Neurological complications involving the central nervous system in neurofibromatosis type 1

To investigate the neurological complications and characteristics of intracranial lesions in patients with neurofibromatosis type 1 (NF1) in Taiwan.

Neurofibromtosis type 1 is a common autosomal dominant disorder characterized by cafe au lait spots, peripheral neurofibromas, Lisch nodules, and axillary freckling. Intracranial lesions such as optic gliomas and neurofibromatosis bright objects (NBOs) are common.

Patients with the diagnosis of NF1 based on criteria from the National Institutes of Health Consensus Conference (1988) between Jan. 1, 1983 and Oct. 30, 2005 were retrospectively evaluated at the Chung-Gung Memorial Hospital (CGMH). Case histories were analyzed for neurological complications of epilepsy, stroke, and pituitary as well as other intracranial lesions. Magnetic resonance imaging (MRI) examinations were also focused on the number, distribution, and change of NBOs as well as intracranial pathology including optic pathway or brain gliomas.

The study population included 69 patients (28 females and 41 males) mean 25.1 +/- 15.0 years. Brain MRIs for 24 patients identified 1 meningioma, 1 optic glioma, and 4 other intracranial gliomas. In total, 14 patients had 52 NBOs. The most common anatomical sites for the NBOs were the globus pallidus and thalamus (15.4%), followed by the cerebellum and subcortical white matter (11.5%). The most commoly identified neurological complications were epilepsy (8.7%) and cerebral infarction (7.2%). These complications, however, were not correlated with intracranial lesions.

Neurofibromatosis bright objects are frequent neuroimaging findings in patients with NF1, and are at high risk of transforming into tumors. The incidences of epilepsy and young-onset cerebral infarction in NF1 patients in this study are higher than those in the general population. Neuroimaging studies are thus essential for NF1 patients to determine the extent of neurological complications; although the imaging findings may not be completely correlated with the clinical manifestations.