Multinodular and vacuolating neuronal tumors with suggested slow progression

Abstract

Multinodular and vacuolating neuronal tumors（MVNT）were recently included in the 2016 World Health Organization classification of central nervous system tumors. In previous case reports and pub-lished papers, MVNTs are described as benign tumors associated with epilepsy and rarely presenting with progressive features. Herein, we report three cases of resected MVNTs with slow progression. None of the patients exhibited neurological symptoms or had a history of epilepsy, and all were diagnosed incidentally using magnetic resonance imaging（MRI）. In all three cases, MRI of the subcortical region revealed hypoin-tensity on T1‒weighted images（T1‒WI）and hyperintensity on T2‒WI and fluid‒attenuated inversion recovery（FLAIR）images. The T1‒WI lesions were not enhanced with gadolinium. One patient demonstrated suggested slow expansion of the lesion during the 7‒year follow‒up visit. As the results suggested the possibility of progressive tumors, including lower‒grade gliomas, surgery was performed to obtain pathological and genetic diagnoses. Histopathological findings revealed typical features of MVNT such as multinodular lesions in the cerebral subcortex and proliferating atypical cells with vacuolating features in the tumors. Immunohistochemical tests demonstrated that anti‒synaptophysin and anti‒Olig2 antibodies stained the tumor cells. DNA sequencing analysis revealed that IDH1‒R132, IDH2‒R172, H3F3A‒K27, ‒G34, HIST1H3B‒K27, ‒G34, TERT promoter‒C228, ‒C250, and BRAF‒V600 were not mutated. Additional data Multinodular and vacuolating neuronal tumors（MVNT）were recently included in the 2016 World Health Organization classification of central nervous system tumors. In previous case reports and pub-lished papers, MVNTs are described as benign tumors associated with epilepsy and rarely presenting with progressive features. Herein, we report three cases of resected MVNTs with slow progression. None of the patients exhibited neurological symptoms or had a history of epilepsy, and all were diagnosed incidentally using magnetic resonance imaging（MRI）. In all three cases, MRI of the subcortical region revealed hypoin-tensity on T1‒weighted images（T1‒WI）and hyperintensity on T2‒WI and fluid‒attenuated inversion recovery（FLAIR）images. The T1‒WI lesions were not enhanced with gadolinium. One patient demonstrated suggested slow expansion of the lesion during the 7‒year follow‒up visit. As the results suggested the possibility of progressive tumors, including lower‒grade gliomas, surgery was performed to obtain pathological and genetic diagnoses. Histopathological findings revealed typical features of MVNT such as multinodular lesions in the cerebral subcortex and proliferating atypical cells with vacuolating features in the tumors. Immunohistochemical tests demonstrated that anti‒synaptophysin and anti‒Olig2 antibodies stained the tumor cells. DNA sequencing analysis revealed that IDH1‒R132, IDH2‒R172, H3F3A‒K27, ‒G34, HIST1H3B‒K27, ‒G34, TERT promoter‒C228, ‒C250, and BRAF‒V600 were not mutated. Additional data on characteristics features of MVNT Revealed MRI are required to determine treatment stragies for hyperintensity lession detected on T2-WI. Incliuding Lower grade gliomas.