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.
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