<prompt> The origin of Klatskin tumors is fromLiverGall bladderConfluence of cystic duct and hepatic ductConfluence of right and left hepatic ducts  <response>: The tumours arising at the confluence of right and left hepatic ducts at the liver hilus are called Klatskin tumours. These tumours are notable for their slow growing behaviour, marked sclerosing characteristics, and infrequent occurrence of distal metastasis. 