Duodenal gastrointestinal stromal tumors appear similar to pancreatic neuroendocrine tumors: A case report

INTRODUCTION: Duodenal gastrointestinal tumors (GISTs) are rare. Duodenal GISTs and pancreatic neuroendocrine tumors (NETs) may appear similar on imaging studies. GISTs arising from the second or third portions of duodenum may be incorrectly diagnosed as pancreatic NETs. PRESENTATION OF CASE: The patient is a 79-year-old man who was referred to our hospital with a history of tarry stools and loss of consciousness. Urgent upper digestive tract endoscopy revealed a bleeding submucosal duodenal lesion, which was controlled using endoscopic clips. Enhanced computed tomography scan showed a hyper-vascular mass 50 mm in diameter, at the pancreatic uncus. The patient underwent a pylorus-preserving pancreaticoduodenectomy. Histologically, the tumor was composed of spindle-shaped cells immunohistochemically positive for c-kit and CD34, and the lesion diagnosed as a duodenal GIST. DISCUSSION: Duodenal GISTs often present with gastrointestinal bleeding, which can necessitate emergency surgery. Surgical resection with regional lymph node dissection is the optimal treatment for pancreatic NETs. In contrast, GISTs are generally treated with a minimal resection and without lymph node dissection. Thus, establishing the diagnosis is important in the management of these tumors. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is effective to establish the diagnosis of these lesions. CONCLUSION: A tumor located in the pancreatic head or mesenteric side of the duodenum cannot always be diagnosed based on imaging, and is ideally diagnosed histologically to guide the extent of resection. While EUS-FNA can establish the diagnosis, the complications of this procedure must be considered.