[Autoimmune thyroiditis and thyroid cancer]

Association between autoimmune thyroiditis (CLT) and thyroid cancer remains not clear. Although both diseases often occur simultaneously in histological samples, it is not yet clear whether CLT can be regarded as a risk factor for thyroid malignancy. This review focus on the known epidemiological and molecular genetics links between both diseases. Most studies have shown a significant association between thyroid cancer and positive antibodies to thyroglobulin and histological evidence of CLT, as well. Both disorders share some risk factors (greater incidence in women, in areas with adequate supply of iodine and in patients after radiotherapy of the neck) and molecular genetics linkage. For example: RET/PTC rearrangements could be more often found in carcinomas associated with CLT, but this mutation could be found in benign lesions such as CLT, as well. CLT seems to be a positive prognostic factor in patients with differentiated thyroid cancer. It is associated with less invasive forms of tumor, lower occurrence of infiltrated lymphatic nodes and a lower risk of recurrence.