title: High Frequency of Normal Response during GH Stimulation Tests in Patients with Ectopic Posterior Pituitary Gland: A Source of False-Negative Diagnosis of Pituitary Insufficiency.
abstract: OBJECTIVE
  To report false-negative normal growth hormone (GH) peak response in patients with ectopic posterior pituitary gland (EPP) identified with a simplified magnetic resonance imaging (FAST1-MRI).
  
  
  METHODS
  We analyzed 75 EPP patients with short stature and reduced growth velocity. Sagittal-T1 imaging (thickness: 2 mm and gap: 0.2 mm) without gadolinium administration was used. A GH peak of ≥5 ng/ml after clonidine or insulin stimulation was considered normal.
  
  
  RESULTS
  Normal GH response was observed in 15 of 75 (20%) patients [mean (SDS) peak = 8.2 (4.1) ng/ml]. Age at diagnosis [6.5 (3.0) years vs. 7.8 (4.1) years], gender (10 males/5 females vs. 44 males/16 females), pubertal stage (14 prepubertal/1 pubertal vs. 51 prepubertal/7 pubertal), and target height [-0.4 (0.6) vs. -0.4 (0.9)] were recorded. The perinatal history did not differ between responsive and nonresponsive patients. There was a trend to more frequent multiple hormone deficiency in nonresponsive when compared with responsive patients [3/15 (20%) and 31/60 (51.7%), respectively (p = 0.055)]. Height at diagnosis was lower in nonresponsive patients (p = 0.042). No significant difference in the IGF1 levels (p = 0.598) was observed between the groups.
  
  
  CONCLUSIONS
  Normal GH values after stimulation tests do not exclude EPP-associated GH deficiency. A simplified fast acquisition sagittal-T1 MRI protocol investigation included at the initial diagnostic approach is able to prevent misdiagnosis of GH deficiency in patients with short stature.
authors.affiliation: Pediatric Endocrinology Unit, Santa Casa de Sx00E3;o Paulo, Sx00E3;o Paulo, Brazil.
authors.forename: Cristiane
authors.initials: C
authors.lastname: Kochi
authors.forename: Cindy Greicy Bruginski
authors.initials: CG
authors.lastname: Scuderi
authors.forename: Lara
authors.initials: L
authors.lastname: Barros
authors.forename: Letícia
authors.initials: L
authors.lastname: Ribeiro
authors.forename: Gustavo
authors.initials: G
authors.lastname: Amadei
authors.forename: Marcelo Damaso
authors.initials: MD
authors.lastname: Maruichi
authors.forename: Antonio José
authors.initials: AJ
authors.lastname: da Rocha
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Longui
mesh_terms: D002648:Child; D002675:Child, Preschool; D002828:Choristoma; D005188:False Negative Reactions; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007018:Hypopituitarism / Q000175:diagnosis*; D008297:Male; D010904:Pituitary Gland, Posterior; D012189:Retrospective Studies
chemical_list: D013006:Growth Hormone