Chronic mucosal changes of the colon in graft-versus-host disease

The histologic features of acute graft-versus-host disease (GVHD) of the colon are well documented, but chronic mucosal changes associated with GVHD are poorly described. We report here the clinicopathologic findings from five patients with a history of bone marrow transplantation in which colonoscopic biopsies showed chronic mucosal changes reminiscent of chronic idiopathic inflammatory bowel disease (IBD). The patients ranged in age from 2.5 to 31 years. Bone marrow transplantations were performed for leukemia (3 patients), Hodgkin's disease (1 patient), and metachromatic leukodystrophy (1 patient). Endoscopy was performed because of complaints of abdominal pain and diarrhea in all of the five patients. The mean time after transplantation in which histologic features of chronicity were identified was 5.8 months (range, 3-16 mo). All of the five patients had prior colonic biopsies showing acute GVHD. One patient had a previous episode of cytomegalovirus infection. Chronicity was characterized by mild-to-moderate architectural distortion, ie., villiform surface with crypt branching and atrophy, similar to that seen in chronic idiopathic IBD. The lamina propria was hypocellular, with prominent small blood vessels. Focal fibrosis of the lamina propria was noted. One patient had active cryptitis. Superimposed changes of acute GVHD were mild to absent. None of the patients had a history of IBD before receiving the bone marrow transplant. Changes associated with chronicity can be observed in mucosal biopsy specimens from patients with GVHD. It is uncertain whether these changes are directly caused by GVHD or are the result of superimposed infections. The association of chronic mucosal change in the setting of GVHD with the clinical diagnosis of chronic GVHD needs additional investigation.