title: Prevalence of thyroid cancer in familial adenomatous polyposis syndrome and the role of screening ultrasound examinations.
abstract: OBJECTIVE
  Thyroid carcinoma is an extraintestinal manifestation of familial adenomatous polyposis (FAP) syndrome, but the precise risk is unknown. The optimal approach for thyroid cancer screening has not been established. We sought to define the prevalence of thyroid cancer and the role of screening ultrasound in FAP patients.
  
  
  METHODS
  We performed a retrospective chart review of 51 patients with a proven diagnosis of FAP at a single tertiary institution. Clinical records, genetic test results, ultrasound examinations, and histopathology were reviewed.
  
  
  RESULTS
  Papillary thyroid cancer was diagnosed in 6 female patients (12%). The mean age of thyroid cancer diagnosis was 33 years, and mean tumor size was 12 mm. However, all patients had additional malignant foci that were small (1-9 mm), and none had suspicious features of malignancy on ultrasound. Of 28 patients who had at least one screening ultrasound, 22 (79%) had thyroid nodules, and 2 (7%) had papillary thyroid carcinoma. Of those with nodules, 68% had multinodular disease. A follow-up ultrasound in 12 patients after a mean of 15 months revealed no changes in either the number or size of nodules.
  
  
  CONCLUSIONS
  The 12% prevalence of thyroid cancer in this series of FAP patients is significantly higher than in previous reports. Among patients undergoing screening ultrasound, 7% had thyroid cancer. Nodular thyroid disease is very common in FAP. Because small nodules (<9 mm) might also be malignant, close follow-up with ultrasound and fine-needle aspiration might be warranted.
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
authors.forename: Maite
authors.initials: M
authors.lastname: Herraiz
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Barbesino
authors.forename: William
authors.initials: W
authors.lastname: Faquin
authors.forename: Gayun
authors.initials: G
authors.lastname: Chan-Smutko
authors.forename: Devanshi
authors.initials: D
authors.lastname: Patel
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Shannon
authors.forename: Gilbert H
authors.initials: GH
authors.lastname: Daniels
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Chung
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000175:diagnosis / Q000453:epidemiology*; D000328:Adult; D017677:Age Distribution; D001707:Biopsy, Needle; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D016019:Survival Analysis; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler