Date: 26 November 2013
Halo sign in IPA
Copyright: n/a
Notes:
CT scan of a neutropenia patient with leukaemia who has 2 lesions. One, on the right, is nodular, abuts on the pleura and is surrounded by a (grey) low attenuation area, referred to as the “halo” sign. This is virtually only seen in invasive fungal infections of the lung, especially early in the course of the disease, during neutropenia. The other lesion visible on this scan, posteriorly on the left, is also typical of invasive pulmonary aspergillosis in that it is pleura-based and has sharply angulated sides typical of vascular invasion and infarction of small lung segments. There is the suggestion of a “halo” sign anteriorly, but there is less confidence in this appearance (compared with the other) because it is only on one side of the lesion.
Images library
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The periphery of the fungus ball is deeply eosinophilic because of the deposition of Splendore-Hoeppli material.
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Single fungal ball, moving. Radiographic appearance of a fungus ball, showing movement as the patient’s position changes.
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Oxalate crystals in the cavity wall surrounding an Aspergillus niger fungus ball (H&E, dark field, x 25).
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Aspergilloma patient. Gross pathology appearance of a fungus ball.
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Conidiophores of Aspergillus fumigatus in the mass of the fungal ball surrounded by mycelia (H&E, x 400).
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Aspergillus niger fungal ball. Calcium oxalate crystals in Aspergillus niger fungal ball. Also shown are darkly pigmented, rough-walled conidia associated with Aspergillus niger infection.
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Aspergillus niger fungus ball within an old tuberculous cavern. This patient had diabetes, a disease commonly associated with A. niger infection.
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