Glioneuronal tumours in neurofibromatosis type 1: MRI-pathological study.

Neurofibromatosis type 1 (NF1) is an inherited disorder in which affected individuals develop both benign and malignant tumours at an increased frequency. Glioneuronal tumours, such as ganglioglioma and dysembryoplastic neuroepithelial tumour, have been previously reported in patients with NF1. We describe two patients with glioneuronal tumours and typical clinical features of NF1. Molecular analysis of these tumours did not demonstrate loss of the NF1 gene by fluorescence in situ hybridization (FISH) or immunohistochemistry analysis, suggesting they might not be causally associated with gross defects in NF1 expression. Because of the excellent prognosis following the resection of these tumours, it is important to distinguish them from other NF1-associated tumours.