EXTRAHEPATIC BILIARY CYSTADENOCARCINOMA MIMICKING KLATSKIN TUMOR Cistoadenocarcinoma biliar extra-hepático mimetizando tumor de Klatskin

Biliary cystadenocarcinoma (BCAC) is a very rare malignant cystic neoplasm. Some authors think this particular neoplasm was conversion of biliary cystadenoma over several years of evolution. In the majority of the cases, it habitually occurs in the liver parenchyma (intrahepatic cystadenocarcinoma); sometimes can be observed extrahepatic biliary origin3,4,6,7,8,10,11 extrahepatic biliary cystadenocarcinoma, (EBCAC), which generally leads jaundice associated with palpable mass1,2,5,6,9. In the past, the diagnosis was done by means of endoscopic retrograde cholangiopancreatography. However, actually the computed tomography or even nuclear magnetic resonance are preferred due non-invasive approaches1,2,3,4,5,6,7,8,9,10. Sometimes, EBCAC has difficulties on differential diagnosis with cholangiocarcinoma, mainly when occurs in the hepatic hilum6. The surgical treatment provides good prognosis; however, en-bloc biliary tract resection with hepatectomy may be necessary to get free margins3,6,10. To date, was not found any case reported in Brazil, nor successful operation using a enbloc biliary resection with hepatectomy to treat it.