University Journal of Surgery and Surgical Specialties

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1 University Journal of Surgery and Surgical Specialties ISSN Volume 2 Issue DORSAL INTRAMEDULLARY SUBEPENDYMOMA - A RARE CASE REPORT WITH LITERATURE REVIEW BABA DHOULATH KHAN MOHAMEDISMAIL Department of Neuro Surgery, MADURAI MEDICAL COLLEGE AND HOSPITAL Abstract : Subependymomas of the spinal cord are rare tumors with very few cases described in the literature. They are biologically benign with low proliferative index hence postoperative prognosis is very good. Surgical removal is usually curative and no further adjunct treatment is needed after gross total tumor removal. We present a case of 37 year old male patient with an intramedullary supependymoma located in the thoracic region of the spinal cord. The tumor was totally excised with complete recovery Keyword : spinal cord, intramedullary tumour, subependymoma INTRODUCTION: Subependymomas are slow growing tumors usually found inthe ventricular system 1 They possibly account for less than2% of all spinal cord tumors 2.These tumors are biologicallybenign with very low proliferation index 3. They areeccentrically located within the spinal cord, enablingcomplete tumor removal in most cases 4.We present a caseof 37 year old male patient with an intramedullarysupependymoma located in the thoracic region of the spinalcord. CASE REPORT: 37 year old male presented with gradually progressive weakness of all four limbs. Examination revealed grade 3 power in all four extremities with diminished sensations below C5 with sphincter involvement. MRI revealed a well defined homogenous contrast enhancing intramedullary lesion at D1, D2 level with tumor syrinx above (upto C5) and below (upto D11) the lesion. Fig.1(a) Fig.1(b) Fig.1(c)

2 Fig.1: MRI IMAGES OF THE PATIENT (a) T 2 weighted sagittal image (b) T1 weighted contrast image (c) axial images showing a well defined homogenous contrast enhancing intramedullary lesion at D1,D2 levelwith tumour syrinx above (upto C5) and below (upto D11) the lesion. Patient was assessed for surgery. Tumour approachedthrough Posterior Midline Approach with C7- D3Laminectomy done under GA. A myelotomy was done overthe DREZ region, the syrinx cavity near the lower pole of the tumour was entered. There was a good plane of cleavage around the lesion. Gross total removal of the Fig.2: intraoperative photographs showing good plane of clevage around the lesion and gross total removal of the tumour.was done.fig.2(c) Fig2(d) Histopathology of the tumor revealed ependymal cells forming pseudorosettes in a fibrillary background suggestive of subependymoma. Five months later, patient was walking without support and had regained continence.

3 Fig.3: Excised lesion. Fig.4: Histopathology of the lesion showing ependymal cells forming pseudorosettes in a fibrillary background. DISCUSSION: Spinal subependymomas are much less frequent than their intracranial counterparts, though they become symptomatically obvious quite early 5. These tumors are first recognized as a separate pathological entity by SCHEINKER in They are characterized by a distinctive microscopic appearance of cellular nests with intervening hypocellular fibrillary regions. Since the original description of spinal cord subependymomas by Boykin, et al., 7 in1954 approximately 40 more cases have been described in the literature and that too in the last two decades. To the best of our knowledge, our case is the 42 nd case to be reported in English literature. Bret et al found in their review of 29 cases that this tumor accounts for approximately <2% of all spinal cord tumors and that the majority are located in the cervico thoracic region 2. Review of literature performed by Sarkar C et al., revealed a mean age of 47.2 years and male predominance. They also found that the majority of tumors were intramedullary and were located in the cervical region 4.The cell from which subependymomas originate has been a subject of dispute since this tumor was recognized by Scheinker in He proposed the origin to be from the subependymal plate, which is also known as the residual periventricular matrix layer. In 1954 Boykin, et al., reviewed nine cases of subependymoma and they believed that these tumors originated from subependymal astrocytes in the walls of the ventricles or central canal of the spinal cord.hence they called them subependymal glomerate astrocytoma. French and Bucy 8 reviewed a series of three supependymomas from the septum pellucidum in1948 and concluded that these were astrocytomas and not derived from elements of the subependymal plate. The situation was not further elucidated until the invention of electro microscope. In 1974 Fu, et al., 9 in their electron microscopy examination found that the cells have ultrastructural features of both ependymal cells and astrocytic cells. Tissue culture also revealed two distinct cell lines of which one resembled ependymal cells and the other astrocytes.

4 On this basis they concluded that subependymoma was a variant of ependymoma and that the astrocytic component represented reactive astrocytic cells. In 1984, Moss 10 studied four cases of fourth ventricular subependymomas by electron microscopy and found cells similar to ependymal glial precursor cells seen in the adult subependymal cell layer. He therefore considered that subependymoamas were different from ependymomas and astrocytomas, probably arising from ependymal glial cells in the subependymal cell layer. Horstmann, 11 in1954 described a cell in the subependymal zone of the elasmobranch, the processes of which spanned the brain from the pial to the ventricular surface. He named these cells tanycytes after the Greek word tanyos meaning to stretch and they have subsequently been found in many other species including mammals. They vary in their orientation in different species and even from region to region in the subependymal plate zone within the same species. It is interesting that tanycytes have the ultrastructural appearance of both astrocytes and ependymocytes which are similar to the ultrastructural findings in subependymomas. In review of 43 ependymomas and 71 astrocytomas, Friede and Pollak 12 found 11 spinal tumors which they considered had an appearance reminiscent of tanycytes. From their histological description as well as the photomicrographs in the paper, however these do not appear to be subependymomas. Despite this the tanycytes remains a strong contender for the cell of origin of subependymomas due to their similar ultrstructural appearances. The clinical features of the spinal subependymomas are similar to other intra medullary spinal tumors, with a mixture of upper and lower motor neuron findings together with progressive sensory dysfunction and early bladder and bowelinvolvement. Sarkar et al 4 on reviewing the literature found no difference on imaging studies between ependymomas and subependymomas. They reviewed the imaging findings of forty cases reported in the literature and found that computed tomography (CT) scan reported in eight cases showed spinal cord enlargement in three and cyst in one. Only two patients showed post contrast enhancement. MRI findings were available for 23of the 40 reported cases and revealed segmental fusiform dilatation of the cord with low T1-weighted and high T2- weighted signal intensities. Contrast studies were available in 18 of these 23 cases. Ten of 18 cases showed enhancement with contrast, either well circumscribed sharply demarcated areas of homogenous signal enhancement or multiple nodular enhancements.they are biologically benign with low proliferative index hence postoperative prognosis is very good. They are eccentrically located within the spinal cord, enabling complete tumor removal in most cases. Surgical removal is usually curative and no further adjunct treatment in the form of radiotherapy or chemotherapy is needed after gross total removal of the tumour. Radiotherapy given in patients with partial removal of tumour has shown no evidence of any efficacy. 13 Prognosis thus determined largely by surgical factors. Norecurrence or CSF seedings have been reported till date. 14 REFERENCES: 1 ndymomaoccupying the right half of the throracic spinal cord: A casereport. Neurol Med Chir Tokyo 2002;42: Bret P, Bougeard R, Saint-Pierre G, Guyotat J, Ricci AC,Confavreux C. Intramedullary

5 subependymoma of thecervical spinal cord: Review of the literature a propos of acase. Neruchirurgie 1997;43: Jallo GI, Zagzag D, Epstein F. Intramedullarysubependymoma of the spinal cord. Neurosurgery1996;38: Sarkar C, Mukhopadhyay S, Ralte AM, Sharma MC,Gupta A, Gaikwad S, et al. Intramedullary subependymomaof the spinal cord: A case report and review of literature. ClinNeurol Neurosurg 2003;106: Weistler OD, Schiffer D. Subependymomas. In:Kleihues P, Cavenee WK, editors, Pathology and genetics:tumours of the nervous system. Lyon: IARC Press; p Scheinker JM. Subependymoma: Newly recognizedtumour of subependymal derivation. J Neurosurg1945;49: Boykin FC, Cowen D, Iannucci CA, Wolf A. Subependymal glomerate astrocytomas, J Neuropathol Exp Neurol 1954; 13: French JD, Bucy PC. Tumours of the septum pellucidum.j Neurosurg 1948;5: Fu Y, Chen ATL, Kay S, et al. Is subependymoma(subependymal glomerate astrocytoma) an astrocytoma orependymoma? A comparative ultrastructural and tissueculture study. Cancer 1974, 34: Moss TH. Observations on the nature of subependymoma: an electron microscopic study.neuropathol appl Neurobiol, 1984;10: Horstmann E. Die faserglia selachiergehirns. ZZellforschung, 1954;39: Friede RL, Pollak A. The cytogenetic basis for classifyingependymomas. J Neuropathol Exp Neurol, 1978;37: Taciomi L, Johnston FG, Thomas DG. Subependymomaof the cervical cord. Clin Neurol Neurosurg 1996;98: Dario A, Fachinetti P, Cerati M, Dorizzi A.Subependymoma of the spinal cord: Case report and reviewof the literature. J Clin Neurosci 2001; 8: