title: Desmoid tumor patients carry an elevated risk of familial adenomatous polyposis.
abstract: BACKGROUND
  The prevalence of desmoid tumors among patients with familial adenomatous polyposis (FAP) is at least 10%, and the prevalence of FAP among desmoid patients varies between 7.5-16%.
  
  
  METHODS
  Data included 106 desmoid patients identified from the database of the Department of Pathology, Helsinki University Hospital, years 2000-2012. We evaluated the risk of FAP among patients by using endoscopy and we identified individuals with attenuated FAP by APC gene mutation test. We compared sporadic desmoid patients' and FAP patients' clinical characteristics.
  
  
  RESULTS
  Ten of 106 patients already had FAP diagnosis before the desmoid. Eleven patients had had FAP screening already earlier due to desmoid and three of them were found to have FAP. Total of 52 patients participated into prospective screening of FAP. No new cases of FAP were found. The risk of FAP among desmoid tumor patients was 4.8%. In the FAP desmoid group, there were more males and patients were younger than in the sporadic group. Intra-abdominal desmoids were more common in the FAP group.
  
  
  CONCLUSIONS
  Patients with desmoid carry an elevated risk of FAP and therefore screening is indicated. Asymptomatic patients with desmoid situated in extra truncal region may not need to be screened.
authors.affiliation: Department of Colorectal Surgery, Abdominal Center, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Laura
authors.initials: L
authors.lastname: Koskenvuo
authors.affiliation: Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Peltomäki
authors.affiliation: Department of Colorectal Surgery, Abdominal Center, Helsinki University Hospital, Helsinki, Finland.|Research Programs Unit, Genome-Scale Biology, University of Helsinki, Helsinki, Finland.
authors.forename: Laura
authors.initials: L
authors.lastname: Renkonen-Sinisalo
authors.affiliation: Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.
authors.forename: Annette
authors.initials: A
authors.lastname: Gylling
authors.affiliation: Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland.
authors.forename: Taina T
authors.initials: TT
authors.lastname: Nieminen
authors.affiliation: Department of Pathology, Research Programs Unit and HUSLAB, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Ari
authors.initials: A
authors.lastname: Ristimäki
authors.affiliation: Department of Colorectal Surgery, Abdominal Center, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Anna
authors.initials: A
authors.lastname: Lepistö
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000175:diagnosis* / Q000453:epidemiology* / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D016099:Endoscopy, Gastrointestinal; D005260:Female; D018222:Desmoid Tumors / Q000150:complications*; D005387:Finland / Q000453:epidemiology; D017491:Genes, APC; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors
keywords: APC gene testing; desmoid tumor; familial adenomatous polyposis