Where do subcutaneous tophi commonly occur?
In addition to involving the synovium and subchondral bone, tophi can develop at a multitude of subcutaneous sites including on digits of the hands and feet, olecranon bursa, extensor surface of the forearm, Achilles tendon, and, less commonly, the antihelix of the ear. Tophi can ulcerate through the skin and extrude a white, chalky material consisting of a dense concentration of MSU crystals. Although rare, an ulcerated tophus can become infected.
