1. Intracellular accumulations of endogenous or exogenous substances
Lipids: fat may accumulate in the liver as fatty change
Proteins: abnormal protein accumulation is often irreversible.
Glycogen: glycogen storage diseases
Complex Lipids: sphinglolipidoses and other lipid accumulations

2. STANLEY ROBBINS, MD, in his office, Boston University School of Medicine in 1978

3. Intracellular accumulations of endogenous or exogenous substances
Complex carbohydrates: mucopolysaccharidoses and other complex carbohydrate diseases.
Minerals: iron, as hemosiderin, or carbon, as anthracotic pigment
- Pigments: lipofuscin is a benign brown pigment of lipid origin that may accumulate with age, or melanin from melanomas, or bilirubin as in jaundice

7. Fatty Change
Hepatic lipid accumulation is characterized by intracellular accumulation of triglycerides, and due to the failure of metabolic removal.
Defects in fat metabolism are often induced by alcohol consumption, and also associated with diabetes, obesity, and toxins.
Fatty change is most often seen in the liver (and heart), and is generally reversible.

10. FATTY CHANGE – Gross features
hepatomegaly
pale, yellow color
greasy appearance

13. FATTY CHANGE – Microscopic features
Fat vacuoles coalesce and displace the nucleus to the periphery of the cell
vacuoles appear clear, with well-defined edges
lipid accumulations must be distinguished from accumulations of water or glycogen, using special preparation and stain – Oil Red-O.

18. Calcification Dystrophic calcification
Abnormal calcium deposition in dead or degenerating tissues
In areas of necrosis
Atheromas of advanced atherosclerosis

19. Calcification Metastatic calcification
Abnormal calcium deposition in “normal” tissues secondary to hypercalcemia (in soft tissues that are not the site of previous damage )

20. Metastatic Calcification
Hyperparathyroidism
Destruction of bone tissue
Vitamin D related disorders
Renal failure

21. Morphology With H&E stain : basophilic amorphous granular appearance
Von Kossa stain – black deposits

34. Amyloid
Congo red-stained amyloid shows light green birefringence when subjected to polarized light.

37. Lipofuscin “Wear & tear” pigment
derived through lipid peroxidation of polyunsaturated lipids of subcellular membranes
accumulates in tissues undergoing slow, regressive changes – common in liver and heart of aging patients or patients with severe malnutrition and cancer cachexia
appears as a yellow-brown, finely granular, intracytoplasmic (or perinuclear) pigment

39. Lipofuscin/ceroid (Latin: fuscus=brown, “brown lipid”)
Brown discoloration of intestinal muscle due to vitamin E deficiency and smooth muscle lipofuscinosis

42. Haemosiderin derived from hemoglobin
golden yellow, granular or crystalline pigment
storage form of iron
forms in response to local or systemic excess of iron  ferritin forms hemosiderin granules

43. Haemosiderin
local excess: from gross or minute hemorrhage (eg. bruise)
systemic excess: from increased absorption of dietary iron, impaired use of iron, hemolytic anemia, transfusions

44. Chronic passive congestion with hemosiderosis and edema in a lung
Hemosiderin
Chronic passive congestion with hemosiderosis and edema in a lung

46. Chronic passive congestion with hemosiderin in alveolar macrophages

48. PRUSSIAN BLUE

52. Bilirubin

55. Bilirubin (bile) casts in hepatic canaliculi in chronic liver disease

56. Melanin (Greek, melas=black)

58. Melanin (Greek, melas=black)
Melanin in melanoma tumor cells