ISSN: 2320-5407 Int. J. Adv. Res. 6(1), 1575-1580 1575 Journal Homepage: - www.journalijar.com Article DOI: 10.21474/IJAR01/6392 DOI URL: http://dx.doi.org/10.21474/IJAR01/6392 RESEARCH ARTICLE PAPILLARY CARCINOMA OF THYROGLOSSAL DUCT CYST: CASE REPORTS. Mohammed Bassam Ashi 1 , Saif Abdulghani Alghamdi 1 , Omar Abdulaziz Alshehri 1 , Abdulaziz Alqahtani 2 , Mohammed Alqarni 2 and Hatim Almaghrabi 2 . 1. College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs, Jeddah, Saudi Arabia. 2. King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Science, King Abdulaziz Medical City, National Guard Hospital, Jeddah, Saudi Arabia. …………………………………………………………………………………………………….... Manuscript Info Abstract ……………………. ……………………………………………………………… Manuscript History Received: 23 November 2017 Final Accepted: 25 December 2017 Published: January 2018 Thyroglossal duct cysts are most common etiology of midline neck mass in pediatric population representing around 70%. Although thyroglossal duct cysts are common, cases of thyroglossal duct cyst carcinoma are rare with an incidence of 1%. We presented two cases of female patients who presented to our hospital with asymptomatic neck masses developed gradually over years which were diagnosed with papillary carcinoma after Sistrunk’s procedure with total thyroidectomy. Both patients were followed up post-operatively with lab investigations and imaging with no signs of recurrence. Lack of such cases due to its rare entities especially in our region, necessitate more studies to establish clear guidelines for the management of thyroglossal duct cyst carcinoma. Copy Right, IJAR, 2018,. All rights reserved. …………………………………………………………………………………………………….... Introduction:- Thyroglossal duct cysts (TGDC) are the most common cause of neck mass in childhood, accounting for approximately 70% (1). They can originate anywhere in the neck, but most commonly occur in the midline beneath the hyoid bone, with a reported incidence of 7% (2). Roughly 1% of these develop into a carcinoma, with papillary being the most common histological subtype, representing about 92% of such cases (3, 4). One study reviewed all cases since 1915 and deduced that TGDC carcinomas have a prevalence of around 1% (5). They mostly present asymptomatically with a history of a neck mass present for many years, usually since childhood (6). However, a small number of cases have presented with pain and dysphagia. Here we report on two cases of TGDC carcinomas because of its extremely rare occurrence, and the minimal reporting in our country. Case Reports:- Case 1 A 45-year-old female patient had thyroglossal cyst for more than 10 years which was increasing in size recently with no dysphagia, shortness of breath, or hoarseness of voice. The patient complains of otalgia intermittently. On examination, a 2x2 hard mass was felt in the neck, which was firm, non-mobile and fixed to underlying tissue, with smooth borders and no associated skin changes. The mass moved with protrusion of the tongue. Thyroid function test was within normal limits. Corresponding Author:- Mohammed Bassam Ashi. Address:- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs, Jeddah,