Thyroglossal Duct Cyst Carcinoma With Synchronous Thyroid Papillary Carcinoma: A Case Report and Literature Review

Thyroglossal duct cysts (TGDC) are one of the most common congenital anomalies in the neck. Malignant transformation of these cysts is rare and synchronous involvement of the thyroid gland is even rarer. We report a case of synchronous occurrence of carcinoma in the thyroglossal duct cyst and thyroid gland and review the relevant literature. A 24-year-old woman who presented with a midline cervical mass, clinical examination, and complementary study was suggestive of a thyroglossal cyst with papillary carcinoma on fine-needle aspiration biopsy (FNAB) synchronous with thyroid papillary carcinoma with no cervical ganglion metastases documentation. Sistrunk's procedure plus total thyroidectomy was performed. With the clinical resemblance of benign and malignant cysts and the limitations of imaging techniques to distinguish between them, FNAB might be of use. Surgical treatment is warranted for the treatment of thyroglossal duct cyst carcinoma, but controversy still exists as to the extent of the surgical intervention. Sistrunk's procedure seems to be considered the gold standard when there is no evidence of thyroid involvement. However, in the presence of concomitant thyroid carcinoma, total thyroidectomy and cervical lymphadenectomy for evident node metastases are required. In the case of synchronous thyroglossal and thyroid carcinoma, most authors recommend pursuing both radioiodine therapy and hormone ablation. Thyroglossal duct cyst carcinoma is an uncommon feature that can arise from clusters of thyroid cells found within the cyst as in the present case. When confronted with this diagnosis it is fundamental to take into consideration the possibility of synchronous lesions as well as the extent of local and distance disease, since it has a direct influence on the choice of treatment provided to the patient. As there was a synchronous presence of papillary carcinoma in both the thyroglossal cyst and the thyroid gland, both the Sistrunk procedure and total thyroidectomy were performed, and radioiodine therapy was pursued as well as hormone ablation.