Anterior mediastinal mass and Graves' disease.

Radiological evidence of a mass in the anterior mediastinum may provide a difficult problem in diagnosis. Disorders of the thymus, particularly thymomas, are frequently the cause of such mass lesions. Although modest thymic enlargement occurs in many patients with Graves's disease,' rarely is the enlargement great enough to lead to a clinical diagnostic dilemma.2 We report here two patients with thyrotoxicosis, presumably due to Graves's disease, and an enlarged thymus gland. One patient underwent thoracotomy and removal of a considerably enlarged, histologically normal thymus. In the other patient an anterior mediastinal mass was detected by computed tomography during a search for metastatic disease. It disappeared when he became euthyroid after treatment with carbimazole.