Fig. 4

a Representative examples of the gastric tumor under low power view and the view of × 10 and × 20 objective lens using hematoxylin and eosin (H&E) stain. Tumor focally proliferates in the mucosal layer, with negative lymphovascular invasion. The surgical margin is all negative. The tumor contained glycogen-rich and acidophilic cytoplasm exhibiting honeycomb-formed or trabecular structure, resembling the patient’s known RCC. b Representative examples of the gallbladder tumor under low power view. c The tumor cell is similar to the gastric one and also proliferates in the mucosal layer