Sclerosing mesenteritis in small bowel transplantation: Possible manifestation of acute vascular rejection

Background: Acute rejection of human small bowel allografts is characterized by clinical symptoms combined with characteristic morphologic alterations. The typical geographic distribution of acute rejection in the bowel is involvement of the intestinal parenchyma, which can be transmural, particularly when the rejection is more severe. However, little is known concerning the potential for donor-derived soft tissue adjacent to the bowel to become involved by the host alloimmune response. Methods: We describe a male patient who, several weeks after combined small bowel and liver transplantation, demonstrated sclerosing mesenteritis with vasculitis and acute rejection of the bowel. Results: The vascular lesions in the mesentery demonstrated increased IgG deposition and the patient developed an alloantibody to the donor. Conclusions: The changes described herein may represent a novel presentation of acute vascular rejection.