Endocrine Abstracts

Introduction: The thyroglossal duct develops during thyroid gland formation and usually involutes at 7–10 weeks gestation. Its residue can lead to formation of cysts as well as to develop neoplasms within the mass.

Case report: A 40-year-old woman was admitted to Department of Otolaryngology because of an enlarging midline neck mass for the last few months, without other worrisome symptoms. A neck ultrasound and CT scan showed a cystic lesion with solid components measuring 20 × 18 mm in size, located above the larynx. A Sistrunk procedure was performed. On histological postoperative examination, thyroid papillary microcarcinoma with microcalcifications in the cyst wall was revealed. The lesion did not infiltrate the capsule and it was completely resected. The patient was referred to Department of Endocrine Oncology for additional testing. Thyroid ultrasound showed 6 × 8 × 9 mm lesion in the left lobe. FNAB was performed and the diagnosis of benign nodule was made (Bethesda class II). As there were no demonstrable cancer or lymph node metastases, the decision of total thyroidectomy has not been made. Levothyroxine therapy has been started with doses adjusted to achieve thyrotropin levels of 0.4 to 1.0 mU/l and further check-up has been recommended. After two years follow-up, there is no progression of thyroid left lobe nodule but in ultrasound imaging an enlarged heterogenous (with calcifications and vascularization) lymph node (32 × 10 mm) next to the left mandible angle has been observed. The patient is currently being diagnosed to confirm or exclude lymph node metastases to decide of total thyroidectomy and neck dissection as well as postoperative radioactive iodine therapy.

Conclusions: Rare prevalence of thyroglossal duct cyst carcinoma, lack of typical features distinguishing benign and malignant lesions before surgery cause the proper diagnosis can be difficult and is usually made postoperatively. The extent of treatment is also not well agreed upon. Therefore, case reports and case series are needed to determine optimal management.