Dystrophic calcification and its organ manifestation

1. Definition

• Abnormal deposition of Ca²⁺ salts (+ trace Mg²⁺, Fe²⁺) in tissue.
• Dystrophic = in dead/dying tissue with normal serum Ca²⁺ (normocalcemic) — contrast metastatic (hypercalcemia, normal tissue).
• A consequence of coagulative/liquefactive necrosis; marks past injury and can impair organ function.

2. Morphology

• Macroscopic: white granules/clumps.
• Histology: basophilic, amorphous intra-/extracellular deposits.

3. Pathogenesis (ends in calcium phosphate)

Extracellular

• Ca²⁺ in membrane-bound vesicles from necrotic cells → membrane phosphatase liberates PO₄³⁻ → binds Ca²⁺ → calcium phosphate crystals → propagation.

Intracellular

• Begins in mitochondria of dying cells that lost Ca²⁺ regulation.

4. Organ Manifestations / Diseases

• Calcific aortic stenosis: age-related wear-and-tear valve calcification → narrowed valve → ↑outflow resistance → LV hypertrophy.
• Artificial valves: suture-site necrosis or attached cell debris → calcification foci.
• Atherosclerosis: necrotic lipid core calcifies.
• Infections: TB caseous necrosis; Michaelis-Gutmann bodies (malakoplakia of bladder — lamellated intracellular Ca²⁺ in macrophages).
• Neoplasms: central necrosis calcifies → myoma petrificans (uterus), psammoma bodies (thyroid/ovary), breast ductal carcinoma (mammographic microcalcifications).

💡 High-yield: Dystrophic calcification = normal serum Ca²⁺ in damaged/necrotic tissue. Classic sites: atherosclerotic plaques, aortic/mitral valves, TB caseation, fat necrosis, and psammoma bodies (papillary thyroid, serous ovarian, meningioma).