Thymic hyperplasia in a patient with Grave's disease

Thymic hyperplasia (TH) is a common feature in Graves' disease (GD) and the relationship between GD and thymic changes is discussed [1,2]. However, in most cases, thymic enlargement is minimal. Recognizing the association between TH and GD, and existence of the benign course after treatment of the hyperthyroidism may be useful for avoiding unnecessary surgical procedure.We report a 46-year-old 40 × 30 × 50 mm, woman with GD and hyperthyroidism. She had an anterior mediastinal mass that was diagnosed as TH and disappeared after treatment of the hyperthyroid state.A 46 year-old-woman was referred to our hospital, because of weakness and hemopthaesia. Medical history, social history, and family history were non contributory, and the patient took no medications. Her physical examination was normal. The thyroid gland did not appear prominent. Results of routine laboratory studies were all normal. Thyroid function tests demonstrated as follows: free T4 to be 5.8 ng/dL (normal range, 1.0 to 1.8), and thyroid-stimulating hormone to be < 0.005 u IU/mL (normal range, 0.3 to 4.0). Comptud tomography scan of the chest revealed well-circumscribed soft tissue density mass, 30 mm in size, with a regular periphery in the anterior médiastinum.Thyroid-directed antibodies were negatives: anti-thyroglobulin antibody, and antimicrosomal antibody. TSH-receptor antibody were positive. Anti-acetylcholine receptor antibodies and prostigmine test were negatives.The diagnosis of Grave's disease associated to thymoma was made. She was treated with 30 mg per day of Benzylthiouracile (200 mg per day) for several weeks and became clinically euthyroid. Three months later surgery, the anterior mediastinal mass disappeared on a repeat computed tomographic scan of the chest.Thymic hyperplasia is a common and reversible feature in patients with GD and hyperthyroidism [1,2]. In most cases, thymic hypertrophy is minimal and unapparent. Therefore, radiologically detectable thymic enlargement as an anteri