Footnotes

• Contributors EA, specialist registrar, reviewed the literature and wrote the manuscript. CL reported on the MRI scan and selected the appropriate image, and reviewed manuscript. EMcC made the diagnosis, obtained consent from the parent, and reviewed the literature and the manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Patient consent for publication Parental/guardian consent obtained.

• Provenance and peer review Not commissioned; externally peer reviewed.