<prompt> Which of the following is premalignant to cholangiocarcinoma -Biliary intraepithelial neoplasiaMucinous cystic neoplasmsIntraductal pappilary biliary neoplasiaAll the above  <response>: Ans. is d i.e., All the above o Premalignant lesions for cholangiocarcinoma are also known, the most important of which are bibary intraepithelial neoplasias low to high grade, BilIN-1, -2, or -3.o BilIN-3, the highest grade lesion, incurs the highest risk of malignant transformation.o More rare are mucinous cystic neoplasms and intraductal papillary biliary neoplasia 