title: Clinical and biochemical characteristics of adrenocorticotropin-secreting macroadenomas.
abstract: BACKGROUND
  Cushing's disease as a result of a pituitary macroadenoma is an uncommon cause of Cushing's syndrome, and reports in the published literature are few and of limited size.
  
  
  OBJECTIVE
  Our objective was to establish the clinical and biochemical characteristics of macroadenomas associated with Cushing's disease compared with a large cohort of microadenomas and to assess their response to therapy.
  
  
  METHODS
  We conducted a retrospective case-records study for the years 1964-2001.
  
  
  METHODS
  The study occurred at a tertiary referral hospital center.
  
  
  METHODS
  Patients had Cushing's disease presenting with a pituitary macroadenoma, in comparison with a large group of microadenoma patients.
  
  
  METHODS
  Interventions included therapy with surgery and radiotherapy.
  
  
  METHODS
  Outcome measures included basal and dynamically responsive plasma ACTH and cortisol levels and response to treatment.
  
  
  RESULTS
  We identified 18 patients with Cushing's disease secondary to a macroadenoma; basal 0900 h plasma ACTH was 135.8 +/- 32.5 and 45.0 +/- 4.3 ng/liter (mean +/- SEM), respectively, in macroadenomas and microadenomas (P = 0.013). Mean 0900 h serum cortisol was significantly increased in the macroadenomas (27.5 +/- 3.0 microg/dl, 759.6 +/- 82.6 nmol/liter, vs. 22.6 +/- 0.6 microg/dl, 624.7 +/- 16.4 nmol/liter) (P = 0.021). Testing with high-dose dexamethasone showed less suppression in the macroadenomas (57.6 +/- 8.7% vs. 74.4 +/- 2.1%; P = 0.02) and an attenuated ACTH response to CRH. For all biochemical variables there was considerable overlap between the two groups. Few patients with macroadenomas were cured by surgery.
  
  
  CONCLUSIONS
  Pituitary macroadenomas causing Cushing's disease have biochemical features largely distinct from patients harboring microadenomas but represent one end of a continuum.
authors.affiliation: Department of Endocrinology, St. Bartholomew's Hospital, London EC1A 7BE, United Kingdom.
authors.forename: Y Sammy
authors.initials: YS
authors.lastname: Woo
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Isidori
authors.forename: Winnie Z
authors.initials: WZ
authors.lastname: Wat
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Kaltsas
authors.forename: Fari
authors.initials: F
authors.lastname: Afshar
authors.forename: Ian
authors.initials: I
authors.lastname: Sabin
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Jenkins
authors.forename: John P
authors.initials: JP
authors.lastname: Monson
authors.forename: G Michael
authors.initials: GM
authors.lastname: Besser
authors.forename: Ashley B
authors.initials: AB
authors.lastname: Grossman
mesh_terms: D000236:Adenoma / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D000310:Adrenal Gland Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000378:metabolism*; D000328:Adult; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D047748:Pituitary ACTH Hypersecretion / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone