Lecture 18 4/9/24

Question 1

What are the general characteristics of mineralization?

Answer 1

-deposition of mineral in soft tissue
-mostly calcium, but can include phosphorus, magnesium, iron, etc.
-typically white and opaque
-can be pasty, firm, or hard

Question 2

What is dystrophic mineralization?

Answer 2

-occurs in dead or degenerate cells/tissue
-serum calcium levels are normal

Question 3

What are examples of dystrophic mineralization?

Answer 3

-center of granulomas
-dead parasites
-necrotic muscle
-necrotic fat
-pedunculated lipomas in horses

Question 4

What is the pathogenesis of white muscle disease?

Answer 4

-vitamin E/selenium deficiency
-free radical injury
-cell death
-dystrophic mineralization
-white muscle disease

Question 5

What is metastatic mineralization?

Answer 5

mineralization in normal tissue due to hypercalcemia

Question 6

What can cause hypercalcemia?

Answer 6

-primary hyperparathyroidism
-excess vitamin D
-neoplasia if PTHrP is produced

Question 7

What can cause excess vitamin D?

Answer 7

-cholecalciferol rodenticide toxicity
-therapeutic overdose
-plant toxicities
-granulomatous inflammation
-excess in diet due to feed mixing errors

Question 8

Which tumors may produce PTHrP and cause hypercalcemia?

Answer 8

-lymphosarcoma
-anal sac gland adenocarcinoma
-other tumors, especially carcinomas

Question 9

What are the common sites for metastatic mineralization?

Answer 9

-gastric mucosa
-renal tubular basement membranes
-lung
-blood vessel walls

Question 10

Which type of mineralization is a combination of dystrophic and metastatic mineralization?

Answer 10

uremic mineralization (result of renal failure)

Question 11

What is the pathogenesis of uremic mineralization?

Answer 11

-phosphorus is retained by dysfunctional kidney
-phosphorus and calcium product is elevated (metastatic)
-uremia damages tissues (dystrophic)

Question 12

What are the common sites for uremic mineralization?

Answer 12

-gastric mucosa
-lung
-parietal pleura (unique to uremic)
-left atrial endocardium (unique to uremic)

Question 13

What is calcinosis cutis?

Answer 13

-mineralization of dermal collagen in dogs with excess glucocorticoids
-can be iatrogenic or due to adrenal cortex or pituitary tumor

Question 14

What is the gross appearance of calcinosis cutis?

Answer 14

flat, plaque-like lesions that resemble dermatitis or ulceration

Question 15

What is the microscopic appearance of calcinosis cutis?

Answer 15

patchy mineralization of dermal collagen bundles

Question 16

What is calcinosis circumscripta?

Answer 16

focal nodular/circumscribed mineralization most often seen in young, large breed dogs; sometimes related to trauma

Question 17

What are the common sites of calcinosis circumscripta?

Answer 17

-subcutis over pressure points
-tongue (found during spay/neuter intubation)
-sites of previous surgery/incisions

Question 18

How does calcinosis circumscripta appear grossly?

Answer 18

well circumscribed nodule composed of islands of white, pasty material

Question 19

How does calcinosis circumscripta appear microscopically?

Answer 19

irregular lakes of mineral often surrounded by giant cells and fibrosis