Pathology of Gastrointestinal and Liver Complications of Hematopoietic Stem Cell Transplantation.

CONTEXT.—: Despite advances in therapeutic and preventive measures, hematopoietic stem cell transplant recipients remain at risk for a variety of gastrointestinal and liver complications. OBJECTIVE.—: To detail the pathologic features of the various gastrointestinal and liver complications occurring after hematopoietic stem cell transplantation in relation to their clinical context. The specific complications covered include graft-versus-host disease, mycophenolate mofetil-induced injury, timeline of infections, neutropenic enterocolitis, gastrointestinal thrombotic microangiopathy, sinusoidal obstruction syndrome, hepatic iron overload, and the controversy around cord colitis syndrome. DATA SOURCES.—: The content of this article is based on pertinent peer-reviewed articles in PubMed, relevant textbooks, and on the authors' personal experiences. CONCLUSIONS.—: The final histopathologic diagnosis requires the integration of clinical and histologic findings and the exclusion of other competing causes of injury. Review of the clinical data, including the original disease pretransplant, the type of transplant, the timing of the gastrointestinal and/or liver manifestations, the timing of the biopsy after transplant, the presence of graft-versus-host disease in other organs and sites, the list of drug regimens, and the clinical and laboratory evidence of infection, is the key to reaching the proper histologic diagnosis.