CMV colitis mimicking recurrent inflammatory bowel disease: report of three cases.

The association between cytomegalovirus infection and inflammatory bowel disease challenges both the clinician and the pathologist to establish the correct diagnosis and to prescribe the most appropriate form of therapy. To understand this association the authors report three patients who presented with signs and symptoms mimicking reactivated inflammatory bowel disease who responded poorly to aggressive treatment of inflammatory bowel disease. Microscopic examination, in all three cases revealed numerous nuclear and cytoplasmic viral inclusions, as demonstrated by cytomegalovirus immunohistochemistry, as well as histologic findings consistent with inflammatory bowel disease (ulcerative colitis and/or Crohn's disease). Because the clinical pathologic features of cytomegalovirus colitis and inflammatory bowel disease often overlap, and because of the possible coexistence of cytomegalovirus colitis with idiopathic colitis, the possibility of cytomegalovirus infection should be always considered, so that the most appropriate therapy can be instituted for these patients.