Combined hepato-cholangiocarcinoma arising in a gallbladder intracystic papillary neoplasm. A new view on so-called "hepatoid adenocarcinoma of the gallbladder".

A 62-year-old female presented with abdominal pain, weight loss of 20 kg in the prior 6 months, and a palpable mass in the right upper quadrant during physical exam. Standard liver tests, including screening for hepatitis B and C and alpha-fetoprotein were negative or within normal limits. Computerized tomography depicted a transmural gallbladder tumor infiltrating into the adjacent liver with an irregular ill-defined mass occupying segments IV-V-VI, measuring 13.0 x 9.2 x 8.5 cm, with a solid-cystic component and heterogeneous captation of endovenous contrast media. Complete surgical resection of the neoplasm was achieved through an extended cholecystectomy and excision of hepatic segments IV, V and VI, with an uneventful follow-up 29 months until now. Morphological and immunohistochemical assessment favored a diagnosis of combined hepatocellular-cholangiocarcinoma arising in a gallbladder intracystic papillary neoplasm with invasive carcinoma. This case raises the hypothesis that the so-called "hepatoid adenocarcinoma of the gallbladder" may presently be better understood as a neoplasm derived from hepatobiliary stem/progenitor cells. Such cells have been recognized in the canals of Hering, in peribiliary glands within the liver and in the extrahepatic biliary tree, and in gallbladder mucosa.