A mass in the neck is a common clinical finding and differential diagnosis may be extremely broad. Although most masses are due to benign processes, malignant diseases must not be overlooked. Therefore, it is important to develop a systematic approach for the diagnosis and management of neck masses.
Benign thyroglossal duct cysts usually present as aysmptomatic, soft, firm, or hard masses in the midline of the anterior neck, and are nontender and generally movable. Malignant thyroglossal duct cysts present in the same manner. Carcinoma should be suspected in any thyroglossal duct cyst that is hard, fixed and irregular or which has undergone recent change. A history of irradiation of the head and neck or mediastinum during childhood or adolescence sholud also arouse suspicion of carcinoma [1
Malignant tumors developing from the thyroglossal duct have two origins: thyrogenic carcinoma arising from thyroembrionic remnants in the duct or a cyst, and squamous cell carcinoma arising from metaplastic columnar cells that line the duct [1
]. More then 200 cases of thyroglossal duct carcinomas have been reported in which papillary carcinoma accounts for 80% of cases, with the rest being squamous cell carcinoma [5
]. Only one case with both concomitant histologic findings has been reported [8
Excluding medullary carcinoma, which arises from parafollicular cells embryologically unrelated to the thyroid, all forms of primary thyroid carcinoma can arise in the thyroglossal duct [1
The main difficulty encountered with a cancer evolving from a thyroglossal duct cyst is that the diagnosis is usually made during surgery or from definitive pathological samples. Because the frequency of cancer of the thyroglossal duct cyst is very low, the clinician often does not consider an oncologic diagnosis. A second difficulty lies in terms of what approach should be taken during and after surgery when dealing with a preoperatively diagnosed thyroglossal cyst; that is, how extensive should the surgery be and what type of adjuvant therapy should be used [9
]? To be able to respond to these two issues, the procedure used for thyroglossal cyst surgery must be standarized.
When a thyroglossal duct cyst has been excised using Sistrunk's procedure and when the definitive hystological analysis reports malignancy, the thyroid gland must be studied with radiological and scintigraphic examinations and the extension of surgery must be handled according to the criteria established for differentiated thyroid cancer [9
]. In our case, we made a radical surgical method with total tyroidectomy and bilateral neck dissection due to findings on cervical CT.
The common surgical procedure used for a thyroglossal duct cyst is Sistrunk's procedure, consisting of excision of the thyroglossal duct cyst, the central portion of the body of the hyoid bone, and a core of tissue around the thyroglossal tract to open into the oral cavity at the foramen cecum[1
]. In case of malignancy, additional steps should consist of thyroidectomy, radioactive iodine and thyroid supression, as is the case for differentiated thyroid cancers.