The gross specimen of a gallbladder shown above demonstrates multiple calculi. Based on their morphology and color, which of the following best describes the types of gallstones present?

Explanation

## Image Findings * Bisected gallbladder specimen. * Lumen is distended and filled with numerous calculi (gallstones). * Presence of several large, yellowish-green, ovoid, and faceted stones, particularly on the left side of the image. * Presence of multiple small, dark, irregular, and somewhat brittle-appearing stones, predominantly on the right side of the image. ## Diagnosis **Key Point:** The image demonstrates **mixed gallstones**, characterized by the coexistence of cholesterol and black pigment stones within the same gallbladder. 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. ## Differential Diagnosis | 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 | ## Clinical Relevance **Clinical Pearl:** Gallstones can be asymptomatic or cause symptoms ranging from biliary colic to severe complications like acute cholecystitis, cholangitis, pancreatitis, and gallstone ileus. The type of stone can sometimes hint at underlying etiologies (e.g., black pigment stones in hemolytic anemia). ## High-Yield for NEET PG **High-Yield:** **Cholesterol stones** are the most common type of gallstones (80% of cases in Western countries), while **pigment stones** account for the remaining 20%. In India, pigment stones are relatively more common, especially in rural areas, often linked to infections. **Key Point:** **Mixed stones** are very common and often contain a mixture of cholesterol and calcium bilirubinate, with one component predominating. The image clearly shows features of both cholesterol and black pigment stones, making 'mixed' the most accurate description. ## Common Traps **Warning:** Do not confuse black pigment stones with brown pigment stones. Black pigment stones are typically found in the gallbladder and are associated with sterile bile, while brown pigment stones are found in the bile ducts and are associated with infected bile and stasis. ## Reference [cite:Robbins & Cotran Pathologic Basis of Disease, Ch 15]