A solid mass, "pebbles" formed by the precipitation (crystallization) of cholesterol (most common in the U S and Europe) or bilirubin (most common in Asia) in the gallbladder Gallstones may be asymptomatic (without symptoms) or they may result in inflammation and infection of the gallbladder
Gallstones form in the gallbladder when cholesterol or pigments crystallize out of bile They can vary in size from as small as grains of sand to as large as golf balls Sometimes gallstones get stuck in the bile ducts causing attacks of severe abdominal pain The tendency to form gallstones is partially inherited and is more common in people who are obese, overeat or lose weight rapidly through extreme diets