Crohn's disease with fistulae involving joints.

Two cases of Crohn's disease with unusual manifestations of fistulae involving joints are reported. One case with a fistula from the rectum through the pelvis presented with an abscess adjacent to the left hip joint. The second presented acutely with inflammation and swelling of the right thigh suggesting thrombophlebitis. This patient died from septicaemia and was found at postmortem to have ileal Crohn's disease with fistulae into the thigh, producing septic arthritis of the knee. The possibility of underlying Crohn's disease should be considered in patients who develop abscesses adjacent to the pelvis, or physical signs suggesting thrombophlebitis of the thigh.