Cushing's disease with cure by resection of a pituitary adenoma. Evidence against a primary hypothalamic defect.

Abstract A patient with Cushing's disease was treated by transphenoidal resection of a pituitary adenoma. Pituitary-adrenal suppressibility, responsiveness to metyrapone and circadian rhythm were observed postoperatively. Reversion to physiologic regulation after resection of an adenoma implies that the lesion secreted ACTH autonomously (primary hyperpituitarism). Current evidence favors the pituitary adenoma, when present, as the primary etiologic factor in pituitary-dependent Cushing's syndrome. Since adenomas occur in a majority of cases, initial therapy is best directed at the pituitary.