Intraosseous meningioma
Updates to Article Attributes
Intraosseous meningioma, also referred to as primary intraosseous meningioma, is a rare subtype of meningioma that accounts for less than 1% of all osseous tumours. They fall under the subgroup of primary extradural meningiomas.
Terminology
It is important to note that it has been argued by some that this group of meningiomas does not include those intradural meningiomas which present with aan intraosseous extension even when the intracranial (non-osseous component) is a minor feature of the mass. For example, en plaque meningiomas often have prominent hyperostosis or bony invasion. Some authors have suggested that this distinction is somewhat arbitrary 5, and it is certainly true that the terms en plaque meningioma and intraosseous meningioma are often used interchangeably. In the absence of a clearly nodular intracranial component, it is unclear if the distinction can be made on imaging, although en plaque meningiomas are considered far more common.
As a general approach it is probably reasonable to use the term 'intraosseous' meningioma when there is little if any intracranial extra-osseous disease, and use the term 'en plaque' where there is a definite, albeit sessile, intracranial mass.
Epidemiology
As with meningiomas in general, there is a recognised female predilection.
Clinical presentation
Clinical presentation is usually due to mass effect, the manifestations of which will depend on the location. The calvaria and vertebral column are the most frequent sites 2. Presentations include:
- palpable or visible bony mass
- proptosis
- cranial nerve / spinal cord compression
- intracranial mass effect
/hydrocephalus
Pathology
Thought to occur from trapped arachnoid meningothelial cap cells within cranial sutures during development. However, despite this theory, only a small proportion of intraosseous meningiomas actually occur in association with a skull suture 3.
Radiographic features
The majority ~65% are osteoblastic while ~35% are osteolytic 3. Due to this, imaging appearances are non-specificoften nonspecific.
CT
The commoner osteosclerotic type tends to show diffuse sclerosis with bony expansion.
MRI
-
T1: may show an isointense extra
axial-axial mass component with the expanded bony component being low signal similar to the rest of the skull - T2: meningioma component is typically isointense to grey matter while a small proportion can be hyperintense
-
T1 C+ (Gd): as with conventional meningiomas typically tends to have
ana uniform avid contrast enhancement
Treatment and prognosis
They are generally benign and slow-growing but there may be a higher proportion of malignant change compared with standard meningiomas 3. Surgical resection with bone grafting may be performed in symptomatic cases.
Differential diagnosis
For osteoblastic type consider:
- Paget disease: heterogeneous signal, non-enhancing
- craniofacial fibrous dysplasia: tends to be more extensive with more bony remodelling
- osteoma: non-enhancing, more homogeneous contours
- osteosarcoma: irregular contours, heterogeneous signal and enhancement
- osteoblastic metastasis
For osteolytic type consider:
-<p><strong>Intraosseous meningioma</strong>, also referred as <strong>primary intraosseous meningioma</strong>, is a rare subtype of <a href="/articles/meningioma">meningioma</a> that accounts for less than 1% of all osseous tumours. They fall under the subgroup of <a href="/articles/extracranial-meningioma">primary extradural meningiomas</a>.</p><h4>Terminology</h4><p>It is important to note that it has been argued by some that this group of meningiomas does not include those intradural meningiomas which present with a intraosseous extension even when the intracranial (non-osseous component) is a minor feature of the mass. For example, <a href="/articles/en-plaque-meningioma">en plaque meningiomas</a> often have prominent hyperostosis or bony invasion. Some authors have suggested that this distinction is somewhat arbitrary <sup>5</sup>, and it is certainly true that the terms en plaque meningioma and intraosseous meningioma are often used interchangeably. In the absence of a clearly nodular intracranial component, it is unclear if the distinction can be made on imaging, although en plaque meningiomas are considered far more common. </p><p>As a general approach it is probably reasonable to use the term 'intraosseous' meningioma when there is little if any intracranial extra-osseous disease, and use the term 'en plaque' where there is a definite, albeit sessile, intracranial mass. </p><h4>Epidemiology</h4><p>As with meningiomas in general there is a recognised female predilection. </p><h4>Clinical presentation</h4><p>Clinical presentation is usually due to mass effect, the manifestations of which will depend on the location. The calvaria and vertebral column are the most frequent sites <sup>2</sup>. Presentations include:</p><ul>- +<p><strong>Intraosseous meningioma</strong>, also referred to as <strong>primary intraosseous meningioma</strong>, is a rare subtype of <a href="/articles/meningioma">meningioma</a> that accounts for less than 1% of all osseous tumours. They fall under the subgroup of <a href="/articles/extracranial-meningioma">primary extradural meningiomas</a>.</p><h4>Terminology</h4><p>It is important to note that it has been argued by some that this group of meningiomas does not include those intradural meningiomas which present with an intraosseous extension even when the intracranial (non-osseous component) is a minor feature of the mass. For example, <a href="/articles/en-plaque-meningioma">en plaque meningiomas</a> often have prominent hyperostosis or bony invasion. Some authors have suggested that this distinction is somewhat arbitrary <sup>5</sup>, and it is certainly true that the terms en plaque meningioma and intraosseous meningioma are often used interchangeably. In the absence of a clearly nodular intracranial component, it is unclear if the distinction can be made on imaging, although en plaque meningiomas are considered far more common. </p><p>As a general approach it is probably reasonable to use the term 'intraosseous' meningioma when there is little if any intracranial extra-osseous disease, and use the term 'en plaque' where there is a definite, albeit sessile, intracranial mass. </p><h4>Epidemiology</h4><p>As with meningiomas in general, there is a recognised female predilection. </p><h4>Clinical presentation</h4><p>Clinical presentation is usually due to mass effect, the manifestations of which will depend on the location. The calvaria and vertebral column are the most frequent sites <sup>2</sup>. Presentations include:</p><ul>
-<li>intracranial mass effect / <a href="/articles/hydrocephalus">hydrocephalus</a>-</li>-</ul><h4>Pathology</h4><p>Thought to occur from trapped arachnoid meningothelial cap cells within cranial sutures during development. However despite this theory only a small proportion of intraosseous meningiomas actually occur in association with a skull suture <sup>3</sup>.</p><h4>Radiographic features</h4><p>The majority ~65% are osteoblastic while ~35% are osteolytic <sup>3</sup>. Due to this imaging appearances are non-specific. </p><h5>CT</h5><p>The commoner osteosclerotic type tends to show diffuse sclerosis with bony expansion.</p><h5>MRI</h5><ul>- +<li>intracranial mass effect/hydrocephalus</li>
- +</ul><h4>Pathology</h4><p>Thought to occur from trapped arachnoid meningothelial cap cells within cranial sutures during development. However, despite this theory, only a small proportion of intraosseous meningiomas actually occur in association with a skull suture <sup>3</sup>.</p><h4>Radiographic features</h4><p>The majority ~65% are osteoblastic while ~35% are osteolytic <sup>3</sup>. Due to this, imaging appearances are often nonspecific. </p><h5>CT</h5><p>The commoner osteosclerotic type tends to show diffuse sclerosis with bony expansion.</p><h5>MRI</h5><ul>
-<strong>T1:</strong> may show an isointense extra axial mass component with the expanded bony component being low signal similar to the rest of the skull</li>- +<strong>T1:</strong> may show an isointense extra-axial mass component with the expanded bony component being low signal similar to the rest of the skull</li>
-<strong>T1 C+ (Gd):</strong> as with conventional meningiomas typically tends to have an uniform avid contrast enhancement </li>- +<strong>T1 C+ (Gd):</strong> as with conventional meningiomas typically tends to have a uniform avid contrast enhancement </li>
-<a href="/articles/osteoma">osteoma</a>: non-enhancing</li>- +<a href="/articles/osteoma">osteoma</a>: non-enhancing, more homogeneous contours</li>
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