endocrine and metabolic disorders
Thyroid Cancers
Introduction
There are 4 general types of thyroid cancer. Most thyroid cancers manifest as asymptomatic nodules. Rarely, lymph node, lung, or bone metastases cause the presenting symptoms of small thyroid cancers. Diagnosis is often by fine-needle aspiration biopsy but may involve other tests. Treatment is surgical removal, usually followed by ablation of residual tissue with radioactive iodine. (See also Overview of Thyroid Function .) There are 4 general types of thyroid cancer: papillary, follicular, medullary, and anaplastic. Most thyroid cancers are papillary or follicular carcinomas and usually are not highly malignant and are seldom fatal. In contrast, anaplastic carcinoma is quite aggressive and has a poor prognosis, while patients with metastatic medullary carcinoma may live for many years but generally succumb to their cancer. Papillary and follicular carcinoma together are called differentiated thyroid cancer because of their histologic resemblance to normal thyroid tissue and because differentiated function (eg, thyroglobulin secretion) is preserved. Most thyroid cancers manifest as asymptomatic nodules. Rarely, lymph node, lung, or bone metastases cause the presenting symptoms of small thyroid cancers. Diagnosis is often by fine-needle aspiration biopsy but may involve other tests. Treatment of well-differentiated thyroid cancers is surgical removal for lesions>1.5 cm, often followed by ablation of residual tissue with radioactive iodine. Smaller lesions are treated with surgery or active surveillance. 