Pathologic Calcifications & Pigments

Question 1

Abnormal deposition of calcium salts, along with other minerals, in tissue

Answer 1

Pathologic calcification

Question 2

What is the gross appearance of calcification?

Answer 2

Chalky, gritty, white deposits

Question 3

What is the microscopic appearance of calcification?

Answer 3

Granular/basophilic stippling (H&E) or brown/black (von Kossa stain)

Question 4

What are the two types of pathologic calcification?

Answer 4

Dystrophic and metastatic

Question 5

What can cause DYSTROPHIC mineralization?

Answer 5

• Failure to regulate cellular Ca2+ balance
• Occurs in necrotic tissue in animals with a normal serum Ca2+ level

Question 6

White muscle disease (vitamin E/selenium deficiency in ruminants) and granulomas are both types of ___________ mineralization

Answer 6

Dystrophic

Question 7

What can cause METASTATIC mineralization?

Answer 7

• Hypercalcemia (serum Ca2+/phosphate imbalance)
• Occurs in normal tissue in an animal with hypercalcemia

Question 8

Chronic kidney disease, primary hyperparathyroidism, hypercalcemia of malignancy, and vitamin D toxicosis are all examples of ____________ mineralization

Answer 8

Metastatic

Question 9

What is the pathogenesis of chronic kidney disease?

Answer 9

Phosphate retention leads to abnormal Ca2+/phosphorus ratios, and then secondary hyperparathyroidism

Question 10

True or False: Renal failure may lead to hypocalcemia normocalcemia, or hypercalcemia - all are possible!

Answer 10

True

Question 11

Chronic kidney disease is characterized by ______/_______ mineralization; occurs in tongue, parietal pleura, pulmonary interstitium, L atrium, kidney, and gastric mucosa

Answer 11

Uremia; uremic

Question 12

What is the cause and pathogenesis of primary hyperparathyroidism?

Answer 12

Parathyroid adenomas; hyper-secretion of PTH by neoplastic chief cells

Question 13

What is the pathogenesis of hypercalcemia of malignancy?

Answer 13

PTH-rP is produced by tumors (such as lymphoma and anal sac gland carcinoma), and functions similarly to normal PTH

Question 14

What causes vitamin D toxicosis?

Answer 14

Ingestion of certain plants or cholecalciferol-containing rodenticides

Question 15

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)

Answer 15

Heterotopic ossification

Question 16

Colored substances found in tissue (can be exogenous or endogenous)

Answer 16

Pigments

Question 17

Pigments originating outside of the body; examples include carbon dust, tattoos, carotenoids, and tetracycline

Answer 17

Exogenous pigments

Question 18

Pigments synthesized within the body; examples include hemosiderin, bilirubin, melanin, and lipofuscin/ceroid

Answer 18

Endogenous pigments

Question 19

Where does carbon dust common from, and what does carbon dust tissue damage look like?

Answer 19

Pollution exposure; tissues take on a gray-ish pigmentation

Question 20

Creates a yellow/orange pigmentation (often confused with icterus at first glance); apparently harmless aside from discoloration

Answer 20

Carotenoid pigment

Example: beta-carotene

Question 21

Antibiotic; counterindicated for young animals due to association with discoloration of the teeth and delayed bone growth and healing

Answer 21

Tetracycline

Question 22

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

Answer 22

Melanin

Question 23

What often causes hyperpigmentation?

Answer 23

Inflammatory responses associated with atopic dermatitis

Question 24

What is a condition that causes hypopigmentation?

Answer 24

Vitiligo

(Extra note: spots of hypopigmentation may increase as melanocytes are attacked)

Question 25

“Wear and tear pigment”; no deleterious effect on the cells, result of natural lysosomal breakdown of lipids with age; brown/yellow granular pigment

Answer 25

Lipofuscin

Question 26

Pigments derived from RBCs including Hb, hematins, hemosiderin, hematoidin, bilirubin, biliverdin, and porphyrins

Answer 26

Hematogenous pigments

Question 27

Dark blue discoloration of hypoxic tissues as a result of deoxygenated hemoglobin

Answer 27

Cyanosis

Question 28

Bilirubin is a product of the breakdown of ___________.

Answer 28

Hemoglobin

Question 29

A Hb-derived, globular, golden-yellow pigment containing iron; found within MQs at sites of RBC breakdown following hemorrhage

Answer 29

Hemosiderin

Question 30

What stain is best to detect hemosiderosis in tissues?

Answer 30

Prussian blue

(Because of the iron!)

Question 31

During breakdown of erythrocytes in a bruise, what colors are associated with Hb, bilirubin, and hemosiderin respectively?

Answer 31

Hb = red
Bilirubin = yellow
Hemosiderin = brown

Question 32

Brown, amorphous, globular pigment that does not contain iron; notable gross morphology is yellow staining of tissue (typically associated with jaundice/icterus)

Answer 32

Bilirubin

Question 33

What are the 3 types of icterus?

Answer 33

Prehepatic, hepatic, posthepatic

Question 34

Icterus associated with increased unconjugated bilirubin and hemolysis (immune-mediated, infectious, metabolic, trauma, toxins, etc.)

Answer 34

Prehepatic icterus

Question 35

Icterus associated with defective uptake or conjugation of conjugated or unconjugated bilirubin; seen in liver disease or congenital anomalies

Answer 35

Hepatic icterus

Question 36

Icterus associated with increased conjugated bilirubin; seen in bile duct obstruction

Answer 36

Posthepatic icterus

Question 37

What is porphyria?

Answer 37

Deposition of porphyria pigments in tissues (red/pink color)

Question 38

What does a deficiency of uroporphyrinogen III synthase cause in calves, cats, and pigs?

Answer 38

Discoloration of dentin (“pink tooth”) and bone; a condition called congenital erythropoietin porphyria