Solitary fibrous tumors are growths of cells that can form in almost any part of the body. The growths, called tumors, start from cells in the tissues that support other tissues in the body, known as connective tissues. Solitary fibrous tumors are rare. They mainly affect older adults.

Solitary fibrous tumors most often occur in the lining around the outside of the lungs, called the pleura. Solitary fibrous tumors that happen in the pleura are called pleural solitary fibrous tumors. Solitary fibrous tumors have also been found in the head and neck, breast, kidney, prostate, spinal cord, and other parts of the body.

Most solitary fibrous tumors are not cancerous. They don't spread to other parts of the body. Rarely, they can be cancerous, also known as malignant.

Solitary fibrous tumors tend to grow slowly. They might not cause symptoms until they grow large. Symptoms depend on where the tumor is in the body. If it's in the lungs, symptoms might include cough and shortness of breath.

Tests and procedures used to diagnose solitary fibrous tumor include:

• Imaging tests. Imaging tests make pictures of the body. They can show where a solitary fibrous tumor is, how large it is and if it has spread to other areas of the body. Tests for solitary fibrous tumor might include MRI, X-ray, CT, ultrasound and positron emission tomography, also called a PET scan.

• Removing a sample of tissue for testing, also called biopsy. 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 tumor. Sometimes surgery is needed to get the tissue sample.

  The sample is tested in a lab to see if it is cancer. Testing is done by doctors who specialize in analyzing blood and body tissue, called pathologists. Other special tests give more details about the tumor. Your health care team uses this information to make a treatment plan.

Treatment for solitary fibrous tumor often involves:

• Surgery. Most often, surgery is the only treatment needed for solitary fibrous tumors. Surgeons remove the tumor and a small amount of healthy tissue around it. The type of operation used to remove a solitary fibrous tumor depends on where the tumor is in the body.

  Other treatments might be used after surgery to lower the risk that the tumor will come back. These other treatments might include radiation or chemotherapy.

• Radiation therapy. Radiation therapy uses powerful energy beams to kill tumor cells. The energy can come from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around you. The machine directs radiation to precise points on your body.

  Radiation might be used after surgery if all of the tumor can't be removed. It might lower the risk that the tumor will come back after surgery. Sometimes radiation is used before surgery to shrink the tumor. This might make it more likely that the tumor is removed completely.

• Chemotherapy. Chemotherapy uses strong medicines to kill tumor cells. For a solitary fibrous tumor, chemotherapy might be used if the tumor has spread or can't be removed with surgery.
• Targeted therapy. Targeted therapy uses medicines that attack specific chemicals in the tumor cells. By blocking these chemicals, targeted treatments can kill tumor cells. Targeted therapy might be used if a solitary fibrous tumor is cancerous and has spread to other parts of the body.