Table 1.

Extracolonic Manifestations of Adenomatous Polyposis Coli (APC) Mutations

	Incidence	Significance
CHRPE, congenital hypertrophy of the retinal pigment epithelium.
Duodenal adenomas	80–90%	12% Risk of malignancy
Gastric hamartomas	50–70%	Must exclude gastric adenoma
Desmoids	12–35%	27% Risk of complications
Hepatoblastoma	1%	Most common before age 2 years
Osteomas	80%	Usually < 1 cm in size
CHRPE	60%	Marker for screening purposes
Thyroid cancer (papillary)		Predilection for women