Fig. 5
a Macroscopic finding of the resected specimen of the gallbladder showed a partial wall thickening suggestive of gallbladder adenomyosis (arrow). b–d Histological specimen of the gallbladder showing no mucosal epithelial lesions. The lymphatic vessels of the gallbladder wall were extensively filled with tumor cells, which was especially evident in the grossly thickened areas (b × 12.5, D2-40 stain; c × 4, HE stain; d × 100, HE stain)