Endoscopic ultrasonography can diagnose distal biliary strictures without a mass on computed tomography

Table 4 Benign strictures correctly judged as benign on EUS

Final diagnosis	Reason to diagnose as benign stricture	EUS findings
Inflammatory stricture clinically diagnosed as acute cholangitis (n = 1)	No exacerbation during follow-up (> 23 mo)	Stenosis of the distal end of the bile duct
		The normal layered structure of the bile duct wall
		No mass adjacent to the stricture site
Biliary dilation (n = 3)	No change for > 18 mo	The dilated bile duct gradually tapering at the ampulla of Vater (n = 2)
		A 1-cm long narrowing portion at the distal end of the duct smoothly continuous from the dilated proximal duct (n = 1)
Chronic pancreatitis including 1 autoimmune pancreatitis (n = 2)	No exacerbation during follow-up (> 10 mo)	Smooth tapering of the distal end of the bile duct without a mass adjacent to the stricture site (in case of autoimmune pancreatitis)
		Marked calcification at the stricture site (n = 1)
Anomalous arrangement of the pancreaticobiliary duct (n = 1)	Confirmed by MRCP	Connection of the pancreatic duct to the biliary duct outside the papilla of Vater
Congenital choleductal cyst (n = 1)	Confirmed by surgery	Cystic dilatation at the distal end of the bile duct

MRCP: Magnetic resonance cholangiopancreatography.