[A case of Crohn's disease presenting with free perforation and portal venous gas].

Crohn's disease is characterized by its chronic course and transmural inflammation of gastrointestinal tract. The accompanying fibrous reaction and adhesion to adjacent viscera appears to limit the complication of free perforation. The true incidence of free bowel perforation is difficult to assess, however, the anticipated occurrence rate is 1-2% during the course of illness. Moreover, portal venous gas is also an uncommon event in the natural history of Crohn's disease. Portal venous gas occurs when intraluminal gas from the gastrointestinal tract or gas-forming bacteria enters the portal venous circulation. The finding of portal venous gas associated with Crohn's disease does not always mandate surgical intervention. We experienced a case of Crohn's disease presenting with free perforation and portal venous gas. The literatures on the cases with perforation and portal venous gas associated with Crohn's disease were reviewed.