Editing Cholangiocarcinoma (section)

===Pathology===
[[File:Immunohistochemistry for CK19 in metastatic cholangiocarcinoma to the liver.jpg|thumb|[[Immunohistochemistry]] for [[CK19]] in metastatic cholangiocarcinoma to the liver. The positive staining supports the diagnosis, in contrast to a [[hepatocellular carcinoma]] which is typically CK19 negative.<ref>Image by 
Mikael Häggström, MD. Source for caption:<br>- {{cite web|url=https://www.pathologyoutlines.com/topic/stainsck19.html|title=Cytokeratin 19 (CK19, K19)|website=Pathology Outlines|author=Nat Pernick, M.D.}} Last author update: 1 October 2013</ref>]]
Histologically, cholangiocarcinomas are classically well to moderately differentiated [[adenocarcinoma]]s. [[Immunohistochemistry]] is useful in the diagnosis and may be used to help differentiate a cholangiocarcinoma from [[hepatocellular carcinoma]] and metastasis of other gastrointestinal tumors.<ref>{{cite journal | vauthors = Länger F, von Wasielewski R, Kreipe HH | title = [The importance of immunohistochemistry for the diagnosis of cholangiocarcinomas] | language = German | journal = Der Pathologe | volume = 27 | issue = 4 | pages = 244–50 | date = July 2006 | pmid = 16758167 | doi = 10.1007/s00292-006-0836-z | s2cid = 7571236 }}</ref> [[Cytopathology|Cytological scrapings]] are often nondiagnostic,<ref>Darwin PE, Kennedy A. {{EMedicine|med|343|Cholangiocarcinoma}}</ref> as these tumors typically have a [[desmoplasia|desmoplastic]] stroma and, therefore, do not release diagnostic tumor cells with scrapings.