Abstracts

Epilepsy surgery outcomes may differ among the focal malformations of cortical development (MCDs). Specifically, most pathologic studies have suggested that balloon cells portend a better prognosis compared to other [quot]focal cortical dysplasias.[quot] This could impact surgical decision making, since there are several MRI features highly suggestive of balloon cells. For example, focal cortical thickening with T2 signal abnormality extending towards the ventricle has been reported to be 94% specific for balloon cell pathology.
We have previously proposed a categorization scheme for focal malformations of cortical development, discarding the term [quot]focal cortical dysplasia[quot] since these lesions are not precancerous. This study correlates the histopathologic type of focal malformation with epilepsy surgery outcomes., Pathologic specimens were retrospectively reviewed from 49 consecutive focal MCDs resections at Mayo Clinic Rochester. These cases were all removed for intractable epilepsy. Specimens were systematically classified using microscopy and standardized immunohistochemical techniques, according to our recently reported classification scheme. Clinical outcomes were compared between different histopathologic subtypes., Of the 49 cases, three were excluded since there was no post-operative follow-up. Of the remaining 46, 26 patients (57%) remain free of disabling seizures (Engel class I). Average follow-up was 34 months. Patients with cytoarchitectural dysmorphism (with or without balloon cells) trended towards better outcomes compared to architectural disorganization and polymicrogyria. However, balloon cells did not portend the best prognosis. Only 60% of patients with balloon cells ([quot]cytoarchitectural dysmorphism with balloon cells[quot]) were free of disabling seizures compared to 75% of those with cytologically abnormal neurons and architectural disorganization without balloon cells ([quot]cytoarchitectural dysmorphism without balloon cells[quot])., Epilepsy surgical outcomes remain suboptimal in focal MCDs. Other focal lesions causing epilepsy, such as cavernomas or mesial temporal sclerosis, are associated with excellent outcomes in up to 90% of patients. In contrast, we found that only 57% of patients with focal MCDs remained seizure-free. In our cohort, balloon cells did not portend a better prognosis than other focal MCDs.[table1],