[Thymic hyperplasia and Graves' disease: a non-fortuitous association. case report and review of literature].

Thymus hyperplasia and Graves' disease association is not well known and is probably not incidental. We report the case of a young woman affected with Graves' disease in which a retrosternal mass was disclosed during a neck ultrasonographic-examination and confirmed by chest CT-examination. Follow-up ultrasound survey showed a decrease in the thymic mass size. Because of various antithyroid drugs allergy, a surgical procedure was performed, during which both her thyroid and thymic mass were removed. The histopathologic examination of this mass confirmed the hyperplasic nature of the thymic bulging. Ninety-one cases of thymus hyperplasia and Graves' disease association have been reported in literature, of which 20 were histologically confirmed. Among these cases 35 showed a thymic mass regression under medical treatment alone. Accordingly, surgical procedures are most frequently unnecessary in such associations because of the thymic mass decrease incurred by antithyroid drug treatment.