This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thyroid, Subject name: Surgery
An 18 year old patient presents with neck swelling which moves with deglutition . What is your diagnosis? 
Select and explain. 
A. Dermoid cyst, B. Branchial cyst, C. Thyroglossal cyst, D. Cervical lymphadenopathy
C: Thyroglossal cyst
Answer: C: Thyroglossal cyst 
Explanation: Thyroglossal Cyst - Congenital - Age of presentation - 15-30 years - There is cyst in connection to thyroid and tongue. So, on protrusion of tongue, the cyst moves up - MC location - Subhyoid - Other common locations * Suprahyoid * Near thyroid cailage * Near Foramen cecum * In floor of mouth =Clinical features - Midline swelling in anterior pa of neck - Thyroglossal cyst moves with deglutination - Moves up on protrusion of tongue =Complications of Thyroglossal cyst - Infection - Abscess - if Incision and Drainage - Thyroglossal fistula (Acquired condition due to I & D of abscess of thyroglossal cyst) - Increased risk of papillary carcinoma of thyroid =Treatment - TOC - Sistrunk operation. The cyst passes body of hyoid bone - so excision is made - Enbloc removal of central pa of body of hyoid bone + cyst