Subependymoma of the spinal cord: case report and review of the literature

Spinal subependymoma surgery: do no harm. Little may be more!

OBJECTIVE

 Outline the reported diagnostic and operative findings, and evaluate the surgical treatment outcome to clarify the best available recommendations.

METHODS

 Ovid Medline, Embase and PubMed central databases were searched from inception until January 2019 using the terms (subependymoma and (spinal or cervical or thoracic)). The articles were reviewed for reported spinal subependymoma cases perioperative management and treatment outcomes.

RESULTS

 A total of 49 papers provided data on 105 cases. 47 cases were reported in the last 5 years. The reported cases were two medullary-cervical, 35 cervical, 32 cervicothoracic, 21 thoracic, 12 thoracolumbar and three lumbar. Spinal subependymomas typically arise from within the central spinal canal, giving the appearance of an intramedullary mass, usually eccentric to one side. Symptoms at presentation ranged between 1 month to 17 years, (mean 3.5 years, median 2 years) and were over 3 years in 36, and over 8 years in 12 cases. Sensory symptoms are the most frequent 75(80%), followed by weakness in 60(64%), pain in 45(48%) and sphincter disturbance in 24(25%). Postoperative neurological function was reported in 78 cases, and worsening was reported in 40 cases (51%), of which, 29 (72%) had complete resection, 6 (15%) had subtotal resection and 5 (12%) had partial resection. Neurological status remained the same in 24 (30%) and improved in 14 (18%).

CONCLUSION

 The reviewed cases report a rate of 65% total resection of which 57% had worsened function after surgery. There were no reports of malignant transformation; therefore, long-term survival is expected, and surgical caution should be exercised where there is minimal symptom progression.

Subependymoma involving multiple spinal cord levels: A clinicopathological case series with chromosomal microarray analysis

Subependymomas of the spinal cord are rare, do not often involve multiple levels, and very rarely recur. Here, we present a series of spinal cord subependymomas with a detailed description of the clinical, radiological and pathological features, and characterization by chromosomal microarray analysis. Briefly, the four patients included two men and two women, between the ages of 22 and 48 years. The most common presenting symptoms were neck and arm pain with upper extremity weakness. By imaging, the tumors were found to involve multiple spinal levels, including cervical/ cervico-thoracic (three patients) and thoracic (one patient), were all eccentric, and had minimal to no post-contrast enhancement. Two patients underwent gross total resection, one had a sub-total resection, and one underwent biopsy alone with a decompressive laminectomy. Follow up ranged from 6 months to 22 years. One patient (case 4) had recurrence 15 years following gross total resection and chromosomal microarray analysis revealed deletions on the long arm of chromosome 6. Our limited series suggests that spinal cord subependymomas can rarely recur, even following gross total resection, suggesting a possible role for long-term surveillance for these rare tumors.

Subpial Cervical Subependymoma: Report of an Unusual Tumor with Review of Literature

Subependymoma is rare benign neoplasm (World Health Organization Grade I) usually found in the 4^th ventricle and lateral ventricles. They were first described by Boykin as a separate entity in 1954. Subependymoma constitutes only 1%-2% of spinal ependymal tumors. Majority of the spinal subependymoma is intramedullary, with a rare few reported in the extramedullary plane. Clinicoradiologically, subependymoma often mimic more frequent, aggressive tumors of the spine (astrocytoma and ependymoma) which makes them difficult to differentiate. In fact, the diagnosis of subependymoma comes as a histopathological surprise. Maximal safe resection holds the key to good postoperative outcome with a very limited role of adjuvant therapy. Complete excision of the tumor, though desirable, is not feasible in all cases. Owing to their rarity and lack of characteristic clinicoradiological features, there is limited information currently available regarding their preoperative diagnosis and "optimal" management strategy. In this case report, we are discussing a case of eccentric subpial cervical subependymoma discussing important differentiating radiological features, and surgical nuances with an attempt to define "optimal" management strategy.

Spinal Cord Subependymoma Surgery : A Multi-Institutional Experience

OBJECTIVE

A spinal cord subependymoma is an uncommon, indolent, benign spinal cord tumor. It is radiologically similar to a spinal cord ependymoma, but surgical findings and outcomes differ. Gross total resection of the tumor is not always feasible. The present study was done to determine the clinical, radiological and pathological characteristics of spinal cord subependymomas.

METHODS

We retrospectively reviewed the medical records of ten spinal cord subependymoma patients (M : F=4 : 6; median 38 years; range, 21-77) from four institutions.

RESULTS

The most common symptoms were sensory changes and/or pain in eight patients, followed by motor weakness in six. The median duration of symptoms was 9.5 months. Preoperative radiological diagnosis was ependymoma in seven and astrocytoma in three. The tumors were located eccentrically in six and were not enhanced in six. Gross total resection of the tumor was achieved in five patients, whereas subtotal or partial resection was inevitable in the other five patients due to a poor dissection plane. Adjuvant radiotherapy was performed in two patients. Neurological deterioration occurred in two patients; transient weakness in one after subtotal resection and permanent weakness after gross total resection in the other. Recurrence or regrowth of the tumor was not observed during the median 31.5 months follow-up period (range, 8-89).

CONCLUSION

Spinal cord subependymoma should be considered when the tumor is located eccentrically and is not dissected easily from the spinal cord. Considering the rather indolent nature of spinal cord subependymomas, subtotal removal without the risk of neurological deficit is another option.

Subependymomas Are Low-Grade Heterogeneous Glial Neoplasms Defined by Subventricular Zone Lineage Markers

OBJECTIVE

Subependymomas are infrequent, low-grade gliomas associated with the ventricular system and the spinal cord. Little is known about the origin and natural history of these slow-growing lesions.

METHODS

We identified all patients with pathologically proven subependymomas presenting to our institution between 1998 and 2016. We retrospectively reviewed clinical, radiographic, histologic, and surgical outcomes data in all patients who underwent surgical resection. Immunohistochemical analyses for cell lineage markers were performed.

RESULTS

A total of 31 patients with pathologically proven subependymomas were identified. Of these, 7 asymptomatic lesions were discovered at autopsy and 24 symptomatic cases were treated surgically. There were 15 (48%) lateral ventricle tumors, 11 (35%) fourth ventricular tumors, and 5 (17%) spinal tumors. Symptomatic intracranial lesions most commonly presented with headaches and balance and gait abnormalities. Subependymomas had no distinguishing radiographic features that provided definitive preoperative diagnosis. At last follow-up, no patient treated surgically experienced recurrence. Immunohistochemical analyses demonstrated a diffusely GFAP-positive glial neoplasm with mixed populations of cells that were variably positive for Olig2, NHERF1, Sox2, and CD44. The Ki67 proliferation index was generally low (<1% in many of the tumors).

CONCLUSIONS

Subependymomas demonstrate mixed populations of cells expressing glial lineage markers as well as putative stem cell markers, suggesting these tumors may arise from multipotent glial progenitors that reside in the subventricular zone. Definitive diagnosis requires surgical sampling. Although the clinical course of subependymomas appears benign, the inability to radiographically diagnose these lesions, and the possibility of an alternative malignant lesion support a low threshold for early and safe maximal resection.

Bamboo Leaf Sign as a Sensitive Magnetic Resonance Imaging Finding in Spinal Subependymoma: Case Report and Literature Review

Background and Importance. Subependymoma occurs very rarely in the spinal cord. We report another case of spinal subependymoma along with a review of the literature and discussion of a radiological finding that is useful for preoperative diagnosis of this tumor. Clinical Presentation. A 51-year-old man presented with a 2-year history of progressive muscle weakness in the right lower extremity. Sagittal magnetic resonance imaging (MRI) showed spinal cord expansion at the Th7–12 vertebral level. Surgical resection was performed and the tumor was found to involve predominantly subpial growth. Histological diagnosis was subependymoma, classified as Grade I according to criteria of World Health Organization. We made an important discovery of what seems to be a characteristic appearance for spinal subependymoma on sagittal MRI. Swelling of the spinal cord is extremely steep, providing unusually large fusiform dilatation resembling a bamboo leaf. We have termed this characteristic MRI appearance as the “bamboo leaf sign.” This characteristic was apparent in 76.2% of cases of spinal subependymoma for which MRI findings were reported. Conclusion. The bamboo leaf sign on spinal MRI is useful for differentiating between subependymoma and other intramedullary tumors. Neurosurgeons encountering the bamboo leaf sign on spinal MRI should consider the possibility of subependymoma.

Spinal ependymoma with regional metastasis at presentation

BACKGROUND

Ependymomas are the most common glial neoplasms in the spinal cord. However, spinal cord ependymomas presenting with regional dissemination along the neuroaxis are rare, with a yet undetermined standard of care. We retrospectively evaluated the management and outcomes of patients who were diagnosed with spinal ependymoma with regional metastases at presentation (SERMP).

METHODS

Between 2002 and 2012, 16 patients with regionally metastatic spinal ependymomas were diagnosed and treated. The patients were retrospectively divided into two groups according to tumor grading and histological features. Nine patients were diagnosed with myxopapillary ependymomas (MPE), and seven patients were diagnosed with other low-grade ependymomas.

RESULTS

With a median follow-up of 46.4 months, 13 out of 16 patients had no postsurgical recurrence/progression of the disease. In three patients, the disease recurred/progressed, leading to death in one patient. There was no correlation between gross total removal (GTR) of the main tumor, or resection of the main lesion and the metastatic foci and increased progression free survival in patients of the MPE group. There was an advantage for patients diagnosed with other low-grade ependymomas. Adjuvant radiotherapy did not prove beneficial.

CONCLUSIONS

SERMP has a relatively benign course. Achieving GTR of both the main lesion and the metastases is preferable, but should not be achieved at any cost, especially in MPE interfering with the conus medullaris. The benefit of adjuvant radiotherapy remains unproven.

Thoracolumbar intramedullary subependymoma with multiple cystic formation: a case report and review

BACKGROUND

An intramedullary subependymoma is rare, particularly in the thoracolumbar region. Moreover, a radiographical obvious cystic formation of subependymoma of spinal cord rarely occurs in comparison to ependymoma.

CASE REPORT

A 57-year-old woman presented with paraparesis. MRI revealed a multinodular and multicystic lesion in the spinal cord that was difficult to diagnose correctly. Intraoperative observation via midline myelotomy revealed a grayish, gelatinous solid mass with an eccentric localization. In addition, DREZtomy on the caudal side of the tumor revealed cystic formation. The cyst was punctured and xanthochromic fluid was collected. Attenuation of motor evoked potential (MEP) resulted in the partial removal of tumor. A pathological examination revealed the mass to be a subependymoma. The patient experienced transient worsening of symptoms, but improved gradually. No adjuvant radiosurgery was administered. Follow-up estimation 30 months after surgery revealed no evidences of regrowth.

CONCLUSIONS

This report presents this rare case, a review of the literature associated with thoracolumbar subependymomas, and a discussion of the clinical and radiographical characteristics.

Intramedullary subependymoma of the cervical spinal cord: a case report with immunohistochemical study

Spinal subependymomas, which have a relatively benign nature, are very rare tumors. It is difficult to distinguish spinal subependymomas from other intramedullary spinal tumors based on neuroradiological findings. A case of cervical intramedullary subependymoma in a 63-year-old female is reported. The diffused enlargement of the spinal cord at C2 level involved the lesion with isointensity on a T1-weighted MRI and relatively high intensity on a T2-weighted MRI. Enhancement in the small part of the tumor was observed on a T1-weighted MRI with gadolinium administration. The tumor occupied the left side of the spinal cord, and was totally removed through a laminoplasty of C2. Immunohistochemistry was useful for pathological diagnosis. The clinical feature of this patient is described with the review of literatures.

Characteristics of thoracolumbar intramedullary subependymomas

OBJECT

Thoracolumbar intraspinal subependymomas are very rare intramedullary low-grade tumors. The authors report on the clinical and morphological features of 2 cases of thoracolumbar intraspinal subependymomas and provide midterm follow-up data.

METHODS

The clinical and radiological profiles of 2 patients with progressive spinal cord dysfunction due to thoracolumbar intraspinal subependymomas were retrospectively studied and compared with previously reported cases.

RESULTS

Patients with intraspinal subependymomas initially presented with back pain and long-tract signs. The tumors were hyperintense on T2-weighted MR imaging, isointense on T1-weighted imaging, and noncontrast enhancing. Within 1 of the tumors, a medial septum was present on axial T2-weighted imaging. The tumors were intramedullary but grew exophytically and were amenable to gentle surgical separation from normal neural structures. Therefore, gross-total resection was feasible, and neurological outcome was good. No further adjuvant therapy was conducted. On follow-up (at 58 and 18 months, respectively), no tumor recurrence was observed.

CONCLUSIONS

Symptomatic thoracolumbar intraspinal subependymomas with a distinct appearance on MR imaging are amenable to complete excision with favorable neurological outcome. In this study no tumor recurrence was observed at midterm follow-up in either patient, neither of whom underwent adjuvant therapy.

Intramedullary subependymoma of the spinal cord: a case report and review of literature

A case of cervical spine intramedullary subependymoma in a 52-year-old female is reported. Also, the relevant literature on the 40 cases reported till date is reviewed. Magnetic resonance imaging, even with enhancement, does not show any distinctive features making pre-operative diagnosis often difficult. These tumours are eccentrically located within the spinal cord, thus enabling complete tumour removal in most cases. They are benign with low proliferative potential and hence no post-operative radiotherapy should be administered.

Subependymoma of the spinal cord and review of the literature

Subependymoma is a tumor of the central nervous system, which frequently occurs in the ventricles and rarely in the spinal cord. Most of the intraventricular subependymomas are subclinical and thus incidentally encountered at autopsy, whereas the spinal ones are inevitably accompanied by myelopathy and are often diagnosed clinically as ependymomas or astrocytomas. Two cases of spinal cord subependymomas are reported, one of which recurred 9 years after the initial operation. All specimens of both cases showed similar microscopic features. Within a highly fibrillary background, round to ovoid tumor cells were unevenly distributed and arranged in cell clusters. Mitoses were rarely encountered. No necrosis was demonstrated in any of the specimens. Ultrastructural examination demonstrated many slender processes containing abundant intermediate filaments and occasional small lumen-like structures with many microvillous projections and cell junctions. Subependymomas arising in the spinal cord should be distinguished from other more aggressive gliomas, such as diffuse astrocytomas and ependymomas. Characteristic microscopic features and the ultrastructural studies support the diagnosis.