Cholangiocarcinoma

Malignancy arising from the bile duct epithelium, classified by anatomical location as intrahepatic (arising within the liver parenchyma, increasingly grouped and managed alongside hepatocellular carcinoma given overlapping presentation), perihilar (Klatskin tumor, at the confluence of the right and left hepatic ducts, the most common location), and distal (extrahepatic, closer to the pancreatic head, sharing much of its clinical presentation and management pathway with pancreatic cancer).

Risk factors include primary sclerosing cholangitis (a major and well recognized association, see Ulcerative Colitis entry), liver fluke infection (Clostorchis sinensis and Opisthorchis viverrini, endemic in parts of Southeast Asia), choledochal cysts, hepatolithiasis, and chronic viral hepatitis.

Perihilar and distal tumors present similarly to pancreatic head cancer: painless, progressive obstructive jaundice, pale stools and dark urine, pruritus from cholestasis, and weight loss. Intrahepatic cholangiocarcinoma more often presents with nonspecific abdominal pain, weight loss, and a hepatic mass detected on imaging, since jaundice only occurs late once major ducts are compressed. Fever suggests superimposed cholangitis from biliary obstruction, and should be actively assessed for given the need for urgent drainage if present (see Cholangitis entry).

LFTs show a cholestatic pattern. CA19-9 is used as a tumor marker to support diagnosis and monitor treatment response, though it lacks the sensitivity and specificity to be diagnostic alone, and can be markedly elevated by biliary obstruction of any cause including benign disease. Cross sectional imaging with contrast enhanced CT or MRI with MRCP characterizes the tumor, its relationship to the biliary tree and vasculature, and assists staging. ERCP or percutaneous transhepatic cholangiography allows tissue sampling (brushings or biopsy, though sensitivity is limited given the typically desmoplastic, hypocellular nature of these tumors) and, importantly, therapeutic biliary drainage. PET CT and staging laparoscopy assess for occult metastatic or peritoneal disease prior to considering resection.

Differentials include pancreatic cancer (for distal tumors), benign biliary stricture (particularly in the context of primary sclerosing cholangitis, where distinguishing benign dominant stricture from malignant transformation can be genuinely difficult and requires close surveillance), hepatocellular carcinoma (for intrahepatic tumors), and other periampullary malignancy.

Resectable disease is treated with surgical resection tailored to tumor location: major hepatectomy with extrahepatic bile duct resection for perihilar tumors, pancreaticoduodenectomy for distal tumors (following the same principles as for pancreatic cancer), and hepatic resection for intrahepatic tumors, followed by adjuvant chemotherapy (commonly capecitabine). Liver transplantation, combined with neoadjuvant chemoradiotherapy under a strict protocol, is an option for carefully selected perihilar cholangiocarcinoma at specialist centers. Unresectable or metastatic disease is managed with palliative chemotherapy (gemcitabine and cisplatin is the standard first-line combination), with targeted therapy increasingly available for tumors harboring specific molecular alterations (FGFR2 fusions, IDH1 mutations) identified on molecular profiling. Biliary decompression, whether by ERCP stenting or percutaneous transhepatic drainage, is a central component of management at every stage, both to relieve symptomatic jaundice and pruritus and to permit safe delivery of chemotherapy in patients with obstructive jaundice.

Referral: hepatobiliary surgery and oncology multidisciplinary team for all confirmed or suspected cases; gastroenterology for biliary drainage and tissue sampling.