Clinical and Instrumental (Magnetic Resonance Imaging [MRI] and Multimodal Evoked Potentials) Follow-Up of Brain Lesions in Three Young Patients With Neurofibromatosis 1

Abstract

Diagnosis of neurofibromatosis 1 is based on clinical criteria. In a large number of children with neurofibromatosis 1, magnetic resonance imaging (MRI) reveals high-signal T(2)-weighted intensities in different brain regions, defined as unidentified bright objects. These lesions are asymptomatic; most of them regress spontaneously with age, but the presence of contrast enhancement or mass effect in them usually strongly suggests an increased risk of proliferative changes. To date, few studies have focused on evoked potentials in patients with neurofibromatosis 1, and the reported abnormalities did not have significant clinical correlations. We describe the clinical and instrumental (MRI and evoked potentials) follow-up of three patients with neurofibromatosis 1. MRI and evoked potentials showed subclinical involvement of the central nervous system. Some MRI T(2)-weighted hyperintensities showed enhancement and mass effect of uncertain significance. During follow-up, the MRI lesions spontaneously decreased in size or enhancement, allowing us to exclude the hypothesis of proliferative lesions; in the same way, some asymptomatic evoked potential abnormalities disappeared. These findings suggest that both MRI and evoked potentials could be useful in the detection and monitoring of cerebral complications of neurofibromatosis 1.

Regression of gadolinium-enhanced lesions in patients affected by neurofibromatosis type 1

“…Our cases and the few already reported [10][11][12][13] illustrate how also malignantlooking lesions may have unexpected positive evolution.…”

“…Less frequently, this evolution has been observed in extra-optic pathway tumors [7,8]. A benign evolution of gadolinium-enhancing lesions has been reported only in few cases so far [10][11][12][13]. In these rare cases, the lesions, which involved the brainstem [11] or the forebrain [10,12,13] showed a spontaneous regression during the follow-up without therapy administration or clinical changes.…”

“…However, they have been poorly studied and their disappearance has been described just in few scattered cases [10][11][12][13].…”

Correlation Between Unidentified Bright Objects on Brain Magnetic Resonance Imaging (MRI) and Cerebral Glucose Metabolism in Patients with Neurofibromatosis Type 1

“…3,4) Of the 31 patients with UBOs that were included in this study, 20 (65%) were younger than 18 years. Twenty (60%) of the 33 patients aged under 18 years had UBOs, whereas 11 (26%) of the 42 patients aged 18 years and above had a UBO.…”

“…3,4) The most commonly involved anatomic sites are the basal ganglia, cerebellum, midbrain, and the subcortical white matter. 4) However, UBOs are not always correlated with neurological symptoms, and are even present in patients without neurological symptoms. Pathologically, UBOs may represent increased fluid within myelin associated with hyperplastic or dysplastic glial proliferation.…”