Endoscopic ultrasound-guided fine-needle aspiration for diagnosing a rare extraluminal duodenal gastrointestinal tumor

Figure 5 Histological analysis of resected tumor tissue. A: Macroscopic finding showed 30 mm × 22 mm × 22 mm sized tumor showing extraluminal growth from duodenum (black arrow); B: Hematoxylin and eosin-stained sections showed that the tumor was mainly composed of spindle-shaped cells without necrosis; C: The tumor cells appeared immunohistochemically positive for c-kit; D: Mitosis was detected in 2/50 high-power fields, and MIB-1 labeling index (Ki-67 stain) was < 1%.