[1644] Perihilar Cholangiocarcinoma: S100P Distinguishes Bile Duct Cancer from Cholangiocarcinoma Involving the Hepatic Hilum

F Pedica, L Bortesi, S Pachera, A Guglielmi, I Cataldo, M Chilosi, F Menestrina, G Martignoni, P Capelli. University of Verona, Verona, Italy; University of Verona, Negrar, Verona, Italy

Background: Cholangiocarcinomas (CC) are classified into intrahepatic, perihilar and distal CC. Based on the anatomical origin, perihilar CC have been further divided into hilar bile duct cancer (BDC) and intrahepatic cholangiocarcinoma involving the hepatic hilus (CCC). BDC is supposed to originate from the epithelium of the common hepatic, right or left hepatic duct, while CCC originates in the intrahepatic bile duct or bile ductules. BDC and CCC have not been immunophenotipically and biologically characterized until now. Recently S100P immunoexpression has been investigated in pancreatic adenocarcinoma, which is known to have morphological similarities to CC. We analyzed S100P expression in CC, focusing on perihilar CC, in particular on BDC and CCC, comparing also to other categories of CC, like intrahepatic and distal types. As controls we investigated hepatocarcinomas (HCC) and liver benign proliferations, such as focal nodular hyperplasia (FNH), biliary adenomas and biliary hamartomas.
Design: We collected 74 cases of CC. As controls we analyzed 20 HCC, 10 FNH, 3 biliary adenomas and 5 biliary hamartomas. In particular, we analyzed 31 intrahepatic CC, 37 perihilar CC and 6 distal CC. Perihilar CC were subdivided into 27 BDC and 10 CCC. Immunohistochemistry was performed using S100P monoclonal antibody (clone 16, diluition 1:1000 BD Biosciences Pharmingen, San Diego) and it was evaluated semiquantitatively.
Results: In the normal liver tissue, hepatocytes and normal intrahepatic bile ducts were negative for S100P. Perihilar were positive in 68% of cases. Moreover, BDC were strongly positive in 85% (23/27 cases), while CCC in 20% of cases (2/10 cases). Positive immunoreactivity for S100P was identified in 100% distal CC, but only in 6% of intrahepatic CC. S100P was positive only in 1 of 20 HCC, while all benign proliferations did not express S100P.
Conclusions: S100P expression distinguishes BDC from CCC and their different immunophenotype may reflect a different biological origin. Moreover, intrahepatic CC and CCC have a similar expression of S100P, which may reflect possible biological similarities. Distinguishing these categories is important because they have different prognosis and distinct biological behaviour.
Category: Liver & Pancreas

Tuesday, March 23, 2010 1:00 PM

Poster Session IV # 192, Tuesday Afternoon


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