Other Cellular Alterations During Injury
Lipids that can accumulate intracellularly include triglycerides (e.g., fatty change in liver cells), cholesterol (e.g., atherosclerosis, xanthomas), and complex lipids (e.g., sphingolipid accumulation).
OTHER CELLULAR ALTERATIONS DURING INJURY
- Lipids that can accumulate intracellularly include triglycerides (e.g., fatty change in liver cells), cholesterol (e.g., atherosclerosis, xanthomas), and complex lipids (e.g., sphingolipid accumulation).
- Proteins can accumulate in proximal renal tubules in proteinuria and can form Russell bodies (intracytoplasmic accumulation of immunoglobulins) in plasma cells.
- Glycogen storage diseases
- Exogenous pigments include anthracitic pigmentation of the lung (secondary to the inhalation of carbon dust), tattoos, and lead that has been ingested (e.g., gingival lead line, renal tubular lead deposits).
- Lipofuscin is a wear-and-tear pigment that is seen as a perinuclear yellow-brown pigment. It is due to indigestible material within lysosomes and is common in the liver and heart.
- Melanin is a black-brown pigment derived from tyrosine found in melanocytes and substantia nigra.
- Hemosiderin is a golden yellow-brown granular pigment found in areas of hemorrhage or bruises. Systemic iron overload can lead to hemosiderosis (increase in total body iron stores without tissue injury) or hemochromatosis (increase in total body iron stores with tissue injury). Prussian blue stain can identify the iron in the hemosiderin.
- Bilirubin accumulates in newborns in the basal ganglia, causing permanent damage (kernicterus).
Hyaline change is a nonspecific term used to describe any intracellular or extracellular alteration that has a pink homogenous appearance (proteins) on H&E stains.
- Examples of intracellular hyaline include renal proximal tubule protein reabsorption droplets, Russell bodies, and alcoholic hyaline.
- Examples of extracellular hyaline include hyaline arteriolosclerosis, amyloid, and hyaline membrane disease of the newborn.
Pathologic forms of calcification
- Dystrophic calcification is the precipitation of calcium phosphate in dying or necrotic tissues. Examples include fat necrosis (saponification), psammoma bodies (laminated calcifications that occur in meningiomas and papillary carcinomas of the thyroid and ovary), Mönckeberg medial calcific sclerosis in arterial walls, and atherosclerotic plaques.
- Metastatic calcification is the precipitation of calcium phosphate in normal tissue due to hypercalcemia (supersaturated solution). The many causes include hyperparathyroidism, parathyroid adenomas, renal failure, paraneoplastic syndrome, vitamin D intoxication, milk-alkali syndrome, sarcoidosis, Paget disease, multiple myeloma, metastatic cancer to the bone. The calcifications are located in the interstitial tissues of the stomach, kidneys, lungs, and blood vessels.