Thyroid cancer is the most common malignant disease in endocrine system and is rapidly
increasing in incidence.
The increasing incidence partially reflects earlier detection of small asymptomatic
cancers because of prevalence of screening. However, the incidence has also increased
across all tumor sizes and stages. Most of thyroid cancers show biologically indolent
phenotype and have an excellent prognosis with survival rates of more than 95% at
20 years although the recurrence or persistent rate is still high. The incidence of
thyroid cancer is about three to four times higher among females than males worldwide,
ranking the sixth most common malignancy diagnosed in women.
Most primary thyroid cancers are epithelial tumours that originate from thyroid follicular
cells. These cancers develop three main pathological types of carcinomas: papillary
thyroid carcinoma (PTC), follicular thyroid carcinoma (FTC) and anaplastic thyroid
carcinoma (ATC).
Thyroid cancer can occur at any age but it is rare in childhood. Most tumors are
diagnosed during third to sixth decade of life. The general pathological classifications
and clinical features of follicular cell derived thyroid carcinomas are overviewed,
and recent advances of genetic alterations are discussed in this review.
