The cause of metastatic calcification is hypercalcemia.
Hypercalcemia most often results from any of the following causes:
Hyperparathyroidism
Osteolytic tumors with resultant mobilization of calcium and phosphorus
Hypervitaminosis D
Excess calcium intake, such as in the milk-alkali syndrome (nephrocalcinosis and renal stones caused by milk and antacid self-therapy)
Dystrophic calcification
Dystrophic calcification is defined as calcification in previously damaged tissue, such as areas of old trauma, tuberculosis lesions, scarred heart valves, and atherosclerotic lesions (Figure 1.7).
This is an example of dystrophic calcification, that is, calcification of a previously damaged structure.
(Reprinted with permission from Rubin R, Strayer D et al., eds.: Rubin’s Pathology. Clinicopathologic Foundations of Medicine, 6th ed. Baltimore, Lippincott Williams & Wilkins, 2012, Figure 1-10, p. 13.)
The cause is not hypercalcemia; typically, the serum calcium concentration is normal.