Adenocarcinoma of Extrahepatic Bile Ducts

 3 forms: Perihilar, distal, and diffuse



• Klatskin tumor: Perihilar tumor occurring at confluence of right and left hepatic ducts




Etiology/Pathogenesis




• Numerous risk factors, including developmental anomalies, flukes, primary sclerosing cholangitis


Clinical Issues




• Poor prognosis with 10% overall 5-year survival
image Surgical resection is only hope for long-term survival

• Rare (incidence is 0.53-2.00 per 100,000)

• Primarily 6th and 7th decades of life

• Nonspecific symptoms, signs of biliary obstruction

• Elevated serum CA19-9, CEA-M, CA125


Microscopic




• Wide spectrum of histologic appearances
• Malignant glands are arranged in haphazard pattern, infiltrating duct wall

• Often associated with desmoplastic stroma

• Nuclear pleomorphism with increased N:C ratio, nuclear grooves, and brisk mitotic activity

image Cytologic features may be deceptively bland

• Frequent lymphovascular &/or perineural invasion


Ancillary Tests




• Positive: CK-PAN, CK7, CK19, CEA-M, CA19-9, MUC1, and MUC5AC
image CK20, CDX-2 positive in < 50% of cases


Top Differential Diagnoses




• Reactive periductal glands

• Pancreatic ductal carcinoma: Indistinguishable histologically and immunophenotypically

image
Gross Appearance
This cross section from a Whipple resection shows distal bile duct carcinoma involving the intrapancreatic portion of the common bile duct. Note the marked thickening of the duct wall image .


image
Widely Spaced Irregular Glands
This case of extrahepatic cholangiocarcinoma features widely spaced, irregular glands infiltrating the duct wall. The duct lumen is partially denuded image. Note the presence of residual benign periductal glands arranged in a lobular pattern image .

image
High-Power View
These tumors are often very well differentiated, such as this case featuring well-formed glandular structures lined by a single layer of cuboidal epithelial cells with minimal cytologic atypia.

image
CK7
An extrahepatic bile duct biopsy shows poorly differentiated adenocarcinoma with cord-like clusters and individual cells infiltrating desmoplastic stroma. The tumor cells are immunoreactive with CK7.


TERMINOLOGY


Synonyms




• Extrahepatic cholangiocarcinoma


Definitions




• Malignant biliary epithelial neoplasm arising from right or left hepatic duct, common hepatic duct, or common bile duct
• Perihilar: Arises in extrahepatic bile ducts upstream from origin of cystic duct (70-80%)

image Klatskin tumor: Perihilar tumor occurring at confluence of right and left hepatic ducts

• Distal: Arises in common bile duct, including intrapancreatic portion, above ampulla of Vater (20-30%)

• Diffuse (∼ 2%)


ETIOLOGY/PATHOGENESIS


Risk Factors




• Developmental (choledochal cyst, abnormal choledochopancreatic junction)

• Primary sclerosing cholangitis

• Parasitic infection (i.e., flukes)

• Familial adenomatous polyposis

• Molecular alterations [ KRAS mutations (30%), overexpression of p53 oncoprotein (50%)]

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Apr 20, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Adenocarcinoma of Extrahepatic Bile Ducts
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