Well-differentiated adenocarcinoma of the gallbladder mimicking minimal deviation adenocarcinoma of the cervix.

We report a case of well-differentiated adenocarcinoma of the gallbladder, histologically mimicking minimal deviation adenocarcinoma (MDA) of the cervix. A 71-year-old Japanese male underwent cholecystectomy because of the suggestion of gallbladder carcinoma. The resected gallbladder showed a localized thickening of the gallbladder wall with a polypoid lesion measuring 12x7 mm in diameter. Microscopically, the polypoid lesion proved to be a well-differentiated adenocarcinoma composed of columnar cells with a clear cytoplasm. In the thickened gallbladder wall, well-formed glands were extensively distributed; they were surrounded by a slightly desmoplastic reaction instead of lamina propria, or were directly in contact with smooth muscle cells. The diagnostic criteria for cervical MDA may be useful in distinguishing well-differentiated adenocarcinoma of the gallbladder from benign conditions, such as Rokitansky-Aschoff sinus and adenomyomatosis. It is remarkable that the tumor cells of the present case expressed gastric type mucin which is characteristic of mucinous type cervical MDA.