Tophi deposition is a well-recognized complication of chronic gout, but usually lacks obvious symptoms. Magnetic resonance imaging (MRI) findings may allow a relatively specific diagnosis to be rendered. In this study, we report an unusual case of gouty tophi presenting as an intra-articular synovial tumor of the knee, blocking the range of motion. We also describe its MRI appearance, which was compatible with the clinical suspicion. After arthroscopic excision of the "tumor," the patient was symptom free.