Dsyembryoplastic neuroepithelial tumour with discrete bilateral multifocality: further evidence for a germinal origin

We report the case of a middle aged woman who developed refractory complex partial seizures in her early twenties. She had a right coloboma and neurol ogical examination was normal. Neuropsychological assessments revealed mild impairments of non-verbal memory, and visuospatial and constructional diff iculties. Serial CT and MRI showed multiple nodular abnormalities in her mi d-brain, diencephalon, subependymal region and both mesial temporal lobes. EEG recording revealed a right medial temporal focus. She underwent en bloc temporal lobectomy. The surgical pathology revealed mesial temporal dysemb ryoplastic neuroepithelial tumour (DNET) in association with extensive, con tiguous neocortical dysplasia. The proliferation marker MLB-1 revealed up t o 2% labelling in tumour areas resembling conventional oligodendroglioma. I n the two years since surgery she has been seizure free and the remaining M R brain abnormalities have not changed. The very unusual centripetal MRI pa ttern of discrete multifocal lesions with the characteristic T1 and T2 feat ures of DNET would support the dysembryoplastic germinal origin that was pr oposed by Daumas-Duport et al. (1988) in their original description of the lesion. The neuroradiological, neuropathological and clinical features of t his case are compared with the two previous cases of multifocal DNET.