Dysembryoplastic neuroepithelial tumour
The neuroectodermal tumor Dysembryoplastische (abbreviated DNET or DNT) is a rare benign brain tumor that was first described in 1988 by Daumas - Duport. These tumors occur mainly in children, adolescents and young adults and are manifested by epileptic seizures, some with years of history. The tumors are usually located superficially in the cerebrum, but there are also infratentorial locations ( cerebellum ) have been described. Apart from the difficult to treat epileptic seizures, but only occasionally and headaches they cause no other symptoms. The prognosis is favorable, why DNET are classified as grade I according to the WHO classification of tumors of the central nervous system.
- 4.1 Notes and references
Epidemiology
The incidence (frequency ) of DNET is difficult to estimate, since several reports from specialized centers with a focus on epilepsy treatment originate. It is estimated that approximately 1.2% of neuroepithelial tumors fulfill the criteria of DNET. Patients are usually young, most kids. In adults, the primary diagnosis of DNET is rare.
Diagnostics
Imaging
The imaging by magnetic resonance imaging (MRI, MRI) or computed tomography ( CT) shows lesions in the cerebral cortex. The lesions often extend over the entire thickness of the bark.
In CT you can see dense impaired ( hypodense ) well-demarcated cortex lesions. Cysts are often encountered calcifications rare. An accumulation of contrast agent is not typical. A space-occupying displacement of the surrounding tissue does not occur. Sometimes shows a deformation of the skull over the tumor.
On MRI, the lesions show well defined, not demanding space and without perifocal edema ( fluid intake in the surrounding brain parenchyma ). The multinodular configuration ( knot-like structures consisting of many ) is described as typical. Again, there are, in the majority of cases, no contrast enhancement.
Pathology
Grossly, the tumors are soft and gelatinous. The tumors can form multiple nodes in the cortex and occasionally extend into the medulla ( white matter ). The most affected area of the brain is the temporal lobe ( temporal lobe ), followed by the frontal lobes ( frontal lobe ) and less from the parietal lobe ( parietal lobe ).
Microscopically, the essential feature is a complex structure consisting of glial and neuronal elements ( glioneuronal elements ). The glial elements are strands of glial fibers and vessels. They define " mucus lakes ", in which there are largely mature neurons.
Differential Diagnosis
The main differential diagnoses of DNET are oligodendrogliomas and gangliogliomas.
Treatment and prognosis
Treatment consists of surgical removal of the tumor, which also seizure control can be achieved in general. Neuroectodermal tumors carry Dysembryoplastische probably no increased risk of malignant transformation, even if only partial removal they show no progredientes growth.
Swell
- WHO Classification of Tumours of the Central Nervous System. IARC Press Lyon, 2007.