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Exogenous Pigments

Exogenous pigments are characterized as agents containing color that are formed outside of the body but found within tissues. Exogenous pigments can find their way into the body in a variety of ways. Examples of exogenous pigments are carbon, asbestos fibers, tattoo ink, and metals. Copper is the most commonly visualized exogenous pigment found in liver tissue.
The table describes some exogenous pigments found within tissues:
Exogenous PigmentComments
Copper deposits
  • Accumulation found within the liver is characteristic of Wilson's disease.
  • Hematoxylin and eosin (H&E) stained tissue slides commonly do not reveal the presence of copper.
  • Stains such as rhodanine or rubeanic acid, shown in the image, can be used to positively identify copper in liver biopsy tissue.
Drug induced deposits
  • Pigment in liver tissue may be deposited from intravenous (IV) gold (used to treat rheumatoid arthritis) or illicit drug use.