Cellular Inclusions

Viruses

• Either in the nucleus or cytoplasm.

Storage Products

• Due to hereditary storage diseases in which there is a missing or defective cellular enzyme. There are many types known in domestic animals.
  • Break down/ build up of intracellular substances is halted.
    • The intermediate substance accumulates in the lysosomes.
  • Affects all tissues
    • The central nervous system is particularly vulnerable.
• Due to age
  • Lysosomes will accumulate non-degradable products
    • E.g. lipofuscin - the 'ageing' or 'wear and tear pigment'.
      • Commonly seen in middle-aged cats in the hepatocytes nearest the centrilobular veins.

Intracellular Bacteria

• For example, Mycobacterium tuberculosis in macrophages.

Protein Accumulation

• In the renal tubular epithelium.
• Occurs when there is leakage of protein out through a damaged glomerulus.