CORRESPONDENCE 1287 tive anions determine the potential for crystal precipi-though the location within the stone is not identified.
Thus, their data would seem to confirm our findings tation within bile. Certain disease states predispose and be in conflict with the statement in their letter to supersaturation and precipitation of cholesterol and that ''palmitate is a specific compound of 'infectious' specific calcium salts. In addition, gallbladder motility brown gallstones . . . but not other gallstones.'' The influences crystal precipitation and stone growth. Bile lower prevalence of palmitate in cholesterol gallstone obtained at cholecystectomy for symptomatic gallperipheries in our study (3%) suggests that calcium stones may not be reflective of bile composition during palmitate is less important as cholesterol stones grow the early stages of stone nidation and growth. Therethan in the initial events of cholesterol gallstone formafore, information regarding human gallstone pathogention. If calcium palmitate precipitates are simply esis may be best obtained from determination of galltrapped within cholesterol gallstone cores during the stone microstructure and composition.
initial events of stone nidation as suggested by Cetta The purpose of our article was to describe in detail et al., then the prevalence of this salt should be similar the distribution of calcium salts in the core, periphery, in the periphery of cholesterol gallstones. and shell of cholesterol, black pigment, and brown pig-Cetta et al. have also misinterpreted our efforts to ment gallstones. This description allows one to delindescribe in detail the microstructure and composition eate specific similarities and differences in microstrucof gallstones as an attempt to reclassify gallstones. This ture and composition of human gallstones. We is not the case. On the contrary, we agree with these concluded from this detailed analysis of 146 gallstone authors that gallstones should be classified by gross cross sections that cholesterol, black pigment, and surface and cross-sectional characteristics. In fact, our brown pigment gallstones had more similarities than original stone classification by these macroscopic critedifferences in core calcium salt composition. Furtherria was confirmed by both stone cholesterol content and more, gallstones differed more in peripheral calcium scanning electron micrograph/energy dispersive x-ray salt patterns, suggesting that the growth of gallstones microanalysis data, with no gallstones reclassified was influenced more by bile composition (and therefore based on these observations. underlying disease state) than the initial events at ni-In conclusion, we agree with Cetta et al. that galldation. Cetta et al. agree with our methods and results stone pathogenesis is multifactorial and that certain but have reached a different conclusion.
disease states create a bile composition milieu that fa-In their letter, Cetta et al. focus on the pathogenesis vors the precipitation of specific calcium salts and stone of brown pigment gallstones. Brown pigment stones growth. However, the observation that the central reclassically form in the setting of biliary infection and gions of gallstones contain distinct similarities in calcontain mostly calcium bilirubinate, calcium palmitate, cium salt composition rather than marked differences and microscopic cholesterol crystals in addition to suggests that these specific disease processes affect trapped bacteria. We have documented calcium palmistone growth and ultimate macroscopic features more tate precipitates in the core of 32% of cholesterol gallthan the initial events of gallstone formation. stones, 31% of black pigment gallstones, and 100% of brown pigment gallstones. These findings would sug-HOWARD S. KAUFMAN, M.D. gest that calcium palmitate is found both in ''infectious'' KEITH D. LILLEMOE, M.D. brown pigment stones and in stones not typically asso-Department of Surgery ciated with infection. Cetta et al. have also detected
The Johns Hopkins Medical Institutions Baltimore, MD calcium palmitate in 20% of cholesterol gallstones, al-* Available only in the 43 patients with an identified route of transmission (16 1a patients and 27 1b patients).
β Two patients lost to follow-up.