summary Ganglion Cysts are mucin-filled synovial cysts and are the most common masses found in the wrist and hand. Diagnosis can be made clinically with a firm and well circumscribed mass that transilluminates. Treatment can be observation for majority of ganglions. Surgical excision is indicated for ganglion cysts associated with severe symptoms or neurovascular manifestations. Epidemiology Incidence common most common hand mass (60-70%) Anatomic location dorsal carpal (70%) originate from SL articulation volar carpal (20%) originate from radiocarpal or STT joint volar retinacular (10%) originate from herniated tendon sheath fluid dorsal DIP joint (mucous cyst, associated with Heberden's nodes) may also occur in the lower extremity most commonly about the knee Etiology Mechanism trauma mucoid degeneration synovial herniation Pathophysiology filled with fluid from tendon sheath or joint no true epithelial lining Associated conditions median or ulnar nerve compression may be caused by volar ganglion hand ischemia due to vascular occlusion may be caused by volar ganglion Presentation Symptoms usually asymptomatic may cause issues with cosmesis Physical exam inspection transilluminates (transmits light through tissue) palpation firm and well circumscribed often fixed to deep tissue but not to overlying skin vascular exam Allen's test to ensure radial and ulnar artery flow for volar wrist ganglions Imaging Radiographs normal MRI indications not routinely indicated findings shows well marginated mass with homogenous fluid signal intensity Ultrasound useful for differentiating cyst from vascular aneurysm may provide image localization for aspiration while avoiding artery Histology Biopsy indications not routinely indicated findings will show mucin-filled sac with no true epithelial/synovial lining Treatment Nonoperative observation indications first line of treatment in adults children 76% resolve within 1 year in pediatric patients closed rupture home remedy high recurrence aspiration indications second line of treatment in adults with dorsal ganglions aspiration typically avoided on volar aspect of wrist due to radial artery outcomes higher recurrence rate (50%) than surgical resection but minimal risk so reasonable to attempt Operative surgical resection indications technique requires adequate exposure to identify origin and allow resection of stalk and a portion of adjacent capsule at dorsal DIP joint: must resect underlying osteophyte results volar ganglions have higher recurrence after resection than dorsal ganglions (15-20% recurrence) Complications With aspiration infection (rare) neurovascular injury With excision infection neurovascular injury (radial artery most common) injury to scapholunate interosseous ligament stiffness