Intracholecystic Papillary-Tubular Neoplasms (ICPN) of the Gallbladder: A Short Review of Literature.

Increasing use of radiographic studies of the hepatobiliary system has led to a growing diagnostic rate of many asymptomatic polyps of the gallbladder which would have gone undiagnosed otherwise. Neoplastic polyps of the gallbladder are 5% of the total number of polyps of this organ. However, due to their malignant potential, the correct diagnosis and classification become of crucial importance. Lack of unified terminology and reporting criteria have led to a limited body of scientific evidence regarding their classification and management. Therefore in 2012 the novel and unified terminology, Intracholecystic papillary-tubular neoplasm was proposed for these lesions when they measure >1 cm. Smaller lesions are usually of no adverse outcome. Intracholecystic papillary-tubular neoplasms show 5 histologic subcategories: (1) pyloric gland subtype which is the most commonly encountered neoplastic polyp in the gallbladder and has the lowest rate of harboring high-grade dysplasia and invasive carcinoma and it shows diffuse cytoplasmic positivity with MUC6, a specific pyloric marker; (2) biliary subtype which is diffusely positive for MUC1 and has the highest risk of concurrent adenocarcinoma; (3) gastric foveolar subtype which is MUC5AC positive in all the cases. Most of the cases in this category are associated with some extent of high-grade dysplasia; (4) intestinal subtype which is the easiest one to recognize as it mimics tubular adenomas of the gastrointestinal tract and show MUC2 and CDX2 positivity; and (5) oncocytic subtype which is the least common.