Diffuse leptomeningeal glioneuronal tumor

Abstract

Objective To explore the clinicopathological features and molecular genetics of diffuse leptomeningeal glioneuronal tumor (DLGNT). Methods and Results A 5 - year- old boy presented with severe hydrocephalus and two times of convulsions. Head MRI showed obvious broadening of bilateral lateral ventricles, suggesting hydrocephalus, and abnormal patchy mildly high-intensity signals scattered in bilateral cerebellar superior sulci; spinal MRI revealed thickened spinal cord at the level of T_5-7 and mildly high-intensity signals within the spinal cord; enhanced MRI showed thickening and enhancement of the surface of brainstem, meninges on the surface of bilateral cerebellar hemispheres, whole spinal meninges and partial spinal dura mater, and cauda equina. The patient underwent exploratory resection of thoracic lesions and spinal canal reconstruction. Intraoperative findings showed semi - transparent gelatinoid hyperplasia between subarachnoid and soft meningeal, which blocked the subarachnoid cavity. Histological findings showed low-to moderate-density monomorphic oligdendroglial-like tumor cells with diffusely growth or in small nests in the leptomeninges. Mitotic activity and necrosis were not found. Immunohistochemical staining showed oligdendroglial-like tumor cells expressed oligodendrocytes transcription factor-2 (Olig-2) in nuclei, synaptophysin (Syn), microtubule - associated protein - 2 (MAP - 2) and S - 100 protein (S -100) in cytoplasm. Ki-67 labeling index was 4%-10%. Fluorescence in situ hybridization (FISH) analysis revealed deletion of 1p, whereas 19q was intact. The final diagnosis was DLGNT. The patient was hospitalized for 22 d and died 3 months after discharge. Conclusions DLGNT is a group of primary brain neoplasm of recent acquisition in the 2016 World Health Organization (WHO) classification of central nervous system tumors and does not yet assign a distinct WHO grade to the entity. At present, DLGNT has not been reported in China. DLGNT is very rare and always confused with other central nervous system tumors and inflammatory lesions. Therefore, histological morphology, immunohistochemistry and characteristics of molecular genetics are very important for diagnosis.

DOI: 10.3969/j.issn.1672-6731.2018.07.010