What is Epithelioid Sarcoma?
Epithelioid sarcoma is a type of soft tissue sarcoma that typically appears in the extremities (especially in the arms and hands). It also can develop in the main part of the body. It can affect both children and adults but is most common in young adulthood.
Epithelioid sarcoma is rare and commonly misdiagnosed. That is why it is so important for people who have this condition to receive care from specialists who have extensive experience in diagnosing and treating it.
What Causes Epithelioid Sarcoma?
Experts do not know what causes epithelioid sarcoma, but the disease is linked with an abnormality in the SMARCB1 gene (sometimes called INI-1). Doctors can order testing of the tumor to identify this abnormality when confirming a diagnosis of epithelioid sarcoma.
What Are the Signs and Symptoms of Epithelioid Sarcoma?
People who have epithelioid sarcoma usually notice a lump or mass somewhere in the soft tissue of their body. The mass can range in size from small to large. You can feel and sometimes see it. Sores or ulcers may appear over the mass or lump.
Epithelioid sarcoma can be present for months or even years before a person notices a mass.
In most cases, epithelioid sarcoma does not spread. If it does spread, lymph nodes, the lungs and bones are the most common sites.
How Is Epithelioid Sarcoma Diagnosed?
Patients will need a physical exam, blood work and imaging tests to diagnose epithelioid sarcoma. These tests help the doctor learn the exact size and location of the tumor and help to see if the cancer has spread. They also can be used to help with surgical planning.
Imaging tests might include:
- Magnetic resonance imaging (MRI)
- Computed tomography (CT)
- A chest CT
- Positron emission tomography (PET), a test that measures important body functions and also can show whether the cancer has spread.
Patients will also have a biopsy where the doctor removes a small piece of the tumor. A specialist examines the tissue under a microscope to check for the SMARCB1 or INI-1 marker. The results may guide the team as it develops a treatment plan.
What Are the Stages of Epithelioid Sarcoma?
Staging of epithelioid sarcoma is based on the size of the tumor and whether it has spread to lymph nodes or distant sites in the body. If the tumor has not spread, it is considered to be localized. Metastatic epithelioid sarcoma means the tumor has spread past nearby tissues to lungs or other organs.
How Is Epithelioid Sarcoma Treated?
The patient may have a procedure, called a wide resection with margins, to remove the tumor and some tissue around the tumor. If the doctor is concerned that the cancer has also spread to nearby lymph nodes, they may also be removed.
Patients may have radiation treatment before surgery to make the tumor smaller. After surgery, additional radiation therapy can help kill any tumor cells left in the body.
The doctor will make a plan for radiation based on the treatment goals and the location of the tumor.
Two types of radiation are used, regular radiation or proton radiation. Proton radiation has less side effects because it kills the tumor but does not hurt organs and healthy tissue. Cincinnati Children’s is one of the few pediatric hospitals in the country that offers proton therapy.
If the tumor is large or has spread to other areas, the doctor may recommend chemotherapy or other types of drugs to help kill the cancer cells.
Clinical Research Trials
Epithelioid sarcoma can be challenging to treat. In some situations, the doctor may recommend participating in a clinical trial at Cincinnati Children's. Researchers − including those at Cincinnati Children’s − are testing experimental therapies that target the SMARCB1 genetic mutation that is associated with epithelioid sarcoma and other tumor types.
Follow-up imaging tests can help monitor how the cancer is responding to treatment.
What Is the Long-Term Outlook for People with Epithelioid Sarcoma?
Prompt diagnosis and treatment can greatly improve the outcome for patients with epithelioid sarcoma. That is why it is vitally important for patients to receive care at a hospital such as Cincinnati Children’s, whose sarcoma team has experience in diagnosing and treating this rare type of cancer.
Most people who are treated for epithelioid sarcoma before the cancer spreads fare well. But the disease is more challenging to treat if it has spread. Other factors, such as the gender or age of the patient, do not seem to affect the outcome significantly.