Abstract
RATIONALE: Fibroma of tendon sheath (FTS) is a rare benign tumor arising from the synovial membrane of the tendon sheath. It seldom causes peripheral nerve compression or extends into a synovial joint. We report an unusual case of FTS within the radiocarpal joint, compressing the median nerve and leading to secondary changes in the radius and scapholunate joint. PATIENT CONCERNS: A 59-year-old woman presented with a 2-year history of a progressively enlarging, tender mass on the volar aspect of her right wrist. She exhibited positive Tinel's sign and Phalen's test. Magnetic resonance imaging revealed a hypointense mass on T1-weighted images and a heterogeneously hyperintense mass on T2-weighted images, extending into the radiocarpal joint. DIAGNOSES: The patient was diagnosed with FTS based on histopathological analysis. INTERVENTIONS: Surgical excision of the tumor was performed, along with decompression of the median nerve. OUTCOMES: At the 6-month follow-up, the patient had complete resolution of symptoms with no signs of recurrence. LESSONS: FTS should be considered in the differential diagnosis of soft tissue masses causing nerve compression. Magnetic resonance imaging plays a crucial role in early detection and preoperative planning, especially in identifying intra-articular extension. However, histopathological examination remains the gold standard for definitive diagnosis. Complete surgical excision is the primary treatment, requiring meticulous preservation of joint structures and nerve function to minimize recurrence and optimize outcomes.