Brain gliomas, hydrocephalus and idiopathic aqueduct stenosis in children with neurofibromatosis type 1.

PURPOSE: To evaluate the incidence and clinical importance of brain gliomas - optic pathway gliomas (OPGs) and especially gliomas outside the optic pathway (GOOP) for children with neurofibromatosis type 1 (NF1), additionally, to assess the causes of obstructive hydrocephalus in NF1 children with an emphasis on cases caused by idiopathic aqueduct stenosis. SUBJECTS AND METHODS: We analysed data from 285 NF1 children followed up on our department from 1990 to 2010 by the same examination battery. RESULTS: We have found OPGs in 77/285 (27%) children and GOOPs in 29/285 (10,2%) of NF1 children, of who 19 had OPG and GOOP together, so the total number of brain glioma was 87/285 (30,5%). GOOPs were significantly more often treated than OPGs (p > 0.01). OPGs contain clinically important subgroup of 14/285 (4.9%) spreading to hypothalamus. Spontaneous regression was documented in 4/285 (1.4%) gliomas and the same number of NF1 children died due to gliomas. Obstructive hydrocephalus was found in 22/285 (7.7%) patients and 14/22 cases were due to glioma. Idiopathic aqueduct stenosis caused hydrocephalus in 6/22 cases and was found in 2.1% of NF1 children. Two had other cause. CONCLUSIONS: The total brain glioma number (OPGs and only GOOPs together) better reflected the overall brain tumour risk for NF1 children. However, GOOPs occur less frequently than OPGs, they are more clinically relevant. The obstructive hydrocephalus was severe and featuring frequent complication, especially those with GOOP. Idiopathic aqueduct stenosis shows an unpredictable cause of hydrocephalus in comparison with glioma and is another reason for careful neurologic follow up.

[Neurofibromatosis von Recklinghausen type 1 (NF1) - clinical picture and molecular-genetics diagnostic]. / Neurofibromatosis von Recklinghausen typ 1 (NF1) - klinický obraz a molekulárne-genetická diagnostika.

Neurofibromatosis von Recklinghausen type 1 (NF1) is a multisystem, autosomal dominant hereditary neurocutaneous disease characterized by skin, central and peripheral nervous system , eyes , bone, endocrine, gastrointestinal and blood vessel wall involvement. It has an estimated frequency of 1 in 3000. Neurofibromatosis type 1 is caused by mutations in the large NF1 gene located on chromosome 17q11.2, encoding the cytoplasmic protein neurofibromin. It is expressed in multiple cell types but is highly expressed in Schwann cells, oligodendrocytes, neurons, astrocytes and leukocytes. Neurofibromin is known to act as a tumor suppressor via Ras-GTPase activation, which causes down-regulation of cellular signaling via the Ras/mitogen-activated protein kinase (MAPK) pathway. Failure of this function is associated with a tendency to form tumors which are histologically hamartomas as well as benign tumors. Tumors of the central nervous system include low-grade gliomas (pilocytic astrocytomas grade I), especially optic pathway gliomas. They are often clinically asymptomatic. Other intracranial tumors are in the brain stem and also elsewhere in the brain and spinal cord. Hydrocephalus may be a complication of NF1 gliomas or due to stenosis of the distal part of the aqueduct Silvii. Cutaneous and subcutaneous neurofibromas or plexiform neurofibromas are localized in the peripheral nervous system. Plexiform neurofibromas have a significant lifetime risk of malignancy. The clinical diagnosis of NF1 is defined by diagnostic criteria. The NF1 diagnosis is satisfied when at least two of the seven conditions are met. The method of direct DNA analysis of large NF1 gene (61 exons) is available. The results of studies of genotype - phenotype established few correlations. But predicting the disease by finding mutations is not currently possible. NF1 exhibits a wide range of variability of expression and complete penetrance, even within the same family. About half of cases are new mutations. The treatment of patients with neurofibromatosis is symptomatic. Central nervous system symptomatic low-grade gliomas are most often treated with chemotherapy. For plexiform neurofibromas surgical removal is currently the only treatment option.