Gardner syndrome

FAP-Gardner variant · familial adenomatous polyposis with extracolonic features

Gardner syndrome is a phenotypic variant of familial adenomatous polyposis (FAP). It combines colorectal adenomatous polyposis with extracolonic features — epidermoid cysts, osteomas, desmoid tumours, dental abnormalities and congenital hypertrophy of the retinal pigment epithelium (CHRPE). Untreated FAP carries near-100% lifetime colorectal cancer risk. The cutaneous and skeletal features may pre-date colonic polyposis, giving dermatologists and oncoplastic surgeons a sentinel role.

CurrentLast reviewed 16 May 2026

Genetics

Autosomal dominant. APC gene tumour-suppressor on chromosome 5q22.
Allelic with classic FAP, attenuated FAP and Turcot syndrome (CNS) — phenotype depends on mutation position.
~25% are de novo mutations. Penetrance for colorectal polyposis is near complete.

Cutaneous and soft-tissue features

Epidermoid cysts — multiple, often on the face / scalp / extremities; may precede polyposis by years; can occur in childhood (uncommon in unaffected paediatric population).
Pilomatricomas — increased frequency.
Desmoid tumours — locally aggressive (CTNNB1 / APC-driven) fibromatosis; often abdominal post-laparotomy; major cause of morbidity and mortality after colectomy.
Lipomas, fibromas, neurofibromas — variable.

Extracutaneous features

Colorectal adenomatous polyposis — hundreds to thousands of adenomas by adolescence; CRC inevitable without prophylactic colectomy (lifetime risk >90%).
Osteomas — skull / mandible / long bones; often the first radiographic sign.
Dental — supernumerary / unerupted teeth, odontomas.
CHRPE — congenital hypertrophy of retinal pigment epithelium; multiple bilateral lesions support diagnosis.
Other cancers — papillary thyroid (~2-12%), hepatoblastoma (paediatric), pancreatic, biliary, gastric, duodenal / ampullary, brain (medulloblastoma → Turcot).

Diagnosis and surveillance

Refer for germline APC testing when ≥1 of: multiple epidermoid cysts in a child / adolescent; childhood-onset desmoid; multiple jaw osteomas; CHRPE multiplicity; first-degree relative with FAP.
Lower-GI surveillance typically begins at 10-15 years (per NHS regional protocol); flexible sigmoidoscopy or colonoscopy annually.
Upper-GI surveillance (duodenal Spigelman) from age 25.
Annual thyroid USS for papillary thyroid cancer screening.
Prophylactic colectomy (subtotal vs proctocolectomy) usually in late teens / early twenties.

Practical points for skin / plastic surgery

Multiple childhood epidermoid cysts should prompt full family / dental / ophthalmology review.
Abdominal-wall mass after surgery — consider desmoid, not recurrence; imaging plus β-catenin / CTNNB1 staining.
Counsel against unnecessary surgical trauma in known FAP — desmoid risk is provoked by surgery.
Multidisciplinary management via clinical genetics + colorectal MDT + sarcoma MDT for desmoids.

References

Kennedy RD et al. The natural history of familial adenomatous polyposis syndrome: a 24-year review of a single centre experience in screening, diagnosis and management. J Pediatr Surg. 2014;49:82-86.

Half E et al. Familial adenomatous polyposis. Orphanet J Rare Dis. 2009;4:22.

Galiatsatos P, Foulkes WD. Familial adenomatous polyposis. Am J Gastroenterol. 2006;101:385-398.

Monahan KJ et al. Guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/ACPGBI/UKCGG. Gut. 2020;69:411-444.

NICE NG151. Colorectal cancer. London: NICE; 2020 (last updated 15 December 2021).