Background: The incidence of cancer in thyroglossal duct cysts (TDC) is low and management is controversial. The objective was to report the rate of multifocality, lymph node metastases, and long-term results for TDC carcinomas in adults.
Materials and methods: Files from 1979 to 2008 were reviewed for tumor stage, multifocality in the lobes, lymph node metastases, treatment, and follow-up.
Results: A total of 18 patients (13 females, 5 males, average age 41.5 years) were treated for papillary carcinoma arising in a TDC. Of these, 15 underwent total thyroidectomy, 1 isthmusectomy and 2 a Sistrunk procedure only. Also, 16 patients underwent neck dissection of the central and/or lateral compartments. Tumors were staged pT1 (n = 15), pT3 (n = 3), pN0 (n = 4), pN1a (n = 3), pN1b (n = 9), Nx (n = 2), M0 (n = 17), and M1 (n = 1, lung metastases). Tumor foci were found in the thyroid lobes in 9 of 16 patients(56%). Lymph node metastases were found in 12 of 16 (75%). Nodes were positive in 6 of 15 central compartment dissections (40%) and in 9 of 15 lateral neck dissections (60%). Metastases to the lateral compartment, with no central compartment metastasis, were found in 6 of 15 patients (40%). Radioiodine was administered to 12 patients. Median follow-up was 12 years (range 1-22 years). All had negative ultrasound. Stimulated Tg levels available for 11 patients were undetectable for 10 and 2 ng/mL for the remaining patient.
Conclusions: This series shows a high rate of thyroid lobe foci and lymph node metastases but an excellent long-term outcome, characteristics shared with classic papillary carcinoma. Lateral neck metastases seem to be more frequent. These findings are in favor of following the current guidelines for differentiated thyroid cancer in general for the treatment of these rare tumors.