gumma /gum″ə/ pl. gummas, gummata [AS, goma, gum] , 1. a granuloma, characteristic of tertiary syphilis, varying from 1 mm to 1 cm in diameter. It is usually encapsulated and contains a central necrotic mass surrounded by inflammatory and fibrotic zones of tissue. Infectious organisms of the genus Treponema may be found in a gumma. The lesion may be localized or diffuse, occurring on the trunk, legs, and face and on various internal organs, especially the liver. It can also form in the brain, leading to neurological problems. Rupture of a gumma produces a shallow ulcer that heals slowly. 2. a soft granulomatous lesion that sometimes accompanies tuberculosis.
