A ganglion cyst is a common, non-cancerous, fluid-filled mass that frequently develops near joints or tendons in the hand and wrist. These sacs are the most common soft tissue mass found in this area. While many people only notice a visible lump, the cysts can cause discomfort, tingling, or weakness, depending on their location and size. This article explains the nature of these cysts and the specific mechanisms through which they can affect the wrist joint.
Understanding Ganglion Cysts
A ganglion cyst is a sac filled with a thick, jelly-like fluid that originates from a joint capsule or a tendon sheath. This viscous fluid is similar to the synovial fluid that lubricates the body’s joints. Cysts typically form a connection, or stalk, to the underlying joint or tendon structure, allowing the fluid to move into the sac.
The precise cause of formation is not entirely understood, but theories suggest they are linked to micro-trauma or a degenerative process. Repetitive stress can cause a tear in the joint lining, allowing fluid to leak out and coalesce into a lump. Most cysts appear on the back (dorsal side) of the wrist, though they can also form on the palm side. The size of the cyst often fluctuates, becoming larger with increased activity and shrinking with rest.
How Cysts Cause Wrist Pain
Many ganglion cysts are asymptomatic, presenting only as a visible mass. Pain occurs when the cyst physically interferes with adjacent anatomical structures. The discomfort is caused by the pressure it exerts on nearby nerves and soft tissues, ranging from a dull ache to a sharp, localized sensation.
Direct nerve compression is a mechanism where the expanding cyst presses against peripheral nerves like the median or ulnar nerve. This pressure results in radiating pain, numbness, or a tingling sensation (paresthesia) extending into the hand or fingers. Even a small, “occult” cyst not visible on the surface can cause pain if positioned near a nerve pathway.
Mechanical interference, particularly during movement, is another source of discomfort. A cyst can limit the smooth gliding motion of tendons and joint structures, leading to friction and tenderness, especially during gripping or weight-bearing activities. The mass of a large cyst can also stretch the surrounding joint capsule tissue, causing an aching sensation that increases with movement. The size of the cyst does not always correlate with the severity of the pain.
Evaluating Symptoms and Seeking Diagnosis
Professional evaluation is recommended if a wrist lump is painful, rapidly increasing in size, or interferes with wrist function. Diagnosis begins with a physical examination where the provider assesses the location, size, and firmness of the lump. A common initial test is transillumination, where a bright light is shined through the mass to confirm it is fluid-filled, as a ganglion cyst appears translucent.
Imaging tests are utilized to rule out other causes of wrist pain, such as arthritis or bone abnormalities. X-rays visualize the bony structure and exclude conditions like a fracture or degenerative joint disease. Ultrasound or Magnetic Resonance Imaging (MRI) confirms the diagnosis by providing a detailed view of the cyst’s fluid contents and its relationship to surrounding nerves and tendons. These modalities are helpful for detecting smaller cysts that are not easily visible under the skin.
Management and Removal Strategies
Management begins with observation, especially if the cyst is not causing pain or functional limitations. Since many cysts disappear spontaneously over time, a “wait-and-see” approach is often the first recommendation. Conservative measures like immobilization with a wrist brace or splint, combined with anti-inflammatory medications, can help reduce symptoms by limiting activity that might increase the cyst’s size or pressure.
If the cyst remains symptomatic or interferes with daily activities, intervention is considered. Aspiration involves draining the fluid from the cyst using a needle, often followed by a steroid injection. This is a minimally invasive procedure, but recurrence rates after aspiration can be high, ranging from 60% to over 80%. Surgical excision involves the complete removal of the cyst and its connecting stalk. This method offers a lower recurrence rate, typically between 7% and 28%, and is reserved for cases that have failed conservative treatment or aspiration.