Familial Polyposis Syndromes

• Autosomal dominant with high penetrance (80%)

• About 2/3 of affected people have a positive family hx of colonic polyps or ca and about 1/3 are sporadic cases

• Colonic polyps are numerous and of all different sizes

• They may be sessile or pedunculated

• Rectum and left colon are more commonly affected than right side of colon

• Often, however, the entire colon is carpeted with polyps

• Extracolonic polyps are uncommon in American patients but more common in the Japanese

• Generally the polyps arise during the first or second decade of life

• Colon cancer usually develops between 20-40 years of age

• Colon cancer will develop in nearly 100% of untreated patients

• Multiple carcinomas are common

• Treatment is total prophylactic colectomy

• Colectomy with maintenance of the rectum is possible in patients who will undergo routine proctoscopy

Syndrome	Heredity	Distribution (mainly)	Histology	Malignant potential
Familial Polyposis	Auto dominant	Colon	Adenomas	100% colon ca
Gardener’s	Auto dominant	Colon	Adenomas	100% colon ca
Peutz-Jegher’s	Auto dominant	Small bowel 30% colon	Hamartomas in small bowel; adenomas in colon	2-3% overall ca

WH/93