Chou F.CHIH-YUAN WANG2020-06-012020-06-0120181016-7390https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058234951&doi=10.6314%2fJIMT.201810-29%285%29.06&partnerID=40&md5=72d399e9256a7a395c7abe55f19957b6https://scholars.lib.ntu.edu.tw/handle/123456789/496308Differentiating the neck mass between carotid body paraganglioma and recurrent papillary thyroid carcinoma is occasionally difficult. Methods: We report a 66-year-old woman with previous history of papillary thyroid carcinoma, and a 3-cm-sized, non-tender, rapid-growing mass was found over right submandibular region two years later. Recurrent thyroid cancer was suspected initially. Results: Repeated cytology investigations showed metastatic carcinoma. Neck magnetic resonance imaging (MRI) and biopsy finally revealed paraganglioma over carotid bifurcation. Conclusion: Carotid body tumors is highly related with neck paraganglioma, but difficultly indistinguishable from thyroid lesions or metastatic lymphadenopathy. Biopsy is better diagnostic choice than cytology. It might have related with germline mutations. Surgical removal is first-line treatment, and radiotherapy are suggested if unresectable. ? 2018 Society of Internal Medicine of Taiwan. All rights reserved.Carotid body tumor; Chemodectoma; Neck mass; Papillary thyroid carcinoma; Paraganglioma[SDGs]SDG3cisplatin; fluorodeoxyglucose; levothyroxine; thyroglobulin; thyroglobulin antibody; aged; Article; aspiration cytology; cancer radiotherapy; cancer size; cancer staging; carotid body tumor; case report; chemodectoma; clinical article; contrast enhancement; echography; female; human; human tissue; ionizing radiation; nodular goiter; nuclear magnetic resonance imaging; positron emission tomography; surgical risk; thyroglobulin blood level; thyroid papillary carcinoma; thyroidectomy; tumor biopsy; x-ray computed tomographyjournal article10.6314/JIMT.201810-29(5).062-s2.0-85058234951