Six patients who had received gold injections for the treatment of rheumatoid arthritis had histologically visible deposits of gold in the skin. In two of the patients, no gold had been administered for 20 years or more. The identity of the deposits was confirmed by emission spectroscopy using a laser microprobe, as well as by their resistance to microincineration and their removal by Lugol solution.
Cox AJ, Marich KW. Gold in the Dermis Following Gold Therapy for Rheumatoid Arthritis. Arch Dermatol. 1973;108(5):655-657. doi:10.1001/archderm.1973.01620260005001