The large, yellowish-green, faceted stones are characteristic of cholesterol stones. These stones are typically composed predominantly of cholesterol monohydrate, are often solitary or few, and develop facets due to mechanical attrition against each other within the gallbladder.
The numerous small, dark, irregular stones are characteristic of black pigment stones. These are typically composed of oxidized calcium bilirubinate polymers, calcium phosphates, and calcium carbonate. They are often multiple, brittle, and associated with conditions like hemolytic disorders or cirrhosis.
| Feature | Cholesterol Stones | Black Pigment Stones | Brown Pigment Stones |
|---|---|---|---|
| Appearance | Yellowish-green, ovoid, firm, often faceted | Small, dark, irregular, brittle, often multiple | Soft, greasy, laminated, often solitary or few |
| Composition | >50% cholesterol monohydrate | Calcium bilirubinate, calcium phosphate, carbonate | Calcium salts of unconjugated bilirubin, fatty acids |
| Risk Factors | Female, Fat, Forty, Fertile (4 F's), obesity, rapid weight loss, certain drugs | Hemolysis, cirrhosis, advanced age, TPN | Biliary tract infection (e.g., E. coli), parasitic infestations, stasis |
| Location | Gallbladder | Gallbladder | Bile ducts (intrahepatic or extrahepatic) |
| Radiopacity | Often radiolucent (10-20% calcified) | Often radiopaque (50-75% calcified) | Radiolucent |
Robbins & Cotran Pathologic Basis of Disease, Ch 15
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