Table 1. Colorectal Cancer Predisposition Syndromes.
| Syndrome | Colon Presentation | Lifetime Colon Cancer Risk | Extracolonic Manifestations |
|---|---|---|---|
| FAP | Over 100 adenomatous colorectal polyps (average age of polyposis onset is 16 years) | Nearly 100% | Duodenal and periampullary cancers (3–5% risk), childhood hepatoblastoma, other cancers: pancreatic, thyroid, gastric, brain (all rare); desmoid tumors (20% risk); Gardner syndrome: osteomas (often of the jaw), epidermoid cysts, CHRPE, dental anomalies; Turcot syndrome: medulloblastoma |
| Lynch syndrome | Colon cancer (often early onset, average age of onset 44–61 years) | 50–80% | Endometrial cancer (40–60% risk), ovarian cancer (9–14% risk); other cancers: stomach, renal, ureter, small intestine, biliary (all 10% or less); Muir-Torre syndrome: cutaneous keratoacanthomas, sebaceous gland tumors; Turcot syndrome: glioblastoma |
| AFAP | 10–100 adenomatous colorectal polyps with a tendency toward polyps in the right side of the colon (average age of polyposis onset is 26) | 80% | Similar to FAP |
| MAP | 10 to over 100 colorectal polyps | Undefined, but increased over the general population | Not generally seen; some reports of patients with CHRPE, osteomas, dental cysts, duodenal adenomas, and/or gastric cancer |
| HMPS | Colorectal polyposis with polyps of different histologies (adenomas–classic, serrated, tubular; hyperplastic; juvenile; mixed juvenile-adenomatous or hyperplastic adenomatous) | Undefined | Rare extracolonic cancers including pancreatic, breast, thyroid, and kidney |
| HPS | Colorectal polyposis featuring large, hyperplastic polyps and some adenomas/serrated adenomas | Undefined | None reported |
| Peutz-Jeghers | Colorectal polyposis involving characteristic hamartomatous polyps | 39% | Blue/brown pigmentation (starting in childhood around the mouth, nose, and/or eyes and on the buccal mucosa and fingers; spots fade with age); upper GI polyposis (particularly small intestine); other cancers: breast, ovarian, pancreatic, small intestine, gastric, esophageal, cervical (adenoma malignum); sex cord tumors, Sertoli cell tumors |
| JPS | Colorectal polyposis involving juvenile polyps | 17–22% by age 35, ~ 68% by age 60 |
Gastric polyps (if present, 21% risk of gastric adenocarcinoma), other cancers: pancreatic and small intestine |
| Cowden syndrome | Colorectal hamartomas | Unclear, around 9% | Breast cancer (30% risk in women), thyroid cancer (10%), upper GI hamartomas; macrocephaly, fibrocystic breasts, dermatologic features (80% of affected individuals) including oral papillomas, trichilemmomas, keratoses of the hands and feet, and lipomas |
GI, Gastrointestinal; FAP, familial adenomatous polyposis; AFAP, attenuated familial adenomatous polyposis; MAP, MYH-associated polyposis; HMPS, hereditary mixed polyposis syndrome; HPS, hereditary polyposis syndrome; JPS, juvenile polyposis; CHRPE, congenital hypertrophy of retinal pigment epithelium.
From Gammon A, Kohlmann W, Burt R. Can we identify the high-risk patients to be screened? A genetic approach. Digestion 2007;76(1):7–19. Copyright: S. Karger AG, Basel, Switzerland.