1. Department of Otolaryngology and Head & Neck Surgery, University Hospital Aintree, Longmoor Lane, Liverpool L9 7AL, UK
2. Department of Otolaryngology, Wythenshawe Hospital, University Hospital of South Manchester NHS Foundation Trust, Manchester M23 9LT, UK
3. Department of Pathology, Wythenshawe Hospital, University Hospital of South Manchester NHS Foundation Trust, Manchester M23 9LT, UK