The 4 general types of thyroid cancer are papillary, follicular,
medullary, and anaplastic. 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.
Except for anaplastic and metastatic medullary carcinoma, most
thyroid cancers are not highly malignant and are seldom fatal.
Treatment is surgical removal, usually followed by ablation of
residual tissue with radioactive iodine. Papillary carcinoma
accounts for 70 to 80% of all thyroid cancers. The female:male
ratio is 3:1. It may be familial in up to 5% of patients. Most
patients present between ages 30 and 60. The tumor is often more
aggressive in elderly pa