Epilepsy Associated with Dysembryoplastic Neuroepithelial Tumors. Intracranial Recordings and Surgical Outcome.
Abstract number :
L.03
Submission category :
Year :
2001
Submission ID :
1944
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
B.C. Devaux, MD, Neurosurgery, CHSA, Paris, France; F. Chassoux, MD, Neurosurgery, CHSA, Paris, France; E. Landre, MD, Neurosurgery, CHSA, Paris, France; B. Turak, MD, Neurosurgery, CHSA, Paris, France; P. Varlet, MD, Neuropathology, CHSA, Paris, France;
RATIONALE: Dysembryoplastic neuroepithelial tumors (DNTs) are recognized as a surgically remediable cause of partial epilepsy. However surgical strategy - lesionectomy or corticectomy - remains debated and little information is available on tumor epileptogenicity. We studied a series of patients operated for intractable partial epilepsy associated with DNT in order to determine factors related to favorable seizure outcome.
METHODS: Out of 238 patients operated during the last 10 years, 57 (24 %), aged from 3 to 54yrs (mean: 26yrs) had DNT identified on MRI and proved histologically. Tumor location was temporal (43 cases), extra-temporal (10) and multilobar (4). Hippocampal sclerosis was found in 2 cases of temporomesial DNTs. Epilepsy duration ranged from 1 to 37 years (mean:13yrs). Presurgical evalution included ictal video-EEG recordings (52 cases) and stereo-electroencephalography -SEEG- (35 cases, 32 of them had intralesional electrodes).
RESULTS: Intralesional recordings showed evidence of an intrinsic epileptogenicity of DNTs which were the site of interictal spiking and ictal discharges onset. Epileptogenic zone (EZ) was limited to the tumor and immediate perilesional tissue in 6 out of 7 cases of extra-temporal DNTs, while EZ involved mesial structures in 23 out of 28 temporal DNTs. In patients operated without SEEG, electroclinical data were concordant with tumor location except in 2 cases. Surgical resection of temporal DNTs was limited to the lesion and perilesional tissue in 11 cases (26%) and included lesion, mesial and neocortical structures in 32 (74%) - polar in 11, lateral cortex in 21. Resection was limited to the tumor in 4 extratemporal DNTs and associated with perilesional tissue in 6 as well as in 4 multilobar DNTs. Follow-up ranged from 1 to 10 years (mean = 4.2 yrs) in 46 patients : 39 (85%) were in class I (IA: 25), 3 in class II, 2 in class III and 2 in class IV (Engel classification). Unfavorable outcome was observed in 2 patients who had incomplete lesion resection in central region and in 2 with complete resection but generalized EEG pattern. Seizure outcome was not significantly related to epilepsy duration.
CONCLUSIONS: This study demonstrated intrinsic epileptogenicity of DNTs. In extra-temporal lesions, EZ was limited to the tumor. In temporal lesions, EZ frequently included mesial structures, suggesting involvement of a larger epileptogenic network. Seizure-free outcome can be obtained 1) by complete lesionectomy in extra-temporal areas; 2) by lesionectomy associated with cortical resection including mesial structures in 3/4 of temporal DNTs.