Aspergilloma

An aspergilloma, also known as a mycetoma or fungus ball, is a clump of fungus which exists in a body cavity such as the lung. The most common fungus responsible are the Aspergillus species, but Zygomycetes and Fusarium may also form similar structures.

Etiology
The most common place affected by aspergillomas is the lung. Aspergillus fumigatus, the most common species, is typically inhaled as small (2 to 3 micrometer) spores which do not affect people without underlying lung or immune system disease. However, people who have pre-existing lung problems, especially the cavities typically caused by tuberculosis, are at risk for developing aspergillomas. The fungus settles in a cavity and is able to grow free from interference because the immune system is unable to penetrate into the cavity. As the fungus multiplies, it forms a ball which incorporates dead tissue from the surrounding lung, mucus, and other debris.

Clinical syndrome
Typically, individuals who are affected by aspergillomas do not have symptoms related to the infestation. People often co-exist for decades with aspergillomas prior to incidental diagnosis, typically by x-ray or computed tomography. However, a small percentage of aspergillomas invade into the wall of the cavity and can result in bleeding. Thus, the most common symptom of aspergillomas is coughing up blood (hemoptysis). Although this can occasionally be life-threatening, the amount of blood produced is usually inconsequential.

Aspergillomas can form in other body cavities. Aspergillus can form abscesses in the brain, usually in people who are immunocompromised. They can also form within the different sinuses in the face, within the kidneys and urinary system, the ear canal, and on the heart valves.

Treatment
Most cases of aspergilloma do not require treatment. Treatment of diseases which increase the risk of aspergilloma, such as tuberculosis, may help prevent their formation. In cases complicated by severe hemoptysis, surgery may be required to remove the aspergilloma and stop the bleeding. There has been interest in treatment with anti-fungal medications such as itraconazole, but as of 2005, none has been shown to eradicate aspergillomas.