[Extrahepatic manifestations of hepatitis C virus: the thyroid disorders].

The prevalence of thyroid disorders has been studied in patients with chronic hepatitis C virus (HCV) infection by many studies. In general, thyroid dysfunction in chronic C hepatitis may include all forms of thyroid alterations, i.e. hypothyroidism and hyperthyroidism, Hashimoto's disease and isolated increases in antithyroid autoantibodies. The prevalence of various thyroid disorders and serum anti-thyroid autoantibodies is generally higher in chronic hepatitis type C than in hepatitis B or D or control series. The results of most studies in patients with hepatitis C confirm a higher prevalence of autoimmune thyroid involvement and hypothyroidism than in controls. More recently, some epidemiological studies have suggested a possible association between HCV and thyroid cancer. These last data need to be confirmed by other studies, but seem to be sufficient to suggest careful thyroid monitoring during the follow-up of patients with HCV infection.