1. Department of Otolaryngology–Head and Neck Surgery, Okayama University Academic Field of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
2. Department of Otorhinolaryngology–Head and Neck Surgery, Kagawa Rosai Hospital, Kagawa, Japan
3. Department of Internal Medicine, Kagawa Rosai Hospital, Kagawa, Japan
4. Department of Pathology, Kagawa Rosai Hospital, Kagawa, Japan