Liver Pigmentation

Congenital melanosis

• in calves and lambs
• black discoloration of small irregular portions of the liver

Haemosiderin

• in chronic passive congestion and surrounding areas where there has been prior necrosis and haemorrhage
• found within the Kuppfer cells
• use Perls' stain

Lipofuscin

• an insoluble golden brown pigment which occurs within hepatocytes
• use Schmorl's stain - dark blue
• increases with age - called the 'senility' pigment
• it is commonly seen in hepatocytes near to the centrilobular vein in older cats
• no clinical significance

Bile

• especially prominent in obstructive jaundice
• discolours the tissues green
• intrahepatic bile canaliculi are distended with a greenish pigment - called bile plugs
• larger foci are seen in long standing cases when the hepatocytes rupture: the discharged bile is then surrounded by macrophages and perhaps giant cells - called bile lakes
• use Fouchet stain - green