Footnotes

• Contributors YK reviewed the chart, composed the first draft of the manuscript and revised the manuscript. VK reviewed the chart, obtained the radiographic and endoscopic images, and critically revised the manuscript. DL reviewed the chart, confirmed the histological diagnosis, critically revised the manuscript and supervised 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.

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