-Polyps are discrete mass lesions that are flat or protrude into the intestinal lumen. They arise from the epithelial cells lining the colon.
-Most commonly sporadic, may be inherited as part of familial polyposis syndrome
Of polyps removed at colonoscopy, over 70% are adenomatous; most of the remainder are serrated; distinguished by histology
-Of polyps removed at colonoscopy, over 70% are adenomatous
-Most colorectal cancers, regardless of etiology, arise from adenomatous polyps.
–Four major pathological groups
- Mucosal adenomatous polyps (tubular, tubulovillous, villous)
- Mucosal serrated polyps (hyperplastic, sessile serrated polyp, traditional serrated adenoma)
- Mucosal nonneoplastic polyps (juvenile polyps, hamartomas, inflammatory polyps)
- Submucosal lesions (lipomas, lymphoid aggregates, carcinoids, pneumatosis cystoides intestinalis)
-Hyperplastic polyps located in the proximal colon (ie, proximal to the splenic flexure) may be associated with an increased risk of neoplasia, particularly those > 1 cm
–Familial adenomatous polyposis of the colon is a rare autosomal dominant disorder associated with a deletion in the long arm of chromosome 5. Thousands of adenomatous polyps appear in the large colon, generally by age 25 years, and colorectal cancer develops in almost all these patients by age 40 years.
–Peutz-Jeghers syndrome (PJS):It is an autosomal dominant syndrome characterized by multiple hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation, and an increased risk of gastrointestinal and non gastrointestinal cancer.
-Pigmentations occur on the lips and perioral region, palms of the hands, buccal mucosa, and soles of the feet.
-The most common sites of gastrointestinal tract malignancy are the colon and pancreas, and the most common site of extraintestinal tract cancer is the breast.
HEREDITARY NONPOLYPOSIS COLORECTAL CANCER:
–The most common genetic colon cancer syndrome is Lynch syndrome, formerly known as HNPCC.
– It is an autosomal dominant condition
Risk factors:
Older age: 85% in those older than age 60 years
Diet: Increased cholesterol is associated with a greater risk of polyps
Excess body weight
Inflammatory bowel disease
Alcohol consumption
Symptoms & Signs: Most patients with adenomatous and serrated polyps are completely asymptomatic. Chronic occult blood loss may lead to iron deficiency anemia. Large polyps may ulcerate, resulting in intermittent hematochezia
Diagnosis:
Laboratory Tests: Fecal occult blood test (FOBT), fecal immunochemical test (FIT), and fecal DNA tests
Imaging Studies: CT colonography
Endoscopic tests: 1. Colonoscopy, which should be performed in all patients who have positive FOBT, FIT, or fecal DNA tests or iron deficiency anemia.
- Capsule endoscopy
Treatment: Colonoscopic polypectomy; periodic colonoscopic surveillance
Prognosis:
-Chronic occult blood loss may lead to iron deficiency anemia.
-Untreated patients with polyps larger than 10 mm are at increased risk for colon cancer both at the site of the polyp and at other sites.
Q: What is the best means of detecting and removing adenomatous and serrated polyps? Colonoscopy
Q: FIT or FOBT: Which is more sensitive in the detection of colorectal cancer? FIT