Footnotes

• Contributors CL is the main author. XL contributed to the final diagnosis and approved the final draft of the manuscript. JF and QM edited the article prior to submission. Images were contributed by JY and ZC. YJ and QF are the consultant clinicians responsible for the care of this patient and provided the details of the clinical history.

• Competing interests None declared.

• Patient consent Parental/guardian consent obtained.

• Ethics approval Beijing Children’s Hospital Ethics Committee.

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