A spot on the lung produced by the tuberculosis bacillus [Described 1912. After Anton Ghon (1866—1936), Professor of Pathological Anatomy at Prague, Czech Republic.]
The lesion produced in the lung of a previously uninfected person by tubercle bacilli. It is a small focus of granulomatous inflammation, which may become visible on a chest X-ray if it grows large enough or if it calcifies. A Ghon focus usually heals without further trouble, but in some patients tuberculosis spreads from it via the lymphatics, the air spaces, or the bloodstream.