Cortical dysplasia with prominent Rosenthal fiber formation in a case of intractable pediatric epilepsy.

We report a case of a 5-year-old boy with intractable epilepsy who underwent therapeutic corticectomy. Histopathologic findings within the resection specimen included severe cortical dysplasia associated with abundant subpial and intraparenchymal Rosenthal fibers in a large right frontal lesion that merged into the basal ganglia. Rosenthal fiber proliferation may represent a reactive process, are frequent in pilocytic astrocytomas, and are a defining feature of Alexander disease. There was no evidence of neoplasm or leukodystrophy in this case. Genetic analysis of the specimen showed a few previously reported polymorphisms but no mutation in the GFAP gene. This case is unique among several hundred cortical resection specimens that we have studied, including numerous cases of severe cortical dysplasia.