SAT500 Thyroglossal Duct Cyst Cancer: Diagnosis And Management

Disclosure: A.P. Solis Pazmiño: None. C. Rocha: None. L. Figueroa: None. C. Garcia: None. Background: Thyroglossal duct remnants form during the embryologic development of the thyroid gland. In rare cases, with an incidence of about 1%, carcinoma is present within these cysts, most commonly papillary thyroid carcinoma. Sistrunk procedure (SP) is the main treatment and optimal patient management includes multidisciplinary consultation in order to improve survival. However, there is a debate about whether SP is enough if there is a malignancy in the thyroid or if total thyroidectomy should be done on patients 45 years of age and individuals with aggressive disease [1]. TGDCC harbors an excellent prognosis and low recurrence rate. Clinical Case: We present a case of an elderly woman with a large submental mass that had been gradually enlarging for about 2 years. She had symptoms of dysphagia but denied odynophagia, hoarseness, or shortness of breath. Our patient had high blood pressure and a penicillin allergy but was otherwise healthy without a family history of carcinoma. Physical examination revealed a large submental mass (4.5x4x3.5 cm) that was hard and with smooth edges and did not move with deglutition. There was no extension into the oral cavity on bimanual palpation or palpable masses/nodules in the cervical region. There was a thyroid gland enlargement (right lobe 5x3x1.5, left lobe 4.5x2x1.2 cm). The ultrasound showed enlarged cervical lymph nodes. Fine needle aspiration (PAAF) suggested metastasis of thyroid cancer. Clinical lesson: Although Sistrunk surgery is accepted, performing a total thyroidectomy for TGDCC is controversial. Evidence suggests that it should be reserved for patients older than 45 years, like the patient described in this case. Total thyroidectomy is preferably performed based on the FNAB result (high-risk malignant) or if both thyroid lobes do not consist of healthy tissue anymore, regarding postoperative complication. Since TGDCC is a rare malignancy, a broad differential diagnosis should be considered: metastasis from an unknown primary, paraganglioma, hyalinizing trabecular tumor, and thyroglossal duct cyst, among others. The clinicopathological correlation, as well as the use of the FNA and the immunohistochemical markers, improve the diagnosis accuracy and help to decide the best treatment for the patient. Presentation Date: Saturday, June 17, 2023