Cerebellar radiological abnormalities in children with neurofibromatosis type 1: part 1 - clinical and neuroimaging findings

Michael S Salman,Shakhawat Hossain,Katya Rozovsky,Martin Bunge,Lina Alqublan

doi:10.1186/s40673-018-0093-y

Abstract

BackgroundMany children with neurofibromatosis type 1 (NF1) have focal abnormal signal intensities (FASI) on brain MRI, whose full clinical impact and natural history have not been studied systematically. Our aims are to describe the clinical and neuroradiological features in children with NF1 and cerebellar FASI, and report on the natural history of FASI that display atypical features such as enhancement and mass effect.MethodA retrospective review of the hospital charts and brain MRIs was performed on children from Manitoba diagnosed between 1999 and 2008 with NF1, who also had cerebellar FASI on MRI.ResultsFifty patients (mean age: 16.1y, minimum-maximum: 6.4 - 30y, 27 M) were identified. Mean duration of follow up was 10.1y. Developmental delay, learning disabilities, tumors, and visual signs occurred commonly. Cerebellar signs were not reported. Mean age of the patients at baseline MRI was 7.8 (SD: 4.5) years. FASI occurred in several brain locations and were rarely confined to the cerebellum. FASI displayed mass effect and enhancement infrequently but were associated with malignancy only once. The number of FASI at baseline MRI was significantly less in patients with attention deficient hyperactivity disorder and more if a first degree relative had NF1 or if they had decreased visual acuity.DiscussionPatients with NF1 and cerebellar FASI do not have motor or consistent non-motor (e.g. developmental delay or learning disabilities) cerebellar features. The number of FASI may correlate with some clinical features. FASI may display enhancement and mass effect but they rarely become malignant.

Highlights

Many children with neurofibromatosis type 1 (NF1) have focal abnormal signal intensities (FASI) on brain MRI, whose full clinical impact and natural history have not been studied systematically
Electronic MRI neuroimaging reports stored in the radiology information system at our Health Sciences Centre (HSC) for the 10-year period starting January 1, 1999 were read and flagged for the occurrence of posterior fossa abnormalities
Patients with NF1 who had cerebellar radiological abnormalities mentioned on any brain MRI report when they were less than 17 years old between 1999 and 2008, were selected

Summary

Introduction

Many children with neurofibromatosis type 1 (NF1) have focal abnormal signal intensities (FASI) on brain MRI, whose full clinical impact and natural history have not been studied systematically. Diagnosis requires the presence of at least two of seven major criteria: six café-au-lait spots, axillary or inguinal freckling, two neurofibromas or one plexiform neurofibroma, two Lisch nodules, an optic glioma, a distinctive osseous lesion, or a first-degree relative with NF1. The most common intracranial neoplasms in patients with NF1 are optic pathways gliomas followed by low-grade astrocytomas of the posterior fossa [5,6,7]. These tumors are usually less aggressive than comparable lesions in children without NF1 [6, 7]. Screening for these tumors in asymptomatic individuals is controversial [5, 7]

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