ABSTRACT
Mycophenolate mofetil (MMF)-related colitis is one of the common causes of afebrile diarrhea in transplant patients. Pathologic diagnosis of MMF-related colitis is difficult because microscopic findings of MMF effects resemble those of graft-versus-host disease, inflammatory bowel disease and ischemic colitis. However, if diagnosed, MMF-induced colitis can be markedly improved by discontinuing the drug. A 70-year-old man having a history of transplantation presented with a one month history of afebrile diarrhea. Colonoscopy revealed patchy erosions. The colonoscopic biopsy specimen showed not only crypt disarray with degenerated crypts and scattered epithelial cell apoptosis, but also stromal inflammatory cell infiltration. A review of his medical records showed that he had been taking immunosuppressive drugs including MMF since his heart transplantation 6 years prior. The histologic findings of colonic mucosa were consistent with MMF-related colitis. After discontinuing MMF, the diarrhea quickly resolved and has not recurred for 10 months.