[Ganglioglioma with an atypical histopathological phenotype or a new entity of the LEAT group?]

The article reports the discovery of pathological substrates with an atypical histopathological phenotype in the brains of patients undergoing surgery for drug-resistant structural epilepsy. A complete panel of histopathological staining and immunohistochemical analysis with a wide range of antibodies were available at pathological examination. In addition to pathomorphological verification, molecular genetic testing was performed for the presence of mutations in the BRAF genes at codon 600 and BRAF/KIAA1549. MRI was performed at 3.0 Tl tomography using a standard protocol and an epileptic scanning protocol. During pathomorphological examination, the patients showed mixed signs of ganglioglioma CNS WHO grade 1 and focal cortical dysplasia type IIb. This mixed combination of pathological processes in one substrate has not yet been described in publicly available sources and does not fit the definition of double pathology, when they can coexist next door, but have clear differentiation. On MRI, the pathological substrates were localized in the frontal and temporal lobes, did not demonstrate typical radiological criteria of a tumor, had a "transmantle" distribution from the the lateral ventricles to the cortex with local and regional smoothing of the gray-white demarcation and uneven thickening of the cortical plate in the area of interest. In one case, large calcification associated with cavitation of the white matter was found in the structure of the pathological substrate. In another case, the substrate showed decreased blood flow in the substrate structure on perfusion maps. The described epileptogenic substrates differ markedly from classical gangliogliomas with two cell pools according to pathomorphological, molecular genetic and radiological criteria. The published results may indicate a completely new subgroup of gangliogliomas with cellular atypia, or a previously unknown combination of two pathological processes, or argue in favor of a common origin of neuronal-glial tumors and FCD. These data require prospective verification on a larger cohort of patients and an in-depth study of the molecular genetic profile of the described pathological substrates in order to reliably verify their origin.