Journal List > Int J Thyroidol > v.8(2) > 1082730

Int J Thyroidol. 2015 Nov;8(2):226-229. Korean.
Published online November 30, 2015.
Copyright © 2015. the Korean Thyroid Association. All rights reserved.
A Case of Primary Papillary Thyroid Cancer That Caused Vocal Cord Palsy Arising from Thyroid Rest
Mi-Sun Na, Yong-Joo Lee, Gi-Beom Ko and Jung-Hae Cho
Department of Otolaryngology Head and Neck Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.

Correspondence: Jung-Hae Cho, MD, PhD, Department of Otolaryngology - Head & Neck Surgery, St. Vincent Hospital, The Catholic University of Korea, 93-6 Ji-dong, Paldal-gu, Suwon 16247, Korea. Tel: 82-31-249-8306, Fax: 82-31-253-3752, Email:
Received July 17, 2015; Revised September 07, 2015; Accepted October 21, 2015.

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


Thyroid rest is isolated deposit of normal thyroid tissue arising in the thyrothymic tract below the lower pole of thyroid gland. Malignant transformation of thyroid rest is very rare. We report an extremely rare case of papillary carcinoma arising from thyroid rest in a 56-year-old male. He presented with hoarseness due to vocal cord palsy. Paratracheal mass in the upper mediastinum was identified by the cause of vocal cord palsy on CT. During surgery, we identified that the mass invaded recurrent laryngeal nerve but had no connection to thyroid gland. Histopathologic examination revealed that the mass was primary papillary thyroid carcinoma and there was no evidence of malignancy in thyroid gland. The post-therapeutic I-131 whole body scan detected several focal hot uptake in lung and mediastinum, suggesting distant metastasis. We should have knowledge of developmental variations of thyroid gland such as thyroid rest and its malignant transformation.

Keywords: Thyroid rest; Vocal cord palsy; Thyroid cancer


Fig. 1
Preoperative imaging studies. (A) Axial CT scan showing an about 1.5-cm-sized well defined mass with peripheral enhancement in left upper paratracheal area (arrow). (B) Coronal CT scan showing well-encapsulated mass separated from main thyroid gland (arrow). (C) Ultrasonographic image showing about 1.2×1.5×1.4 cm sized hypoechoic mass in the left paratracheal area.
Click for larger image

Fig. 2
Post-therapeutic I-131 whole body scan. (A) Whole body scan with I-131 with 100 mCi at 2 days after administration showing multiple radioactive iodine uptakes at right hilar, left superior mediastinum and left supraclavicular region (arrows). (B) Whole body scan at 7 days after administration showing more intensive radioactive iodine uptake at the same region (arrows) compared with whole body scan at 2 days after administration.
Click for larger image

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