Kidney - Mineralization

Mineralization is more commonly associated with spontaneous and minute background findings of basophilic deposits in the renal cortex, medulla,or papilla of rats and mice (Figure 1). In general, these depositshave no pathologic significance. However, mineralization may also be seen as a consequence to degeneration and necrosis. Mineralization may be induced by chemicals, hormones, or diet. Mineralized deposits usually involve tubule epithelia but may also involve the interstitium. Alizarin red S or von Kossa’s special stains are used to demonstrate mineral in histologic sections. Mineralized deposits seen particularly in female rats are noted in the pars recta and thin loops of Henle near the junction of the outer stripe of the outer medulla and the inner stripe of the outer medulla (Figure 2). Linear deposits of papillary mineralization are characteristic of chronic chemical administration that induces α2u-globulin nephropathy (Figure 3). Artifactual mineralization is sometimes encountered in the outer cortex. The cause of this mineralization often cannot be identified.