Abstracts

RATIONALE: Patients with PNH often have intractable focal epilepsy, and electro- clinical features suggestive of temporal lobe (TL) seizures. All but one of 10 had poor outcome after TL resection (Li et al, Ann Neurol, 1997;41:662).
METHODS: We reviewed surgical outcome in six patients (4 men, mean age at seizure onset, 15.3 years) with PNH. The nodules were bilateral, diffuse and contiguous in one patient (1), unilateral focal in two (2, 3), and bilateral focal in the remaining three (4, 5, 6).
RESULTS: The first patient (1) had epileptic ictal discharges originating in the right and left hippocampi with an 85% right-sided preponderance. She underwent right selective amygdalo-hippocampectomy (SAH) with satisfactory outcome after eight years of follow-up (Li et al, case 5). Patient 2 with focal and unilateral heterotopia had no seizure recorded from a nodule and no interictal spiking arose in it. He had two adjacent occipital nodules, active interictal and ictal discharges from the adjacent occipital cortex (within 2cm). He had removal of the nodules and part of the overlying occipital cortex. In patient 3, a single nodule was found in the right trigone and the epileptic discharges originated in the left contralateral, atrophic hippocampus. He underwent left SAH. Both patients 2 and 3 have a five years follow-up with a satisfactory outcome. Patients 4 and 5 had focal bilateral temporal-occipital PNH, and showed bilateral and widespread temporo-parieto-occipital interictal and ictal discharges. Patient 6 had in addition scattered nodules along the body of both lateral ventricules, and bilateral epileptic activity. In two the nodules were found retrospectively and in none of these three patients was a nodule explored. They underwent anterior temporal resections and all had poor results (Li et al, cases 3, 4, 6, follow-up 8-15 years).
CONCLUSIONS: Patients with PNH often have [dsquote]pseudo-temporal localization and epilepsy[dsquote]. This explains the failure of temporal resections in patients with PNH. On the other hand, they may have additional abnormalities such as hippocampal atrophy that act as the primary epileptogenic substrate. When few congruent unilateral nodules are present investigation may suggest a focal resection and good outcome. Dual pathology with mesial temporal resection may also lead to a good result. Some nodules seem inert or not related to epileptogenesis. Bilateral multiple nodules often lead to widespread epileptogenesis where classical surgical approaches are unlikely to be effective.