CALCIFYING DISORDERS OF THE SKIN

Calcium is vital to many biologic processes. In skin, it has a profound effect on keratinocyte proliferation, differentiation, and cell-cell adhesion. Serum calcium is tightly regulated by parathyroid hormone and 1,25(OH)(2)D-3. Despite this careful regulation, calcification and ossification of cutaneous and subcutaneous tissues may occur. Cutaneous calcification may be divided into four major categories: dystrophic, metastatic, idiopathic, and iatrogenic. Dystrophic calcification occurs as a result of local tissue injury or abnormalities. Metastatic calcification results from abnormal calcium and/or phosphate metabolism. Virtually any process that calcifies may secondarily ossify. Primary ossification may rarely occur.