The Diagnostic Dilemma of Malignant Biliary Strictures

Abstract

The differential diagnosis for biliary strictures is broad. However, the likelihood of malignancy is high. Determining the etiology of a biliary stricture requires a comprehensive physical exam, laboratory evaluation, imaging, and ultimately tissue acquisition. Even then, definitive diagnosis is elusive, and many strictures remain indeterminant in origin. This literary review examines the diagnostic dilemma of biliary strictures and presents innovations in both histochemical and endoscopic techniques that have increased the diagnostic power of differentiating benign and malignant strictures. The field of tissue biopsy is revolutionizing with the advent of free DNA mutation profiling, fluorescence in situ hybridization (FISH), and methionyl t-RNA synthetase 1 (MARS 1), which allow for greater testing sensitivity. Endoscopic ultrasound, endoscopic retrograde cholangiopancreatography (ERCP), cholangioscopy, confocal laser endomicroscopy, and intraductal ultrasound build upon existing endoscopic technology to better characterize strictures that would otherwise be indeterminate in etiology. This review uses recent literature to insert innovative technology into the traditional framework of diagnostic methods for malignant biliary strictures.

Keywords: cholangioscopy; confocal laser endomicroscopy; endoscopic retrograde cholangiopancreatography; endoscopic ultrasound; fine-needle aspiration and biopsy; hepatobiliary malignancy; intraductal ultrasound; malignant biliary stricture; pancreatic cancer.

Figure 1

The Bismuth–Corlette classification is a system for characterizing hilar strictures. Type I is limited to the common hepatic duct, below the main confluence of the hepatic ducts. Type II involves the confluence of the left and right hepatic ducts. Type IIIa involves the main hepatic confluence and extends to the bifurcation of the right hepatic duct. Type IIIb involves the main hepatic confluence and extends to the bifurcation of the left hepatic duct. Type IV involves the main, right, and left hepatic confluence.

Figure 2

A,B: Axial contrast computed tomography (CT) shows enhancing intraductal polypoid mass consistent with intraductal cholangiocarcinoma (arrow); C: The circle demonstrates a T2W hypointense lesion found on magnetic resonance cholangiopancreatography (MRCP); D: Postcontrast MR showing an incidentally found subtle mural thickening of the gallbladder fundus later diagnosed as synchronous gallbladder carcinoma.

Figure 3

A: Axial contrast-enhanced CT shows enhancing dilated common duct (arrow); B: there is abrupt cutoff of the common duct and there is diffuse mural thickening and enhancement (arrow); C: The circle demonstrates an infiltrative mass in the distal duct found on coronal CT; D: endoscopic retrograde cholangiopancreatography (ERCP) shows a short-segment tight stricture corresponding to the mass. Biopsy confirmed cholangiocarcinoma.

Figure 4

A: Axial arterial phase CT shows dilated intrahepatic ducts and a hypodense mass (arrow) at the hilum; B,C: venous phase images show enhancement of the mass. This signifies excessive fibrous stroma in the tumor and is consistent with cholangiocarcinoma.

Figure 5

A–C: CT shows a pancreatic head mass with central necrosis (circle, C). Additional findings include no calcifications to support underlying chronic pancreatitis, no ductal dilatation, peripancreatic fat planes are not maintained (blue arrow, A) and superior mesenteric artery (SMA) (red arrow, A)/superior mesenteric vein (SMV) (yellow arrow, A) ratio is ≥ 1. The gastroduodenal artery (green arrow, B) is encased by the mass. Dilated common bile duct (star, C). Overall, there are at least three signs suggesting the diagnosis of malignancy.

Figure 6

ERCP with brushings and resultant cytology. A: Cholangiography showing distal bile duct stricture with upstream ductal dilatation. B: Balloon dilation of distal bile duct stricture. C: Brushings obtained from distal bile duct stricture during ERCP. D: Plastic stent placed in bile duct across stricture for biliary drainage. E: Brush cytology showed biliary tract adenocarcinoma. The group shows loss of polarity, irregularly spaced nuclei. The nuclei are angulated and pointed with subtle grooves and folding. Small nucleoli are present in the cells (Papanicolaou stain).

Figure 7

A: Cholangioscopy revealing hilar stricture with irregular mucosa and neovascularization. B: Stricture sampling with SpyBite biopsy forceps.

Figure 8

A: Endoscopic ultrasound (EUS)-guided fine-needle aspiration of a pancreatic head mass. B: The malignant cells are crowded and overlapping. The nuclei are enlarged and show nuclear size variation in a range of 1:3. (FNA, Papanicolaou stain).

Figure 9

A: Malignant glands admixed with normal pancreatic parenchyma (core biopsy, H&E stain). B: On high power, the tumor cells form solid nest with focal glandular formation. There is nuclear enlargement and irregularity, abnormal chromatin, and prominent nucleoli (core biopsy, H&E stain).