Giant cell tumor of tendon sheath at the volar aspect of the third metacarpophalangeal joint presenting as a pseudo-trigger finger: A case report

Background: Giant Cell Tumor of Tendon Sheath (GCTTS) is a benign, slow-growing soft-tissue tumor arising from synovial lining of tendon sheaths. It is the second most common tumor of the hand after ganglion cysts. It is commonly seen on the volar aspect of the fingers. Although usually painless, Lesions occurring at the level of the A1 pulley may cause mechanical obstruction to tendon gliding, can occasionally present with pain, mechanical symptoms, or mimic trigger finger. Presentation: We report a case of a 39-year-old female presenting with a gradually progressive, painful swelling on the volar aspect of the right hand at the base of the third digit over the metacarpophalangeal (MCP) joint. Symptoms progressed over 3 months and caused pseudo-triggering during finger flexion. Clinical examination and imaging suggested a soft-tissue tumor arising from the flexor tendon sheath. Complete surgical excision was performed under regional anesthesia. Histopathology confirmed a Giant Cell Tumor of Tendon Sheath (localized type). Conclusion: GCTTS should be considered in the differential diagnosis of volar hand swellings presenting with painful mechanical symptoms or pseudo-trigger phenomena. Thorough anatomical knowledge and complete Surgical excision are essential for symptom resolution and prevention of recurrence and gives excellent outcomes.