The pulmonary aspergilloses: three distinct entities or a spectrum of disease.

The fungus Aspergillus can cause any of three clinical presentations--invasive aspergillosis, mycetoma, or allergic bronchopulmonary aspergillosis--or a disease process in which one of these entities overlaps with another process such as mucoid impaction, eosinophilic pneumonia, bronchocentric granulomatosis, "farmer's lung," or asthma. More than one form of the disease may be present at the same time; in addition, limited invasion may occur even in "noninvasive" forms of the disease, and the clinical and pathological aspects of allergic aspergillosis are often indistinguishable from those of unrelated allergic conditions. Thus it is no longer possible to compartmentalize the various types of pulmonary aspergillosis into exclusive forms of the disease; rather, the radiologist should be aware that various factors can modify the mode of growth of the fungus as well as the patient's response.