Thymic lymphoid hyperplasia with Graves' disease in a 28-year-old female: a case report

Thymic lymphoid hyperplasia with Graves' disease (GD) is not uncommon in adults. Generally, cases are newly diagnosed with GD when they refer to the department of endocrinology in hospital, and an anterior mediastinal mass is found on a computed tomography scan by accident. Almost half of them receive thymectomy due to the concern about thymoma or thymic carcinoma. In the past literature, an enlarged thymus can gradually shrink after treatment of antithyroid drugs. In this paper, a 28-year-old woman presented to our hospital with a 11-month history of dizziness, left hand convulsion and paralysis, without chest pain, difficulty swallowing, dyspnea. Chest computed tomography revealed an anterior mediastinal mass without obvious nodules. However, in this case, the mass did not shrink obviously after regularly taking antithyroid drugs. In order to figure out the diagnosis of the mass, we performed a thoracoscopic thymic resection, and the pathologic result was thymic lymphoid hyperplasia. There is no thymus gland tissue left on a repeated CT scan four months later after surgery. In this report, we discuss the optimal therapeutic strategy for this rare case. In conclusion, if an anterior mediastinal mass in GD patients did not shrink obviously upon treatment of antithyroid drugs, minimally invasive surgery should be taken into consideration seriously to exclude the possibility of malignancy.