Adult Thyroglossal Duct Carcinoma of Thyroid Epithelial Origin: A Retrospective Observational Study.

Thyroglossal duct or cyst carcinoma (TGDCCa) is uncommon. Current treatments follow those of thyroid cancer but controversy exists over the extent of thyroid and lymph node surgery. Our aim was to study the presentation, treatment strategies and clinical outcomes in patients presenting with TGDCCa. Of 637 patients diagnosed with thyroid cancer over 15-years, 4 patients (0.6 %) with TGDCCa were identified. Two patients were diagnosed outside this time period. Details of demographics, presentation, diagnosis, management and outcomes of all 6 patients were reviewed. 5 females and 1 male with a median (range) age of 41 (21-70) years were treated for TGDCCa. Five patients were diagnosed after initial surgery for thyroglossal cyst-cyst excision (n = 2) and Sistrunk's procedure (n = 3). This was followed by a total thyroidectomy (TT) in 4 of these patients. One patient underwent Sistrunk's operation, total thyroidectomy and central neck dissection at the first operation. I131 therapy was used in patients who had TT. Three patients had additional tumour foci in the thyroid. However, lymph node recurrence occurred in 2 patients at 6 and 16 months. At a median follow up of 55 months, all 6 patients were disease free. All patients had papillary TGDCCa and did well with conventional treatment as for thyroid cancer. The extent of treatment required is debatable as half the patients had additional thyroid foci and no patient had clinically or radiologically involved lymph nodes at presentation. A systematic review of published cases will help summarise the existing knowledge base.