Colonic Polyps and Tumors Flashcards
What is the definition of a colorectal polyp?
It is an overgrowth of cells into the lumen of the colon or rectum.
What are the three categories of colonic polyp?
Nonneoplastic, hamartomatous, and neoplastic.
What are nonneoplastic colonic polyps?
Polyps that typically do not progress to cancer.
What are hamartomatous colonic polyps?
Polyps consisting of disorganized tissue growth.
What are neoplastic colonic polyps?
Dysplastic polyps with malignant potential.
What is the classic presentation of juvenile polyps?
A 4-6 year old child who presents with intermittent, painless hematochezia with bowel movements.
What are juvenile polyps?
They are the most common type of polyp in children. They are inflammatory, and usually classified as pedunculated hamartomas.
What is the difference in cancer risk between a solitary juvenile polyp and juvenile polyposis?
Solitary juvenile polyps are not cancer-prone. In contrast, juvenile polyposis occurs when there are > 5 polyps, and these have a high long-term risk of malignancy (affected individuals are 30x more likely to develop colorectal cancer).
What is the inheritance pattern and genetic defect associated with Peutz-Jeghers syndrome?
It is an autosomal dominant disease with variable penetrance. There is a mutation of the STK11 gene on chromosome 19p.
What are the presenting symptoms of Peutz-Jeghers syndrome?
It presents with GI hamartomatous polyps and mucocutaneous hyperpigmentation of the lips and gums. ***Include Image 10-13
What is the cancer risk in patients with Peutz-Jeghers syndrome?
Nearly half of patients develop cancers outside of the colon during their lifetime, with the most common involving the breast, cervix, ovary, testicle, and pancreas; 2-13% develop colon cancer.
Which three syndromes are associated with PTEN gene mutations?
PTEN hamartoma tumor syndrome, Bannayan-Riley-Ruvalcaba syndrome, and Cowden syndrome.
What are the characteristics of Bannayan-Riley-Ruvalcaba syndrome?
Macrocephaly, pigmented penile lesions, and hamartomatous intestinal polyps. There may also be café-au-lait spots, lipomas, intellectual disability, and lipid storage abnormalities.
What gene mutation is responsible for Bannayan-Riley-Ruvalcaba syndrome?
It most commonly results from mutations on the PTEN tumor suppressor gene.
What are the characteristics of Cowden syndrome?
It is very rare and is characterized by the presence of multiple hamartomata of the skin, mucous membranes, breast, and thyroid. Hyperkeratotic papillomas of the lips and tongue are also characteristic. They may also have gastric, duodenal, and/or colonic polyps.
