A granuloma is a small area of inflammation. Granulomas are often found incidentally on an X-ray or other imaging test done for a different reason. Typically, granulomas are noncancerous (benign).

Granulomas frequently occur in the lungs, but can occur in other parts of the body and head as well. Granulomas seem to be a defensive mechanism that triggers the body to "wall off" foreign invaders such as bacteria or fungi to keep them from spreading. Common causes include an inflammatory condition called sarcoidosis and infections such as histoplasmosis or tuberculosis.

Granulomas in people without symptoms almost never require treatment or even follow-up imaging tests.