black gallstone

A gallstone composed of bilirubin polymers mixed with mucin glycoprotein matrix. Black gallstones are most common in a background of cirrhosis and chronic hemolysis, as occurs in sickle cell anemia or thalassemia

black gallstone

Internal medicine A gallstone composed of bilirubin polymers mixed with mucin glycoprotein matrix; BGs are most common in a background of cirrhosis and chronic hemolysis, as occurs in sickle cell anemia or thalassemia; BGs comprise 10-90% of all gallstones, depending on the population being studied, and have more calcium, carbonate and unmeasured residue, but less cholesterol and fat. See Gallstone. Cf Brown gallstone.