PATHOLOGICAL CALCIFICATION

‘Deposition of salts in tissues other than osteoid or enamel’

DYSTROPHIC CALCIFICATION	METASTATIC CALCIFICATION
Dead or degenerated tissues	Normal tissues
Normal Ca metabolism and serum Ca level	Deranged

Histologically,

Ca salts – deeply basophilic, irregular, granular clumps (in H&E)

Stain – silver impregnation, alizarin red S

↓

Diffuse/ granular deposits of iron in Peri’s stain

DYSTROPHIC CALCIFICATION

 

CALCIFICATION IN DEAD TISSUE	CALCIFICATION IN DEGENERATED TISSUES
Caseous necrosis	Dense old scars
Liquefactive necrosis	Atheromas
Fat necrosis	Monckeberg”s sclerosis
Gamma – Gandy bodies (CVC)	Stroma of tumours
Infarcts	Goiter
Thrombi	Some tumours show psammona bodies or calcospherites
Haematomas	Cysts
Dead parasites	Senile degenerative changes
Breast cancer
Congenital toxoplasmosis

Pathogenesis

Formation of normal hydroxyapatite of bone i.e. binding of phosphate ions with calcium ions

Initiation – cell injury

↓

Membarane damage + release of membrane phospholipids (phosphatases associated)

Cell injury  → excess uptake of Ca² by injured mitochondria → ↓

Precipitates of calcium phosphate

 ↓

Structural changes

↓

Further propagation of deposits

↓

Mineral crystals

METASTATIC CALCIFICATION

EXCESSIVE MOBILISATION OF Ca+2 FROM THE BONE	EXCESSIVE MOBILISATION OF Ca+2 FROM THE GUT
Hyperparathyroidism	Hypervitaminosis D
Bony destructive lesions	Mild alkali syndrome
Hypercalcemias	Idiopathic hypercalcemia
Prolonged immobilisation	Renal causes

Sites: kidneys, lungs, stomach, blood vessels, cornea, synovium

Pathogenesis:              metabolic derangements → excessive bonding of phosphate ions with                                                                                               elevated  Ca⁺²

(reversible)

↓

At preferential sites

↓

Acid secretions or rapid changes in _pH levels

↓

Precipitation of calcium phosphate at preferential                                                                                                     sites