Biliary sludge—ultrasonic appearance simulating neoplasm

Biliary sludge is the term applied to the material causing layered ultrasonic echoes in the gall bladder. It may be due to thick or inspissated bile, multiple tiny non-shadowing calculi, pigment granules or cholesterol crystal formation, haemobilia, purulent bile or pus (Conrad et al., 1979; Buschi et al., 1979; Filly et al., 1980). The appearance usually has a medium-to-coarse echo pattern, shows a horizontal fluid/fluid interface, no acoustic shadowing and being gravity-dependent moves when the patient assumes an oblique or lateral decubitus position (Anderson and Harned, 1977; Conrad et al., 1979; Filly et al., 1980; Leopold et al., 1976). The appearance of biliary sludge may be variable, however; movement under gravity may be very slow (Filly et al., 1980); in empyema of the gall bladder diffuse echogenic densities may fill the gall bladder and show no gravity dependence or layering effect (Kane, 1980). Inspissation of bile in long-standing biliary obstruction may appear as a uniform solid mass lying in the position of the gall bladder (Weeks et al., 1977). In this paper we report four cases of biliary sludge with an unusual appearance. The patients were referred with symptoms of gall-bladder disease or obstructive jaundice and in each case the ultrasonic picture suggested the presence of a sessile tumour arising from the gall-bladder wall.