Abstract: We report herein the case of an 81-year-old woman in whom a mass in the gallbladder was revealed by an ultra-sound examination conducted as part of a follow-up study for a silent gallstone. The mass showed evidence of invasion into the adjacent liver parenchyma. Under the tentative diagnosis of malignant neoplastic disease originating in the gallbladder, a cholecystectomy with partial hepatectomy was performed. Histological examination of the tumor confirmed a diagnosis of small-cell carcinoma of the gallbladder, which is considered to be a rare type of neoplasm.