Epithelioid sarcoma is a rare type of cancer that starts as a growth of cells in the soft tissue. It can happen anywhere on the body. It often starts under the skin on the finger, hand, forearm, knee or lower leg.

Epithelioid sarcoma can happen at any age. It most often affects teenagers and young to middle-aged adults. Epithelioid sarcoma tends to grow slowly. It can come back after treatment.

Epithelioid sarcoma is a type of cancer called a soft tissue sarcoma. These cancers happen in the body's connective tissues. There are many types of soft tissue sarcoma. Soft tissue sarcomas, including epithelioid sarcoma, are not common. It is best to seek care at a cancer center that has experience treating people with sarcoma.

Symptoms

Epithelioid sarcoma symptoms include a small, firm growth under the skin called a nodule. The nodule usually isn't painful or tender. Sometimes there is more than one nodule. Sometimes the nodule forms a sore on the skin that won't heal.

The nodules caused by epithelioid sarcoma most often grow on the fingers, hands or forearms. They also may grow on the knee or lower leg.

Causes

The cause of epithelioid sarcoma isn't known. This cancer causes a growth of cells in the soft tissue.

Epithelioid sarcoma starts when soft tissue cells get changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to grow and multiply quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells.

The cancer cells might form a growth that can be felt through the skin. The cells can break away and spread to lymph nodes and to other parts of the body. When cancer spreads, it's called metastatic cancer.

Risk factors

The risk of epithelioid sarcoma is higher in younger people. This cancer can happen at any age. But it happens most often in adolescents and young to middle-aged adults. It is less common in children and older adults.

There is no way to prevent epithelioid sarcoma.

Diagnosis

Epithelioid sarcoma can be hard to diagnose. It looks like problems that are much more common. Often healthcare professionals consider those more common problems first. For example, a sore on the skin that is not healing could be mistaken for a skin infection.

Tests and procedures used in the diagnosis of epithelioid sarcoma include:

• Imaging tests. Imaging tests take pictures of the body. They can show the location and size of an epithelioid sarcoma. Tests might include X-ray, MRI, CT and positron emission tomography, which is also called a PET scan.
• Getting tissue for testing. A biopsy is a procedure to remove a sample of tissue for testing in a lab. The tissue might be removed using a needle that is put through the skin and into the cancer. Sometimes surgery is needed to get the tissue sample. The sample is tested in a lab to see if it is cancer. Other special tests give more details about the cancer cells. Your healthcare team uses this information to make a treatment plan.

Treatment

Surgery is the most common treatment for epithelioid sarcoma. Sometimes other treatments may be used in addition to surgery. Treatment options may include:

• Surgery. Surgery involves removing the cancer and some of the healthy tissue around it. Taking some healthy tissue helps make sure that all the cancer cells are removed. Getting all of the cancer cells lowers the risk that the cancer will come back.
• Radiation therapy. Radiation therapy uses powerful energy beams to kill cancer cells. Radiation therapy is sometimes used before surgery to shrink the tumor. This can make it more likely that all of the cancer will be removed during surgery. Radiation therapy may be used after surgery to kill any cancer cells that might be left.
• Targeted therapy. Targeted therapy uses medicines that attack specific chemicals in the cancer cells that help them to grow. By blocking these chemicals, targeted treatments can cause cancer cells to die. Targeted therapy might be an option if you can't have surgery or if other treatments do not work. One targeted therapy used for epithelioid sarcoma is tazemetostat (Tazverik).
• Chemotherapy. Chemotherapy uses strong medicines to kill cancer cells. Chemotherapy may be an option for treating epithelioid sarcoma that spreads to other parts of the body. It also might be used when surgery is not an option.
• Clinical trials. Clinical trials are studies of new treatments. These studies provide a chance to try the latest treatment options. The side effects may not be known. Ask your healthcare team whether you might be able to take part in a clinical trial.

Preparing for an appointment

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you. If your health professional thinks you may have epithelioid sarcoma, that person may refer you to a specialist. Often, this is a doctor who specializes in cancer, called an oncologist.

Appointments can be short and being prepared can help. Here's some information that may help you get ready for your visit.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fasting before having a specific test. Make a list of:

• Your symptoms, including any that seem unrelated to the reason for the appointment.
• Key personal information, including recent life changes and family medical history.
• All medications, vitamins or other supplements you take, including the doses.
• Questions to ask your healthcare professional.

For epithelioid sarcoma, some basic questions to ask your healthcare professional include:

• Do I have cancer?
• Do I need more tests?
• What are my treatment options?
• What are the potential risks for these treatment options?
• Do any of the treatments cure the cancer?
• Can I have a copy of the pathology report?
• How much time can I take to consider the treatment options?
• Are there brochures or other printed materials that I can take with me? What websites do you recommend?
• What would happen if I choose not to have treatment?

Don't hesitate to ask other questions.

What to expect from your doctor

Your healthcare professional is likely to ask you several questions, such as:

• When did your symptoms begin?
• Have your symptoms been continuous or occasional?
• How bad are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?