Spinal Intradural Extramedullary Ependymoma with Intracranial Metastasis and Leptomeningeal Spread: A Case Report and Comprehensive Review of Literature
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.271269
Source of Support: None, Conflict of Interest: None
Keywords: Ependymoma, extramedullary, intracranial dissemination
Ependymomas are slow growing tumors emerging from cells lining the cerebral ventricles or the central canal of the spinal cord. The most common location of spinal ependymomas is intramedullary or in the cauda equina or filum terminale. It is very rare for a spinal ependymoma to present as an intradural extramedullary lesion. Spinal metastasis in patients with intracranial ependymoma are well described and are seen in approximately 11–17% cases, but it is very rare for a spinal ependymoma to metastasize to brain. We describe a patient with long segment intradural extramedullary ependymoma, mimicking arachnoid cyst radiologically, who developed multiple leptomeningeal deposits in the spine and brain, along with a review of the literature.
A 17-year-old male first presented in 2006 with headache and blurring of vision of 1month duration. On clinical examination, the patient had a visual acuity of 6/9 in both eyes with papilledema in both eyes. Apart from visual diminution, rest of the neurological examination was unremarkable. Magnetic resonance imaging (MRI) of the brain was suggestive of communicating hydrocephalus with no other mass lesion [Figure 1]. Lumbar puncture was unremarkable. A ventriculoperitoneal (VP) shunt was done, which was followed by clinical improvement. MRI done 14 months after shunt revealed mild decrease in the size of ventricle with no evidence of any intracranial mass lesion. He developed backache, weakness in both lower limbs, and loss of bladder/bowel control in 2008 (25 months after VP shunt). Neurological examination revealed increased tone in both lower limbs with a power of 1/5 (MRC grading) in both lower limbs. There was complete loss of pain and temperature sensation below the T1 level. MRI of dorsal and lumbosacral spine revealed a large thin-walled ventral intradural extramedullary lesion spanning the entire dorsal and lumbosacral thecal space with signal intensity paralleling cerebrospinal fluid (CSF) and no mural nodule along with postcontrast peripheral enhancement [Figure 2]. There was also posterior scalloping of posterior vertebral bodies and thinned out posterior neural arches. There were intramedullary cord signal changes likely due to compression and nonhomogenous area of signal alteration at the S2/S3 level suggestive of hemorrhagic changes. These features were suggestive of arachnoid cyst, and with this diagnosis, he underwent L5 laminectomy with aspiration and marsupialization of the cyst at an outside center. Cyst wall was sent for histopathological analysis. The histopathological diagnosis was ependymoma (clear cell variant) with prominent cystic change (WHO grade 2). The patient improved clinically and regained power of 4/5 in both lower limbs. Patient was advised surgery for the residual spinal disease but he did not undergo the surgery. He developed headache with one episode of loss of consciousness in 2010 (12 months after spinal surgery). MRI brain was done which revealed a multicystic lesion in the basifrontal region with extension into the suprasellar and interpeduncular cistern. The lesion was hypointense on T1-weighted images (WI), hyperintense on T2-WI with patchy enhancement after contrast administration. Patient underwent craniotomy and biopsy of the lesion at the same center. Biopsy was suggestive of anaplastic ependymoma (WHO grade 3). He received radiotherapy and chemotherapy thereafter. He subsequently presented to the emergency department of our hospital in July 2013 in altered sensorium. His Glasgow coma scale (GCS) was E1V1M2. Plain computed tomography (CT) of the head revealed hydrocephalous and multiple ill-defined lesions in bilateral cerebral hemisphere with evidence of bleed. External ventricular drain was inserted, following which the patient's GCS improved to E2VtM4. Contrast-enhanced MRI of the brain and whole spine revealed extensive leptomeningeal deposits all along the spine and multiple intracranial metastatic lesions [Figure 3]. In view of extensive spread of the disease, decision of not operating the patient was taken.
Tumors of the spinal cord are unusual. Approximately5% of spinal tumors are intramedullary, 40% are intradural extramedullary, and 55% are extradural. Ependymomas typically have an intramedullary location and represent 60% of intramedullary tumors.
Primary intradural extramedullary ependymomas of the spinal cord are rare. Cooper et al. reported the first case in 1951, and since then only 19 cases have been described in English literature [Table 1].,,,,,,,,,,,,,,,,,,,, Occasional cases of ectopic ependymoma outside the spine have been mentioned, developing in the subcutaneous tissue over the sacrococcygeal region, mesoovarium, ovary, and broad ligament. The origin of intradural, extramedullary ependymomas is uncertain. The lack of connection between the lesion and the central nervous system excludes the hypothesis of an exophytic ependymoma of the spinal cord., An ependymal metastasis is equally unlikely due to the absence of any primary cerebral or medullary tumor. The proposed source being heterotopic glial tissue pinched off from the neural tube during its closure.,
Duffau et al. proposed a hormonal mechanism playing a role in tumordevelopment based on their observation of this tumor occurring in only males; however, this has been recently challenged., Although a hormonal influence on the histogenesis of these lesions has been postulated, no hormonal assessment data has been published.,
In the cases described in the literature, age of the patients ranged from 21 to 69 years, with only 5 patients younger than 30 years of age. Thoracic location is the most common location forthese tumors [Table 1]. Fifteen of the cases were females and 4 were females. Ours is the fifth case of a male patient.
Most of the previously reported patients mimicked the clinical presentation and the radiographic characteristics of more common intradural extramedullary lesions such as neurinomas, meningiomas, or, rarely, as in our case, an arachnoid cyst, with symptoms and signs of progressive medullary compression being the most common presentation.
Most cases described in the literature were well-delineated solid tumors showing an isointense signal intensity on T1-WI and hyperintense signal intensity on T2-WI. Moreover, these tumors exhibited a homogeneous enhancement after gadolinium administration with the spinal cord compressed and displaced, which is very similar to meningiomas or neurinomas. In two cases, including our case, the lesion was cystic with no or peripheral contrast enhancement, mimicking an arachnoid cyst.
Hence, a differential of ependymoma should be considered in cases of intradural extramedullary spinal cord tumors, and one should consider imaging the rest of the neuroaxis to exclude additional lesions.
These lesions have been described to be encapsulated with only a microvascular attachment to the CNS, making complete resection possible.,, However, in few cases, there was a thin stalk that attached the tumor to the spinal cord which was amputated., The intradural extramedullary ependymoma is often histopathologically benign, with most cases being WHO grade 2. Five patients had WHO grade 3 primary lesion. Four patients developed recurrence at the primary site, three of these were WHO grade 2 tumors. One patient with WHO grade 2 lesion developed recurrence, which was WHO grade 3. One patient with cervical WHO grade 3 primary lesion developed intracranial recurrence. Malignant transformation of this neoplasm can occur, leading to CSF dissemination and recurrence. Our patient was unique as he had WHO grade 2 lesion and developed both local recurrence as well as intracranial disease.
Dissemination at multiple spinal levels, retrograde intracranial dissemination, and metastases outside the nervous system have been described very rarely in ependymomas. There are few reports of spinal ependymoma leading to intracranial dissemination. Wang et al. reviewed 15 such cases described in English literature [Table 2].,,,,,,,,, However, all these were myxopapillary ependymomas. Intracranial dissemination in a case of intradural extramedullary ependymoma has been described only in one case in English literature. Leptomeningeal dissemination of intradural extramedullary ependymoma has also been rarely reported in the literature. The first MRI brain in the present case was a noncontrast scan, and hence, it is possible that leptomeningeal dissemination might have been missed. Therefore, it is important to obtaincontrast imaging.
Schuurmans et al. described the case of a 29-year-old woman who presented with neck pain irradiating to the right arm for 4months. MRI revealed intraspinal extramedullary mass extending from C3 to C6 with spinal cord compression, which was excised. A few days later she was diagnosed to have a lumbar mass, which was also excised. Biopsy was anaplastic ependymoma (WHO grade 3), and she received radiotherapy. Two years after the first surgery, she developed seizures and was diagnosed to have a right temporal lesion, which was excised; the biopsy revealed anaplastic ependymoma. It was postulated by the authors that the lumbar ependymoma may have undergone an anaplastic transformation, and thereafter anaplastic ependymoma cells may have migrated cranially with CSF circulation, leading to the formation of a cervical subdural metastasis. A similar mechanism may have led to the development of intracranial metastasis, although an additional role of spinal surgery favoring the spread of malignant cells within the subdural space cannot be excluded.
Another possible mechanism for this retrograde intracranial spread could be violation of tumor capsule during initial surgery. Sonneland et al. reported that encapsulated tumors of the filum terminale, which were removed en bloc exhibited a lower proportion of dissemination (10%) than tumors removed piecemeal (19%). Thus, violation of the capsule during surgery may lead to CSF seeding and dissemination.
This report highlights the fact that differential diagnosis of ependymoma should be consideredwhile evaluating intradural extramedullary lesion of the spine. Also attempt at tumor removal in cases of ependymoma should be aimed at en-bloc resection, which may prevent dissemination of such tumors.
We describe a primary extramedullary ependymoma that presented on MRI as an arachnoid cyst and discuss this unusual finding. An ependymoma should be included in the differential diagnosis of intradural extramedullary tumors. Most cases have been reported in females but the present case is the fifth case in a male patient. Hormonal influence may not completely explain the pathogenesis of this neoplasm, as our patient was a male. Our case highlights the need of close follow-up in this neoplasm, which is often described as a benign lesion, as there is potential for recurrence, metastasis, and anaplastic transformation resulting in fatal outcome. The best treatment for this lesion is complete resection with adjunctive radiotherapy in malignant cases. In patients with a spinal ependymoma, performing an MRI of the entire neuraxis may be useful to exclude metastases at distant sites.
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The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initial will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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