title: Adrenocorticotrophin-dependent hypercortisolism: imaging versus laboratory diagnosis.
abstract: BACKGROUND
  Cushing's syndrome results from inappropriate exposure to excessive glucocorticoids. Untreated, it has significant morbidity and mortality.
  
  
  METHODS
  A 38-year-old woman with a typical appearance of Cushing's syndrome was admitted for further evaluation of hypercortisolism. The serum cortisol level was elevated without diurnal rhythm, without adequate suppression of cortisol after 1 mg dexamethasone suppression test. 24-hour urinary-free cortisol level was elevated. Differential diagnostic testing indicated adrenocorticotrophin (ACTH)-dependent lesion of the pituitary origin. Pituitary abnormalities were not observed during repeated MRI scanning. Inferior petrosal sinus sampling (IPSS) was performed: 1) Baseline ratio ACTH inferior petrosal sinus/peripheral was <2; 2) Corticotropin-releasing hormone (CRH) stimulated ratio ACTH inferior petrosal sinus/peripheral was <3; 3) Baseline intersinus ratio of ACTH was <1.4; 4) Increase in inferior petrosal sinus and peripheral ACTH of more than 50 percent above basal level after CRH; 5) Baseline ratio ACTH vena jugularis interna/peripheral was >1.7. Transsphenoidal exploration and removal of the pituitary tumor was performed inducing iatrogenic hypopituitarism. Postoperative morning serum cortisol level was less than 50 nmol/l on adequate replacement therapy with hydrocortisone, levothyroxine and estro-progestagen.
  
  
  CONCLUSIONS
  No single test provides absolute distinction, but the combined results of several tests generally provide a correct diagnosis of Cushing's syndrome.
authors.affiliation: Clinic for Endocrinology, Diabetes and Metabolic Diseases, Clinical Center of Serbia, Belgrade, Serbia. mtancicgajic@yahoo.com
authors.forename: Milina
authors.initials: M
authors.lastname: Tancić-Gajić
authors.forename: Svetlana
authors.initials: S
authors.lastname: Vujović
authors.forename: Miomira
authors.initials: M
authors.lastname: Ivović
authors.forename: Milos
authors.initials: M
authors.lastname: Stojanović
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Marina
authors.forename: Marija
authors.initials: M
authors.lastname: Barać
authors.forename: Dragan
authors.initials: D
authors.lastname: Micić
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000328:Adult; D003346:Corticotropin-Releasing Hormone; D003480:Cushing Syndrome / Q000097:blood / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005260:Female; D006729:Hormones, Ectopic / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D017591:Petrosal Sinus Sampling; D010902:Pituitary Gland / Q000378:metabolism / Q000473:pathology
chemical_list: D006729:Hormones, Ectopic; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone