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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