Pathologic Calcifications & Pigments Flashcards
Abnormal deposition of calcium salts, along with other minerals, in tissue
Pathologic calcification
What is the gross appearance of calcification?
Chalky, gritty, white deposits
What is the microscopic appearance of calcification?
Granular/basophilic stippling (H&E) or brown/black (von Kossa stain)
What are the two types of pathologic calcification?
Dystrophic and metastatic
What can cause DYSTROPHIC mineralization?
- Failure to regulate cellular Ca2+ balance
- Occurs in necrotic tissue in animals with a normal serum Ca2+ level
White muscle disease (vitamin E/selenium deficiency in ruminants) and granulomas are both types of ___________ mineralization
Dystrophic
What can cause METASTATIC mineralization?
- Hypercalcemia (serum Ca2+/phosphate imbalance)
- Occurs in normal tissue in an animal with hypercalcemia
Chronic kidney disease, primary hyperparathyroidism, hypercalcemia of malignancy, and vitamin D toxicosis are all examples of ____________ mineralization
Metastatic
What is the pathogenesis of chronic kidney disease?
Phosphate retention leads to abnormal Ca2+/phosphorus ratios, and then secondary hyperparathyroidism
True or False: Renal failure may lead to hypocalcemia normocalcemia, or hypercalcemia - all are possible!
True
Chronic kidney disease is characterized by ______/_______ mineralization; occurs in tongue, parietal pleura, pulmonary interstitium, L atrium, kidney, and gastric mucosa
Uremia; uremic
What is the cause and pathogenesis of primary hyperparathyroidism?
Parathyroid adenomas; hyper-secretion of PTH by neoplastic chief cells
What is the pathogenesis of hypercalcemia of malignancy?
PTH-rP is produced by tumors (such as lymphoma and anal sac gland carcinoma), and functions similarly to normal PTH
What causes vitamin D toxicosis?
Ingestion of certain plants or cholecalciferol-containing rodenticides
Formation of bony tissue at an extra skeletal site; gross appearance of hard spicules or nodules; common incidental finding in lungs of older dogs (osseous metaplasia)
Heterotopic ossification
Colored substances found in tissue (can be exogenous or endogenous)
Pigments
Pigments originating outside of the body; examples include carbon dust, tattoos, carotenoids, and tetracycline
Exogenous pigments
Pigments synthesized within the body; examples include hemosiderin, bilirubin, melanin, and lipofuscin/ceroid
Endogenous pigments
Where does carbon dust common from, and what does carbon dust tissue damage look like?
Pollution exposure; tissues take on a gray-ish pigmentation
Creates a yellow/orange pigmentation (often confused with icterus at first glance); apparently harmless aside from discoloration
Carotenoid pigment
Example: beta-carotene
Antibiotic; counterindicated for young animals due to association with discoloration of the teeth and delayed bone growth and healing
Tetracycline
Produced by melanocytes (present in skin, hair, and iris) and transferred to keratinocytes; functions include solar protection, UV light absorption/protection, and scavenging free radicals
Melanin
What often causes hyperpigmentation?
Inflammatory responses associated with atopic dermatitis
What is a condition that causes hypopigmentation?
Vitiligo
(Extra note: spots of hypopigmentation may increase as melanocytes are attacked)
“Wear and tear pigment”; no deleterious effect on the cells, result of natural lysosomal breakdown of lipids with age; brown/yellow granular pigment
Lipofuscin
Pigments derived from RBCs including Hb, hematins, hemosiderin, hematoidin, bilirubin, biliverdin, and porphyrins
Hematogenous pigments
Dark blue discoloration of hypoxic tissues as a result of deoxygenated hemoglobin
Cyanosis
Bilirubin is a product of the breakdown of ___________.
Hemoglobin
A Hb-derived, globular, golden-yellow pigment containing iron; found within MQs at sites of RBC breakdown following hemorrhage
Hemosiderin
What stain is best to detect hemosiderosis in tissues?
Prussian blue
(Because of the iron!)
During breakdown of erythrocytes in a bruise, what colors are associated with Hb, bilirubin, and hemosiderin respectively?
Hb = red
Bilirubin = yellow
Hemosiderin = brown
Brown, amorphous, globular pigment that does not contain iron; notable gross morphology is yellow staining of tissue (typically associated with jaundice/icterus)
Bilirubin
What are the 3 types of icterus?
Prehepatic, hepatic, posthepatic
Icterus associated with increased unconjugated bilirubin and hemolysis (immune-mediated, infectious, metabolic, trauma, toxins, etc.)
Prehepatic icterus
Icterus associated with defective uptake or conjugation of conjugated or unconjugated bilirubin; seen in liver disease or congenital anomalies
Hepatic icterus
Icterus associated with increased conjugated bilirubin; seen in bile duct obstruction
Posthepatic icterus
What is porphyria?
Deposition of porphyria pigments in tissues (red/pink color)
What does a deficiency of uroporphyrinogen III synthase cause in calves, cats, and pigs?
Discoloration of dentin (“pink tooth”) and bone; a condition called congenital erythropoietin porphyria
