Neuropathological spectrum of lesions associated with intractable epilepsies: A 10-year experience with a series of 153 resections

Background: Surgical management of intractable epilepsies is currently an established mode of therapy in various clinical settings.
Aims: To retrospectively evaluate the neuropathological findings in both temporal and extratemporal lobe resections in such patients.
Materials and Methods: The study included resected specimens from patients with intractable epilepsy managed at a tertiary care hospital of India, during a 10-year period (1995-2004).
Results: A total of 153 patients, with mean age of 19.4 years and male predominance (73.2%) were included in the study. Overall, there was a predilection for the temporal lobe (73.2%), while 41cases were extratemporal in location. On histopathology, mesial temporal sclerosis (MTS) (24.8%) was the commonest lesion, followed by tumors (19.6%) and isolated focal cortical dysplasia (FCD - 15.11%). Other less common findings included Rasmussen encephalitis, non-specific gliosis and vascular malformations. In addition, 20.9% (32 cases) had dual lesions, majority of which included FCD with ganglioglioma (15 cases) or with dysembryoplastic neuroepithelial tumor (12 cases). In the temporal lobe, neoplasms and dual lesions formed the majority (apart from MTS), unlike dual lesions followed by neoplasms and FCD, in the extratemporal location.
Conclusion: This series demonstrates that most patients with chronic intractable epilepsy have significant histopathological findings and highlights the neuropathological spectrum of such lesions, in the Indian context. This was similar to that reported from the West, but different from the single Indian series available in the literature. Further, the overall profile of temporal lobe lesions was not different from the extratemporal ones.