Cholangiocarcinoma



Cholangiocarcinoma


Todd M. Blodgett, MD

Alex Ryan, MD

Omar Almusa, MD









Graphic shows a typical Klatskin tumor image, which is cholangiocarcinoma near the bifurcation of the main right and left intrahepatic bile ducts.






Coronal PET (A), axial CT (B) and fused PET/CT (C) show focal intense activity in the portacaval region image of this patient with a history of cholangiocarcinoma.


TERMINOLOGY


Abbreviations and Synonyms



  • Cholangiocarcinoma (CC), Klatskin tumor, malignant bile duct tumor


Definitions



  • Malignancy that arises from ductular epithelium of intrahepatic biliary tree and extrahepatic bile ducts



    • Note: Gallbladder cancer 9x more common than CC


  • Klatskin tumor: Perihilar cholangiocarcinoma involving bifurcation of hepatic duct; accounts for more than 70% of all bile duct cancers


IMAGING FINDINGS


General Features



  • Best diagnostic clue



    • PET: Hypermetabolic activity corresponding to primary tumor in liver, extrahepatic metastatic disease


    • Ultrasound, CT, MR: Bile duct obstruction w/small central mass suggests hilar lesion (Klatskin tumor)


  • Location



    • Extrahepatic tumors (87-92% of CC): Proximal, middle, distal ductal tumors


    • Extrahepatic tumor at bifurcation of proximal common hepatic duct = Klatskin tumor


    • Intrahepatic tumors (8-13% of CC) arise from small ducts


    • Nodular or papillary type is most common in distal duct and periampullary region


    • Intrahepatic tumors have tendency for perineural spread, but spread to liver, peritoneum, lung is extremely rare


    • Extrahepatic tumors spread to celiac nodes in ˜ 16% of cases


  • Size



    • Peripheral lesions are usually larger, measuring 5-20 cm at presentation


    • More central lesions (Klatskin) smaller at diagnosis


  • Morphology



    • Variable


    • Most intrahepatic CC present as mass, whereas 90% of extrahepatic CC reveal diffusely infiltrating growth pattern



Imaging Recommendations



  • Best imaging tool



    • CT: Staging regional/distant metastases; similar to US for demonstrating ductal dilation, large mass lesions


    • MRCP/ERCP: Sensitivity of 71-81% for detecting tumor in malignant stenoses, particularly central lesions


    • PET for staging distant metastases and characterizing peripheral CC


    • ERCP with brush cytology, DNA analysis, and serum analysis of CA 19-9 and CEA for initial workup



      • Have been shown to increase sensitivity significantly


      • Diagnosis of CC, especially in primary sclerosing cholangitis (PSC), may remain uncertain until invasive and aggressive approaches such as exploratory laparotomy provide biopsy


  • Protocol advice



    • Delayed PET imaging at ˜ 120 minute time point shown to better discriminate tumor from inflammation


    • Delayed imaging helps differentiate tumor from background liver activity


CT Findings



  • NECT



    • Mass predominantly hypoattenuating with irregular margins


    • Intrahepatic biliary duct (IHBD) dilation common with obstruction


    • Larger peripheral lesions may be isodense with central low attenuation and scarring



      • Central and satellite lesions


    • Hilar masses often not visible on NECT



      • IHBD dilation = clue


    • Capsular retraction may reveal intrahepatic tumor


    • Large common duct (extrahepatic) masses may be identified on NECT


  • CECT



    • Solitary, small, well-demarcated tumors are difficult to differentiate from primary hepatocellular carcinoma (HCC)


    • Arterial phase: Peripheral CC seen as intrahepatic mass showing early peripheral rim enhancement and progressive patchy central enhancement


    • Portal phase: Portal vein invasion, ductal wall thickening with minimal enhancement, and portal lymphadenopathy


    • Delayed phase



      • Enhancement with increasing attenuation seen in up to 74% of lesions, usually ↑ CT sensitivity/specificity


      • Persistent tumor enhancement due to fibrous stroma


    • Low reported sensitivity for small hilar lesions (approximately 50%)


    • Regional lymph node spread rarely detected (24-40% of cases)


Nuclear Medicine Findings



  • FDG PET



    • Primary uses



      • Identification of new lesions


      • Evaluation of metabolic activity and associated malignancy


      • Characterization of response to neoadjuvant therapy


      • Detection of lesions in liver that are not suspected on US or MR in up to 50% of patients


    • Peripheral CC: Intensely hypermetabolic activity, may be ring-shaped


    • Hilar CC: Low activity with focal nodular or linear branching pattern



      • Lower FDG uptake may be related to tumor size or arrangement of fibrous stroma and mucin pool in tumor


      • Can be difficult to discriminate between extrahepatic tumor itself and FDG-accumulating lymph nodes in perihilar region



      • Extrahepatic CC may have low uptake due to loosely connected cell nests and poor detection with PET due to infrequency of evident mass formation


    • PET sensitivity



      • 61-90% for primary CC


      • 85% for nodular CC


      • 18% for infiltrating CC


      • 65-70% for distant metastases


      • Only 13% for regional or hepatoduodenal mets


    • False negatives are seen with mucinous adenocarcinomas (rare)


    • False positives are seen due to foci of inflammation (e.g., intrahepatic stone)



      • Uptake likely to be seen along tract of biliary stents


    • Primary sclerosing cholangitis (PSC)



      • PET can be used to discriminate between PSC with and without CC


      • Not reliable for early diagnosis of CC in patients with PSC


      • Liver in patients with PSC may have ↑ background signal than those of healthy control patients


  • PET/CT



    • Allows better identification of non-FDG avid tumors & carcinomatosis and helps distinguish stent-related uptake from malignant disease


    • Shown to change oncological management in up to 17% of patients


    • No diagnostic advantage over CECT in detection of intrahepatic CC or primary tumor site of extrahepatic CC


    • Generally cost-effective method, avoids unnecessary surgery


  • Hepatobiliary scintigraphy: Focal photopenic lesion


  • Tc-99m sulfur colloid: Focal photopenic lesion


  • Ga-67 scintigraphy: Variable Ga-67 uptake


DIFFERENTIAL DIAGNOSIS


Hepatocellular Carcinoma (HCC)

Sep 22, 2016 | Posted by in MAGNETIC RESONANCE IMAGING | Comments Off on Cholangiocarcinoma
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