Restoration of dexamethasone suppression by incomplete adenomectomy in Cushing's disease.

Two cases of pituitary-dependent Cushing's disease are described. Selective transphenoidal adenomectomy was attempted in each, but proved incomplete. Although both patients had persistent Cushing's disease after the operation, both were shown to have been rendered fully dexamethasone suppressible. The pathophysiological basis of partial suppressibility is discussed, as are the criteria for the diagnosis of cure in Cushing's disease treated by selective adenomectomy.