Abstract
Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors primarily located in the stomach and small intestine; their occurrence in the terminal ileum is particularly rare. Although GISTs can develop throughout the gastrointestinal tract, cases of perforation in elderly individuals are even less common, posing significant diagnostic and therapeutic challenges. This case report describes an 86-year-old male patient with an acute abdomen caused by a terminal ileum perforated GIST requiring urgent surgical intervention. An immunohistochemical examination of the tumor confirmed a GIST with a GILT (gastrointestinal leiomyogenic tumor) immunophenotype. The rarity of this condition makes it diagnostically challenging, as its symptoms are often nonspecific, and GISTs are frequently overlooked, particularly in older patients. This case supplements the existing literature by emphasizing the importance of considering GIST perforation in the differential diagnosis of an acute abdomen, even in elderly patients and in rare anatomical locations.