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Page 2 of 16 Chandrasekar et al. Mini-invasive Surg 2021;5:33 https://dx.doi.org/10.20517/2574-1225.2021.12

INTRODUCTION
Biliary tract malignancies are broadly classified into three categories: (1) intra-hepatic biliary tract cancers;
(2) cancer of the extra-hepatic biliary tract and the gall bladder; and (3) ampulla of vater cancer.
Cholangiocarcinoma (CCA) includes tumors of the intra-hepatic bile ducts, peri-hilar and extra-hepatic bile
[1]
ducts . Cancers in the distal bile duct can present with biliary strictures due to CCA, pancreatic head
cancers or cancer of the ampulla of vater and they behave clinically similar, thus being broadly categorized
as peri-ampullary tumors. Among CCAs, about 5%-10% are intra-hepatic and about 60% of the extra-
[2]
hepatic CCAs are in the peri-hilar region, classified as the Klatskin tumors [Table 1]. CCA is the most
common biliary tract malignancy but accounts for less than 2% of all cancers . It is often the most difficult
[3]
to diagnose among all gastrointestinal cancers with a dismal 5-year survival rate of about 5% . Risk factors
[4]
for CCA include primary sclerosing cholangitis (PSC), choledochal cyst, parasitic infections like Clonorchis,
[5]
exposure to thorotrast, hepatolithiasis and familial polyposis but the majority occur sporadically .
Malignant biliary strictures can present with symptoms and signs due to obstruction of the bile ducts
including abdominal pain in the right upper quadrant, jaundice, fever or chills due to cholangitis, but they
can also be non-specific. They are often insidious in growth and can present late in their clinical course with
a poor prognosis. With the advent of advanced imaging technologies, biliary tract malignancies are
diagnosed at an earlier stage, offering a potential surgical cure or liver transplant options for patients.
Despite all this, only about 20% of malignant biliary obstructions (MBO) are resectable at the time of
[6]
diagnosis . This review will address the diagnostic steps for evaluation of MBO due to biliary etiology,
tissue sampling methods and the management strategies for biliary drainage, with a predominant focus on
CCA.

Diagnostic approach
Diagnosis of a biliary malignancy should be suspected in a patient who presents with symptoms and signs of
biliary obstruction, including jaundice, abdominal pain, abnormal liver enzymes with mainly a cholestatic
pattern or evidence of biliary ductal dilatation on imaging. Presence of an intra-hepatic mass on imaging
warrants further investigation to rule out CCA. In patients with PSC, any deterioration in clinical status
with worsening jaundice or weight loss, with or without the presence of biliary ductal dilatation should be
further investigated to look for the presence of any dominant stricture and evaluated for CCA, especially in
the setting of wall thickening of the bile duct.

The approach for diagnosis depends on the location of the suspected lesion, if it is intra-hepatic, peri-hilar
or in the distal biliary tract. Once a biliary tumor is suspected, the patient should undergo further testing
with tumor markers, imaging studies and endoscopic or percutaneous procedures for sampling to establish
a diagnosis. A tissue diagnosis is generally necessary prior to any surgical planning, documentation prior to
non-operative treatment modalities like chemoradiation and especially in indeterminate strictures, where
establishing a diagnosis will change the management. Distal biliary tumors can cause both intra- and extra-
hepatic biliary ductal dilatation while peri-hilar tumors cause intrahepatic ductal dilatation with normal
extrahepatic ducts.

CROSS-SECTIONAL IMAGING STUDIES
Ultrasonography
Trans-abdominal ultrasonography (US) is often the first imaging modality obtained for any patient with
abnormal liver enzymes with jaundice or right upper quadrant abdominal pain. US can provide information
on biliary ductal dilatation with a possible level of obstruction, presence of gall stones or common bile duct
(CBD) stones and intra-hepatic CCA as masses with mixed echogenicity. Direct visualization of a mass in
the extra-hepatic bile duct is usually unlikely with US. Albu et al. in their series of 124 patients with extra-
[7]