[Ectopic primitive thyroid papillary carcinoma: report of a fatal case and review of literature].

One percent of excised thyroglossal duct remnants exhibit histologic malignancy, a thyroid papillary carcinoma in 80% of the cases. The prognosis is excellent except for anaplastic types. We report the case of a 44-year-old woman with primitive thyroid papillary carcinoma diagnosed histologically as thyroglossal cyst. Its unusual aggressiveness produced local and regional spread, metastases and the patient's death in spite of treatment: Sistrunk operation, local excision of a recurrence and laryngothyroidectomy. Thyroid histology revealed the absence of carcinomatous foci. We discuss the most noteworthy aspects of the case in relation to other reports.