Lecture 18 4/9/24 Flashcards
What are the general characteristics of mineralization?
-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
What is dystrophic mineralization?
-occurs in dead or degenerate cells/tissue
-serum calcium levels are normal
What are examples of dystrophic mineralization?
-center of granulomas
-dead parasites
-necrotic muscle
-necrotic fat
-pedunculated lipomas in horses
What is the pathogenesis of white muscle disease?
-vitamin E/selenium deficiency
-free radical injury
-cell death
-dystrophic mineralization
-white muscle disease
What is metastatic mineralization?
mineralization in normal tissue due to hypercalcemia
What can cause hypercalcemia?
-primary hyperparathyroidism
-excess vitamin D
-neoplasia if PTHrP is produced
What can cause excess vitamin D?
-cholecalciferol rodenticide toxicity
-therapeutic overdose
-plant toxicities
-granulomatous inflammation
-excess in diet due to feed mixing errors
Which tumors may produce PTHrP and cause hypercalcemia?
-lymphosarcoma
-anal sac gland adenocarcinoma
-other tumors, especially carcinomas
What are the common sites for metastatic mineralization?
-gastric mucosa
-renal tubular basement membranes
-lung
-blood vessel walls
Which type of mineralization is a combination of dystrophic and metastatic mineralization?
uremic mineralization (result of renal failure)
What is the pathogenesis of uremic mineralization?
-phosphorus is retained by dysfunctional kidney
-phosphorus and calcium product is elevated (metastatic)
-uremia damages tissues (dystrophic)
What are the common sites for uremic mineralization?
-gastric mucosa
-lung
-parietal pleura (unique to uremic)
-left atrial endocardium (unique to uremic)
What is calcinosis cutis?
-mineralization of dermal collagen in dogs with excess glucocorticoids
-can be iatrogenic or due to adrenal cortex or pituitary tumor
What is the gross appearance of calcinosis cutis?
flat, plaque-like lesions that resemble dermatitis or ulceration
What is the microscopic appearance of calcinosis cutis?
patchy mineralization of dermal collagen bundles
What is calcinosis circumscripta?
focal nodular/circumscribed mineralization most often seen in young, large breed dogs; sometimes related to trauma
What are the common sites of calcinosis circumscripta?
-subcutis over pressure points
-tongue (found during spay/neuter intubation)
-sites of previous surgery/incisions
How does calcinosis circumscripta appear grossly?
well circumscribed nodule composed of islands of white, pasty material
How does calcinosis circumscripta appear microscopically?
irregular lakes of mineral often surrounded by giant cells and fibrosis
