A case of biliary cast developed in a patient with long-standing biliary sludge.

Development of biliary casts is very unusual, especially in patients who have not undergone liver transplantation. Variable causes of biliary cast formation in nonliver transplantation patients have been suggested. However, stasis of bile flow and/or gallbladder hypocontractility is known to eventually result in the promotion of biliary sludge and subsequent cast formation.