Solitary Fibrous Tumors (SFTs) are a rare form of sarcoma, making up to 2% of all sarcoma diagnoses. SFTs are rare but aggressive tumors that typically develop in older individuals.
These tumors can occur anywhere in the body. The signs and symptoms of solitary fibrous tumor vary greatly based on the location and size of the tumor. SFTs begin in connective tissue that supports and surrounds other body structures. These tumors most often originate around the lungs, abdomen, head and neck and are most frequently found in the brain, pleura/chest wall, the membrane surrounding the lungs, and extremities. Solitary fibrous tumors can also grow in tissues in the breast, kidneys, prostate, spinal cord and other body regions. In the past, SFT was called hemangiopericytoma. If SFT originates in the central nervous system (which includes the brain), it’s referred to as hemangiopericytoma, in some cases.
The Horowitz Solitary Fibrous Tumor Initiative at Sylvester was established to support research toward a cure for this extremely rare type of soft tissue sarcoma.
Are solitary fibrous tumors cancerous?
While most SFTs are benign (not cancerous) or locally aggressive, about 15% show malignant (cancerous) characteristics or can become malignant, in some cases.
Causes of Solitary Fibrous Tumor
The exact cause of solitary fibrous tumors is unknown, and there is no known way to prevent them. These tumors begin when cells undergo DNA changes that tell the cells to grow and divide more rapidly than they should. This causes abnormal cell growth that can form an SFT. Research points to the presence of a specific gene mutation (NAB2, STAT6) in SFT patients. But, it remains unknown if this mutation causes SFT or is the result of SFT. The cause of this mutation is also unknown.
Risk Factors
The main risk factor for solitary fibrous tumors is advancing age. SFTs are most commonly found in patients age 50 to 70. A predisposition to SFT may be hereditary (passed down in the genes). In addition, the cause of SFT may be environmental (such as exposure to a toxin that causes cancer).
Diagnosis
SFTs often grow slowly and unpredictably and may not cause noticeable symptoms until they reach a larger size. In many cases, SFT is discovered incidentally through imaging or after surgery. Because SFT can arise anywhere in the body and mimic other conditions, it is often misdiagnosed at first. Accurate diagnosis usually requires a biopsy and molecular testing, including STAT6 immunostaining or identification of a NAB2-STAT6 gene fusion.
To locate and diagnose solitary fibrous tumors, providers at Sylvester Comprehensive Cancer Center perform one or more of the following tests.
- Imaging tests for SFTs might include MRI, X-ray, CT, ultrasound and positron emission tomography (PET) scan. These scans can show where a solitary fibrous tumor is, how large it is and if it has spread to other areas of the body.
- A biopsy procedure removes a sample of tissue for lab testing to check for the presence of cancer cells and provide other details about the tissue. This requires the use of a needle or minor surgery to get the sample.
- Genetic and molecular testing may provide a deeper understanding of what’s contributing to a solitary fibrous tumor’s behavior and growth at the DNA and RNA levels.
Treatments for Solitary Fibrous Tumor
Patients with SFT must receive treatment from a multidisciplinary team of experts. Primary care physicians cannot create nor manage treatment plans for SFT. Sylvester Comprehensive Cancer Center, part of the University of Miami Health System, offers a research-based, multidisciplinary approach to patient care. Each patient’s treatment options are based on several factors, including the patient’s age and the location, size and appearance of the tumor(s). The team also evaluates each patient’s risk level to estimate the chance of the tumor metastasizing or recurring after treatment.
For nonmetastatic SFTs, the primary treatment is surgical resection. Given the risk of metastasis, follow-up monitoring is highly recommended for all patients. When the disease is metastatic, a more systemic approach, such as chemotherapy and targeted agents, is recommended.
Localized Treatments (targeting one area)
Surgery is commonly used to remove a solitary fibrous tumor and a small amount of healthy tissue around the tumor. For some patients, this is the only treatment needed. The type of operation used to remove a SFT depends on where the tumor is in the body. For some patients, other treatments like radiation therapy or chemotherapy might be recommended after surgery to lower the risk that the tumor will come back or spread to other parts of the body.
Radiation Therapy uses X-rays, protons or other energy sources to kill tumor cells inside the body. Patients undergoing this type of therapy lie on a table while a radiation machine moves around them, directing radiation to targeted points on the body. Radiation therapy can be used before or after surgery to lower the risk that a SFT will return. If a tumor is in a location that is not safe for surgery, radiation therapy may be recommended instead.
Systemic Treatments (medication)
Chemotherapy (a type of medication typically administered via IV) might be recommended to kill tumor cells if the tumor has spread or can’t be removed with surgery.
Targeted Therapy uses medicines to block specific chemicals in tumor cells, which can kill these cells. This type of therapy might be recommended if a SFT has spread to other parts of the body.
Experimental Treatments
Participating in clinical trials is a way for SFT patients to contribute to Sylvester research seeking better tolerated and more effective therapies while possibly receiving novel treatment options.
Follow-up and Survivorship Care
The experience of living with SFT extends far beyond the operating room or infusion chair. The Sylvester Survivorship Care program helps patients understand and manage the physical, emotional, and lifestyle challenges that may persist or arise after diagnosis and treatment. Whether you’re newly diagnosed, recovering from surgery, managing long-term side effects, or living with metastatic disease, Sylvester can offer insights and resources to help you and your loved ones adapt, cope, and thrive.
SFT can recur years or even decades after the end of initial treatment. Follow-up care focuses on managing treatment side effects and disease monitoring to determine if the cancer has recurred or spread (metastasized) to another part of the body. Sylvester’s multidisciplinary care team includes surgeons, medical oncologists, radiation oncologists, and cancer support services including nutrition guidance, acupuncture, art and music therapy, physical therapy, exercise oncology, support groups, and more.
At Sylvester, follow-up care includes patient-specific guidance on:
- new symptoms to look for
- frequency of recommended bloodwork
- which imaging scans are needed and how often
- how recurrence patterns differ by tumor location and malignancy score
- follow-up consultations with the patient’s care team
- managing treatment side effects
Research on Solitary Fibrous Tumor
An extremely limited number of studies to date have evaluated the molecular process of SFT to include characterizing the NAB2-STAT6 translocation, understanding the causes, developing cell lines and a prospective trial for SFT. Data are limited to retrospective studies and one cell line manufactured by a mouse PDX model. Treatment options are limited, and there are currently no FDA-approved treatments specifically for SFT.
Research shows that SFTs are marked by CD34 and STAT6, although they are often misdiagnosed because of features that match those of other tumors. In 2013, three research groups published the identification of NAB2–STAT6 fusion within chromosome 12. The molecular hallmark of these tumors is the recurrent fusion of NAB2 and STAT6 genes located at chromosomal region 12q13.
To date, no studies have examined risk factors specific to solitary fibrous tumor.
The Horowitz Solitary Fibrous Tumor Initiative was established in 2023 to help fund and advance much-needed research on this disease. The Initiative’s research efforts, conducted by Sylvester physician-scientists, aim to find better tolerated, more effective therapies and a cure for solitary fibrous tumor. Patient registration and donations are accepted on the Initiative’s website.
Why Choose Sylvester Comprehensive Cancer Center?
Sylvester is an NCI-designated cancer center. The National Cancer Institute has reaffirmed us as South Florida’s only NCI-designated cancer center. We have been recognized for our scientific leadership, our commitment to training the next generation of cancer researchers and providers, as well as our engagement with the communities that we serve. For patients, this designation translates into greater access to leading-edge treatment options, including clinical trials that prioritize your specific cancer.
One of only six designated Cancer Centers of Excellence in Florida. We treat cancer, and only cancer, giving you the best potential outcomes. You can be confident knowing you are in the best possible place to treat your cancer in South Florida.
High volume experience treating many cases of sarcoma, bone, and soft tissue cancers. Our experience means better outcomes and fewer potential complications.
Targeted therapies and clinical trials for patients with tumor mutations. You can receive the most advanced treatment options available in the South Florida region.
Advanced radiation oncology tools. Our sophisticated technology provides precise tumor targeting, improved results, and less potential damage to nearby healthy tissue. These tools include RapidArc® intensity modulated radiation therapy (IMRT), and a Siemens 4D-CT scanner.
Expertise in custom-designed artificial prostheses, joints, and bone grafts. We can offer improved mobility and greater self-confidence for those with advanced cancers.
NanoKnife® treatment for previously considered inoperable tumors. This advanced approach, done under general anesthesia, produces very little pain and requires only a brief hospital stay — usually overnight — because it causes fewer side effects. Also called irreversible electroporation (IRE), NanoKnife can be repeated if new lesions develop. Sylvester was the first provider in Florida to provide this advanced treatment.
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