Adeno-endocrine cell carcinoma of the gallbladder.

We encountered a rare case of adeno-endocrine cell carcinoma of the gallbladder in an 81-year-old woman. Imaging study revealed a common bile duct stone. Endoscopic sphincterotomy was performed, and the stone was extracted successfully. Thereafter, cholecystectomy was performed. A papillary tumor was found in the neck of the gallbladder. Histologically, the tumor consisted of two components, well differentiated adenocarcinoma and endocrine cell carcinoma. However, no clinical signs of tumor hormonal activity were observed. The tumor cells in the area of the endocrine cell carcinoma were small and round. Histochemical studies of these tumor cells were positive for chromogranin A and Grimelius silver impregnation. The tumor cells in the area of the adenocarcinoma were well differentiated adenocarcinoma and included goblet-type cells with a tubular structure or solid growth pattern. These adenocarcinoma cells stained positively for Alcian blue and periodic acid-Schiff, and both types of tumor cells stained positively for carbohydrate antigen and carcinoembryonic antigen. It was suggested that the histogenesis of the endocrine cell carcinoma of the gallbladder was closely related to that of the adenocarcinoma.