Synovial lipomatosis is a rare, synovial based disorder that typically affects a single knee. Magnetic resonance imaging and synovial biopsy established this diagnosis in a patient who presented with a 20 year history of painless swelling of the knees, wrists, and hands. Such extensive involvement, particularly of hand joints and tendon sheaths, has not been described previously. Superimposed on this chronic soft tissue joint swelling were acute knee effusions, which responded to intraarticular steroid injections. The co-occurrence with congenital short bowel syndrome may have etiological implications for this disorder of inappropriate fat deposition.