Sonography of tumefactive biliary sludge.

Five patients with low-amplitude echoes taking the shape of a mass within the lumen of their gallbladders are reported. Disappearance of the mass on repeat examination in four cases and surgical proof in the fifth case established that the finding was a pseudotumor due to a collection of sludge. Knowledge of this tumefactive appearance of biliary sludge is important and should help avoid misinterpretation.