What is a Ganglion Cyst?
A ganglion cyst is a benign, noncancerous, fluid-filled swelling that typically forms near joints or tendons, most commonly occurring in the wrist and hand. 1
Characteristics and Composition
Ganglion cysts contain a mucoid, gel-like material rich in mucopolysaccharides and are encapsulated in dense connective tissue. 1, 2 They can vary significantly in:
- Size: From small pea-sized bumps to formations as large as a golf ball
- Texture: Ranging from firm to spongy consistency
- Shape: Usually round or spherical, particularly when smaller
- Appearance: The overlying skin may appear stretched and shiny 1
Location and Presentation
While the wrist and hand are the most common sites (representing the majority of cases), ganglion cysts can occur in other locations including:
- Lower extremities (knee, leg) 1, 3, 2
- Intramuscularly within muscles like the extensor digitorum longus 3
- Rarely, the spine (lumbar region) 4, 5
Some cysts extend intratendinously into underlying muscle, while others may extend into carpal bone, causing pain in the affected area. 1
Clinical Significance
Smaller, asymptomatic ganglion cysts typically do not require treatment. 1 However, symptomatic cysts may cause:
- Pain or discomfort
- Limited mobility
- Radicular symptoms (when located near nerves, particularly in spinal locations) 4, 5
Diagnostic Approach
According to ACR guidelines, soft tissue masses including ganglion cysts causing chronic wrist pain are covered under specific imaging protocols for soft tissue mass evaluation. 6 MRI is particularly useful for diagnosis, showing characteristic hypointense signals on T1-weighted images and hyperintense signals on T2-weighted images. 5
Common Pitfalls
When evaluating suspected ganglion cysts in uncommon anatomical locations (such as intramuscular or spinal), maintain a thorough differential diagnosis as these presentations can mimic other pathologies including myxomas or even malignancy. Surgical excision with histological confirmation remains crucial in atypical locations to rule out malignancy and prevent recurrence. 3