Desmoplastic (des-moe-PLAS-tik) small round cell tumors are a rare and aggressive type of cancer that often starts in the belly. But it can happen in other parts of the body too.

Desmoplastic small round cell tumors (DSRCT) begin as a growth of cells. They often form on the tissue that lines the inside of the belly and pelvis. That tissue is called the peritoneum. The cancer cells can quickly spread to other organs, such as the liver, lungs and bones.

Desmoplastic small round cell tumors are a type of soft tissue sarcoma. Soft tissue sarcoma is a term used to describe a large group of cancers that all start in the tissues that connect, support and surround other body structures.

Desmoplastic small round cell tumors can happen to anyone. But they're more common in teen and young adult males.

Treatment for this cancer typically involves a few different options. Those options might include surgery, chemotherapy, radiation therapy and targeted therapy.

The symptoms of desmoplastic small round cell tumors depend on where the cancer begins. Most often it begins in the belly.

Signs and symptoms of desmoplastic small round cell tumors in the belly include:

• Swelling in the belly.
• Belly pain.
• Constipation.
• Nausea.
• Problems urinating.
• Weight loss.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you.

It's not clear what causes desmoplastic small round cell tumors.

In general, cancer begins when a cell develops changes in its DNA. A cell's DNA contains the instructions that tell a cell what to do. The changes tell the cell to multiply quickly. This creates a clump of cells called a tumor. The cancer cells can invade and destroy healthy body tissue. In time, the cancer cells may break away and spread to other parts of the body.

Healthcare professionals haven't found many risk factors for desmoplastic small round cell tumors. This cancer can affect anyone. But it's most common in males who are 15 to 35 years old.

To diagnose desmoplastic small round cell tumors, healthcare professionals may do imaging tests and a procedure to remove some tissue for testing, called a biopsy.

Biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. For desmoplastic small round cell tumors, the sample might be collected during surgery. Or the healthcare team may take the sample using a needle that's passed through the skin.

Lab tests can show whether there's cancer in the tissue sample. If there are cancer cells in the sample, other lab tests can be used to look at those cells to understand their DNA changes. The results can help rule out other similar types of cancer and make sure the diagnosis is correct. The test results also help guide the care team in choosing the best treatments.

Imaging tests

Imaging tests can help the care team understand the size and location of the cancer. Imaging tests may include ultrasound, CT, MRI and positron emission tomography (PET) scans.

Treatments for desmoplastic small round cell tumors include surgery, chemotherapy, radiation therapy and targeted therapy. Your treatment plan may depend on the cancer's location and whether it has spread to other parts of the body. Because this is an aggressive form of cancer that can be hard to control, most people need more than one type of treatment.

Surgery

The goal of surgery is to remove all the cancer. But that isn't always possible. That's because desmoplastic small round cell tumors often have irregular shapes that make them hard to remove completely. Surgery to remove all the cancer also can be hard if the cancer has spread to other organs. When that happens, chemotherapy may be used to shrink the cancer before surgery.

In other situations when it's not possible to remove all the cancer, surgery may be used to remove as much of it as possible. Then chemotherapy and radiation may be used after surgery to kill the cancer cells that remain.

Chemotherapy

Chemotherapy treats cancer with strong medicines. Chemotherapy may be used before surgery to shrink desmoplastic small round cell tumors. This makes it easier to remove the cancer with surgery. Chemotherapy also can be used after surgery to kill cancer cells that remain.

Chemotherapy may be a treatment option for cancer that spreads to other parts of the body. And it might help control symptoms, such as pain.

Different kinds of chemotherapy used for desmoplastic small round cell tumors include:

• Chemotherapy that affects the whole body. Chemotherapy is most often given as medicine that's put into a vein, so it travels throughout the body. It kills cells that grow quickly, including cancer cells. This kind of chemotherapy can be used to treat desmoplastic small round cell tumors anywhere in the body.
• Chemotherapy given only within the belly. Chemotherapy may be given directly to the area around the organs in the belly. That part of the body is called the peritoneal cavity. To give chemotherapy this way, the chemotherapy medicine is heated and then placed into the belly. The medicine is left in place for a set amount of time and then removed. This procedure is called hyperthermic intraperitoneal chemotherapy (HIPEC).

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. The energy can come from sources such as X-rays and protons. During radiation therapy, you lie very still on a table and a machine moves around you. The machine directs radiation to precise points on the body.

For desmoplastic small round cell tumors that affect the belly, radiation might be an option to kill cancer cells that remain after surgery. If cancer has spread to other areas of the body, radiation may be an option to help control symptoms such as pain.

Targeted therapy

Targeted therapy for cancer is a treatment that uses medicines that attack specific chemicals in the cancer cells. By blocking these chemicals, targeted treatments can cause cancer cells to die.

For desmoplastic small round cell tumors, targeted therapy might be used if cancer comes back after other treatment. It also may be offered if cancer has spread to other parts of the body. Your healthcare professional may have the cancer cells tested to see if targeted therapy is likely to work against the cancer. Targeted therapy can be used alone or with chemotherapy.

In time, you may find what helps you cope with the worries that may come with a diagnosis of desmoplastic small round cell tumors. Until then, you may find that it helps to:

Learn enough about desmoplastic small round cell tumors to make decisions about your care

Ask your healthcare team about your condition, including test results and treatment choices. As you learn more about desmoplastic small round cell tumors, you may become more confident in making treatment decisions.

Find a good listener

Finding someone who is willing to listen to you talk about your hopes and worries can be helpful as you manage your diagnosis. This could be a friend or family member. A counselor, medical social worker or clergy member also may offer helpful guidance and care.

Connect with others

Other people who've had desmoplastic small round cell tumors may be able to offer you support and insight because they understand what you're experiencing. Ask a member of your healthcare team about support groups in your area or contact the American Cancer Society. Find support online through Mayo Clinic Connect, which is a community where you can connect with others for support, practical information and answers to everyday questions.

Make an appointment with a healthcare professional if you have any symptoms that worry you. If your healthcare professional thinks you might have desmoplastic small round cell tumors, you may be referred to a doctor who specializes in treating cancer, called an oncologist.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do beforehand, such as not eating or drinking for a certain amount of time. Make a list of:

• Your symptoms, including any that may not seem related to the reason for which you scheduled the appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins or supplements you're taking and the doses.
• Questions to ask your healthcare professional.

Take a family member or friend along, if possible, to help you remember the information you're given.

For desmoplastic small round cell tumors, some basic questions to ask your healthcare professional include:

• What most likely is causing my symptoms?
• Are there other possible causes for my symptoms?
• What tests do I need?
• What are my treatment options?
• What are the potential side effects of each treatment option?
• I have other health conditions. How can I best manage them together?
• Should I see a specialist?
• Are there brochures or other printed materials I can take with me? What websites do you recommend?

Be sure to ask any other questions you may have.

What to expect from your doctor

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

• When did your symptoms begin?
• Are your symptoms always present, or do they come and go?
• How severe are your symptoms?
• What, if anything, makes your symptoms better?
• What, if anything, makes your symptoms worse?