[Minute gallbladder cancer--case report with suggestions regarding a possibly unique histogenesis]

A 35-year-old woman with minute gallbladder cancer is presented. Cholecystectomy for gallstones resulted in recurrent colic lasting for a few years. Examination of the resected bladder under a dissection microscope disclosed a minute polypoid tumor with cylindroid appearance measuring 2.0 X 0.5 mm; it was located on a thin membraneous stalk in the neck region. Histologically, the tumor consisted chiefly of well-differentiated adenocarcinoma, in its periphery there were adenomatous residues; the stalk was free of neoplastic change. Blood group substances were completely absent in the cancerous tissues, they were present in adenomatous tissues. We hypothesize that the present cancer derived from the minute gallbladder adenoma via malignant change at an early stage development, suggesting a unique mode for an adenoma-carcinoma sequence in the gallbladder. The present case is believed to be the smallest cancer among reported cases and we propose to define minute gallbladder cancer as that less than 5 mm in maximum diameter.