Pigmented Stones

• “Black”: Morphology:

  – Present in sterile gallbladder bile

  – Contain oxidised polymers of the calcium salts of unconjugated bilirubin, small amounts of calcium carbonate, calcium phosphate, and mucin glycoprotein, and some cholesterol monohydrate crystals

  – Mostly, less than 1,5 cm in diameter

  – Present in great number

  – Contours: Speculated and moulded

  • Imaging: 50-75% of black stones = Radiopaque (because of calcium carbonates and phosphates)
• “Brown”: Morphology:

  – Present in infected intra-hepatic or extra-hepatic ducts

  – Contain pure calcium salts of unconjugated bilirubin, mucin glycoprotein, a substantial cholesterol fraction, and calcium salts of palmitate and stearate

  – Laminated and soft

  – Soap-like or greasy consistency

  Imaging: Radiolucent (contain calcium soaps)