[Multinodular goiters].

The incidence of multinodular goiters (MNG) differs according to the countries, and seems to be widely dependent of the iodine status. In France, the SU.VI.MAX study indicates that 4.75% of the active population is suffering from MNG, this incidence is increased with gender and age. The role of genetic factors is estimated as being around 80%. The remaining 20% are related to environmental factors, some of them being still unknown. Admit these external factors, the iodine deficiency is predominant and should be theoretically easy to avoid. Most of MNG develop on diffuse goiters and could be prevented when these underlying lesions are treated early by the administration of thyroid hormone alone or associated with iodide potassium. Once the nodularity of the thyroid tissue is present, the medical treatment is of weak efficacy, it usually stabilises the goiter and prevents the occurrence of new nodules. The two main treatments are surgery and radioactive iodine, the latter is currently used not only when the former is contra-indicated. In some countries, radioactive iodine is considered as the best alternative in the majority of cases.