Hyperpigmented concentric rings over the tibia are secondary to prior inflammation. Residual hemosiderin from broken down red blood cells in macrophages, left behind after inlammation pigments the skin.
Update Date 5/15/2013
Updated by: Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial Team.