1. Department of Otorhinolaryngology, Yonsei Head & Neck Cancer Center, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Surgery, Yonsei Head & Neck Cancer Center, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Pathology, Thyroid Cancer Center, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.