Papillary thyroid carcinoma of thyroglossal duct cyst: A retrospective analysis

Background: The incidence of thyroglossal duct cyst (TDC) carcinoma is uncommon (approximately 1%) and rarely reported in the literature. Treatment modalities have included tumourectomy, Sistrunk's procedure and/or total thyroidectomy. Aim: To try and determine the most adequate surgical approach for papillary thyroid carcinoma (PTC) arising in TDC. Results: We reviewed the clinical charts of 22 patients with PTC of TDC treated between January 1974 and December 2008 (0.63% of the total of 3458 patients with PTC treated over that period). All patients underwent the Sistrunk's procedure. Fourteen (64%) were submitted to total thyroidectomy and 11 of these patients were ablated with Iodinel31. Seven (50%) of the 14 patients treated with total thyroidectomy had tumour both in the thyroid gland and in TDC but lymph node metastases were present only in four. None of the patients died of the disease and all of them are still alive without recurrence with a mean follow-up of 8 years (range: 2-27 years). The mean survival rate of the patients submitted to total thyroidectomy (n= 14) was not statistically different from that of patients treated with the Sistrunk's procedure alone (9.23 ±7.65 vs. 8.95 ±6.22, p= 0.940). Conclusion: Papillary thyroid carcinoma arising in thyroglossal duct cysts is a very rare malignant tumour. In spite of the multifocal character of several of our cases, their analysis showed that the prognosis in the vast majority of patients with TDC carcinoma is excellent. Moreover, we found no relation between outcome and surgical procedure.