An endoscopic ultrasound and histological comparison. A: An endoscopic ultrasound (EUS) revealed a heterogeneous tumor; B: The 5 layers shown in the EUS and HE stain (× 20) (yellow circle) consisted of a normal mucosa layer, immature fibroblast cells, pyloric glands, muscularis mucosa, and another normal mucosa layer. The surface mucosa was inverted into the submucosal layer (red arrow); C and D: The hyperechoic solid portion had tiny low echoic cystic spots (blue circle) and showed the proliferation of pseudo-pylorus glands, cystic glands, fibroblast cells, smooth muscle, and nerve elements.