Case Reports / Journal of Clinical Neuroscience 18 (2011) 147–148
147
Temporo-mesial extraventricular neurocytoma and cortical dysplasia in focal temporal lobe epilepsy Marco Giulioni a,⇑, Matteo Martinoni a, Guido Rubboli b, Gianluca Marucci c, Anna Federica Marliani d, Stella Battaglia d, Filippo Badaloni a, Eugenio Pozzati a, Fabio Calbucci a a
Division of Neurosurgery, Department of Neurosciences, Bellaria Hospital, Via Altura 3, Bologna 40139, Italy Division of Neurology, Department of Neurosciences, Bellaria Hospital, Bologna, Italy c Section of Pathology, Bellaria Hospital, University of Bologna, Italy d Section of Neuroradiology, Bellaria Hospital, University of Bologna, Italy b
a r t i c l e
i n f o
Article history: Received 18 March 2010 Accepted 23 March 2010
Keywords: Cortical dysplasias Epilepsy surgery Extraventricular neurocytoma Glioneuronal tumors Pharmacoresistant epilepsy
a b s t r a c t We describe a 17-year-old boy with a left extraventricular temporo-mesial neurocytoma associated with cortical dysplasia causing focal pharmacoresistant temporal lobe epilepsy. He presented with a long history of medically refractory, temporal complex partial seizures. MRI showed a left temporomesial lesion suspect to be a low-grade tumor. Based on the pre-operative non-invasive neurophysiological studies, the patient underwent a left tailored temporal antero-mesial resection. Histopathological examination showed an extraventricular neurocytoma associated with architectural dysplasia (Type 1a) of the temporal pole. The patient was seizure-free at 2 years follow-up. Extraventricular neurocytomas must be considered in the differential diagnosis of the plethora of low-grade tumors associated with focal epilepsy that typically involve the temporal lobe, and are frequently associated with focal cortical dysplasia. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Central neurocytoma, first described by Hassoun et al. in 1982, is a rare neuronal tumor of the central nervous system (CNS), accounting for 0.25% to 0.5% of all CNS tumors.1,2 Extraventricular neurocytoma (World Health Organization 2007) are primary tumors of the brain parenchyma, devoid of any apparent connection with the ventricular system.3 Although there have been a few reports of patients with extraventricular neurocytoma in the temporal lobe associated with focal epilepsy,2,4–7 to our knowledge there has been only one report of an association between extraventricular neurocytoma and cortical dysplasia.5 2. Case report A 17-year-old-boy had been suffering from pharmacoresistant focal seizures since the age of 9. On admission, his neurological and physical examinations were normal. The ictal clinic-neurophysiological data (long-term video electroencephalogram [EEG] and ictal EEG) indicated an epileptogenic zone involving the left antero-mesial temporal lobe. The neuropsychological study was normal. In the left temporal mesial lobe a hyperintense lesion, compared to gray matter, was found on a T2-weighted fluid-attenuated inversion recovery MRI and which was slightly hypointense on T1-weighted images. The lesion involved the uncus-amygdala and part of the hippocampus, without enhancement after gadolinium injection, which was consistent with a low-grade tumor (Fig. 1). 2.1. Surgical treatment and clinical results Based on the results of the presurgical non-invasive neurophysiological studies, the patient was submitted to a tailored left ⇑ Corresponding author: Tel.: +39 051 6225111; fax: +39 051 6225344. E-mail address:
[email protected] (M. Giulioni).
temporal antero-mesial resection involving the temporal pole, the lesion located at the uncus-amygdala area, the hippocampus and the parahippocampal gyrus (Fig. 2). The post-operative course was uneventful. At 2 years follow-up, the patient was seizure free (Engel ‘‘Class Ia”) with a normal neurological and neuropsychological examination.8 2.2. Pathology Tissue was fixed in formalin and embedded in paraffin. Blocks were serially cut and stained with hematoxylin and eosin, Nissl, Kluver and reticulin stains. All specimens were immunostained with anti-glial fibrillary acidic protein (GFAP) (clone 6F2, dilution 1:1200) (Dako; Glostrup, Denmark), anti-synaptophysin (polyclonal, dilution 1:40) (NeoMarkers; Fremont, CA, USA) and anti-NeuN (clone A60, dilution 1:1000) (Chemicon, Millipore; Billerica, MA, USA). The Ki67-labeling index (clone Mib1, dilution 1:200) (Novocastra Laboratories; Newcastle upon Tyne, UK) was calculated as the percentage of positive cells per high power field (400) using a Zeiss NeoFluar, 0.25 mm2 objective (Carl Zeiss MicroImaging; Jena, Germany). The tumor was composed of soft gray tissue. It had replaced most of the uncus and was composed of round to oval cells, and the cells were often arranged in a streaming pattern with fine granular, slightly eosinophilic to clear cytoplasm. Perinuclear halos were often prominent. Neither significant cytologic atypia nor mitoses were observed (Supplementary Fig. 1a). Necrosis was not present. Neoplastic cells were positive for synaptophysin (Supplementary Fig. 1b) and anti-NeuN while they were negative with anti-GFAP. The Ki-67 labeling index was lower than 1%. The temporo-polar cortex showed abnormal cortical lamination (Supplementary Fig. 1c); therefore, a diagnosis of focal cortical dysplasia (architectural or Type Ia cortical dysplasia according to Palmini et al.9) was also reported. Histological examination of hippocampal specimens did not provide evidence (neuronal loss) of Ammon horn sclerosis.
148
Case Reports / Journal of Clinical Neuroscience 18 (2011) 147–148
Fig. 1. Presurgical (a) T1-weighted coronal inversion recovery, (b) T2-weighted fluid attenuated inversion recovery; and (c) post-gadolinium T1-weighted MRI showing a lesion in the left temporal mesial lobe, involving the uncus-amygdala and part of the hippocampus, slightly hypointense on T1-weighted MRI and hyperintense on T2weighted MRI.
Fig. 2. Postoperative (a) coronal and (b) sagittal T1-weighted MRI; and (c) coronal T2-weighted MRI.
3. Discussion
References
The lesion in our patient was located in the anterior temporomesial basal area, similar to previous reports of extraventricular neurocytoma.2,7,10 The MRI features and histology of extraventricular neurocytoma make it difficult to differentiate it from other types of low-grade tumor, or glioneuronal tumors (GNT) such as gangliogliomas or dysembryoplastic neuroepithelial tumors (DNET).3,10–13 Focal epilepsies associated with GNT are extremely responsive to an epilepsy-oriented surgical treatment.11–13 We obtained an excellent result in our patient with temporo-mesial extraventricular neurocytoma, since the patient, 2 years after surgery, was seizure free (Engel ‘‘Class Ia”).8 This case also highlighted the association between extraventricular neurocytoma and temporal pole architectural (type 1a) cortical dysplasia.9 We believe that under these circumstances, a non-invasive, neurophysiological presurgical evaluation may be useful to correctly identify the epileptogenic zone, and to plan the best surgical strategy (lesionectomy or tailored surgery).12 Extraventricular neurocytomas must be considered in the differential diagnosis of the plethora of epileptogenic low-grade tumors that typically involve the temporal lobe, and which are frequently associated with focal cortical dysplasia.
1. Hassoun J, Gambarelli D, Grisoli F, et al. Central neurocytoma: an electron-microscopic study of two cases. Acta Neuropathol (German) 1982;56: 151–6. 2. Tortori-Donati P, Fondelli MP, Rossi A, et al. Extraventricular neurocytoma with ganglionic differentiation associated with complex partial seizures. AJNR Am J Neuroradiol 1999;20:724–7. 3. Louis DN, Ohgaki H, Wiestler OD, et al. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007;114:97–109. 4. Iannelli A, Pieracci N. Tumors in the temporal horn of the lateral ventricle as a cause of epilepsy. J Child Neurol 2008;23:315–20. 5. Morioka T, Nishio S, Shigeto H, et al. Surgical management of intractable epilepsy associated with cerebral neurocytoma. Neurol Res 2000;22: 449–56. 6. Nishio S, Takeshita I, Kaneko Y, et al. Cerebral neurocytoma, a new subset of benign neuronal tumors of the cerebrum. Cancer 1992;70:529–37. 7. Rabinowicz AL, Abrey LE, Hinton DR, et al. Cerebral neurocytoma: an unusual cause of refractory epilepsy. Case report and review of the literature. Epilepsia 1995;36:1237–40. 8. Engel Jr J, Van Ness PC, Rasmussen TB, et al. Outcome with respect to epileptic seizures. In: Engel Jr J, editor. Surgical treatment of the epilepsies. 2nd ed. New York: Raven Press; 1993. p. 609–21. 9. Palmini A, Najm I, Avanzini G, et al. Terminology and classification of the cortical dysplasias. Neurology 2004;62(Suppl. 2):S2–8. 10. Yang GF, Wu SY, Zhang LJ, et al. Imaging findings of extraventricular neurocytoma: report of 3 cases and review of the literature. AJNR Am J Neuroradiol 2009;30:581–5. 11. Blumcke I, Wiestler OD. Gangliogliomas: an intriguing tumor entity associated with focal epilepsies. J Neuropathol Exp Neurol 2002;61:575–84. 12. Giulioni M, Rubboli G, Marucci G, et al. Seizure outcome of epilepsy surgery in focal epilepsies associated with temporomesial glioneuronal tumors: lesionectomy compared with tailored resection. J Neurosurg 2009;111: 1275–82. 13. Daumas-Duport C, Scheithauer BW, Chodkiewicz JP, et al. Dysembryoplastic neuroepithelial tumor: a surgically curable tumor of young patients with intractable partial seizures. Report of thirty-nine cases. Neurosurgery 1988;23: 545–56.
Appendix A. Supplementary material Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.jocn.2010.03.058. doi:10.1016/j.jocn.2010.03.058
