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Aspergilloma (fungal ball), aka saprophytic aspergillosis is a mass of Aspergillus hyphae, mucus, and cellular debris that colonizes a pre-existing pulmonary cavity without invading the surrounding lung tissue. It is a non-invasive form of pulmonary aspergillosis.

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https://www.youtube.com/watch?v=Pyfk6h9xJAo

Etiology

Cause of Pre-existing Cavity	Examples
Post-tuberculosis	Most common global cause
Sarcoidosis	Especially in fibrocystic stages
Emphysema	Bullae may serve as colonization sites
Previous lung abscess	Necrotic cavities
Bronchiectasis / CPA	Structural lung damage

Clinical Features

Symptom	Details
Hemoptysis	Most common and potentially life-threatening
Chronic cough	May produce sputum or blood-streaked mucus
Asymptomatic	Often incidental finding on imaging
Weight loss, fatigue	Occasionally in large, chronic lesions

Complications

Massive hemoptysis (can be fatal)
Secondary bacterial infection of the cavity
May transition to chronic cavitary pulmonary aspergillosis (CCPA)

Diagnosis

Investigation	Findings
Imaging (CT)	Mobile fungal mass with air crescent in known cavity
Sputum culture	Aspergillus species may be isolated
Serum IgG (Aspergillus-specific)	Often elevated, useful for confirmation
Bronchoscopy	Direct visualization ± culture, may provoke hemoptysis
Histopathology (if resected)	Fungal hyphae without tissue invasion

Radiology

Modality	Imaging features
XR	• Rounded or oval opacity within a pre-existing cavity
• Air crescent (Monod’s sign): Crescent of air surrounding the fungal ball
• Usually upper lobe predominant (e.g., post-TB cavities)
CT	• Mobile intracavitary mass: Shifts position with patient posture
• Air crescent sign (Monod sign): Air surrounding the non-adherent fungal ball
• Chronic inflammation: Wall thickening of the cavity and/or adjacent pleural thickening
• No parenchymal invasion (differentiates from invasive aspergillosis)

![Coronal (a) and sagittal (b) CT images showing pathognomonic aspergilloma: mass within a lung cavity surrounded by air, which is called the “air crescent” sign. Aspergilloma cannot be diagnosed on chest X ray (c), because the air crescent sign is not visible.

Chabi ML, Goracci A, Roche N, Paugam A, Lupo A, Revel MP. Pulmonary aspergillosis. Diagnostic and Interventional Imaging. 2015;96(5):435-442. doi:10.1016/j.diii.2015.01.005](attachment:205d10c1-614b-432a-b1b1-36519b760381:1-s2.0-S2211568415000625-gr3.jpg)

Coronal (a) and sagittal (b) CT images showing pathognomonic aspergilloma: mass within a lung cavity surrounded by air, which is called the “air crescent” sign. Aspergilloma cannot be diagnosed on chest X ray (c), because the air crescent sign is not visible.

Chabi ML, Goracci A, Roche N, Paugam A, Lupo A, Revel MP. Pulmonary aspergillosis. Diagnostic and Interventional Imaging. 2015;96(5):435-442. doi:10.1016/j.diii.2015.01.005