| Disease | Extra-colonic manifestations | Lifetime CRC or GI malignancy risks | Extra-gastrointestinal malignancy |
| Non-neoplastic Polyps | |||
| Inflammatory “cap” polyposis | None | No | - |
| Hyperplastic polyposis | None | Increased risk of CRC (mostly R-sided) | - |
| Adenomatous polyposis | |||
| Classical Familial adenomatous polyposis (FAP) | ・ Upper GI polyposis: gastric FGP, duodenum and ampullary adenomas /adenocarcinomas ・ Desmoids tumors, osteomas , epidermoid cysts, dental abnormalities, CHRPE | 100% CRC (left-sided predominance) Duodenal and periampullary cancer (4% - 12%) | Thyroid cancer (1% - 2%), hepatoblastoma (1% - 2%), medulloblastoma (<1%) |
| Attenuated FAP (AFAP) | ・ Upper GI polyposis: gastric FGP, duodenum and ampullary adenomas /adenocarcinomas ・ Usually lack the extra-intestinal manifestations of classic FAP | 80% - 100% CRC (usually right-sided) Duodenal and periampullary cancer (4% - 12%) | Thyroid cancer (1% - 2%) |
| MUTYH- associated polyposis (MAP) | ・ Gastric FGP, duodenal adenomas/adenocarcinomas ・ CHRPE, osteomas,and Muir-Torre phenotype with sebaceous gland tumors | 80% - 100% CRC (2/3 right sided) Duodenal cancer (4%) | Increased risk of ovarian, bladder, skin, and breast cancer |
| Hamartomatous polyposis | |||
| Juvenile polyposis syndrome (JPS) | ・ Pulmonary arterio-venous malformations ・ Mucocutaneous telangiectasias | CRC (68%), gastric (21%), small bowel, and pancreatic cancer | No increased risk in extra-GI site |
| Peutz-Jeghers syndrome | ・ Mucocutaneous melanosis (lips, buccal mucosa) | CRC (39%), gastric (29%), small bowel (13%), pancreatic cancer (36%) | Breast (54%), lung (15%), ovarianor testicular cancer; ovarian sex-cord tumors with annular tubules (SCTAT), cervical adenoma malignum, male Sertoli-cell testicular tumors |
| Cowden syndrome | ・ Mucocutaneous lesions (facial trichilemmomas, acral keratosis, papillomatous papules), LDD, macrocephaly, mental retardation ・ Glycogenic acanthosis of the esophagus | Low | Breast (50%), thyroid (10%), endometrial, ovarian or cervical cancer, renal cell carcinoma, bladder transitional carcinoma |
| Cronkhite-Canada syndrome | Unique dermatologic triad: alopecia, skin hyperpigmentation, onychodystrophy | CRC (mostly left sided) Gastric cancer | - |