Unusual intestinal and extra intestinal findings in Crohn's disease seen on abdominal computed tomography and magnetic resonance enterography

The magnetic resonance (MR) enterography technique has improved over the past few years to provide an excellent means of evaluating the gastrointestinal tract for suspected Crohn's disease. Although the prevalent intestinal manifestations of Crohn's disease have been extensively discussed in the radiology literature, some of its rare complications, especially extra intestinal, have received less attention. Uncommon findings that may be seen on MR enterography and abdominal CT examinations performed in patients with Crohn's disease include hepatic sinusoidal dilatation, primary sclerosing cholangitis, fistulas in unusual locations, hepatic and splenic abscesses, and spondylarthritis. Radiologists should be aware of these potentially rare manifestations. They should be kept in mind during clinical examinations and should be routinely searched for and reported if present. •unusual sites of involvment: althought the ileum is the most common site of involvment in CD, other less common sites have been described, such as stomach, duodenum, proximal small bowel, Meckel's diverticulum•unusual types of complications: enteric rare fistulas, extra enteric complications including sepsis related hepatic sinusoidal dilatation, avascular necrosis of the femoral head, non bacterial ostéomyelitis, acalculous ureteral inflammatory entrapment•unusual associated diseases: including PSC, granulomatous CD's hepatitis, PSC auto immune hepatitis overlap syndrome, ankylosing spondylitis, oestomalacia, pancreatitis, hidradenitis suppurativa