|Patorn Piromchai, Teeraporn Ratanaanekchai, Pornthep Kasemsiri|
Anaplastic Thyroid Carcinoma; Thyroid; Cancer
Anaplastic thyroid carcinoma (ATC) is a poorly differentiated thyroid cancer. It cannot uptake iodine or synthesis thyroglobulin. The incidence is low; about 2% – 5% of thyroid cancer. The peak age incidence is 60 – 70 years and it is more common in females (55% – 77% of all patients). In recent years, the incidence has declined; however, it may be higher in areas of endemic goiter. ATC may occur with a coexisting carcinoma and may represent transformation of a well-differentiated thyroid cancer. Patients typically present with a rapidly growing anterior neck mass and aggressive symptoms. The most reliable tool in detecting thyroid malignancies is fine-needle aspiration cytology (FNAC). Sensitivity of FNAC for thyroid malignancy ranged from 61% to 97.7%. Fine-needle aspiration can diagnose ATC by the demonstration of spindled or giant cells, bizarre neoplastic cells that may be multinucleated, or atypical cells with high mitotic activity. A syncytial pattern is the predominant cellular pattern of anaplastic thyroid carcinoma. Other laboratory tests, including tumor markers (cytokeratin, vimentin, and carcinoembryogenic antigen) are helpful in diagnosis and follow-up of the patients. Multimodality therapy (surgery, external beam radiation, and chemotherapy) is the recommended treatment and it seems to have slightly improved outcomes. The prognosis is not as bad in younger patients with smaller tumors. The most common cause of death is lung metastasis. The mean survival time is less than 6 months from the time of diagnosis. The prompt diagnosis and aggressive treatment are essential modality to achieve optimal outcomes.