title: PITUITARY MRI FINDINGS IN PATIENTS WITH PITUITARY AND ECTOPIC ACTH-DEPENDENT CUSHING SYNDROME: DOES A 6-MM PITUITARY TUMOR SIZE CUT-OFF VALUE EXCLUDE ECTOPIC ACTH SYNDROME?
abstract: OBJECTIVE
  Expert opinion and a consensus statement on Cushing syndrome (CS) indicate that in a patient with a clinical presentation and biochemical studies consistent with a pituitary etiology, the presence of a pituitary tumor ≥6 mm is highly suggestive of Cushing disease (CD). The purpose of the present study was to determine the optimal pituitary tumor size that can differentiate between patients with CD and ectopic adrenocorticotrophic hormone (ACTH) secretion (EAS) and obviate the need for inferior petrosal sinus sampling (IPSS).
  
  
  METHODS
  We performed a retrospective study of 130 patients seen between 2000 and 2012 including 104 patients with CD and 26 patients with EAS.
  
  
  RESULTS
  A pituitary lesion was reported in 6/26 (23%) patients with EAS and 71/104 (68.3%) patients with CD, with median (range) sizes of 5 mm (3-14) and 8 mm (2-31), respectively. All tumors in the EAS group measured ≤6 mm except for 1 that measured 14 mm. The presence of a pituitary tumor >6 mm in size had 40% sensitivity and 96% specificity for the diagnosis of CD. ACTH levels >209 pg/mL and serum potassium <2.7 mmol/L were found in patients with EAS. All patients with EAS had a 24-hour urine free cortisol (UFC) >3.4 times the upper limit of normal (×ULN) Conclusion: Pituitary incidentalomas as large as 14 mm in size can be seen in patients with EAS. However, the 6-mm tumor size cut-off value provided 96% specificity and may be a reasonable threshold to proceed with surgery without the need for IPSS when the biochemical data support a pituitary etiology.
authors.forename: Divya
authors.initials: D
authors.lastname: Yogi-Morren
authors.forename: Mouhammed Amir
authors.initials: MA
authors.lastname: Habra
authors.forename: Charles
authors.initials: C
authors.lastname: Faiman
authors.forename: James
authors.initials: J
authors.lastname: Bena
authors.forename: Betul
authors.initials: B
authors.lastname: Hatipoglu
authors.forename: Laurence
authors.initials: L
authors.lastname: Kennedy
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Weil
authors.forename: Amir H
authors.initials: AH
authors.lastname: Hamrahian
mesh_terms: D000182:ACTH Syndrome, Ectopic / Q000175:diagnosis* / Q000473:pathology; D000236:Adenoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D000293:Adolescent; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000592:standards; D008297:Male; D008875:Middle Aged; D017591:Petrosal Sinus Sampling; D047748:Pituitary ACTH Hypersecretion / Q000175:diagnosis* / Q000473:pathology; D010902:Pituitary Gland / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D012016:Reference Values; D012189:Retrospective Studies; D047368:Tumor Burden / Q000502:physiology*; D055815:Young Adult
chemical_list: D000324:Adrenocorticotropic Hormone