Elsevier

Pediatric Neurology

Volume 86, September 2018, Pages 63-65
Pediatric Neurology

Short communication
Spinal Cord Hyperintensities in Neurofibromatosis Type 1: Are They the Cord Equivalent of Unidentified Bright Objects in the Brain?

https://doi.org/10.1016/j.pediatrneurol.2018.07.005Get rights and content

ABSTRACT

Background

Focal areas of T2 hyperintensity are seen on magnetic resonance imaging (MRI) in patients with neurofibromatosis type 1 (NF1). These lesions are commonly known as "unidentified bright objects" of the brain. We have seen similar lesions in the spinal cord of the same patient population. Our aim was to determine the prevalence and characterize the imaging features of these T2 hyperintense spinal cord lesions in children with NF1.

Methods

A search of our hospital's medical imaging database yielded all children with NF1 and MRI of the brain and/or spine between February 2014 and April 2017. Medical imaging was reviewed for T2 hyperintense signal changes and medical records were reviewed of those children with T2 hyperintense spinal cord lesions.

Results

During the study period 155 children underwent a brain MRI and 72 had a spine MRI. One hundred twenty-three (79%) showed multiple cerebral T2 hyperintense lesions and six (8%) had non-contrast enhancing spinal cord T2 hyperintensities with five children having had a follow-up scan. The one child without follow-up imaging was not further pursued. Interval scanning showed stable appearance of the spinal cord lesions in four children and signal reduction in one child. All five children with T2 hyperintense changes in the spinal cord had an MRI brain and all (100%) also exhibited cerebral T2 hyperintensities.

Conclusions

Focal areas of signal hyperintensity in the spinal cord are the corollary of the better described cerebral T2 hyperintensities in individuals with NF1.

Introduction

Neurofibromatosis type 1 (NF1) is one of the most common inherited neurocutaneous disorders, affecting about 1 in 3000 children.1 The diagnosis of NF1 is based on defined criteria with the patient having two or more distinctive clinical features including cafė-au-lait macules, axillary and/or inguinal freckling, optic pathway gliomas, Lisch nodules, neurofibromas, unique osseous lesions, and a first degree relative with NF1.2 In a majority of patients with NF1, focal areas of T2 hyperintensity are seen on their brain magnetic resonance imaging (MRI).3 These are commonly known as “unidentified bright objects” (UBOs) and are of uncertain etiology. In our neurofibromatosis clinic we have seen children with NF1 and focal T2 hyperintense spinal cord lesions. An association of NF1 with spinal cord hyperintensities has only recently been suggested. We describe seven patients with NF1 and medullary UBOs.4 Prevalence data have not previously been reported.

Section snippets

Objective

The goals of this study were to (a) determine the prevalence of T2 hyperintense spinal cord lesions in children with NF1 who have undergone spine MRI, (b) describe the imaging appearance of these lesions, and (c) determine if the lesions are static on follow-up imaging which would make them more likely to be the cord equivalent of UBOs rather than low-grade gliomas. This study will help management of patients with NF1 by informing prognosis and the need for follow-up imaging.

Method

We performed an electronic search of our hospital's medical imaging database using Boolean operators and combinations of keywords “neurofibromatosis 1”, “MRI brain”, and “MRI spine” to search medical imaging records of patients with NF1 younger than 18 years of age at the time of imaging performed between February 2014 and April 2017. MRI spines were performed on a 1.5 Tesla Siemens MRI machine with a standardized protocol including multiplanar T1- and T2-weighted sequences. All imaging was

Results

During the study period, 292 children with NF1 were reviewed in the neurofibromatosis clinic. One hundred and fifty-five (53%) children underwent a brain MRI and 72 (25%) underwent a spine MRI. One hundred and twenty-three (79%) showed multiple T2 hyperintense lesions on the brain MRI. We identified six (8%) patients with T2-weighted hyperintensities in the spinal cord. Five children had follow-up imaging. One child did not have a follow-up scan and therefore was not further described. All five

Discussion

In this retrospective study we identified five children with stable focal areas of spinal cord T2 signal hyperintensity. There is only one recently published case series which describes medullary UBOs in patients with NF1.4 Symptoms or signs referable to the lesions were not described, and no child showed progression on follow-up imaging. Only a small percentage of children with NF1 underwent a spine MRI during the study period. In comparison, focal T2 hyperintense lesions in the brain MRI

Conclusions

We suggest that focal areas of T2 signal hyperintensity seen in the spinal cord of children with NF1 represent myelin vacuolization similar to the better described benign focal areas of T2 signal hyperintensity in the brain of the same patient population. Although we are confident that these lesions are benign, given the novel nature of this entity, a short period of interval scanning is recommended until the natural histories of a greater number of cases are described.

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Cited by (4)

Declarations of interest: The authors declare no conflict of interest.

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