[2] Colorectal polyps are often classified by their behaviour (i.e. benign vs. malignant) or cause (e.g. as a consequence of inflammatory bowel disease).

[2] Anemia arising from iron deficiency can also present due to chronic blood loss, even in the absence of bloody stools.

[6]: 1342 Hereditary syndromes causing increased colorectal polyp formation include: Several genes have been associated with polyposis, such as GREM1, MSH3, MLH3, NTHL1, RNF43 and RPS20.

[8] Familial adenomatous polyposis (FAP) is a form of hereditary cancer syndrome involving the APC gene located on chromosome q521.

[9] It was later further studied by Henry Lynch who recognized an autosomal dominant transmission pattern with those affected having relatively early onset of cancer (mean age 44 years), greater occurrence of proximal lesions, mostly mucinous or poorly differentiated adenocarcinoma, greater number of synchronous and metachronous cancer cells, and good outcome after surgical intervention.

[9] The Criteria required that the patient has three family members all first-degree relatives with colorectal cancer that involves at least two generations with at least one affected person being younger than 50 years of age when the diagnosis was made.

[9] The Amsterdam Criteria is too restrictive and was later expanded to include cancers of endometrial, ovarian, gastric, pancreatic, small intestinal, ureteral, and renal pelvic origin.

[9] The syndrome is associated with malfunction of serine-threonine kinase 11 or STK 11 gene, and has a 2–10% increase in risk of developing cancer of the intestinal tract.

[9] The syndrome also causes increased risk of extraintestinal cancer such as that involving breast, ovary, cervix, fallopian tubes, thyroid, lung, gallbladder, bile ducts, pancreas, and testicles.

[9] Any polyp larger than 1.5 cm needs removal and patients should be monitored closely and screen every two years for malignancy.

[9] Individuals with multiple juvenile polyps have at least 10% chance of developing malignancy and should undergo abdominal colectomy with ileorectal anastomosis, and close monitoring via endoscopy of rectum.

Any invasive carcinoma that has penetrated the muscularis mocos has the potential for lymph node metastasis and local recurrence which will require more aggressive and extensive resection.

They contain mucus-filled glands, with retention cysts, abundant connective tissue, and chronic cellular infiltration of eosinophils.

Peutz–Jeghers syndrome is associated with polyps of the GI tract and also increased pigmentation around the lips, genitalia, buccal mucosa feet and hands.

[citation needed] Diet and lifestyle are believed to play a large role in whether colorectal polyps form.

Studies show there to be a protective link between consumption of cooked green vegetables, brown rice, legumes, and dried fruit and decreased incidence of colorectal polyps.