title: Interest of systematic screening of pheochromocytoma in patients with neurofibromatosis type 1.
abstract: OBJECTIVE
  Pheochromocytoma (PHEO) may occur in 0.1-5.7% of patients presenting with a neurofibromatosis type 1 (NF1). Current recommendations are to explore only symptomatic patients. The objective of the study is to evaluate the prevalence and the interest of a systematic PHEO screening in this population.
  
  
  METHODS
  A prospective study in a French tertiary center including consecutive NF1 patients older than 18 years.
  
  
  METHODS
  A systematic screening combining abdominal imaging and urinary fractionated metanephrines was proposed. In case of positivity of one or both exams, (123)I-metaiodobenzylguanidine scintigraphy or [(18)F]-fluoro-dihydroxyphenylalanine PET imaging was performed. The diagnosis of secreting PHEO was retained in case of elevated urinary metanephrines associated with positive scintigraphy and non-secreting PHEO when urinary metanephrines were normal with a positive scintigraphy.
  
  
  RESULTS
  Between January 2014 and August 2015, 234 patients were included and 156 patients (66.7%) completed both exams. In these 156 patients, 12 PHEOs were diagnosed, representing a prevalence of 7.7%. Of these, six PHEOs were secreting, with only two symptomatic patients. The tumor size of these PHEOs were bigger than that of non-secreting PHEO (25.2 ± 6.6 vs 14 ± 6.9 mm, P = 0.0165). One lesion was bilateral. Mean metanephrine and normetanephrine levels were 3.2 ± 2.6N and 2.8 ± 1N respectively. Three patients underwent surgery. The six patients with non-secreting PHEO were asymptomatic. One of them had bilateral lesion and one underwent surgery.
  
  
  CONCLUSIONS
  PHEO in NF1, whether or not secreting, are mostly asymptomatic. The current strategy to explore only symptomatic patients leads to an underestimation of prevalence with the risks inherent to the existence of an unrecognized PHEO.
authors.affiliation: Department of Endocrinology and DiabetologyHospices Civils de Lyon, Groupement Hospitalier Est, Hôpital Louis Pradel, Bron Cedex, France.
authors.forename: Lori
authors.initials: L
authors.lastname: Képénékian
authors.affiliation: Department of Nuclear MedicineLéon Bérard Comprehensive Cancer Center, Lyon, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Mognetti
authors.affiliation: Department of GeneralDigestive and Endocrine Surgery, Centre Hospitalier Lyon Sud, Université Claude Bernard Lyon 1, Pierre Bénite, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Lifante
authors.affiliation: Department of Nuclear MedicineLéon Bérard Comprehensive Cancer Center, Lyon, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Giraudet
authors.affiliation: Nuclear Medicine UnitImaging Department, Centre Hospitalier Lyon Sud, Pierre-Bénite, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Houzard
authors.affiliation: Molecular Genetics LaboratoryHôpital Edouard Herriot, Bâtiment E, Lyon, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pinson
authors.affiliation: Department of Endocrinology and DiabetologyHospices Civils de Lyon, Groupement Hospitalier Est, Hôpital Louis Pradel, Bron Cedex, France francoise.borson-chazot@chu-lyon.fr.
authors.forename: Françoise
authors.initials: F
authors.lastname: Borson-Chazot
authors.affiliation: Rhône-Alpes Auvergne Competence Center for the treatment of Neurofibromatosis type 1Léon Bérard Comprehensive Cancer Center, Lyon, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Combemale
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000209:etiology; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009456:Neurofibromatosis 1 / Q000150:complications*; D010673:Pheochromocytoma / Q000000981:diagnostic imaging* / Q000209:etiology; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D055815:Young Adult