Graves' Disease after Adrenalectomy for Cushing's Syndrome

A 44-year-old woman presented with a 3-month history of back pain, gait disturbance, and insomnia. She had moon face and central obesity but no goiter. Cushing's syndrome due to left adrenal adenoma was diagnosed. She also had low triiodothyronine syndrome and central hypothyroidism. Treatment involved adrenalectomy followed by 30 mg/day of hydrocortisone. Inappropriate secretion of thyroid-stimulating hormone occurred postoperatively. She developed Graves' disease nine months postoperatively and was treated with methimazole. Excess glucocorticoids followed by their withdrawal may influence the hypothalamic-pituitary-thyroid axis and immune system. Therefore, a careful evaluation of the thyroid function and antibodies is important after surgery for Cushing's syndrome.