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Neuroradiology Case of the Week

Case 51

Ravinder Sidhu MD, Lawrence Buadu MD, PhD, Henry Wang MD, PhD,
and P-L Westesson MD, PhD, DDS

Clinical Presentation: An 85-year-old female presented with history of numbness and progressive difficulty in walking.

Radiological Findings: Sagittal T-2 weighted MR images showed an ovoid shaped, hypointense, intradural, extramedullary lesion at the level of the T4 region. The lesion was causing widening of the thecal column and also compressing the cord (Fig. 1). Post-contrast MR images showed enhancement of the lesion along with marked enhancement of adjoining dura,”dural tail sign”(Fig. 2).

Diagnosis: Intradural extramedullary tumor — Meningioma

Discussion:  Intradural extramedullary tumors account for two-thirds of intraspinal neoplasms and are mainly represented by meningioma and schwannoma. Meningioma constitutes 35% of all primary intraspinal neoplasm. Ninety percent of spinal meningioma are intradural, whereas 5-10% are intradural or both intra-and extradural [1]. There is a strong female preponderance (80%), and the peak period of occurrence is in the fifth and sixth decades. The thoracic spine is the most common site (80%), followed by the cervical spine (15%). The lumbar spine is an uncommon location. Multiple spinal meningiomas are rare. Malignant degeneration is extremely uncommon [2]. The most common symptoms are local and/or radicular pain, weakness of the limbs, and paraesthesia. Surgical removal is the treatment of choice [3].
   Imaging appearances: Plain films are usually normal. Calcification is rare and is visible in only 1% to 5% of cases. Myelography shows a mass localized to the intradural, extramedullary compartment. The thecal column on the side of the lesion is widened with sharp meniscus sign [4]. On CT scan, spinal meningiomas usually appear as extramedullary tumors with a higher density than the spinal cord.
    The primary radiological investigation of spinal meningioma is MR imaging. MR clearly demonstrates the extent and its relationship to the spinal cord. Spinal meningiomas are usually isointense relative to the spinal cord on both T-1 and T- 2 weighted MR images. They often have a broad based dural attachment and show moderate homogenous enhancement on contrast administration. An even greater enhancement is seen at the borders of the tumor. This is due to rich vascular supply in the intradural component of the tumor, which is surrounded by the vascular arachnoid membrane. This leads to appearance of “dural tail sign”, characteristic of spinal meningioma [5]. Inhomogeneous contrast enhancement may be seen due to presence of necrosis, cyst formation/hemorrhage, or dense calcification [6].
    Differential diagnosis of intradural extramedullary lesion includes meningioma, schwannoma, ependymoma, arachnoid cyst and dermoid. Schwannoma is usually associated with bony changes. The rest of the lesions can be differentiated from their location and signal variation on MR images.
    To conclude, gadolinium-enhanced MR imaging of the spine in sagittal, axial, and especially coronal planes should be performed to detect dural tails, which are highly suggestive of intraspinal meningioma. These planes are necessary to localize the extent of tumors and their dural tails prior to surgery.

References:

1. Albanese V, Platania N. Spinal intradural extramedullary tumors. Personal experience. J Neurosurg Sci. 2002; 46: 18-24.
2. Solero CL, Fornari M, Giombini S, Lasio G, Oliveri G, Cimino C, Pluchino F. Spinal meningiomas: review of 174 operated cases. Neurosurgery 1989; 25:153-160.
3. Levy WJ, Bay J, and Dohn D. Spinal cord meningioma. J Neurosurg 1982; 57:804-812.
4. Osborn AG. Diagnostic neuroradiology. St. Louis: Mosby, 1994.
5. Yoshiura T, Shrier DA, Pilcher WH, Rubio A. Cervical Spinal meningioma with unusual MR contrast enhancement. Am J Neuroradiol 1998; 19:1040-1042.
6. Russell EJ, George AE, Kricheff II, Budzilovich G. Atypical computed tomographic features of intracranial meningioma: radiologic-pathological correlation in a series of 131 consecutive cases. Radiology 1980; 135:673-682.