Aspergilloma

Excerpt

Inert saprophytic colonization of preexisting cavitary spaces in pulmonary parenchyma, its presentation, and complications are referred to as aspergilloma and CCPA. These conditions fall within the broader class of CPA, of which several distinct clinical entities are recognized, including aspergilloma, CCPA, chronic fibrotic pulmonary aspergillosis, aspergillus nodules, and subacute invasive aspergillosis. It is important to emphasize that overlap in these CPA entities' clinical and radiographic features has led to confusion when interpreting the literature on their natural history and management aspects. Additional confusion is attributed to the differences in cumulative clinician experience when managing these entities. Published case series from regions with high TB prevalence may differ in diagnostic and management approaches compared to areas with lower prevalence, where aspergilloma is less common. Management approaches are controversial because small case series exist in the literature, but extensive, prospective, randomized studies are lacking. Diagnosing and managing these chronic fungal infections are complex and challenging. The diagnosis is difficult as radiographic features may overlap with other lung diseases. Moreover, since CPA develops most often in diseased lungs, it is difficult to determine how much of the radiological distortion reflects pathology due to the fungus versus the underlying lung disease.

The European Society for Clinical Microbiology and Infectious Diseases, The European Respiratory Society, and The Infectious Diseases Society of America have developed consensus definitions of CPA.

Their diagnostic criteria are as follows:

Simple Aspergilloma

Single pulmonary cavity containing a fungal ball, with serological or microbiological evidence implicating Aspergillus spp in a non-immunocompromised patient with minor or no symptoms and no radiological progression over at least 3 months of observation (see Image. CT Lung Showing Aspergilloma Mass That Indicates Monod's Sign).

Chronic Cavitary Pulmonary Aspergillosis (CCPA)

One or more pulmonary cavities (with either a thin or thick wall) possibly containing 1 or more aspergillomas or irregular intraluminal material with serological or microbiological evidence implicating Aspergillus spp with significant pulmonary and/or systemic symptoms and overt radiological progression (new cavities, increasing pericavitary infiltrates or increasing fibrosis) over at least 3 months observation.

Chronic Fibrosing Pulmonary Aspergillosis (CFPA)

Severe fibrotic destruction of at least 2 lobes of the lung complicates CCPA, leading to a major loss of lung function. Severe fibrotic destruction of 1 lobe with a cavity is called CCPA, affecting that lobe. Usually, the fibrosis manifests as consolidation, but large cavities with surrounding fibrosis may be seen.

Aspergillus Nodule

An unusual form of CPA is one or more nodules that may or may not cavitate. They may mimic tuberculoma, carcinoma of the lung, coccidiomycosis, and other diagnoses and can only be definitively diagnosed on histology. Tissue invasion is not demonstrated, although necrosis is frequent.

Subacute Invasive Aspergillosis (SAIA)

Invasive aspergillosis, usually in mildly immunocompromised patients, occurs over 1 to 3 months and has variable radiological features, including cavitation, nodules, and progressive consolidation with abscess formation. Biopsy shows hyphae in invading lung tissue, and microbiological investigations reflect those in invasive aspergillosis, notably positive Aspergillus galactomannan antigens in blood or respiratory fluids.

The above definitions are not mutually discreet; progressive evolution between the disease categories may ensue. While poorly understood, the factors contributing to disease progression likely include a combination of immune function, treatment response, and preexisting lung pathology. Pulmonary aspergilloma and CCPA are the focus of this article, and the terms aspergilloma, pulmonary mycetoma, and fungus ball are considered to describe the chronic colonization by aspergillus species within preexisting lung cavities or bronchiectatic parenchyma.