Endocrine Abstracts

Introduction: Neoplasias in the thyroglossal duct cyst (TDC) are rare, their prevalence varies from 1 to 1.5%. The most common cancer is papillary cancer representing 85% of cases. The diagnosis is often fortuitous following to the anatomopathological examination of the surgical specimen.

Patient and method: Our patient has 33-years-old, with no previous medical history, which underwent a resection of a TDC of 29 mm in diameter, diagnosed by an anterior cervical tumefaction. The anatomopathological examination of the cyst was in favor of papillary carcinoma. The evolution is marked by the appearance of a left cervical adenopathy. The patient has benefited by a biopsy excision, and histology was in favor of a metastasis of a papillary carcinoma. Cervical ultrasound: normal, without cervical adenopathies. The patient had a total thyroidectomy whose anatomopathology returned without anomaly. The hormonal assessment showed an undetectable level of thyroglobulin (TG). (TSH: 30.24 Uu/ml, TG: 0.55 μg/l and anti-TG antibody: 1.2 IU/ml). Levothyroxine was increased to 150 μg/day. Iratherapy is considered for our patient.

Conclusion: The papillary cancer on TDC is an exceptional localization. It can develop at the expense of residues of thyroid follicles within the cyst of the TDC, or may be secondary to thyroid papillary carcinoma metastasis. Its management consists of an excision of the cyst. Hormone replacement therapy is systematic. Total thyroidectomy is indicated in cases of thyroid suspicious of malignancy, also if extra-cystic extension. Lymph node dissection is indicated in the presence of adenopathy. A complement by Iratherapy is not systematic, however in our patient it is indicated because the presence of a lymph node metastasis. The monitoring will be on long term and generally the evolution is favorable.