Diffuse leptomeningeal glioneuronal tumor in a Chinese adult: a novel case report and review of literature.

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare glioma tumor classified by the World Health Organization as a central nervous system tumor in 2016. DLGNT is most common in children and adolescents but is rare in adults. A 25-year-old male patient was admitted due to recurrent seizures. Head magnetic resonance imaging revealed lesions in the right temporal lobe, which were considered to be intracranial tumors with variable properties. The patient was admitted for surgical treatment. After admission, it was confirmed that seizures were associated with right temporal lobe lesions. Right temporal epileptogenic focus resection was performed by craniotomy. Immunohistochemistry revealed that tumor cells were reactive for oligodendrocyte transcription factor 2, synaptophysin, S100 proteins, and α-thalassemia mental retardation X-linked; and partially reactive for neuronal nuclei, glial fibrillary acidic protein, and nestin. The vascular wall was reactive for vimentin, CD34, CD31, and smooth muscle actin. Ki-67 was 4%. Molecular detection demonstrated 1p36 deletion, O6 -methylguanine-DNA-methyltransferase methylation, and positive v-raf murine sarcoma viral oncogene homolog B mutation. DLGNT. The patient recovered well after surgery and received 54 Gy/27f radiotherapy without neurological dysfunction and seizures. In this study, onset age, tumor site, tumor increment coefficient, molecular detection, treatment methods, and prognosis of 54 patients were summarized from 19 studies. DLGNT patients are characterized by more singular tumor site, smaller volume, lower increment coefficient, and longer stable disease period. Patients with DLGNT may also have a longer stable condition in cases of molecular detection of 1p/19q deletion, or BRAF fusion.