Case: We present a case of rice-body formation and partial flexor tendon rupture in a 3-year-old child with seronegative juvenile idiopathic arthritis (JIA), which presented as a painless soft-tissue mass of the volar aspect of the hand. The diagnosis was not confirmed until histologic examination. The patient was managed with a tenosynovectomy and oral medication; he made a full recovery.
Conclusion: JIA is one of the most common rheumatologic conditions of childhood. Establishing the diagnosis can be challenging in very young children, particularly when clinical presentation is atypical and serology is negative. Surgical intervention may be warranted in the appropriately selected patient with JIA.