colon polyps Flashcards
screening has reduced colorectal cancer incidence and mortality
yep
colorectal cancer has a high incidence in
african american men
colorectal cancer over the age of 50
has gone down thought to be due to colonoscopy
between the ages of 20-49 in both men and women in colorectal cancer
has gone up but cause is unknown
colorectal cancer types (5):
- sporadic
- family history
- HNPCC/lynch syndrome
- FAP- fmailial adenomatous polyposis
- other rare syndromes
types of colorectal polyps
- sessile- found on the left side of the colon
- pedunculated
- Flat- found on the right side of the colon, hard to find requiring a high degree of prep before colonoscopy
colorectal polyps are what type of lesions
mucosal
what type of histology are serrated polyps
neoplastic except hyperplastic polyp
two types of hamartomatous polyps
- sporadic- known as a juvenile polyp found in the rectum have benign course with rectal bleeding or prolapse
- syndromic: associated with hereditary inheritance has two different types (1) juvenile polyposis syndrome and (2) Peutz- Jeghers syndrome
- Autosomal dominant
- 50-100 hamartomatous polyps
- 39% risk colon cancer (increased incidence of adenomas)
Polyposis Syndrome Juvenile
- Autosomal dominant: STK11 gene
- Oral and lip pigmentation
- Polyps in colon, small intestine, and stomach
- Risk for GI and non-GI cancers
Peutz-Jeghers Syndrome
types of adenomatous polyps (3)
- tubular adenoma
- tubulovillous adenoma
- villous adenoma
greater cancer risk with adenomatous polyps correlates swith how
villous it is
what type of treatment is needed for high grade dysplasia or intramucosal carcinoma polyps
surgery
serrated polyps types
- hyperplastic polyp
- sessile serrated adenoma/polyp
- traditional serrated polyp
serrated polyp found in the rectum and sigmoid
usually hyperplastic and non-neoplastic
proximal to sigmoid on the right colon
usually sessile serrated lesion and neoplastic
- Small (<5 mm), on top of mucosal folds
- Usually multiple, common in rectosigmoid
- Composed of mature cells
- No malignant potential
NON-NEOPLASTIC SERRATED POLYP: Hyperplastic Polyp
boot like appearance in histo polyp slide
sessile serrated adenoma/polyp
Innumerable colon adenomas
Duodenal (periampullary) adenomas,
100% progression to colon CA and its altered gene is APC
Familial adenomatous polyposis (FAP) - Classic
80% lifetime risk of colon CA;
CA stomach, small intestine, urinary tract, brain, skin, endometrium, ovary and the altered gene defect in DNA repair gene leading to microsatellite instability
Hereditary non-polyposis colon cancer (HNPCC)
= Lynch syndrome
when polyps are associated with syndromes then they have a risk for
colorectal cancer
amsterdam criteria
it is the way we can diagnose lynch syndrome through generations
stain that shows MLH1+ signifies that
there is activation of the mismatch repair genes which is normal it si when there is an absence of them that we suspect there is an inactivation of the genes
what do we need to so if a patient has FAP syndrome showing innumerable adenomatous polyps
total colectomy but we also need surveillance of stomach and duodenum with endoscopy due to increase risk of adenocarcinoma in the duodenum or ampulla of vater
most common pathology for sporadic colon cancer
chromosomal instability leading to a loss of heterozygosity at multiple loci
colorectal cancer on the left side of the colon
chromosomal instability
colorectal cancer on the right side of the colon
microsatellite instability associated with lynch syndrome and MLH1 silencing
Most tumors occur sporadically
Absence of well-defined familial syndromes
Characterized by chromosomal instability
Morphologically identifiable stages
adenoma-carcinoma
K-ras at 12p12
target of a chemotherapy for colorectal cancer
A 75 year old man has a colonoscopy to evaluate iron deficiency anemia. A 4cm ulcerating mass is found in the cecum. Biopsies are obtained and pathology is consistent with adenocarcinoma. A flat polyp is removed from the ascending colon and pathology reveals a sessile serrated adenoma. Which of the following would you most likely find on further pathologic analysis?
- MLH1 inactivation
- Little lymphocytic infiltration
- Extensive chromosomal instability
- Low microsatellite instability
- Germline mutation in MSH2
- MLH1 inactivation
primary tumor (T) staging
depth of invasion
Tx
tumor cannot be assessed
Tis
carcinoma in situ
T1
tumor invades submucosa
T2
tumor invades muscularis propria
T3
tumor invades subserosa
T4
tumor directly invades adjacent organs/structures or through the visceral peritoneum
Colorectal tumor with wild-type K-ras:
benefit from cetuximab / panitumimab
improves overall and progression-free survival
- A well-differentiated neuroendocrine neoplasm
- Appendiceal and rectal carcinoids rarely metastasize
- Ileal and colonic tumors may invade deeply and metastasize
carcinoid tumor
- MALT lymphoma is most common; t(11;18) translocation
- T-cell lymphoma; associated with malabsorption
- Good prognosis (other than T-cell)
lymphoma
Lipoma, leiomyoma, GIST (c-KIT expression)
mesenchymal tumors
Primary melanoma may arise in the
anal canal
Pure anal canal squamous carcinomas associated with
chronic HPV
tumors of the anal canal may be (30
- adenocarcinoma
- basaloid
- squamous
Appendiceal tumors:
Enlargement by inspissated mucus due to obstruction
mucocele
Appendiceal tumors:
- Most common mucinous neoplasm
- Perforation may cause intraperitoneal mucin
Mucinous Cystadenoma (benign)
Appendiceal tumors:
- Grossly similar to cystadenoma
- May cause pseudomyxoma peritoneii
Mucinous Cystadenocarcinoma
anal cancer treatment
surgery with or w/out radiation
endometriosis is associated on which side in women
left side
why screen for colon cancer?
treatment before symptoms show a better survival prognosis and there is a slow progression from adenoma to carcinoma
tests that detect cancer 2
- stool based test
2. blood-based test: detect ciruclating methylated septin 9 DNA
tests that detect cancer and pre-cancerous polyps
structural tests
Guaiac based fecal occult blood testing
detects peroxidase activity of heme (not specific for human blood)
not used
FIT - Fecal immunochemical test (FIT)
antibodies specific for human hemoglobin, albumin, or other blood components
Stool DNA tests
Detect mutations associated with colon neoplasia in stool samples
Cologuard
structural tests used
- colonoscopy- standard pf care
- CT colonography
- capsule colonoscopy
CT clonography cannot see
flat serrated polyps
when do we start screening individuals for colonoscopy
50 but ACS recommendation at age 45
- if african american at age 45
- family history of CRC age 40
- has lynch syndrome age 20
- has FAP age 12
Inflammatory bowel disease for CRC:
- Pancolitis
- Higher risk in PSC patients
- Pancolitis – begin 8 years after diagnosis – annual colonoscopy
- Higher risk in PSC patients – begin annual colonoscopy at time of diagnosis
risk reduction for colorectal cancer
- reduction in incidence of CRC in most studies
- useful to reduce adenoma burden in FAP
- Post-menopausal hormone use:
- Discontinue ______use
- Aspirin – reduction in incidence of CRC in most studies
- Celecoxib – useful to reduce adenoma burden in FAP
- Post-menopausal hormone use: estrogen + progesterone
- Discontinue cigarette use
Family history of CRC or colorectal adenoma
First degree relative with CRC or advanced adenoma < 60
Two first degree relatives with CRC or adenoma at any age
Begin screening at age 40
or 10 years younger than age
at first diagnosis, repeat every
5 years
One first degree relative with CRC or advanced adenoma > 60
Two second degree relatives with CRC or adenoma
Begin age 40, repeat
every 10 years
