Fig. 3

Macroscopic and histopathological findings of the resected specimen. a The resected specimen was a solid tumor with a diameter of 75 × 55 × 42 mm and with a clear border. The resection margins were tumor-free (R0 resection). The non-tumorous portion of the liver was normal. b Hematoxylin and eosin staining showed atypical cells with round hyperchromatic nuclei and scanty cytoplasm, forming large and small tumor nests. The tumor was arranged in rosette-like structures around the small blood vessels. Necrosis was identified at the center of the tumor nests, and high mitotic activity was observed in the 28/10 high-power field. c–f Immunohistochemical examination revealed that the tumor cells were diffusely positive for chromogranin A (c) and synaptophysin (d) and focally positive for CD 56 (e). The Ki-67 index was 40% (f)