Pulmonary aspergilloma is usually located in the upper lobes and it develops in the pre-existing cavities which has a direct communication to a bronchiole, usually sequels of tuberculosis, bullous emphysema, cysts, or cancer.[sup][3],[4] The radiological signs include
air crescent sign and finger-in-glove appearance and movement of the fungus ball within the cavity when comparing upright and decubitus, which strongly suggested the diagnosis of pulmonary aspergilloma.[sup][5] The “ball-in-hole” aspect was found in our patients, but, if observed closely, we can discover that the shape of the ball in the cavity was different between the supine and prone positions.
A Plain CT scan of the thorax revealed right upper lobe & a left lower lobe air crescent sign; there was shift in air crescent with change in patient position (figure 2).
CONCLUSIONS: Rasmussen's aneurysm should be considered in the differential diagnosis of air crescent sign both in chest radiograph and plain CT.
The histopathology of this transition lesion forms the basis for the analogous radiological air crescent sign, which is an imaging indicator of late IPA.
Gardiner, "The air crescent sign: causes and characteristics," Texas Heart Institute Journal, vol.
Initially there is pulmonary opacification which progresses to necrosis with a central cavity (
air crescent sign).
(86,87) The air crescent sign is often considered characteristic of retraction of infected lung in invasive aspergillosis (Figure 18).88 However, this sign can be seen in other conditions such as tuberculosis, Wegener's granulomatosis and lung cancer.
Adeno-carcinoma of the lung presenting as a mycetoma with an air crescent sign. Chest.
Air crescent sign was more common in bacterial pneumonia (24) than in aspergillosis (6).
In current study cases, in aspergillosis, air crescent sign was seen 2(3.3%) cases with aspergilloma, CT halo sign was seen in 2(3.3%) cases with invasive pulmonary aspergillosis and bronchiectasis was seen in 3(5%)cases with allergic bronchopulmonary aspergillosis and 2(3.3%) cases with aspergilloma.