Flashcards in CH10 - Gastrointestinal Pathology Deck (345)
How is screening for polyps performed?
by colonoscopy and testing for fecal occult blood
How do polyps present clinically?
they are usually clinically silent, but can bleed.
What is the goal in term of polyps?
it is to remove adenomatous polyps before progression to carcinoma
On colonoscopy can you tell the difference between hyperplastic and adenomatous polyps?
No they look identical. Hence, all polyps are removed and examined microscopically
With polyps what is the risk for progression from adenoma to carcinoma related to?
size > 2 cm, sessile growth, and villous histology.
What is familial adenomatous polyposis?
(FAP)Autosomal dominant disorder characterized by 100s to 1000s of adenomatous colonic polyps
What is familial adenomatous polyposis (FAP) due to?
inherited APC mutation (chromosome 5); increases propensity to develop adenomatous polyps throughout colon and rectum
How is familial adenomatous polyposis treated?
Colon and rectum are removed prophylacticly ; otherwise, almost all patients develop carcinoma by 40 years of age.
What is gardner syndrome?
it is FAP with fibromatosis and osteomas
What is fibromatosis?
it is a non-neoplastic proliferation of fibroblasts
Where does fibromatosis arise?
in retroperitoneum (desmoid) and locally destroys tissue
What is Osteoma?
it is a benign tumor of bone that usually arises in the skull
What is Turcot syndrome?
it is FAP with CNS tumors (medulloblastoma and glial tumors)
What is a juvenile polyp?
Sporadic, hamartomatous (benign) polyp that arises in children (< 5 years)
How does juvenile polyp usually present?
as a solitary rectal polyp that prolapses and bleeds
What is juvenile polyposis characterized by?
multiple juvenile polyps in the stomach and colon; large numbers of juvenile polyps increase the risk of progression to carcinoma.
What is peutz-jeghers syndrome?
Hamartomatous (benign) polyp throughout GI tract and mucocutaneous hyperpigmentation (freckle-like spots) on lips, oral mucosa, and genital skin; autosomal dominant disorder
In Peutz-Jeghers Syndrome what is there an increased risk for?
colorectal, breast, and gynecologic cancer
What is colorectoal carcinoma?
Carcinoma arising from colonic or rectal mucosa
What is the 3rd most common site of cancer?
What is the 3rd most common cause of cancer-related death?
What is the peak incidence for colorectal carcinoma?
it is 60-70 years of age
What does colorectal carcinoma most commonly arise from?
For colorectal carcinoma what is a second important molecular pathway?
the microsatellite instability (MSI) pathway
What are microsatellites in the MSI pathway?
they are repeating sequences of noncoding DNA; integrity of the sequence (stability) is maintained during cell division.
What does instability in the microsatellite instability pathway indicate?
defective DNA copy mechanisms (eg. DNA mismatch repair enzymes).
What is HNPCC
Hereditary non polyposis colorectal carcinoma
What is HNPCC due to?
Inherited mutations in DNA mismatch repair enzymes.
With HNPCC what is there an increased risk for?
colorectal, ovarian, and endometrial carcinoma