Gallstone composition: are children different?

During a 5-year period (1997-2002) 20 consecutive children (11 boys; median age, 8 years; range, 0.3-13.9 years) underwent cholecystectomy for cholelithiasis at a regional pediatric surgical center. Multiple stones were present in 16 patients (80%). All stones were collected prospectively. Composition studies were performed after grinding an aliquot of stone and examining a layer of crushed powder by Fourier transform infrared microspectroscopy. The relative proportions of each major stone component were assessed: cholesterol, protein and calcium salts of bilirubin, fatty acids, carbonate, and hydroxyapatite. Of the 20 children, 10 had black pigment stones, 2 had cholesterol stones, 1 had brown pigment stones, and 7 had calcium carbonate stones; the latter are exceptionally rare in adults. The composition of pediatric gallstones in this series differs from that found in adults.