Aspergilloma is formed when conidia are inhaled in a preexisting lung cavity (tuberculosis, emphysema); if there is not a cavity, aspergilli develop in lung tissue causing invasive infection (spreading through the tissue and involving blood vessels); then spread can occur to other organs.

Diagnosis of aspergilloma is radiological (CT scan); invasive aspergillosis can be diagnosed from respiratory secretions or lung biopsy; test for circulating galactomannan is also diagnostic.