Fig. 3

Macroscopic and microscopic findings on examination of the resected specimen. a Macroscopic findings. b Loupe image. c–f Microscopic findings. b, c Hematoxylin and eosin stain. b Microscopic findings showing coexisting neuroendocrine (blue area) and adenocarcinoma components (red area). The neuroendocrine component is exposed in the superficial layer in the center of the tumor. c The adenocarcinoma components invade neuroendocrine component. d Tumor cells are positive for chromogranin A. e The tumor cells are positive for synaptophysin. f Tumor cells are positive for CD56. Scale bars (black lines, bottom right), 200 µm (c), 500 µm (d) and 50 µm (d–f)