Thyroid cancer is cancer of the thyroid gland. There are four forms: papillary, follicular, medullary and anaplastic. The most common forms (papillary and follicular) are fairly benign, and the medullary form also has a good prognosis; the anaplastic form is fast-growing and poorly responsive to therapy.
Masses of the thyroid are diagnosed by fine needle aspiration (FNA) or frequently by thyroidectomy (surgical removal and subsequent pathological examination). As the thyroid concentrates iodine, radioactive iodine is a commonly used modality in thyroid carcinomas.
Thyroid cancers can be classified according to their pathological characteristics. The following variants can be distinguished: Papillary thyroid cancer (75%, incl. mixed papillary/follicular), Follicular thyroid cancer (16%), Medullary thyroid cancer (5%), Anaplastic thyroid cancer (3%), Lymphoma (1%), Squamous cell carcinoma, sarcoma (0.5 - 2%).
Unlike its counterparts, anaplastic thyroid cancer is not curable by surgery, and is in fact usually unresectable due to its high propensity for invading surrounding tissues. Treatment consists of radiation therapy usually combined with chemotherapy.