1. Department of Endocrine Surgery, Nippon Medical School Graduate School of Medicine, Tokyo, Japan.
2. Research Group for the Management of Papillary Thyroid Microcarcinoma, Japan Association of Endocrine Surgery & Japanese Society of Thyroid Surgery, Tokyo, Japan.
3. Department of Surgery, Kuma Hospital, Kobe, Japan.
4. Department of Surgery, National Hospital Organization, Higashinagoya National Hospital, Nagoya, Japan.
5. Department of Thyroid and Endocrinology, Fukushima Medical University School of Medicine, Fukushima, Japan.