Graft-versus-host disease (GVHD) is a common complication of bone marr
ow transplantation and often involves the gastrointestinal system. It
is unclear whether there can be severe enough damage by GVHD to perman
ently injure the bowel and thereby prevent mucosal regeneration. We de
scribe a patient who had successful treatment of GVHD, but who had suc
h severe scarring of the bowel mucosa that the colonic epithelium coul
d not regenerate even 50 days after biopsy-demonstrated resolution of
GVHD. Surveillance cultures and histological analysis indicate that th
is denudation was not caused by infection or continued GVHD. This is a
n important observation with implications for monitoring response to G
HVD therapy and using rectal biopsy to evaluate GVHD.