Ganglion cyst is a benign cystic lesion originating from the joint capsule or tendon sheath, filled with mucinous (gelatinous) fluid. It most commonly involves the dorsal wrist (60-70%), followed by the volar wrist, foot, and periarticular knee. It is more common in women aged 20-50. The cyst is connected to the joint or tendon sheath through a thin stalk (pedicle) — this connection is critical for pathogenesis and diagnosis. Ganglion cysts constitute 50-70% of soft tissue masses and are the most common hand/wrist mass. Clinically, it presents as a slow-growing, firm-elastic, transillumination-positive nodule whose size may fluctuate with activity. Ultrasonography is the primary diagnostic modality, and the triad of anechoic content, posterior enhancement, and joint/tendon connection (stalk) strongly supports the diagnosis.
Age Range
15-55
Peak Age
30
Gender
Female predominant
Prevalence
Common
The pathogenesis of ganglion cyst is not fully understood, but the most accepted theory involves mucinous degeneration of mesenchymal cells in the joint capsule or tendon sheath, followed by cystic cavity formation. Repetitive mechanical stress or microtrauma leads to degeneration of connective tissue → mucinous material (hyaluronic acid and glycosaminoglycans) accumulates between collagen fibers → small microcysts form → coalescence into larger cystic cavity. The cyst maintains connection to the joint or tendon sheath through a thin stalk — this stalk typically functions as a one-way valve: during joint movement, synovial fluid is pushed into the cyst but return is restricted → cyst enlarges. On ultrasonography, mucinous fluid appears anechoic because the gelatinous fluid is acoustically homogeneous without particles → no sound wave scattering. The cyst wall consists of thin fibrous tissue without synovial lining (different from true synovial cysts). Posterior acoustic enhancement results from minimal attenuation of mucinous fluid. The stalk has the same fibrous tissue structure as the joint capsule and appears as a thin tubular hypoechoic structure on ultrasound.
A thin tubular hypoechoic structure (stalk/pedicle) extending from the cystic lesion to the joint capsule or tendon sheath on ultrasonography is pathognomonic for ganglion cyst. This connection proves the lesion originates from the joint/tendon sheath. Stalk movement can be observed during dynamic evaluation with joint motion. The stalk may not always be demonstrable but its presence confirms the diagnosis.
On B-mode ultrasonography, a well-defined, anechoic or low-echogenic, smooth-walled cystic lesion is seen. Internal structure is typically homogeneously anechoic — reflecting acoustic homogeneity of mucinous fluid. Posterior acoustic enhancement is prominent. The cyst wall is thin (<1 mm), smooth, hyperechoic fibrous capsule. Septations may rarely be seen (especially in multiloculated cysts). May deform slightly with pressure but is not compressible (due to gelatinous consistency). Size is generally 1-3 cm.
Report Sentence
A well-defined, anechoic, smooth-walled cystic lesion is seen on the dorsal wrist with prominent posterior acoustic enhancement; consistent with ganglion cyst.
On dynamic ultrasonography, a thin tubular hypoechoic structure (stalk/pedicle) may be seen between the cyst and joint capsule or tendon sheath. This connection has pathognomonic value for ganglion cyst diagnosis. The stalk is generally 1-3 mm in diameter with variable length. During dynamic evaluation, stalk movement can be observed during joint motion. The stalk may not always be demonstrable — small or obliquely coursing stalks may be missed. On the dorsal wrist, the stalk typically extends to the scapholunate ligament or dorsal radiocarpal joint capsule.
Report Sentence
A thin hypoechoic stalk extending from the cystic lesion to the joint capsule/tendon sheath is seen; pathognomonic finding confirming ganglion cyst diagnosis.
No vascular signal is detected within the cyst on Color and Power Doppler — completely avascular structure. No vascular signal in cyst wall or stalk. This confirms cystic nature and is critical for differentiation from solid hypoechoic lesions (giant cell tumor of tendon sheath, synovial sarcoma). Perilesional vascularity may be seen if inflammation is present.
Report Sentence
No vascular signal detected within the cyst or its wall on Color Doppler; avascular structure consistent with ganglion cyst.
Some ganglion cysts show lobulated or multiloculated morphology — multiple cystic compartments connected by thin septa. This appearance reflects ongoing coalescence or coexistence of multiple microcysts. Septa are thin (<1 mm), avascular, and low-echogenic. Multiloculated cysts are important for surgical planning as incomplete excision increases recurrence risk.
Report Sentence
The cystic lesion shows lobulated morphology with multiple compartments separated by thin septa.
On T2-weighted MRI, the ganglion cyst shows markedly hyperintense (fluid-like) signal — reflecting the long T2 relaxation time of mucinous fluid. Homogeneous hyperintense signal is typical. The thin wall shows low T2 signal. Stalk connection can also be demonstrated on MRI — thin hypointense structure extending to joint capsule or tendon sheath. In multiloculated cysts, septa appear as thin lines with low T2 signal.
Report Sentence
The lesion shows markedly hyperintense signal on T2-weighted images consistent with mucinous/cystic content; a thin stalk extending to the joint capsule is seen.
On T1-weighted images, the ganglion cyst shows low signal — reflecting long T1 relaxation time of fluid content. Cyst content does not enhance on contrast-enhanced sequences; thin cyst wall may show mild enhancement. Low T1 + high T2 + no enhancement triad confirms simple cystic nature.
Report Sentence
The lesion shows low signal on T1-weighted images with no internal enhancement on contrast-enhanced sequences.
Criteria
Most common type (60-70%). Originates from scapholunate ligament or dorsal radiocarpal joint capsule.
Distinct Features
Clinically prominent swelling on dorsal wrist. Stalk extends to scapholunate interval on US. Occult ganglions are small and detected only by US.
Criteria
Second most common type (18-20%). Originates from radiocarpal or scaphotrapezial joint near radial artery.
Distinct Features
Close proximity to radial artery is critical for surgical planning — vascular anatomy should be mapped with US. Allen test preoperatively.
Criteria
Originates from flexor tendon sheath, usually at A1 or A2 pulley level. Small, firm nodule on volar finger surface.
Distinct Features
Small (3-8 mm), on tendon surface, may move with joint motion. Seen as anechoic nodule on tendon on US. May be confused with trigger finger.
Distinguishing Feature
Epidermoid cyst is subcutaneous without joint/tendon connection (stalk). Shows laminated (onion-skin) pattern — ganglion is anechoic. Epidermoid has skin connection (punctum).
Distinguishing Feature
Seroma is postoperative/post-traumatic anechoic collection without joint/tendon connection. Surgical/trauma history present. May have irregular shape — ganglion is oval/round and capsulated.
Distinguishing Feature
Schwannoma is a solid hypoechoic lesion along nerve course — tail sign pathognomonic. Shows internal vascularity. Ganglion is anechoic and avascular. Schwannoma may show posterior enhancement but contains solid component.
Urgency
routineManagement
conservativeBiopsy
Not NeededFollow-up
no-follow-upGanglion cyst is completely benign with no malignancy potential. No treatment needed for asymptomatic cysts — 40-58% resolve spontaneously. For symptomatic cysts, aspiration (recurrence rate 30-50%) or surgical excision (recurrence rate 10-20%) may be performed. Aspiration of gelatinous mucinous fluid confirms diagnosis. Surgical excision should include the stalk — leaving stalk increases recurrence. For volar wrist ganglions, preoperative US vascular mapping is mandatory due to radial artery proximity.
Ganglion cysts are benign lesions with no malignant potential. Asymptomatic cysts require no treatment — 40-58% spontaneously resolve. Aspiration can be performed for symptomatic cysts but recurrence rate is high (50%). Surgical excision should include the stalk, recurrence rate 5-15%. Caution with volar wrist ganglions due to radial artery proximity.