Syphilis is a sexually transmitted bacterial disease and in its tertiary phase, which can occur between three and fifteen years after initial infection, is characterised by the formation of chronic gummas typically on the skin, bone and liver but they can form anywhere. Gummas are soft tumour like balls of inflammation which can vary considerably in size. Co-infection with HIV is common and left untreated syphilis has a high mortality rate. In 1999 it is believed to have infected over 12 million people worldwide - most of these cases in the developing world. Abstinence from sexual activity is the only real preventer.