RESUMO
Familial nonmedullary thyroid carcinoma means to two or more first-degree relatives of the family with NMTC,in the absence of other known family syndromes (such as Gardner's syndrome,Cowden disease,Carney complex,Werner syndrome,and so on),and common thyroid cancer risk factors including the neck radiation and iodine deficiency,and so on.The genes involved in the pathogenesis of familial nonmedullary thyroid carcinoma (FNMTC) are yet to be elucidated,although some recent studies identified several predisposition loci with a high degree of genetic heterogeneity.Several studies demonstrated that patients with FNMTC have increased rates of multifocal disease,extrathyroidal invasion,and involved lymph nodes compared with sporadic disease.It has been hypothesized that this increased aggressiveness translates into higher recurrence rates and decreased survival of patients with FNMTC.