Endocrine Abstracts

The prevalence of differentiated thyroid carcinoma (DTC) in lingual thyroid (LT) and thyroglossal duct cysts (TDC) is around 1%. Nowadays, almost 200 cases of DTC were reported in TDC and <60 cases in LT. Here we report four cases of neoplasia in LT (1/4) and TDC (3/4) in a consecutive series of 950 DTC patients (0.4%).

Case 1: D.F. 63 year-old woman with thyroid follicular carcinoma in ectopic gland located at her tongue’s basis. March 2009: the lesion, infiltrating surrounding tissues, presented insular-like areas (T3N1Mx). July 2009 and 2010: two radiometabolic treatment (cumulative dose of 224 mCi of ¹³1I) with no evidence of local/distant metastases and undetectable serum thyroglobulin (Tg), following the last radioiodine administration.

Case 2: B.B. 37 year-old woman with TDC. October 2001: exeresis of a thyroid papillary carcinoma (PC) in TDC infiltrating soft local tissues (T3NxMx). December 2001: Total thyroidectomy (tTx) with histologic finding of benign adenomatous goiter. 2002–2008: five radiometabolic treatment (cumulative dose of 500 mCi of ¹³1I) due to iodine uptaking lung metastases. September 2009: persistence of elevated Tg levels (56.1 ng/ml) following recombinant human TSH stimulation. Proposal of further radiometabolic treatments refused.

Case 3: B.S. 42 year-old man. November 2001: PC of thyroglossal duct infiltrating the surrounding fibro-adipose tissue with lymphatic and intravascular diffusion. March 2002: tTx with evidence of two foci of PC (T3bN0Mx). July 2002: 100 mCi of ¹³1I, Tg undetectable and WBS negative.

Case 4: D.B. 21 year-old woman with a PC follicular variant in TDC. July 2010: tTx with histologic evidence of benign macrofollicular goiter.

Conclusions: The higher prevalence of DTC (also in form of aggressive variants) in dysembrogenetic than in eutopic thyroid tissue (0.4 vs 0.004%) argues in favor of a close monitoring of all the dysembriogenetic thyroid lesions.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.