Fig. 2

Macroscopic and microscopic findings of MINEN in ampulla of Vater. a Macroscopic finding of the tumor. b Microscopic finding showed the transitional part of neuroendocrine and non-neuroendocrine component. c Tumor cells were positive for synaptophysin. d Tumor cells were partially positive for CD56. e Tumor cells were negative for chromogranin A. f Tumor cells had a Ki-67 index > 20%. MINEN, mixed neuroendocrine–non-neuroendocrine neoplasm