Neuropathological findings in 224 patients with temporal lobe epilepsy

• Published in: Acta neuropathologica Vol. 86; no. 5; p. 433
• Main Authors: Plate, K H, Wieser, H G, Yasargil, M G, Wiestler, O D
• Format: Journal Article
• Language: English
• Published: Germany 01.10.1993
• Subjects: Adolescent; Adult; Aged; Brain Diseases - metabolism; Brain Diseases - pathology; Brain Neoplasms - metabolism; Brain Neoplasms - pathology; Child; Child, Preschool; Epilepsy, Temporal Lobe - metabolism; Epilepsy, Temporal Lobe - pathology; Female; Humans; Infant; Infant, Newborn; Male; Middle Aged; Retrospective Studies
• ISSN: 0001-6322; 1432-0533
• DOI: 10.1007/BF00228577

During the period between 1976 and 1990, 247 patients with pharmaco-resistant complex partial seizures and a documented unilateral epileptogenic area in the mediobasal temporal lobe underwent a selective amygdalo-hippocampectomy procedure at our institution. Biopsy specimens from 224 patients (91% of the total) were available for a retrospective histopathological and immunohistochemical review. The tissue specimens of 23 patients without evidence for a macroscopic lesion have been used for neurochemical studies and could not be evaluated histopathologically. The most common temporal lobe pathology were neoplasms in 126 patients, i.e. 56%. Tumor entities observed included 23 astrocytomas (18% of all tumors), 17 gangliogliomas (13%), 15 oligodendrogliomas (12%), 15 cases of glioblastoma multiforme (12%), 13 pilocytic astrocytomas (10%), 12 oligo-astrocytomas (10%), 11 anaplastic astrocytomas (9%) and 20 tumors of various other histologies. In 23 specimens (10%), small foci of oligodendroglia-like clear cells were found. The frequent association of these foci with low-grade gliomas or neural hamartomas raises the possibility that these structures may serve as precursor lesion for neuroepithelial tumors of the temporal lobe. In 98 cases, pathological changes of non-neoplastic origin were encountered. The most common diagnoses in this group included hippocampal gliosis/sclerosis (49 cases, 22%) and vascular malformations (20 cases, 9%). Hamartomas, i.e. focal accumulations of dysplastic neuro-glial cells were diagnosed in 14 patients (6%). In only four cases have we not been able to detect any microscopic pathology. These results indicate that a high proportion of pharmaco-therapy-resistant complex-partial seizures are caused by neoplasms of the temporal lobe, some of which appear to be strikingly overrepresented in this group of patients.