What is a ganglionic cyst, typically occurring in adults with a history of joint pain or musculoskeletal issues, often associated with osteoarthritis?

What is a Ganglion Cyst

A ganglion cyst is a benign, fluid-filled (mucinous or gelatinous) tumor that arises from a joint capsule, tendon, or tendon sheath, most commonly occurring on the dorsal or volar aspects of the wrist, though it can develop anywhere in the body including the hand, knee, ankle, and even within joints or bones. 1

Pathophysiology and Location

• Ganglion cysts represent the most common soft-tissue mass in the hand and wrist 1
• They are cystic swellings that typically arise close to tendons or joints, formed by mucoid degeneration of the joint capsule, tendon, or tendon sheaths 2
• While most commonly found at the wrist (dorsal or volar), they can also arise from:
  • Flexor tendon sheaths 1
  • Interphalangeal joints 1
  • Extensor tendons 1
  • Intraosseous locations (within bone) 1
  • Intraneural locations (within nerves) 1
  • Anterior or posterior cruciate ligaments in the knee 3
  • Semimembranosus tendon in the popliteal region 2

Clinical Presentation

• Symptoms vary widely depending on size and location, ranging from small, asymptomatic, incidentally detected lesions to large masses causing symptoms 4
• Pain and swelling are common presenting complaints, particularly when the cyst compresses adjacent structures 5
• Some patients report a history of trauma, though the exact etiology remains unclear 5, 3
• The cyst may be detected on ultrasound as part of musculoskeletal evaluation for joint pain or other conditions 6

Diagnostic Approach

Diagnosis relies primarily on history and physical examination, with transillumination and aspiration serving as useful adjunctive diagnostic tools. 1

Imaging Recommendations

• Ultrasound is the initial imaging modality of choice to confirm the fluid-filled nature of the cyst and distinguish it from solid masses 7, 8
• Ultrasound has high accuracy for superficial lesions (sensitivity 94.1%, specificity 99.7%), but accuracy decreases for deep-seated lesions 7
• Plain radiography may be indicated to evaluate for associated conditions such as degenerative joint disease 1
• MRI is reserved for suspected occult ganglion cysts, intraosseous ganglions, or when there is concern about solid tumors including sarcoma 8, 1
• MRI typically shows smooth, well-circumscribed, thin-walled, unilocular, homogeneously T2-hyperintense lesions, often with an identifiable thin stalk communicating to the joint space 4

Important Diagnostic Pitfalls

• Ganglion cysts can mimic intra-articular lesions like tears of the anterior cruciate ligament or meniscus 3
• Older cysts or those with complications may show septae and internal debris, which must be differentiated from worrisome cystic-like lesions 4
• CT is not indicated for characterizing cystic structures already identified on ultrasound, as it cannot reliably differentiate cystic from solid lesions without contrast and provides inferior soft tissue characterization compared to ultrasound 7

Association with Joint Disease

• Ganglion and synovial cysts occur mainly, but not necessarily, in association with osteoarthritis 4
• They are listed among detectable pathologies on musculoskeletal ultrasound in rheumatology guidelines 6
• Popliteal cysts (Baker's cysts) represent fluid accumulation in bursae that frequently communicate with the joint space 6

Management Options

Treatment includes observation, aspiration or puncture with possible corticosteroid injection, and surgical excision, with nonsurgical management resulting in cyst resolution in over 50% of patients. 1

• Follow-up with physical examination with or without ultrasound every 6-12 months for 1-2 years is recommended to ensure stability after conservative management 7, 8
• Surgical excision is associated with recurrence rates of 7% to 39% 1
• Arthroscopic ganglion excision has recurrence rates similar to open management 1
• If the cyst increases in size during follow-up, further evaluation is warranted 8