04-15-2011, 01:46 PM
Adenomatous polyps precancerous. Malignant risk is associated with ↑ size, villous Histology, ↑ epithelial dysplasia. Precursor to colorectal cancer (CRC). The more villous the polyp , the more likely it is to be malignant
Hyperplastic polyp Most common non-neoplastic polyp in colon (> 50% found in rectosigmoid colon).
Juvenile Polyp Mostly sporadic lesion in children < 5 years of age. 80% in rectum. If single, no malignant potential. - Juvenile polyposis syndrome-multiple juvenile polyps in GI tract, ↑ risk of adenocarcinoma
Peutz-Jegher syndrome Single polyps are not malignant. - autosomal-dominant syndrome featuring multiple non malignant hamartomas throughout Gl tract, along with hyperpigmented mouth, lips, hands, genitalia. Associated with ↑ risk of CRC and other visceral malignancies
Colorectal carcinoma epidemiology 3rd most common cancer; 3rd most deadly in United States. Most patients are > 50 years of age. - 25% have a family history
Familial adenomatous polyposis (FAP) autosomal-dominant mutation of APC gene on chromosome 5q. Two-hit hypothesis - 100% progress to CRC. Thousands of polyps; pancolonic; always involves rectum.
Gardner's syndrome FAP + osseous and soft tissue tumors, retinal hyperplasia.
Turcot's syndrome FAP + malignant CNS tumor. TURcot = TURban.
Hereditary nonpolyposis colorectal cancer (HNPCC/Lynch syndrome) -autosomal dominant mutation of DNA mismatch repair genes. - 80% progress to CRC. Proximal colon is always involved.
Hyperplastic polyp Most common non-neoplastic polyp in colon (> 50% found in rectosigmoid colon).
Juvenile Polyp Mostly sporadic lesion in children < 5 years of age. 80% in rectum. If single, no malignant potential. - Juvenile polyposis syndrome-multiple juvenile polyps in GI tract, ↑ risk of adenocarcinoma
Peutz-Jegher syndrome Single polyps are not malignant. - autosomal-dominant syndrome featuring multiple non malignant hamartomas throughout Gl tract, along with hyperpigmented mouth, lips, hands, genitalia. Associated with ↑ risk of CRC and other visceral malignancies
Colorectal carcinoma epidemiology 3rd most common cancer; 3rd most deadly in United States. Most patients are > 50 years of age. - 25% have a family history
Familial adenomatous polyposis (FAP) autosomal-dominant mutation of APC gene on chromosome 5q. Two-hit hypothesis - 100% progress to CRC. Thousands of polyps; pancolonic; always involves rectum.
Gardner's syndrome FAP + osseous and soft tissue tumors, retinal hyperplasia.
Turcot's syndrome FAP + malignant CNS tumor. TURcot = TURban.
Hereditary nonpolyposis colorectal cancer (HNPCC/Lynch syndrome) -autosomal dominant mutation of DNA mismatch repair genes. - 80% progress to CRC. Proximal colon is always involved.