New Patient Guide

Understanding Solitary Fibrous Tumor

Solitary fibrous tumor (SFT) is a rare type of tumor that develops from connective tissue. It belongs to the family of soft tissue tumors and can sometimes behave like a cancer.

SFT can develop almost anywhere in the body, including the chest, abdomen, pelvis, arms, legs, head, and neck. It can also develop in the membranes covering the brain and spinal cord.

Some SFTs grow very slowly and never cause serious problems. Others grow more quickly, return after treatment, or spread to other parts of the body.

Because SFT behaves differently from person to person, understanding the characteristics of your own tumor is important.

You may see the name hemangiopericytoma (HPC) in older medical records, particularly for tumors involving the brain or spinal cord.

Many tumors previously called HPC are now classified as SFT. This change reflects advances in understanding the disease.

If your records use either name, ask your doctor whether they refer to the same diagnosis.

Most SFTs have a characteristic genetic change called the NAB2-STAT6 fusion. This happens when parts of two genes become joined together, changing how tumor cells regulate their growth.

This genetic change generally develops in the tumor during a person’s lifetime. SFT is not usually inherited, and there are no established links to diet, exercise, or other lifestyle choices.

There is no known action you could have taken to prevent SFT.

Making Sure Your Diagnosis Is Correct

Because SFT is rare, an accurate diagnosis is especially important.

Doctors usually diagnose SFT by examining a sample of tumor tissue from a biopsy or surgery. A specialist called a pathologist studies the tissue under a microscope and may perform additional laboratory tests.

One commonly used test looks for a protein called STAT6. A particular pattern of STAT6 staining strongly supports an SFT diagnosis when considered with the other pathology findings.

Some cases also require molecular testing to identify the NAB2-STAT6 fusion or help distinguish SFT from other tumors.

Ask your doctor

• Has a pathologist experienced with sarcoma reviewed my tumor?
• Was STAT6 testing performed?
• Is any additional testing needed to confirm my diagnosis?

You may benefit from having your pathology reviewed at a center that specializes in sarcoma, especially if your diagnosis is uncertain.

For more information, see Part 2: Getting the Diagnosis Right.

Understanding Your Tumor’s Risk

One of the first questions many people ask is, “How serious is my SFT?”

Unfortunately, there isn’t one simple answer.

Some tumors have a low likelihood of returning or spreading. Others have a higher risk, even after successful treatment. SFT can also return many years later.

You may hear your tumor described as benign, malignant, low risk, intermediate risk, or high risk. These terms can be confusing, and their meanings depend on the clinical situation.

For many SFTs outside the brain and spinal cord, doctors use a tool called the Demicco risk model.

It considers several factors:

Together, these findings help doctors estimate the risk of the tumor spreading.

For SFTs involving the brain and spinal cord coverings, doctors generally use a different grading system developed by the World Health Organization (WHO).

Other factors, including where the tumor is located, whether it can be completely removed, and certain pathology findings, also influence care decisions.

Risk models help doctors make decisions about treatment and follow-up care. They estimate what may happen among groups of patients with similar tumor characteristics.

Your risk score is an estimate, not a prediction of your individual future.

People with similar tumors can have very different experiences.

Ask your specialist to explain which risk assessment applies to your tumor, what your results mean, and how they affect your care plan.

You may hear about additional tumor changes involving genes such as TERT or TP53.

Researchers are studying whether these findings can help predict tumor behavior or guide treatment. Some are associated with more aggressive disease, but their clinical usefulness is still being evaluated.

Not every patient needs extensive molecular testing. Your specialist can help determine which tests may be useful in your situation.

Understanding Your Treatment Options

Treatment depends on several factors, including your tumor’s location, size, behavior, and whether it has spread.

When SFT is confined to one area and can be safely removed, surgery is usually the main treatment.

The goal is generally to remove the entire tumor while preserving important organs and normal function.

For some patients, surgery may be curative. Others may need additional treatment or monitoring because SFT can return, sometimes many years later.

If surgery is being considered, ask whether your case can be reviewed by a surgeon experienced in sarcoma or SFT.

This is especially important before a first operation, since the initial surgical plan can affect future treatment options.

Radiation uses focused energy to damage tumor cells.

It may be considered before or after surgery, or when a tumor cannot be safely removed. Decisions depend on where the tumor is located, how it behaves, and the potential benefits and risks of treatment.

For SFT involving the brain or spinal cord coverings, radiation may play an important role in selected cases.

Some patients may receive drug treatments, particularly if SFT cannot be removed or has spread.

These treatments can include medicines that target blood vessel growth, chemotherapy, or treatments being studied in clinical trials.

Your doctors may also discuss other local treatments depending on your situation.

Because SFT is rare, treatment plans are often individualized. Decisions are best made with clinicians experienced in treating sarcoma and, when possible, discussed by a multidisciplinary team.

If you have metastatic or advanced disease, see Part 5: Metastatic and Advanced SFT.

Finding the Right Care Team

You may already have an excellent doctor who is helping you through your diagnosis. However, because SFT is uncommon, many doctors will see very few cases during their careers.

A sarcoma specialist or multidisciplinary sarcoma team can help with diagnosis, treatment planning, and long-term follow-up.

An experienced team may include a medical oncologist, surgeon, radiation oncologist, pathologist, and radiologist.

Your local doctors and a specialized sarcoma center can often work together, allowing you to receive some care close to home.

Getting a second opinion is a reasonable part of planning care for a rare tumor.

If you have already had surgery or started treatment, a specialist can still review your records and help evaluate your next steps.

See Part 6: Finding a Sarcoma Center.

Planning for Long-Term Follow-Up

Even after successful treatment, SFT may return in the original location or spread to another part of the body.

Sometimes this happens many years after the first diagnosis.

For that reason, long-term follow-up is an important part of SFT care.

Your doctor may recommend regular imaging, such as MRI or CT scans, depending on where your tumor was located and your individual risk.

The timing and type of scans will vary. Your follow-up plan may change over time based on your medical history and new findings.

Before finishing treatment, make sure you understand

• What scans or tests you’ll need
• How often they’ll be scheduled
• Who will review your results
• What symptoms or changes you should report
• Who will coordinate your long-term care

See Part 3: Follow-Up and Surveillance.

Your First Steps After Diagnosis

You may already have completed some of these steps. Use this checklist to help identify what comes next.

• Confirm the diagnosis. Ask whether your pathology has been reviewed by a sarcoma pathologist and whether additional tests are needed.
• Connect with a sarcoma specialist. Ask your doctor for a referral or arrange a second opinion.
• Understand your tumor. Ask about its location, whether it has spread, and what is known about its risk.
• Discuss your treatment options. Understand the goals, potential benefits, risks, and alternatives before making decisions.
• Gather your medical records. Keep copies of pathology reports, scan reports, images, and treatment summaries.
• Understand the follow-up plan. Ask what monitoring will be needed and who will coordinate it.
• Find support. Talk with family, friends, your care team, or others who have experience with SFT.

You can also ask about participating in an SFT registry, research study, or patient community when you’re ready.

See Part 9: Joining Research.

A RARE COMPLICATION TO KNOW ABOUT

Low blood sugar (Doege-Potter syndrome)

A small number of people with SFT develop episodes of low blood sugar because their tumor produces an abnormal form of a hormone called IGF-2. This condition is known as Doege-Potter syndrome.

Possible symptoms include sweating, shakiness, weakness, dizziness, or confusion.

If you experience these symptoms, contact your medical team promptly. Severe confusion, seizures, or loss of consciousness require emergency medical attention.

This complication is uncommon, and most people with SFT will never experience it.