Remitting seronegative symmetrical synovitis with pitting oedema after surgical remission of Cushing's syndrome

A 64-year-old woman with refractory cellulitis in the lower legs was referred for inadequate glycaemic control. Physical examination revealed cushingoid features including central obesity. CT of the abdomen revealed a right adrenal mass that was positive on ¹³¹I-adosterol imaging. Findings on endocrine evaluation confirmed a diagnosis of Cushing's syndrome, which was cured with a right adrenalectomy. Two months after surgery, the patient complained of pain and marked swelling of the hands during hydrocortisone replacement therapy (20 mg per day) given for postoperative adrenal insufficiency. Laboratory examination was unremarkable. However, contrast-enhanced T2-weighted MRI of the hands revealed enhanced signals surrounding the flexor tendons, leading to a diagnosis of remitting seronegative symmetrical synovitis with pitting oedema. Prednisolone (15 mg per day) was then initiated, and the symptoms disappeared within a few days. This case illustrates the possibility that successful treatment of Cushing's syndrome may trigger emergence of a glucocorticoid-responsive disease.