Tumefactive biliary sludge: a sonographic pseudotumour appearance in the common bile duct.

Two patients with obstructive biliary symptoms were shown to have dilated bile ducts on ultrasound. Within the lumen of both distal common ducts (CBD) large low echogenicity polypoid masses without acoustic shadowing were seen. MRI in one patient showed a polypoid filling defect in the lower CBD corresponding to the ultrasound appearance. Instrumentation at the lower end of both CBDs caused disintegration of the polypoid configuration resulting in the more typical layered appearance of biliary sludge. Sludge in the gall-bladder as seen on ultrasound is rarely known to cause a pseudotumour appearance. It has not previously been reported as occurring in the CBD and awareness of the tumefactive appearance of biliary sludge in the common duct is important and should help avoid possible misinterpretation.