A 50-year-old woman with chronic kidney disease and secondary hyperparathyroidism dies of complications. At autopsy, calcium deposits are found in the basement membranes of renal tubules, the alveolar walls of the lungs, and the gastric mucosa. These tissues were otherwise structurally normal. This pattern of calcification differs from dystrophic calcification chiefly because:
- A It occurs in dead and dying tissue with normal serum calcium levels
- B It begins with membrane-bound phosphorus released from degenerate organelles
- C It occurs in normal tissue secondary to hypercalcemia ✓
- D It is always confined to blood vessels and never affects visceral organs
Correct answer: C. It occurs in normal tissue secondary to hypercalcemia
Explanation
Metastatic calcification reflects deranged calcium metabolism with elevated serum calcium and phosphate, causing precipitation of calcium salts in morphologically normal, viable tissues. It preferentially affects tissues that excrete acid, such as gastric mucosa, kidney, lungs, and systemic arteries, because local alkalinity favors deposition. Option A describes dystrophic calcification, which occurs in injured or necrotic tissue despite normal serum calcium. Initiation via membrane-bound phospholipids applies to dystrophic calcification.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.