Polypoid invasive carcinoma of bile duct: report of four cases.

Recently, "polypoid invasive carcinoma (PICA)" showing grossly visible polypoid, invasive carcinoma with no adenoma component was proposed as a neoplastic polyp of the gallbladder. Herein, we report four cases of PICA of the bile duct. PICA cases of bile duct showed single, sessile polypoid growth grossly, and polypoid components were composed of invasive carcinoma of papillary/tubular patterns with active desmoplasia, and invaded directly and continuously into the bile duct wall and periductal tissue. While PICA and other intraductal papillary neoplasm of bile duct (IPNB) shared several features, PICA showed an invasive carcinoma growing in the duct lumen and also invading into the bile duct wall, thus different from IPNB which is the intraluminal polypoid, preinvasive epithelial neoplasia with back-to-back epithelial units. Taken together, PICA and IPNB could be differentiated from each other.

Pyloric gland adenoma of gallbladder-reports of two cases and a brief review of literature.

Adenomas of the gallbladder are uncommon benign epithelial neoplasms. Rarely, they can give rise to gallbladder cancer, which is the most common malignancy of the biliary tract, carrying a poor prognosis and decreased survival. Here we report the case histories of two patients, 40-year-old and 53-year-old males who presented with >1 cm gallbladder polyps, which were detected and confirmed using various imaging studies. Cholecystectomy was performed on both patients and the subsequent pathologic exam revealed 1.2 and 1.6 cm polyps in the lumen. Histopathologically, both polyps showed features reminiscent of "pyloric" gland type of adenoma. The differences between the two cases in regard to histopathological and immunohistochemical characteristics will be discussed. We will also briefly review the latest nomenclature on such low-grade polypoid gallbladder entities.