Artikel
Low-grade leptomeningeal glioneuronal tumors: A new entity?
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
Text
The radiological and pathological findings of four paediatric cases admitted to the University Hospital of Padua between 1990 and 2007 are reported. All cases presented with a brief history of progressively worsening neurological signs, such as ataxia, nausea and vomiting. MR imaging did not show the presence of a well defined intraparenchymal mass, whereas thickened and abnormally enhancing subarachnoid spaces of brain (particularly in the basal cisterns and interhemispheric fissure) and spine were observed in all cases. Furthermore, small cystic lesions widespread in the brain, mainly in the cerebellum, were always present. In two cases, a small intramedullary lesion was noted in the cervical spine during the follow-up. The main differential diagnosis included inflammatory/infective disorders and tumour lesions. A biopsy was performed in all cases and the histological findings revealed thickened fibrous meninges, diffusely infiltrated by a monotonous population of round cells with clear cytoplasm. No mitosis (proliferation index, as percentage of MIB1 positive cells, <1%), no necrosis or endothelial vascular proliferation was observed. The immunohistochemical profile of tumour cells included a positive reactivity for synaptophysin, and negative for glial fibrillary acidic protein (GFAP), neurofilaments and epithelial membrane antigen (EMA). The morphological and immunohistochemical findings strongly suggest a glioneuronal commitment of the tumours. All cases presented an indolent long-term follow-up. During this time, MR images showed progression of the enhancement in the subarachnoid spaces and an increased formation of intra-axial cysts. Only one child dead after 10 years from the first clinical presentation. We report the largest series of this rare and unusual neoplasm, and suggest the hypothesis of considering leptomeningeal glioneural tumor as a new pathological entity.