Histology of the gallbladder showed well-to-moderately differentiated adenocarcinoma, according to the UICC 8th edition), with a focal NEC component (< 30%), which was positive for synaptophysin (Syn), chromogranin A (CgA), and clusters of differentiation (CD) 56, and Ki-67 index > 80% on immunohistochemistry (T2bN1M0 Stage IIIB, according to the UICC 8th edition) (Fig. 3). Here, SYP is linked to neuroendocrine carcinoma.