Mixed adenoneuroendocrine carcinoma of the gallbladder.

A 58-year-old woman presented with a 1-day history of abdominal pain. Abdominal CT showed an oval soft tissue density mass in the fundus of the gallbladder (red arrow), approximately 4.0 cm × 3.0 cm in size. The level of cancer antigen 199 was elevated (275.80 U/mL; normal level, 0.0-27.0 U/mL). Other tumor markers were normal including alpha fetoprotein, carcinoembryonic antigen. Abdominal magnetic resonance imaging demonstrated the mass with characteristic of mixed signals, containing marked enhanced ingredient (yellow arrow) and poor blood supply ingredient (blue arrow). Radical cholecystectomy, partial liver resection, and regional lymphadenectomy were performed. Pathological examination indicated mixed adenoneuroendocrine carcinoma, with the following immunohistochemistry results: CD56 (+) (Figure 1F), Syn (+) (Figure 1G), CK19 (+) (Figure 1H), CgA (+), MLHL (+), PMS2 (+), MSH2 (+), MSH6 (+), Ki-67 (60%+).