Destructive monarthritis and granulomatous synovitis as the presenting manifestations of Crohn's disease.

A twenty-two-year-old woman and a fourteen-year-old boy with Crohn's disease presented with progressive monarticular arthritis with radiologic evidence of altered articular cartilage and subchondral bone. In one individual, granulomatous inflammation of the synovium was demonstrated. Intestinal symptoms were not prominent. In both individuals, the development of the monarthritis led to the discovery of the underlying inflammatory bowel disease.