Meningiomas are the second most common tumor in the intradural extramedullary location, second only to tumors of the nerve sheath. Meningiomas account for approximately 25% of all spinal tumors. Approximately 80% of spinal meningiomas are located in the thoracic spine, followed by cervical spine (15%), lumbar spine (3%), and the foramen magnum (2%). Most intradural spinal tumors are benign and potentially resectable. The prognosis after surgical resection is excellent. [1, 2, 3, 4, 5]
From 2004 to 2010, there were 7,148 newly diagnosed cases of spinal meningioma (age adjusted incidence, 0.33/100,000 population). The highest incidence was in 75 to 84 year olds, and females were more greatly affected than men. 
Images of spinal menigioma are provided below.
Summary of the 2007 WHO Grading Scheme for Meningiomas
Grade I: Meningothelial, fibroblastic, transitional, angiomatous, microcystic, secretory, lymphoplasmacytic, metaplastic, psammomatous; does not fulfill criteria for grade II or III.
Grade II (Atypical): Chordoid, clear cell; 4 or more mitotic cells per 10 hpf and/or 3 or more of the following: increased cellularity, small cells, necrosis, prominent nucleoli, sheeting, and/or brain invasion in an otherwise grade I tumor.
Grade III (Anaplastic):Papillary, rhabdoid; 20 or more mitoses per 10 hpf and/or obviously malignant cytologic characteristics such that tumor cell resembles carcinoma, sarcoma, or melanoma.
Magnetic resonance imaging (MRI) with intravenous injection of gadolinium-based contrast agent is the preferred examination. If MRI is not available, computed tomography (CT) myelography may demonstrate the lesion. [7, 8, 9]
MRI can provide information regarding tumor signal intensity and contrast enhancement. Because MRI has multiplanar imaging capability, the extra-axial location of a meningioma is illustrated clearly.
Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Systemic Fibrosis. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans.
NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape.
Limitations of techniques
MRI is contraindicated in patients with pacemakers, certain types of aneurysm clips, metallic foreign bodies in the eye and elsewhere. Patients with claustrophobia may have difficulty holding still in the MRI unit long enough to complete the examination.
Plain radiographic findings are usually normal. On occasion, localized widening of the canal may be seen. In rare cases, spinal meningiomas may have an extradural component, which can cause enlargement of the neuroforamen. Calcifications are rarely visible on plain radiographs (1-5%) and usually psammomatous in nature.
Degree of confidence
On plain images, the degree of confidence is low.
CT scans obtained without the intravenous injection of contrast material occasionally demonstrate a hyperattenuating lesion resulting from psammomatous calcification or dense tumor tissue. CT scans obtained with the intravenous injection of contrast material may show a homogeneous enhancing tumor. CT image of spinal meningioma is provided below.
Myelography or CT myelography is required to demonstrate the intradural extramedullary location of the mass.
The spinal cord is displaced away from the lesion and usually compressed. A sharp meniscus is seen where the contrast agent caps the lesion from above and below. The subarachnoid space on the side of the lesion is widened.
Degree of confidence
On CT scans, the degree of confidence is moderate.
Magnetic Resonance Imaging
MRI demonstrates the intradural extramedullary location of meningiomas. Lesions are usually isointense to spinal cord on both T1-weighted and T2-weighted images. Lesions are sometimes hypointense on T1-weighted images and hyperintense on T2-weighted images. Homogeneous intense enhancement of the lesion is seen after an intravenous injection of gadolinium-based contrast agent.
Most spinal meningiomas demonstrate broad-based dural attachment. On occasion, a densely calcified meningioma may demonstrate hypointensity on T1-weighted and T2-weighted images. The spinal cord is displaced away from the lesion and usually compressed. The subarachnoid space above and below the lesion is widened, and a meniscus capping the lesion may be seen.
MRI images of spinal meningioma are provided below.
Degree of confidence
On MRI, the degree of confidence is high.
A meningioma with intradural and extradural components occasionally mimic a nerve sheath tumor, or a nerve sheath tumor with a predominant intradural component may mimic a meningioma. However, nerve sheath tumors usually have hyperintensity on T2-weighted images, whereas meningiomas usually are isointense to the spinal cord on T2-weighted images. Most meningiomas are lateral or dorsal, whereas most nerve sheath tumors are ventral. Furthermore, a mass lesion with both intradural and extradural components is most likely to be a nerve sheath tumor.
Intraoperative ultrasonography may be performed after laminectomy as a tool to localize the mass, which is usually echogenic.
Spinal angiography usually shows a hypervascular lesion with tumor blush. More important, spinal angiography is performed to identify the location of the artery of Adamkiewicz, which is usually in the lower thoracic region, most frequently on the left side. Care must be taken not to damage the artery during surgery because the artery supplies the spinal cord. Spinal angiography is performed for surgical planning if the meningioma is in the lower thoracic region, regardless of the side of the meningioma.