Soft Tissue Cysts
Soft tissue cysts are benign soft tissue masses that develop in tendons or the tissue that surrounds a joint (joint capsule or synovial membrane). The most common sites that cysts form are the tendons of the wrists, hands, ankles, feet, and knees. Soft tissue cysts can become painful if they press on nearby nerves; they can also affect motion if located near a joint.
Why cysts develop isn’t known but they tend to be associated with repeated trauma to an area or joint. People with osteoarthritis often to develop cysts in the joints of the hands and behind the knee if arthritis has affected those joints. Cysts are slightly more common in women.
Many cysts resolve with no treatment or when the underlying problem has been treated (such as when a total knee replacement is done for osteoarthritis of the knee). If symptoms are not relieved by conservative management then surgical excision may be considered. Complete excision usually resolves the symptoms and this typically prevents recurrence.
Some of the more common types of cysts include:
- Ganglion cysts – most common in the tendons of the wrists and hands
- Baker’s cyst (popliteal cyst) – located in the back of the knee
If there is a suspicion that the cyst is behaving differently than a benign mass, the treating physician may recommend a biopsy to rule out a cancerous process like a synovial sarcoma.
It is important to let a physician know of any changes in the size of the cyst or pain associated with a soft tissue cyst.