Definition of Pulmonary aspergilloma (mycetoma):

Pulmonary aspergilloma is a mass caused by a fungal infection that usually grows in pre-existing lung cavities. It can also appear in the brain, kidney, or other organs.

Causes, incidence, and risk factors:

Aspergillomas are formed when the fungus aspergillus grows in a clump in a pre-existing pulmonary (lung) cavity or when the organism invades previously healthy tissue, causing an abscess.

Aspergillus is a common fungus. It grows on dead leaves, stored grain, bird droppings, compost piles, and other decaying vegetation. Pre-existing cavities in the lung may have been caused by a previous infection, such as histoplasmosis, tuberculosis, lung abscess, or by cystic fibrosis, sarcoidosis, or previous lung cancer. See also aspergillosis.