Villous adenoma of the extrahepatic biliary tract: a rare entity.

Patients presenting with large obstructing extrahepatic biliary tumors often are presumed to have cholangiocarcinoma and are labeled with a grim disease with a poor prognosis, given little hope for a cure, and may actually opt for palliative care only. In some instances, however, the diagnosis is that of biliary adenoma (benign until it undergoes malignant degeneration), which can be confirmed via resection and pathologic evaluation of the lesion. Removal of the tumor in its benign stage then provides curative treatment of the obstructing lesion with excellent patient recovery and overall prognosis. We present a rare instance of observation of the presence of high-grade dysplasia in a large villous adenoma arising from the left hepatic duct with relief of biliary obstruction and curative resection.