[Surgical treatment of intramedullary-extramedullary ependymomas. Two clinical cases and a literature review]

A Case of Spinal Ependymoma Developed in the Extramedullary Location: A Case Report and Literature Review

Intradural extramedullary (IDEM) ependymoma except for tumors originated from the filum terminale or conus medullaris is rare. The present study showed a case of IDEM ependymoma. A 16-year-old boy was referred to our hospital with a complaint of right hypochondriac pain and motor weakness in his right leg. MRI revealed a solitary intradural tumor at Th5–8 level with syringomyelia at Th2–4 level. Microscopic total tumor resection was performed with right hemi-laminectomy of Th4–9. Histological diagnosis was ependymoma (WHO grade 2). Although his leg weakness was worsened transiently, he showed improvement in leg weakness being able to go up and down the stairs 1 month after the surgery. There was no tumor recurrence until now, 7 years after the surgery, without any adjunctive therapies. A total of 44 cases of IDEM ependymoma had been reported in the past literatures. They are thought to arise from ependymal cells which remained during the process of neural tube closure. Like intramedullary ependymomas, most of the IDEM ependymomas have clear border to surrounding tissue and often removed completely. However, a small number of recurrences and malignant transformations had been reported after complete resections despite benign histological features tumors. In the case of totally resected low grade IDEM ependymoma, it is thought to be reasonable to perform long-term periodical radiographic follow-up without postoperative adjunctive therapy.

Ependymoma of the spinal cord with multiple intradural extramedullary ependymomas: The first case report and literature review

Ependymomas are the most prevalent intramedullary neoplasms in adults. Few cases have been reported on exophytic intramedullary ependymoma or multiple non-conus, and non-filum intradural extramedullary (IDEM) ependymomas. Here, we reported a 30-years old female with exophytic ependymoma in T10-11 and multiple IDEM ependymomas in T3-S2 and who's condition ultimately improved. This is the first case of exophytic ependymoma of the spinal cord with multiple IDEM ependymomas.

Microsurgical techniques for achieving gross total resection of ependymomas of the fourth ventricle

Ependymomas arising from the ventricular surface present a major challenge to achieving a complete operative extirpation when located in the fourth ventricle given the presence of significant adherence to the floor of the same. Overzealous dissection and removal of a tumor from this zone may precipitate potentially catastrophic neurological deficits attributable to cranial nucleopathies and cranial neuropathies. Consequently, the classic neurosurgical teaching has advised attempted gross total resection, leaving adherent residual in the floor of the fourth ventricle, in order to prevent the development of major cranial nucleopathies and cranial neuropathies. Following surgical tumoral extirpation, residual tumor is adjuvantly stereotactically irradiated. Authors have consequently developed novel neurophysiologically guided microsurgical techniques designed to remove adherent tumor from the fourth ventricular floor. These strategies have successfully and consistently facilitated gross total resection and improved clinical outcomes in patients harboring ependymomas of the fourth ventricle. We discuss and evaluate the innovation in microsurgical strategies developed to achieve complete operative extirpation of tumoral adherence to the floor of the fourth ventricle.

Intradural Extramedullary Nonconus Nonfilum Spinal Ependymomas: Report of a Rare Variant and Newer Insights into Their Histogenesis with Proposal of a Classification Scheme and a Management Algorithm Based on a Review of Literature

BACKGROUND

Ependymomas are common intramedullary spinal tumors but there are scattered reports of this tumor presenting with exophytic growth patterns masquerading as intradural extramedullary (IDEM) tumors. Such IDEM ependymomas are seldom suspected preoperatively and it is only during surgery that their existence is revealed. Little is known of such rare growth patterns of an otherwise common intramedullary spinal cord tumor, their characteristics, and their management considerations.

METHODS

We present a case of an exophytic dorsal ependymoma with a stalk like attachment to the spinal cord and the surgical management in a 24-year old woman. An extensive literature search was carried out on all prominent databases to find out similar cases reported earlier. We excluded filum/conus ependymoma, purely extradural spinal ependymoma as well as the extraspinal ependymomas. Details of each case reported before were obtained and tabulated.

RESULTS

IDEM ependymomas have been reported in 54 patients so far, including the present case. Four patterns of growth emerged from the literature review: intramedullary ependymoma with exophytic component (group I, n = 9), exophytic IDEM ependymoma without intramedullary component (group II, n = 6), IDEM ependymoma arising from nerve roots (group III, n = 7), and pure IDEM ependymoma (group IV, n = 32). Except in group I, IDEM ependymoma affects females more frequently, without any specific age predilection. Thoracic spinal cord/canal is the most common location across all groups. Multifocal disease, craniospinal dissemination, and recurrences tend to be maximum in group IV.

CONCLUSIONS

IDEM ependymomas are more common in thoracic segment of the cord and broadly divisible into 4 subgroups. We suggest a subpial origin of group II IDEM ependymomas. We also advocate proliferation index estimation in grade II ependymomas to enable formulation of an optimal management plan.