Footnotes

• Contributors SK collected data and wrote most of the first draft of the paper. ZJ and SB provided the histopathology images and description. All other authors provided detailed written edits and multiple further drafts of the case report for publication. All authors work fulfilled the following: substantial contributions to the conception or design of the work or the acquisition, analysis or interpretation of data; drafting the work or revising it critically for important intellectual content; gave final approval of the version published; agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

• Funding AR is funded by a Wellcome Trust Postdoctoral Fellowship for Clinicians (110043/Z/15/Z).

• Competing interests None declared.

• Patient consent Obtained.

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

  This paper was reviewed by Robert Hadden, London, UK.