Fig. 3

Gross pathologic findings and microscopic findings of the resected specimen. a Macroscopic findings of the formalin-fixed resected specimen. A cauliflower-like papillary tumor was located in the gallbladder fundus (arrowheads). The inset showed the macroscopic view of the fresh specimen showing the inflamed reddish hyperplastic mucosa of the gallbladder. The cystic duct was dilated (arrows). b Low-power view of the resected ICPN (hematoxylin and eosin [H & E]) showing the protruding tumor with a tubulopapillary architecture covered with neoplastic epithelium. The transient zone from the non-tumorous gallbladder to the ICPN was also covered with the same epithelium (inset). c Gastric pyloric component of the ICPN. Uniform, back-to-back mucinous grounds with features characteristic of pyloric glands. d Gastric foveolar component of the ICPN. Elongated, interconnecting tubules by tall columnar cells with abundant apical mucin with features characteristics of foveolar glands