[A case of pre-Cushing's syndrome].

A 66-year-old female was admitted to Chiba University Hospital for the evaluation of a left adrenal mass which was incidentally discovered by computerized tomography. The patient had no clinical signs of Cushing's syndrome. Although the plasma ACTH level was suppressed, serum cortisol and urinary 17-OHCS levels were normal. Serum cortisol was not suppressed by dexamethasone and loss of diurnal rhythm of cortisol was observed. Uptake of 131I-aldosterone in the left adrenal gland was noted, but no accumulation was observed in the right one. Left adrenalectomy was performed. The tumor resected was 20 x 22 x 26 mm in size. Pathological diagnosis was adreno-cortical adenoma. Whether slight abnormality of adrenocortical function without clinical symptoms observed in the present case would develop into a clinically typical Cushing's syndrome remains to be solved.