Pathologic Calcification

Question 1

What is pathologic calcifications

Answer 1

● Abnormal deposition of calcium salt in tissues. Smaller amounts of Mg, Fe, other minerals may also be present.

Question 2

What are the 2 types of pathologic calcification

Answer 2

○ Metastatic calcification
○ Dystrophic calcification

Question 3

3 characteristics of dystrophic calcification

Answer 3

● Dying tissues
● Normal Ca levels
● No derangement in Ca metabolism

Question 4

3 characteristics of metastatic calcifications

Answer 4

● Normal tissue
● High Ca levels
● Derangement in Ca
metabolism

Question 5

What kind of  necrosis is dystrophic calcification found

Answer 5

regardless of type- caseous, coagulative, liquefactive.

Question 6

How is the calcification in dystrophic calcification brought about

Answer 6

denatured proteins in degenerate or necrotic tissue bind phosphate ions. These bound phosphate ions react with calcium ions to form precipitates of calcium phosphate

Question 7

What is the calcium phosphate mineral formed in the necrosis calcification similar to

Answer 7

The final common pathway is the formation of calcium phosphate mineral as an apatite which is similar to the hydroxyapatite of bone.

Question 8

How is Calcium accumulated in membrane bound vesicles in dystrophic calcification

Answer 8

● Membrane damage causes the accumulation of calcium in membrane bound vesicles.
● The calcium deposit attracts the deposition of phosphate

Question 9

When is a microcrystal formed and what does it do

Answer 9

•The cycle of calcium and phosphate deposition continues until a microcrystal is formed.
● This microcrystal then propagates and leads to more calcium deposition.

Question 10

When is a psammoma body formed

Answer 10

● On occasion, a sigle necrotic cell can bind with calcium and then attract layers of mineral deposition and form a psammoma body

Question 11

What’s the morphology of nectrotic calcification

Answer 11

they appear as fine, white granules or clumps which are gritty to touch.

Question 12

How does dystrophic calcification look microscopically

Answer 12

Ca salts look basophilic (purplish blue), amorphous and may have a lamellated appearance.

Question 13

What part of the cell does dystrophic calcification occur

Answer 13

They may be intracellular or extracellular

Question 14

Give 8 examples of dystrophic calcification

Answer 14

1. In aging or damaged heart valves
2. Uterine leiomyomas
3. Damaged blood vessels
4. Tumours e.g. papillary thyroid carcinoma, papillary serous carcinoma
5. Atherosclerosis
6. Tuberculous lymphnodes
7. Asbestosis in the lungs
8. Lithopaedion

Question 15

What is metastatic calcification

Answer 15

Occurs in tissues when there is hypercalcemia (increased blood calcium levels)
● Calcium level in the body is regulated by a host of organs and hormones. Derangement at any level may lead to an increase in calcium levels.

Question 16

What tissues are affected by metastatic calcification

Answer 16

● Principally affects interstitial tissues of gastric mucosa, lungs, kidneys, pulmonary veins and systemic arteries. These sites tend to have an internal alkaline compartment that predisposes them to metastatic calcification

Question 17

What predisposes tissues to metastatic calcification

Answer 17

Internal alkaline environment

Question 18

What’s the morphology of metastatic calcification

Answer 18

● Similar to that seen in dystrophic calcification
● Usually there is no loss of function in the organ, however massive deposits in the lungs and kidney (nephrocalcinosis) may result in respiratory difficulties and kidney damage.

Question 19

What are the causes of metastatic calcifications

Answer 19

• Hyperparathyroidism; tumors , PTH-rP
• Destruction of bone tissue : tumors (multiple myeloma), cancer, Accelerated bone turnover (pagets) , prolonged immobilization
• Vitamin D related disorders : intoxication , Sarcoidosis (macrophages active Vit D precursor) , Williams syndrome (idiopathic hypercalcemia of infancy)
• * Hyperphosphatemia* : renal failure , exogenous phosphate
• * Milk-alkali syndrome* : Ca supplements taken for osteoporosis with antacid

Question 20

What can accentuate dystrophic calcification

Answer 20

hypercalcemia may also accentuate dystrophic calcification.