From early adolescence, patients with this condition gradually (and much of the time asymptomatically) develop hundreds to thousands of colorectal polyps (and sometimes polyps elsewhere)—small abnormalities at the surface of the intestinal tract, especially in the large intestine including the colon or rectum. These may bleed, leading to blood in the stool. If the blood is not visible, it is still possible for the patient to develop anemia due to gradually developing iron deficiency. If malignancy develops, this may present with weight loss, altered bowel habit, or even metastasis to the liver or elsewhere.<unk>  can also develop 'silently' in some individuals, giving few or no signs until it has developed into advanced colorectal cancer. Because<unk>  polyposis develops very gradually over years, and can also manifest in an 'attenuated' form even more gradually, polyps resulting from<unk>  can lead to cancer developing at any point from adolescence to old age. Depending on the nature of the defect in the APC gene, and whether it is the full or attenuated form,<unk>  polyposis may manifest as polyps in colon or in the duodenal tract, or in any combination of these. Therefore, an absence of polyps in, for example, the rectum, may not of itself be sufficient to confirm absence of polyps. It may be necessary to consider and visually examine other possible parts of the intestinal tract. Colonoscopy is preferred over sigmoidoscopy for this, as it provides better observation of the common right-side location of polyps. thumb The genetic determinant in<unk>  polyposis may also predispose carriers to other malignancies, e.g., of the duodenum and stomach (particularly ampullary adenocarcinoma). Other signs that may point to<unk>  are the development of Gardner fibromas and desmoid tumors (benign skin tumors that may be apparent before other signs of<unk> , pigmented lesions of the retina ("CHRPE—congenital hypertrophy of the retinal pigment epithelium"), jaw cysts, sebaceous cysts, and osteomata (benign bone tumors). The combination of polyposis, osteomas, fibromas and sebaceous cysts is termed Gardner's syndrome (with or without abnormal scarring).
Familial adenomatous polyposis
Hereditary nonpolyposis colorectal cancer
Juvenile polyposis syndrome
MUTYH-associated polyposis
Serrated polyposis syndrome
Pseudopolyps
Ogden syndrome
Polymerase proofreading-associated polyposis