Chest ImagingAspergilloma
a fungus ball or mycetoma caused by one of the aspergillus species which infect humans. Among the common varieties are
A. fumigatus and
A. niger. Aspergillomas are collections of fungal hyphae and cellular debris which occur inside a pre-existing cavity as a saprophytic growth. Initially mycetomas may produce wall thickening of the cavity. In time fungal growth results in a generally free-moving rounded mass which usually does not fill the cavity completely (
Fig.1). Aspergillomas are typically detected on chest radiographs as an incidental finding or are discovered as a cause of haemoptysis. If the mass begins to fill the entire cavity an
air crescent sign may be seen on chest films.
Calcification and fluid levels are rare.
Clinical findings include cough and haemoptysis which may be seen in up to 90% of patients. The aetiology for haemorrhage may be related to irritation of a hypervascular cavity wall by the moving fungal mass or may be related to fungal endotoxins or immune responses. Occasionally haemorrhage is so severe that bronchial artery embolization or surgical resection is necessary. Typically, however, most patients tolerate this fungal colonization well. Little change on the chest film may be noted from year to year. CT can demonstrate the abnormalities better than chest radiography.
Pre-existing cavities are generally a result of prior tuberculosis although a number of different aetiologies including sarcoidosis, ankylosing spondylitis pulmonary manifestations and prior lung abscesses have been implicated as sites for subsequent aspergillomas.
PGO
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A PA chest film demonstrates a large fairly thin-walled cavity in the left upper zone. Within this cavity is a homogeneous mass which was seen to change position on subsequent decubitus view. This is very typical of aspergilloma or other mycetomas.
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Aspergilloma, Fig.1 | |