intradural_extramedullary_spinal_tumor

Intradural extramedullary spinal tumor

While intradural extramedullary spinal disease varies widely, identification of tumors in this location and their radiologic manifestations greatly facilitates narrowing of the diagnostic considerations.

Spinal meningioma and spinal schwannoma are the two most common intradural extramedullary spinal tumors, and both are associated with neurofibromatosis.

Meningiomas are most common in the thoracic spine and show a strong female predilection and a clinical manifestation related to compression of the spinal cord or nerve roots.

Schwannomas typically are associated with radicular pain and other sensory symptoms.

Radiographic features

Intradural extramedullary masses can have a number of general morphological features:

solitary vs multiple may have a dural tail (especially meningiomas) may have a nerual exit foraminal (extradural) component (i.e dumbbell appearance) 3 Plain film

may be normal expansion of the spinal canal or intervertebral foramina may show a paravertebral mass (more suggestive of a nerve sheath tumour) CT

purely intradural lesions may not be shown extradural extension bone erosion and sclerosis heavy calcification is rare in spinal meningiomas and nerve shealth tumours; a heavily calcified intraspinal mass is usually extradural extruded disc material Myelography

deviation of the spinal cord away from mass Ipsilateral subarachnoid space enlargement contralateral subarachnoid space effacement intradural filling defect outlined by sharp meniscus of contrast (“meniscus sign”). the subarachnoid space is blocked and CSF above the block remains unopacified. MRI

MRI is the modality of choice to fully characterise these masses, and the appearance will vary depending on the histology, and is thus discussed as part of individual articles (see above list).

The key benefits of MRI over other modalities, is the ability to clearly define the relationship of the mass to the cord, to identify secondary lesions, to identify large feeding / draining vessels and hopefully to give a pre-operative diagnosis.

Melanotic schwannoma frequently shows T1 hyperintensity at MRI related to the presence of paramagnetic free radicals in melanin. Neurofibroma, known for its T2 hyperintensity, frequently involves the cervical spine, where it may make surgical resection challenging. Less commonly, malignant peripheral nerve sheath tumor commonly mimics the imaging appearance of a schwannoma but has decidedly more aggressive biologic behavior. In the cauda equina, myxopapillary ependymoma and paraganglioma are believed to arise from the filum terminale and have characteristic imaging manifestations based on their underlying pathologic features. Recent identification of a common genetic marker has led to reclassification of what had previously been regarded as separate tumors and are now known as solitary fibrous tumor/hemangiopericytoma. In the proper clinical setting, the presence of nodular intradural enhancement strongly suggests the presence of leptomeningeal metastatic disease, even when results of cerebrospinal fluid analysis are negative 1).


Intradural extramedullary neoplasms are located outside the spinal cord but within the dural sheath.

Schwannomas are the most common intradural extramedullary spinal lesions (30% cases), followed by meningiomas (25% cases).

In the pediatric population, the most common intradural extramedullary neoplasms are leptomeningeal metastases resulting from primary brain tumours.

A full list includes:

benign tumours

spinal schwannoma

Spinal meningioma.

spinal neurofibroma

spinal paraganglioma

myxopapillary ependymoma

cysts and other benign tumourlike masses

spinal lipoma

intradural spinal lipoma

spinal epidermoid cyst

spinal dermoid cyst

spinal neurenteric cyst

spinal arachnoid cyst

malignant tumours

spinal leptomeningeal metastases


Giant spinal schwannomas are defined as intradural extramedullary spinal tumors that span >2 vertebral body lengths.

Intradural extramedullary spinal tumor case series.

Intradural extramedullary spinal tumor treatment.


1)
Koeller KK, Shih RY. Intradural Extramedullary Spinal Neoplasms: Radiologic-Pathologic Correlation. Radiographics. 2019 Mar-Apr;39(2):468-490. doi: 10.1148/rg.2019180200. PubMed PMID: 30844353.
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  • Last modified: 2021/07/21 15:08
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