[Cancer arising in a cyst of the thyroglossal tract].

Two new cases of thyroglossal cyst carcinoma are reported. Such cancers concern rather young women. The diagnosis must be suspected whenever a thyroglossal cyst is associated with cervical adenopathies. The most performing investigation seems to be fine-needle aspiration guided by echography. The malignant diagnosis is made during surgery by frozen section of the lesion, confirmed by histology. Two type of cancer must be distinguished: squamous cell carcinoma and carcinoma of thyroid type. The management of squamous cell carcinoma includes a large resection. For thyroid type carcinomas, total thyroidectomy and bilateral neck dissection are to be considered. Because of up-to-date insufficiency following, it is difficult to make a prognosis.