Head and Neck ImagingOsteoma, sinonasal
most common
tumour of the
paranasal sinuses, most frequently seen in the frontal
sinus and ethmoids. Two varieties are described: the dense 'ivory' type consisting of lamellar bone, and 'cancellous' osteoma showing predominantly a lamellar structure. Many osteomas show a mixture of both types. The majority of
paranasal osteomata are found by chance. A large osteoma in the frontal or ethmoid region may cause prooptosis by displacement of the orbital structures (
Fig.1).
Obstruction of a
sinus ostium may lead to infection or formation of a
mucocele. Some osteomata erode through the dura and may cause cerebrospinal fluid rhinorrhoea or intracranial infection. Multiple
paranasal osteomata are found in
Gardners syndrome.
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a. Conventional X-ray shows large frontal osteoma, extending into the right orbit.
b and c. Axial CT-images (bone window) also show growth into the right orbit (arrow), and reveal extension through the anterior and posterior frontal sinus wall (arrowheads). During surgery, a dural defect was found.
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Osteoma, sinonasal, Fig.1 (a) | | Osteoma, sinonasal, Fig.1 (b) | | Osteoma, sinonasal, Fig.1 (c) |