Differentials

Juvenile polyposis syndrome

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Polyposis is more likely to occur in the colorectum. Increased prevalence of massive gastric polyposis and of hereditary haemorrhagic telangiectasia.[30][31] Mucocutaneous pigmentation is absent.

INVESTIGATIONS

Juvenile polyps do not have the arborising smooth muscle of the muscularis mucosae that characterises Peutz-Jeghers polyps. Genetic testing for SMAD4 and BMPR1A gene mutations may reveal pathogenic variants.[32]

PTEN-hamartoma tumour syndrome

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical presentation may be similar. Macrocephaly is a common feature. Patients may have cutaneous lesions including trichilemmomas and papillomatous papules.[33]

INVESTIGATIONS

Genetic testing for PTEN gene mutations may reveal pathogenic variants.[33]

Mixed hereditary polyposis syndrome

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical presentation may be similar. Mucocutaneous pigmentation is absent.[34]

INVESTIGATIONS

Genetic testing for SCG5/GREM1 gene mutations may reveal pathogenic variants.[35]

Familial adenomatous polyposis

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Clinical presentation may be similar. May have other extra-colonic features (e.g., osteomas, dental abnormalities, congenital hypertrophy of the retinal pigment epithelium, desmoid tumours, and adrenal masses). Mucocutaneous pigmentation is absent.[36]

INVESTIGATIONS

Histology shows adenomatous, rather than hamartomatous, polyps throughout the colorectum. Genetic testing for APC gene mutations may reveal pathogenic variants.[36]

Familial adenomatous polyposis syndromes

Lynch syndrome

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Patients may develop a few adenomas over their lifetime but not hamartomatous polyps. Mucocutaneous pigmentation is absent.

INVESTIGATIONS

Genetic testing or tumour testing may reveal a deleterious mutation in specific DNA mismatch repair genes (MLH1, MSH2, MSH6, and PMS2) or the EPCAM gene.[37]

Carney's complex

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Polyps are not known to occur as part of Carney's complex.

Patients may have a history of myxomas (heart, skin, and breast), endocrine dysfunction and tumours, and schwannomas.[38]

INVESTIGATIONS

Genetic testing for PRKAR1A gene mutations may reveal pathogenic variants.[38]

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