See Table 71-2.

1. Familial polyposis coli (FPC): Diffuse pancolonic adenomatous polyposis (up to several thousand polyps); autosomal dominant inheritance associated with deletion in adenomatous polyposis coli (APC) gene on chromosome 5; colon carcinoma from malignant degeneration of polyp in 100% by age 40. Treatment: Prophylactic total colectomy or subtotal colectomy with ileoproctostomy before age 30; subtotal resection avoids ileostomy but necessitates frequent proctoscopic surveillance; periodic colonoscopic or annual radiologic screening of siblings and offspring of pts with FPC until age 35; sulindac and other nonsteroidal anti-inflammatory drugs (NSAIDs) cause regression of polyps and inhibit their development.
2. Gardner's syndrome: Variant of FPC with associated soft tissue tumors (epidermoid cysts, osteomas, lipomas, fibromas, desmoids); higher incidence of gastroduodenal polyps, ampullary adenocarcinoma. Treatment: As for FPC; surveillance for small-bowel disease with fecal occult blood testing after colectomy.
3. Turcot's syndrome: Rare variant of FPC with associated malignant brain tumors. Treatment: As for FPC.
4. Nonpolyposis syndrome: Familial syndrome with up to 50% risk of colon carcinoma; peak incidence in fifth decade; associated with multiple primary cancers (esp. endometrial); autosomal dominant; due to defective DNA mismatch repair.
5. Juvenile polyposis: Multiple benign colonic and small-bowel hamartomas; intestinal bleeding common. Other symptoms: abdominal pain, diarrhea; occasional intussusception. Rarely recur after excision; low risk of colon cancer from malignant degeneration of interspersed adenomatous polyps. Prophylactic colectomy controversial.
6. Peutz-Jeghers syndrome: Numerous hamartomatous polyps of entire GI tract, though denser in small bowel than colon; GI bleeding common; somewhat increased risk for the development of cancer at GI and non-GI sites. Prophylactic surgery not recommended.