A Rare Extradural Spinal Meningioma with Nocturnal Chest Pain: A Case Report

The patient was a 65-year-old woman with a history of thyroidectomy who complained of nocturnal chest pain. The radiating pain was progressively increased to the right chest wall under nipple for two years. She first visited the cardiac and gastrointestinal departments for the evaluation of chest pain for 2 years. Despite intensive multidisciplinary evaluation, no explanations for the complaint could be found in the heart or other organs. On the computed tomography (CT) scan of the thorax, obtained a few months before the diagnosis, a spinal mass could be seen retrospectively; however, as it was very discrete, it was not described. There were no signs of back pain and neurologic deficits, including motor deficits or sensory changes. The deep tendon reflexes were exaggerated in lower limbs.

On MRI, an extramedullary and extradural mass was observed at T7/8 which had infiltrated the neuroforamen on the right (Fig. 1, 2). The tumor absorbed a gadolinium-containing contrast agent homogeneously and showed a maximum extension of 2 cm. The myelon was significantly shifted to the left (Fig. 3).

Fig. 1
Sagittal T1-weighted (T1W), T2-weighted (T2W), and T1 fat-suppressed and gadolinium-containing contrast-enhanced magnetic resonance imaging scan. (A) T1W image showing an isointense extradural lesion at the T8 level. (B) T2 fat-suppressed image showing a hypointense lesion. (C) T1 gadolinium-containing contrast-enhanced image showing an extradural lesion with some heterogeneity, but mostly a hyperintense signal.

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Fig. 2
Sagittal T1-weighted image showing an isointense extradural lesion on T8, mainly on the right side. The lesion extended along the foramen.

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Fig. 3
Axial T1-weighted fat-suppressed gadolinium-containing contrast-enhanced magnetic resonance imaging scan showing an extradural lesion with some heterogeneity, but mostly a hyperintense signal at T8. The mass on the right side was pushing the cord to the left.

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The patient was taken in a prone position after installation of neuromonitoring. Intervertebral disc area T7/8 and T8/9 were localized with lateral fluoroscopy. The median skin incision was made with the cutting of subcutaneous fat. Pushing off the thoracolumbar fascia from T7 to T9 was done in. Dissection of the paraspinal muscles from the spinous process and lamina to the facet joint was done. Despite normal blood-lab values, this area had a markedly intensified bleeding tendency. A Laminectomy on T8 was performed. Careful inspection of the extradural intraspinal area was done. Caudally a fleshy, partly translucent, partly red mass was seen, which is located dorso-lateral to the dura sac. The latter exceeds the caudal part of the lamina of T9 was undermined caudally on the right side. Under microscopic view, the blunt release of the tumor mass from the dura sac was done. The histologic specimen was sent for pathologic confirmation. As expected, along the root which was totally atrophic and agglutinated, the mass was running on extraspinal space, and it was extensively overgrowth between tumor and root. Gradually the tumor mass could be completely removed from the intraspinal chamber without dura injury. We made the median opening of the dura to explore of intradural mass. We carefully inspected the intradural area under microscopic observation. The spinal cord seems free and no relevant mass could be found. The exiting root appears massively edematous and red colored. To proximal, no tumor mass could be seen. The latter is resected respectively also coagulated. We could remove the whole tumor. We repaired the dura with silk 4.0. It was covered with the stitching application of fibrin glue. The wound was closed layer by layer. The intraoperative SSEP and MEP's were constantly unsuspicious. Postoperatively, the patient could move both legs and feet with good strength. Histological diagnosis was meningioma (meningotheliomatous type, grade 1, according to the World Health Organization classification). The nocturnal chest pain was disappeared after surgery, and the patient was recovered without any complication (IRB KYUH 2019-01-007).

The most frequent location of spinal meningiomas is the intradural space, and purely extradural spinal meningiomas are extremely rare, and information about these tumors is limited. In our case, we were not aware that meningiomas could occur in the extradural space exclusively. On MRI, the extramedullary mass was located posterior to 8 vertebral bodies with infiltration and displacement into the neuroforamen between the 8 and 9 vertebral bodies (Fig. 1, 2). However, the dura tail sign on figure 3 represents the possibility of intradural mass which could be related to common intradural mass like meningioma. In this case, clinical signs and image signs were very extra-ordinary and made the surgeon explore intra and extra dura space. The initial radiological differential diagnosis was a meningioma. The unique feature of our case is that the mass seemed to have an intradural extension or to originate from the intradural extramedullary space on MRI. Spinal meningiomas frequently occur as ventral/ventro-lateral intradural extramedullary tumors, growing from arachnoid cap cells around the nerve root.6) On MRI, the location of the mass was not a frequent site, and it was not helpful in avoiding intradural invasive exploration. In the operating field, through the median opening of the dura, with careful inspection of the intradural area under microscopy, an extradural mass was found compressing the dural sac and exiting root. As the mass showed intradural extramedullary features on MRI, although it looked extradurally located in the operating field, we decided to explore the intradural space. To remove the intradural meningioma, intradural exploration was inevitable. Dural injury during exploration has a risk of complications including meningitis, neural damage, and embolism.2, 4, 7) As foraminal widening is a sign of an extradural mass effect (Fig. 2), the widening of the nerve root foramen, in this case, can be a clue that the tumor was an extradural mass. However, foraminal widening is not a typical sign of meningiomas, but rather of fibromas or schwannomas.

Because they are slow growing, meningiomas induce a slow, indolent course of symptoms. The symptoms largely depend on the tumor location and duration. The most common symptoms are motor deficits and spinal pain.3, 7) In the first stage, spinal pain occurs because of nerve root irritation. In the second stage, the motor deficit develops owing to spinal cord compression. In the first stage, the most notable symptom of nerve root involvement is a pain, which predominates and may precede all other symptoms by months or years. As the tumor gradually enlarges, the spinal cord and nerve roots are first displaced and then compressed within the bony confines of the spinal canal. This is compounded by microtrauma to neural tissues resulting from repetitive motion or stretching of the cord relative to the tumor. The pain may assume a radicular, radiating character or may present as localized back pain. The known pain character caused by spinal neoplasia is typically persistent and progressive and is not alleviated by rest. Often the pain is worse at night, waking the patient from sleep.9) The other common symptoms of this stage are partial weakness and sensory loss (hypoesthesia, paresthesia). As the tumor begins to compress the spinal cord, motor deficits including gait disturbance occur. A substantially larger subarachnoid space in the upper cervical spine and the lumbosacral spine permits larger tumor growth before the onset of symptoms; however, once the spinal cord and roots become compressed, the progression of symptoms is unrelated to the tumor location along the spine. In our case, the first symptom was nonspecific nocturnal chest pain and the patient had to undergo a full cardiac evaluation and then visited the gastrointestinal department to determine which internal organ was involved. No pathology of the heart and internal organs were found. For cardiac evaluation, the patient underwent CT, which led to the incidental diagnosis of a mass in the spinal canal. Owing to advances in diagnostic techniques, the average time to the diagnosis of a spinal mass was shortened by about 6 months; consequently, patients experience less severe neurologic deficits before surgery.2, 7, 8) These advancements have made diagnosis simpler and more accurate; however, they also tend to omit the classical consideration of the possibility of rare diseases.

Awareness of the rarity and nonspecific symptoms of extradural spinal meningiomas will be beneficial for their accurate diagnosis and understanding the image findings of extradural meningioma can provide suitable treatment options.