What is a synovial sarcoma?
A synovial sarcoma is a rare type of soft tissue sarcoma that develops most frequently in tissues deep within the arms, legs, and feet. Also called synovial cell sarcoma, these malignant (cancerous) tumors got their name from similarities to cells in synovial joints—common joints such as the elbows and hips. Despite this connection, synovial sarcoma does not occur within joints.
Synovial sarcoma is the most common soft tissue cancer diagnosed around the foot and ankle. Less often, synovial sarcoma is found in the head, neck, chest, abdomen (belly), pelvis, and back. In some cases, it develops in organs such as the lungs.
Synovial sarcoma often starts as a small mass that doesn’t change for a period of time or may grow quite slowly. It is common for these sarcomas to be present for over a year or more before being diagnosed. As they grow, some tumors invade muscles, bones, nerves, and blood vessels. Synovial sarcomas can also metastasize, most often to the lungs. They may also spread to the bones, lymph nodes, and organs, including the brain.
Synovial sarcoma can recur (come back) to the same spot or spread (metastasize) to another area of the body. Expert, long-term follow-up care is essential to monitor for sarcoma return.
Synovial sarcomas are rare, with under 500 diagnosed in the U.S. each year. The tumors represent just 5 percent of the soft tissue sarcomas found annually. They tend to occur in teens and younger adults, most often affecting males in their 30s.
The Sarcoma Program at Penn Medicine’s Abramson Cancer Center offers one of the nation’s most experienced synovial sarcoma teams. We are experts at diagnosing this challenging cancer and offer sophisticated treatments. Our surgeons can often save arms and legs affected by synovial sarcoma.
Types of synovial sarcoma
Synovial sarcomas are categorized into two types, based on the appearance of the cells in the tumors:
- Monophasic: These tumors are made of just one type of tumor cell, either spindle cells or epithelial cells (less common).
- Biphasic: These tumors include both spindle cells and epithelial cells.
Synovial sarcoma symptoms
Synovial sarcomas often don’t cause symptoms when they are small. As they grow, you may experience:
- Noticeable lump
- Pain
- Swelling
What causes synovial sarcoma?
Cells in almost all synovial sarcomas have genetic changes (translocations). Researchers don’t know for sure why these changes happen.
We do not know definitive factors that may increase your risk for developing one of these tumors.
Making a synovial sarcoma diagnosis
Your care team will do a physical exam, discuss your symptoms, and order imaging tests to assess the size and location of any abnormal growths. After reading the imaging results, your doctor may recommend a tissue biopsy to confirm a diagnosis. This information helps determine the stage of any cancerous growths and plan the most appropriate treatment for you.
Synovial sarcoma treatment
Surgery is typically needed to remove any cancerous growths along with a border of healthy tissue to ensure no cancer cells are left behind. Depending on the characteristics of the tumor, treatment may also include radiation therapy and chemotherapy.
In some cases, advanced therapies may be recommended. These include t-cell therapy drugs, pioneered at Penn Medicine, which uses the body’s own immune system to fight cancer, and kinase inhibitor drugs, which are targeted therapies that stop or slow the growth of cancer cells.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.