A case of a duodenal gastrointestinal stromal tumor diagnosed with the aid of diffusion-weighted magnetic resonance imaging

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of gastrointestinal tract, and bleeding is among the primary symptoms. If the tumor is located in the small intestine, diagnosis might be difficult because of its inaccessibility by endoscope. This report presents a case of duodenal GIST diagnosed with the aid of diffusion-weighted (DW) magnetic resonance imaging (MRI). A 66-year-old male was admitted to the hospital because of shortness of breath and melena. The patient demonstrated marked anemia. Esophagogastroduodenoscopy and colonoscopy revealed no involvement of the mucosa of the gastrointestinal tract in regard to the observed bleeding. Thereafter, computed tomography was done and showed a tumorous lesion 4.2 cm in diameter located around the ligament of Treitz. The area showed significant high intensity by DW-MRI, strongly suggesting malignant character. Examination with a long endoscope demonstrated a large submucosal tumor with wide ulceration located at the third portion of the duodenum. The biopsy sample contained spindle-shaped cells that were positive for CD34 and c-kit on histochemistry, and the tumor was diagnosed as GIST. The patient underwent surgery and survived for 16 months without any recurrence.