Colonic perforation in collagenous colitis: an unusual complication.

Collagenous colitis is generally regarded as a benign disease with few serious complications. We report two women with collagenous colitis who presented with colonic perforation, one spontaneously and one 7 days after a barium enema, and a review of the literature. Including the present cases, 13 patients with collagenous colitis and colonic perforation have been reported, in two patients spontaneously and in 11 patients after a colonoscopy or barium enema. All were operated on except one patient who recovered after medical treatment. The pathogenesis of this complication is unknown. We propose that there might be a connection between mucosal tears and colonic perforation in collagenous colitis.