paranasal sinus mycetoma

Pulmonary and
paranasal sinus aspergillosis. Partial filling of the sinuses of the face, with air-fluid levels in support of acute sinusitis signs. Presence of spontaneously dense elements within sphenoidal and maxillary sinuses (arrows), evoking the diagnosis of invasive aspergillosis infection.
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Sphenoid
sinus aspergilloma clinically mimicking as malignancy—a case report. a, b Computed tomography axial and sagittal images without contrast show hyper dense soft tissue in the expanded sphenoid sinus; its pneumatized portion of greater wing of sphenoid bones, clivus, and posterior ethmoid air cells. There is extension of soft tissue at the left orbital apex (blue arrow). Extension of lesion into sella is seen. Plain CT axial (c) and coronal bone window images (d) show completely thinned out and remodeled surrounding bony walls due to pressure necrosis. Complete rarified medial wall of bilateral internal carotid artery canals also seen (yellow arrows). e Post-operative axial bone window CT image shows air filled sinus cavity with absence of soft tissue
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Sphenoid
sinus aspergilloma clinically mimicking as malignancy—a case report. a T1-weighted axial MRI image shows hyper intense lesion filling the sphenoid sinus extending into adjacent greater wing of sphenoid bone, posterior ethmoid air cells, and clivus (blue arrow). The lesion appears hypo intense/dark on axial T2-weighted image (b) and sagittal T2-weighted image (c) confirming the proteinaceous content within the sinus. There is extension of lesion into bilateral cavernous sinus with partial encasement of bilateral cavernous segment of internal carotid arteries (red arrows). Sella is not seen completely separate from the lesion (c).
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Sphenoid
sinus aspergilloma clinically mimicking as malignancy—a case report. MRI images (a) Lesion appears dark on FLAIR image. Lesion appears dark on diffusion-weighted image (b) and apparent diffusion coefficient (c) confirming no restriction. Post-gadolinium fat sat axial (d) and sagittal (e) image shows no significant enhancement
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Paranasal
sinus mycetoma • Maxillary sinus mycetoma in chronic fungal sinusitis - Ganzer Fall bei Radiopaedia
Hsu C, Maxillary sinus mycetoma in chronic fungal sinusitis. Case study, Radiopaedia.org (Accessed on 25 Nov 2022) https://doi.org/10.53347/rID-19958 • CC by-nc-sa 3.0 (modified)
Radiopaedia • CC-by-nc-sa 3.0 • de

Paranasal sinuses mycetomas, or fungus balls, are indolent and non-invasive fungal colonization of the paranasal sinuses.

Pathology

Pathogenesis is thought to be a cascade of processes from insufficient mucociliary clearance leading to sinus colonization and chronic inflammatory response. The patient may only have a mild symptom or be asymptomatic.

Radiographic features

CT

Commonly only a single sinus is affected by the predilection for the maxillary sinus followed by the sphenoid sinus. The frontal and ethmoid are less often affected. A clue to the diagnosis includes soft tissue density within the sinus with/without foci of calcific deposit. Postobstructive change may be observed if the mycetoma obstructs the sinus drainage pathway leading to partial or complete sinus opacification .

Evidence of chronic inflammation with sclerosis and thickening of the wall of the paranasal sinuses. Careful evaluation of the sinus cavity is prudent to exclude bone erosion that is not a feature of mycetoma / chronic fungal sinusitis rather a feature of acute invasive fungal sinusitis .

MRI

MRI signal characteristics of mycetomas reflect the internal content of the mycelia, vegetative part of a fungus consisting of a conglomerate of hyphae. This contains primarily carbohydrates with some glycoproteins, macromolecular proteins, and iron and manganese.

Signal characteristics
  • T1: low signal
  • T2: low signal. The presences of paramagnetic elements further shorten the relaxation times, and this can be a highlight on the susceptibility weighted sequence
  • T1 C+ (Gd): chronic inflammatory change of the sinus mucosa may enhance

Differential diagnosis

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Sinunasale Aspergillose:
sinunasale
Tuberkulose
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Aspergillom
Sinus sphenoidalis
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