(aka Mycetoma, Fungus Ball)
Chest radiography demonstrates a mass within a cavity. Typically, there is a solid mass surrounded by a radiolucent crescent (crescent sign, Monod's sign). They can be made to "roll" on decubitus films.
An aspergilloma is a ball of aspergillus hyphae, mucus and cellular debris  They tend occur in cavities preformed by TB, sarcoid, neoplasm, other fungi, or de novo. They are usually asymptomatic, but can present with hemoptysis. Host immune system is usually normal. Surgery is mainstay for symptomatic cases, but typically do not respond to medical treatment.
Rarely the mycetoma can cause inflammation and erode the wall and surrounding vasculature causing a Rasmussen's aneurysm and resultant massive hemoptysis.
Importatnt to differentiate from Invasive aspergillosis which occurs in immunocompromised patients. Results in a ground glass appearance around a dense focal consolidation, aka the Halo sign, which is non-specific.
ABPA in hypesensitive patients, upper lobe saccular bronchiectasis.
- William E. Brant and Clyde A. Helms. Fundamentals of Diagnostic Radiology Third Edition. Philadelphia, Lippincott Williams & Wilkins 2007.