A gumma is a soft, tumor-like growth of the tissues (granuloma) caused by syphilis. It
appears during late stage, tertiary syphilis. It usually contains a mass of dead and
swollen fiber-like tissue, and occurs most frequently in the liver but may also occur in
the brain, testis, heart, skin, and bone. Also, similar-appearing granulomatous sores are
sometimes found with tuberculosis.