Cushing disease: successful preoperative lateralization of an ACTH-producing pituitary microadenoma by simultaneous bilateral inferior petrosal venous sinus sampling with corticotropin-releasing hormone stimulation.

A 5 10/12-year-old girl with clinical and laboratory signs of endogenous hypercortisolism had evidence of ACTH hypersecretion in a standardized dexamethasone suppression test but had surprisingly low plasma ACTH concentrations before and after ovine corticotropin releasing hormone (oCRH) stimulation. To establish the diagnosis of pituitary disease and to localize the suspected microadenoma, we performed bilateral simultaneous inferior sinus petrosus blood sampling under CRH stimulation (oCRH 1 microgram/kg as an i.v. bolus). No major side effects were noted. Inferior petrosal blood ACTH concentrations did not differ from peripheral blood under basal sampling conditions but were higher in the effluent of the left half of the pituitary 5 min after oCRH stimulation. During transsphenoidal exploration of the sella an ACTH-producing microadenoma was removed from the left portion of the anterior pituitary gland. Signs of hypercortisolism remitted after surgery. Simultaneous bilateral sinus petrosus blood sampling under oCRH stimulation is a useful lateralization procedure even with small ACTH-producing adenomas. This technique may help to avoid unsuccessful surgical exploration in children with Cushing disease.