Clinicopathological and molecular analysis of multinodular and vacuolating neuronal tumors of the cerebrum

다국어 초록 (Multilingual Abstract)

<P><B>Summary</B></P> <P>Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a recently recognized rare neuronal tumor, and its pathogenesis is unclear. We analyzed 7 cases of histologically typical MVNT: 6 were adults (mean age, 43.0 years [range, 23-56 years]) and 1 was a child (age, 10 years). The most common symptoms were seizures (n = 4) and headache (n = 2). The tumors were supratentorial (temporal, 5; frontal lobes, 2) in origin as reported. Vacuolated tumor cells were robustly positive for α-INA and Olig2 and at least partly positive for synaptophysin and MAP2, but negative for Neu-N, nestin and CD34. GFAP and vimentin were expressed in reactive astrocytes but not in tumor cells. Negative results were obtained for p53, IDH-1, BRAF<SUP>V600E</SUP>, H3 K27M, EGFR, Lin28A, and L1CAM. ATRX, BRG1, INI-1, and TMHH were retained. The Ki-67 labeling index was very low (<1%), and pHH3 revealed no mitotic figure. Ultrastructural features of tumor cells were comparable with those of immature neuronal cells, with several intracytoplasmic myelin-like autophagosomes and pericellular vacuolization. No <I>IDH1</I>/<I>IDH2</I> and <I>BRAF</I> <SUP> <I>V600E</I> </SUP> mutations were found upon direct sequencing. Whole-exome sequencing revealed <I>FGFR2</I>-<I>ZMYND11</I> gene fusion in 1 case. After gross total resection, all patients were alive without seizures. There was no tumor recurrence during an average period of 68 months (range, 23-101 months). The analysis of 7 typical cases of MVNT suggested that these lesions may be clonal tumors because <I>FGFR2</I>-<I>ZMYND11</I> fusion was found (1 case).</P> <P><B>Highlights</B></P> <P> <UL> <LI> “MVNT” of the cerebrum is a recently recognized rare epileptogenic neuronal tumor. </LI> <LI> Whole-exome sequencing revealed <I>FGFR2</I>-<I>ZMYND11</I> gene fusion in one of our MVNT cases. </LI> <LI> The tumor cell is robustly positive for α-INA and Olig2, but negative for Neu-N. </LI> <LI> Ultrastructurally, tumor cells have autophagolysosomes with pericellular vacuolization. </LI> <LI> There was no tumor recurrence during an average period of 68 months. </LI> </UL> </P>