
Because synovial sarcoma does not cause symptoms in the initial stages, it may not be diagnosed until the cancer has advanced.
Synovial sarcoma (also called synovial cell sarcoma or malignant synovioma) is a type of soft tissue tumor that may at first present with painless lumps that are easy to overlook. Advanced tumors may cause symptoms such as pain, swelling, numbness, and reduced range of motion. Tumors in the head and neck region may cause disfigurement along with difficulty swallowing, chewing, and breathing.
If the tumor spreads to other parts of the body, such as the lungs, it may cause additional symptoms depending on the organ affected.
What factors affect the severity of synovial sarcoma?
How badly synovial sarcoma affects a person depends on:
- Location of tumor
- Size of the tumor
- Grade of the tumor (appearance of the tumor cells under the microscope)
- Stage of the tumor (the extent to which the tumor has spread in the body)
- Patient’s general health
- How early treatment was started
- Extent to which the tumor was removed during surgery
If the tumor was diagnosed when it was small and localized, it can be removed completely by leaving adequate tumor-free tissue margins. Such cases tend to have an excellent prognosis.
In the case of an advanced disease where the tumor was spread to other sites, including lymph nodes, the chances of survival may not be as good. The risk of metastasis depends on the grade of the tumor and is higher if the tumor is larger than 5 cm.
Almost 36%-76% of patients with synovial sarcoma live for at least 5 years after their first diagnosis.
Is synovial sarcoma inherited?
Rarely, synovial sarcoma is seen in certain inherited conditions, such as Li Fraumeni syndrome or neurofibromatosis type I, which also increases the risk of other soft tissue tumors.
In most cases, synovial sarcoma is not inherited, and hence, it does not run in families. It is a soft tissue tumor that is caused by the uncontrolled growth of cells in tissues, such as muscles and fibrous tissues (ligaments and tendons).
The exact cause of synovial sarcoma is not well understood. However, synovial sarcoma occurs when the gene SYT breaks from its original position along the chromosome and fuses to the gene SSX in a process called translocation. This translocation and fusion of the SYT gene with the SSX gene is used to diagnose synovial sarcoma.
Genes are bundled together inside cells in structures called chromosomes. There are 23 pairs of chromosomes in the human body, and the SYT gene is present on chromosome 18. The abnormal positioning of the SYT gene leads to the formation of two fusion proteins called SYT-SSX1 and SYT-SSX2. These proteins lead to uncontrolled cell growth and division, leading to tumor formation.
The genetic change that causes synovial sarcoma is called a somatic mutation. A somatic mutation means the genetic abnormality develops in some cells of the body during their lifetime and is not passed on to the next generation.
How common is synovial sarcoma?
Synovial sarcoma affects about 1-2 people out of every million people in the United States. This cancer, however, is one of the most common soft-tissue tumors in teenagers and young adults.
About one-third of patients diagnosed with synovial sarcoma are younger than 30 years old. Synovial sarcoma tends to affect males more than females.

SLIDESHOW
Skin Cancer Symptoms, Types, Images See SlideshowVargas B. Synovial Sarcoma. Medscape. https://emedicine.medscape.com/article/1257131-overview#a4
National Institutes of Health. Synovial sarcoma. https://rarediseases.info.nih.gov/diseases/7721/synovial-sarcoma
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