1. Department of Otolaryngology, Japanese Red Cross Society Himeji Hospital, Himeji, Japan;
2. Department of Otolaryngology – Head and Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan;
3. Department of Otolaryngology – Head and Neck Surgery, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan;
4. Department of Otolaryngology, Nakada ENT Clinic, Himeji, Japan;
5. Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan