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Familial adenomatous polyposis syndromes

Last reviewed: 10 Nov 2023
Last updated: 14 Sep 2023



History and exam

Key diagnostic factors

  • family history of FAP/attenuated FAP
  • teenager
  • onset of colorectal cancer in middle age
  • bilateral pigmentation of the retina
More key diagnostic factors

Other diagnostic factors

  • constipation/diarrhea
  • hematochezia
  • extraintestinal features of FAP
Other diagnostic factors

Risk factors

  • germline adenomatous polyposis coli (APC) gene mutation
  • family history of FAP or attenuated FAP
More risk factors

Diagnostic investigations

1st investigations to order

  • colonoscopy
  • extended-side-viewing esophagogastroduodenoscopy (EGD)
More 1st investigations to order

Investigations to consider

  • genetic testing
  • abdominal imaging with CT or MRI
More investigations to consider

Treatment algorithm



attenuated FAP



Priyanka Kanth, MD, MS, FACG, AGAF

Associate Professor of Medicine

Division of Gastroenterology

MedStar Georgetown University Hospital

Lombardi Comprehensive Cancer Center




PK is a co-investigator for multicenter clinical trials in familial adenomatous polyposis funded by the National Cancer Institute and Janssen Pharmaceutica. She has also served on the advisory board for Provepharm. She has a patent on sessile serrated colon polyp biomarker.


Dr Priyanka Kanth would like to gratefully acknowledge Dr Charles A. Ternent, Dr Alan G. Thorson, Dr Lisa A. Boardman, and Dr Douglas L. Riegert-Johnson, the previous contributors to this topic.


CAT, AGT, LAB, and DLRJ declare that they have no competing interests.

Peer reviewers

Yann Parc, MD, PhD

Professor of General Surgery

Department of Digestive Surgery

Hopital Saint-Antoine

Universite Pierre et Marie Curie Paris VI




YP declares that he has no competing interests.

Gabriela Moslein, MD

Editorial Board

Allgemein- und Viszeralchirurgie

St Josefs-Hospital Bochum-Linden




GM declares that she has no competing interests.

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  • Differentials

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    • Juvenile polyposis
    • Peutz-Jeghers syndrome
    More Differentials
  • Guidelines

    • NCCN clinical practice guidelines in oncology: genetic/familial high-risk assessment: colorectal
    • Informed consent for GI endoscopic procedures
    More Guidelines
  • Patient leaflets

    Colon and rectal cancer: what is it?

    Colon and rectal cancer: what treatments work?

    More Patient leaflets
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