Pigments can be exogenous or endogenous. Exogenous pigments come from outside sources like carbon, air pollution, or tattoos. They are inhaled and transported to lymph nodes by macrophages, causing black coloring of the lungs and lymph nodes. Endogenous pigments are synthesized within the body and include lipofuscin, melanin, and hemosiderin. Lipofuscin is an insoluble polymer associated with aging and oxidative damage found in the liver and heart. Melanin is produced via enzymatic reactions in melanocytes and is responsible for skin and hair color. Hemosiderin stores excess iron from hemoglobin breakdown in phagocytes.

1. PIGMENTS
BY Dr Hasan Askari
PATHOLOGY DEPARTMENT

2. PIGMENTS
 Pigments are colored
substance.
 It may be exogenous &
endogenous.
 Exogenous coming
from outside the body.
 Endogenous
synthesized within the
body.

3. EXOGENOUS PIGMENTS
 Carbon (coal dust),air pollutant & tattooing.
 Mechanism:
 Inhaled  macrophages (alveoli)  transported to
lymph node (tracheobronchial region).
 Black color of lungs (anthracosis) & lymph node.
 In coal miners  carbon dust induce fibroblastic
reaction or emphysema  coal worker’s
pneumoconiosis.
 Tattooing  phagocytosis by dermal macrophages.

4. EXOGENOUS PIGMENTS

5. EXOGENOUS PIGMENTS

6. TATTOOS

7. TATTOO

8. EXOGENOUS PIGMENTS

9. ENDOGENOUS PIGMENTS
 Lipofuscin (lipochrome or wear & tear pigment)
 Melanin
 Hemosiderin

10. ENDOGENOUS PIGMENTS

12. ENDOGENOUS PIGMENTSPIGMENTS
LIPOFUSCIN:
• It is insoluble polymer of lipid & phospholipid with
protein by lipid peroxidation.
• Yellow-brown color.
• Not harmful.
• It shows sign of free radical injury & lipid
peroxidation.
• Mostly in liver & heart of aging, malnutrition &
cancer cachexia.

14. ENDOGENOUS PIGMENTSPIGMENTS
MELANIN:
• It is endogenous , non-hemoglobin derived black –
brown pigment.
• In melanocytes  enzyme tyrosinase catalyze the
oxidation of tyrosine to dihydroxyphenylamine.
• OCHRONOSIS: (Homogentisic acid)
- Occur in patient with alkaptouria (metabolic
disorder)
- Black pigment deposide in skin, connective tissue &
cartilage.

15. ENDOGENOUS PIGMENTS

16. E
ENDOGENOUS PIGMENTSNDOGENOUS
PIGMENTS
HEMOSIDERIN:
• Storage form of iron  hemoglobin derived golden-
brown granular or crystalline pigment.
• Iron transported by transferin  stored in cell by
apoferrin  form ferritin  excess iron  excess
ferritin  form hemosidrin granules.
• Normally seen in mononuclear phagocytes.
• E.g: bruises

18. BRUISE

19. Just chill