What is anaplastic thyroid carcinoma?

Updated: May 14, 2020
  • Author: Pramod K Sharma, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Anaplastic thyroid carcinoma is one of the least common thyroid carcinomas, accounting for 1.6% of all thyroid cancers. However, it has the most aggressive biologic behavior of all thyroid malignancies and one of the worst survival rates of all malignancies in general. Like papillary and follicular carcinomas, anaplastic thyroid carcinomas affect more women than men, with a female-to-male ratio of about 2-3:1. Patients with anaplastic thyroid carcinomas present later than those with other thyroid malignancies; the former most typically present in the sixth or seventh decade of life. [27]

Anaplastic thyroid carcinoma manifests as a rapidly growing thyroid mass in contrast to well-differentiated carcinomas, which are comparatively slow growing. Patients commonly present with associated symptoms due to local invasion. Hoarseness and dyspnea resulting from the involvement of the recurrent laryngeal nerve and airway occur in as many as 50% of patients.

Physical examination reveals a firm thyroid mass or masses that are most often larger than 5 cm at presentation. About 30% of patients have vocal cord paralysis, and cervical metastases are palpable on examination in 40% of patients. At least one half of patients already have distant metastases at the time of diagnosis. The most common sites of involvement are the lungs, bones, and brain.

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