms, Diagnosis, and Treatment

Introduction

Epithelioid hemangioendothelioma (EHE) is an uncommon type of cancer that originates from the endothelial cells lining the blood vessels in the body, including veins, arteries, and capillaries. EHE can develop in multiple locations of the body, including the liver, lungs, and bones, as well as the head, neck, thyroid, stomach, ovary, prostate, brain, spine, and others. EHE can occur as a solitary tumor, multiple tumors in a single organ, or multiple tumors affecting different organs. Unfortunately, EHE is often not diagnosed until it has already metastasized to multiple organs.

Does Epithelioid Hemangioendothelioma Have Malignant Characteristics?

EHE is a malignant tumor that has the ability to grow uncontrollably, infiltrate and harm healthy tissues in other parts of the body. It is a complex disease that varies between individuals. Some tumors can be aggressive and spread rapidly, while others grow slowly or regress spontaneously without medical intervention. This makes it challenging to find the severity of the tumor or how effective a treatment might be.

What Are the Symptoms?

The majority of individuals with EHE do not experience any noticeable symptoms. However, in cases where symptoms manifest, the most frequent indicators include unexplained weight loss, pain, and the presence of a mass that can be felt beneath the skin. The manifestation of symptoms often depends on the location of the tumors within the body. The followings are common signs and symptoms of EHE:

• Presence of a mass that may or may not be accompanied by pain.

• Unexplained weight loss.

• Fatigue and fever.

• Abdominal discomfort or pain (in the case of EHE in the liver).

• Respiratory difficulties, such as shortness of breath (when EHE affects the lungs).

• Coughing, or coughing up blood (when EHE affects the lungs).

• Clubbing of fingers or toes, a condition characterized by the enlargement of the fingertips or toes (when EHE affects the lungs).

• Bone pain, recurring fractures, or broken bones (when EHE affects the bones).

• Difficulty with mobility or walking (when EHE affects the spine).

What Is the Cause?

The development of malignant tumors, such as EHE, occurs when a healthy cell undergoes a transformation into a cancer cell that reproduces uncontrollably. Recent research has found that EHE is caused by a distinct genetic mutation resulting from an abnormal fusion between two chromosomes. This abnormality leads to the fusion of two genes, namely WWTR1 (also known as TAZ) and CAMTA1, which is responsible for the onset of EHE. To diagnose EHE, healthcare providers may search for indications of irregular chromosome attachments.

How Is EHE Diagnosed?

Given that EHE frequently does not produce symptoms, individuals typically discover the presence of one or more tumors incidentally during a diagnostic imaging test unrelated to EHE. Healthcare providers will assess the tumor's location, size, and whether it has metastasized to other body regions. The most common procedures used to diagnose EHE include:

• CT Scan: CT scan is used to identify EHE tumors in the chest, abdomen, and pelvis. A CT scan uses X-rays to scan the body and project images onto a computer screen that the provider sees. A CT scan allows the provider to see structures inside the body, like bones, organs, muscles, and blood vessels.

• MRI: To examine the presence of EHE tumors in the liver and bones, the healthcare provider might request an MRI. This imaging technique employs magnets and radio waves to scan the body and generate images that are displayed on a computer screen. A full-body MRI that examines the body from head to toe is especially effective in detecting bone tumors that have metastasized throughout the body.

• Core-Needle Biopsy: After a tumor is detected through CT or MRI, a core-needle biopsy can be performed to confirm whether it is EHE. This procedure involves using a large hollow needle to extract tissue from the tumor. Afterward, a pathologist examines the tissue under a microscope to detect any signs of cancer. Biopsies also help rule out other conditions that may be similar to EHE, such as breast cancer.

How Is EHE Treated?

Due to the rarity of EHE, there are no established treatment protocols. Therefore, the treatment plan will likely involve collaboration with multiple specialists who have experience treating sarcomas. The healthcare team may include a surgical oncologist, radiologist, and other specialists with expertise in treating specific organs or body systems, such as an orthopedic surgeon, liver transplant specialist, and pathologist. The treatment plan will depend on various factors, such as the number and size of tumors, their location, and whether the cancer has spread. The following treatments may be used:

• Watchful Waiting: If EHE is detected early, and the patient is not experiencing symptoms or is not a good candidate for surgery, the provider may choose a "wait and see" approach and monitor cancer closely without immediate treatment. Sometimes, these tumors shrink without treatment, while in other cases, they grow slowly over several years. If the cancer worsens, the provider may suggest a different approach.

• Surgery: Surgical procedure is the primary approach for treating EHE involving a single tumor. During the procedure, the surgeon will extract the tumor and surrounding healthy tissue to ensure no cancer cells remain.

• Vascular Embolization: The provider may perform embolization to cut off the blood supply to the tumor, either as a standalone procedure or to shrink a tumor before surgery. Types of embolization for EHE include transarterial chemoembolization (TACE) and radioembolization.

• Targeted Therapy: Advanced EHE is most commonly treated with targeted therapy, which uses drugs to prevent tumors from receiving the nutrients and oxygen they need to grow.

• Radiation Therapy: Radiation treatment may be recommended after surgery to kill any remaining cancer cells, as well as for symptom relief. This kind of therapy uses targeted energy beams to destroy cancer cells.

• Chemotherapy: Although not common, the provider may recommend chemotherapy combined with other treatments if the cancer is more advanced. Chemotherapy involves using drugs to eliminate cancer cells, but further research is required to identify the potential uses of chemotherapy for EHE treatment.

• Organ Transplant: An organ transplant is required in case of multiple tumors that affect a major organ, such as the liver.

What Is the Prognosis?

There is limited information available regarding life expectancy for individuals with EHE due to the rarity of the disease, which means that researchers are still gathering data about it. Additionally, the severity of EHE can differ from case to case, with some individuals experiencing aggressive progression despite treatment. In contrast, others may remain asymptomatic and have tumors that do not spread for many years. In some cases, tumors may even shrink without intervention.

Conclusion

Epithelioid hemangioendothelioma (EHE) is a rare and complex cancer that can occur in various parts of the body. It is a malignant tumor that can be aggressive or slow-growing, and its symptoms often depend on the location of the tumors. A genetic mutation causes EHE and is usually diagnosed incidentally during diagnostic imaging tests. Since the disease is uncommon, there are no established treatment protocols, and the course of treatment will depend on several factors, including the number and size of tumors, their location, and the extent of the cancer's spread.