Which is risk factor for cholangiocarcinoma -

Ans. is 'b' i.e., Primary sclerosing choiangiocarcinoma Cholangiocarcinomao Cholangiocarcinoma is malignancy of the biliary tree, arising from bile ducts within or outside the liver,o Risk factors:Primary sclerosing cholangitisCongenital fibropolycystic disease of the biliary system (caroli disease, choledochal cyst).Exposure to thorotrast.Opisthorchis sinensis infection.Pathologyo Cholangiocarcinoma are adenocarcinoma arising from bile ducts epithelium,o Most are well to moderately differentiated.o Markdly desmoplastic, with dens collegenous stroma separating the glandular elements,o Cells are not bile stained, because bile is synthesized by hepatocytes and not by bile duct epithelium.