Abstract
Graft-vs-host disease (GVHD) of the gastrointestinal (GI) tract is notably a serious complication of allogeneic hematopoietic stem cell transplant (HSCT). However, GI GVHD has rarely been reported in autologous HSCT, and the pathophysiology remains unclear. Diagnosing GVHD after autologous HSCT requires a high level of clinical suspicion, given its nonspecific clinical presentation and endoscopic findings necessitating a histological diagnosis for confirmation. We present a case of autologous GVHD involving the GI tract in a patient with multiple myeloma who responded well to corticosteroids, highlighting the importance of early identification of this rare entity to initiate therapy and improve outcomes.