A synovial cyst is a subcutaneous swelling that occurs in the joints. It is in the form of a ball containing a viscous liquid. In the majority of cases, the synovial cyst is harmless and resolves spontaneously. However, treatment may be considered in the event of pain and discomfort.

Definition of synovial cyst

Synovial cyst is a type of cyst, that is, a pocket that contains a liquid or semi-solid substance and develops in a tissue or organ. The synovial cyst contains synovial fluid, a viscous and transparent fluid present in the joints. Synovial fluid plays a role in the nutrition and lubrication of the joints.

Possible locations

A synovial cyst can form in different joints. The most common is the synovial cyst of the wrist. It is also possible to see this type of cyst in the feet, fingers, knees, elbows or even the spine.

Causes of synovial cyst

This type of cyst is usually caused by excessive and / or repetitive movements in a joint.

Diagnosis of synovial cyst

Diagnosis is usually based on:

• a physical examination accompanied by a questioning to assess symptoms and rule out other possible causes;
• an x-ray, a medical imaging examination which makes it possible to specify the nature and location of the cyst, as well as to verify its harmlessness;
• magnetic resonance imaging (MRI), another medical imaging test that is considered in the presence of an atypical form of cyst.

People affected by the synovial cyst

The development of a synovial cyst is often seen in children. However, it can occur at any age and does not seem to be predominant in women or men.

The development of a synovial cyst is favored by over-stressing the joint, especially in the event of intense and / or repeated efforts.

• Skin swelling: The synovial cyst usually results in the appearance of skin swelling in a joint. This cyst looks like a subcutaneous ball that can measure a few millimeters in diameter or sometimes extend several centimeters. The volume of a cyst can indeed be extremely variable. Filled with viscous, gelatinous fluid, a synovial cyst remains relatively flexible to the touch.
• Discomfort and possible pain: A synovial cyst is usually little or no pain. However, over-straining the affected area can cause pain and discomfort. Some movements can be more difficult, especially hand movements during a synovial cyst of the wrist.

In the majority of cases, simple medical surveillance is put in place. Indeed, a large number of synovial cysts are harmless and resolve spontaneously.

Management of the synovial cyst is considered in the event of pain and discomfort. It can be based on two methods:

• removal of the entire cyst by surgery;
• puncture of the synovial cyst which consists of draining / emptying it.

Removal of the cyst is often preferred because it presents a lower risk of recurrence than puncture. Immobilization of the joint followed by functional rehabilitation should be provided after the operation.

To date, there are no preventive solutions. However, it is advisable to limit over-stressing the joint as much as possible. In particular, it is advisable to be vigilant when practicing sports regularly and intensively.