Amyloidosis

• amyloid infiltration occurs in all species
• an inert substance deposited under the endothelium and basement membranes of a variety of tissues
  • renal glomeruli
  • Islets of Langerhans in the pancreas
  • liver (between the sinusoidal reticulum and the hepatic cords)

Causes

May be a primary condition or appear secondary to some chronic tissue destructive process

• an infectious process elsewhere in the body
• a result of sustained antigenic stimulation, eg repeated injections with an antigenic substance or production of excessive antibody by leukocytes

Gross

• pale (greyish waxy appearance)
• enlarged
• rounded edges
• firm
• very prone to rupture

Microscopically

• deposition of amyloid in the space of Disse
• shows 'apple-green' fluorescence under polarised light after staining with Congo Red