Flashcards in Tumors of the Small and Large Bowel Deck (46):
What are risk factors for SI adenocarcinoma?
What is GIST?
gastrointestinal stromal tumor
most common non-epithelial/soft tissue tumor in GI tract
derived from pacemaker cells (interstitial cells of cajal)
What is useful for treatmetn of GIST?
What are the markers of GIST?
Describe carcinoid syndrome
vasomotor disturbances, intestinal hypermotility, wheezing, hepatomegaly, cardiac involvement
Define non-neoplastic polyp
result of abnormal mucosal maturation, inflammation, distorted architecture
no malignant potential
Describe neoplastic polyp
arise as a result of proliferatio nnad dysplasia (adenomas)
precursor of carcinoma
What are the types of non-neoplastic polyps?
What is a hamartoma?
benign w/no malig pot
composed of mature, histologically normal elements from that site growing in a disorganized manner
What are different types of hamatomatous polyps?
peutz jeghers polyps
Features of juvenile polyps?
80% in rectum
expanded lamina propria
What genes are associated with juvenile polyposis syndrome? other features?
increased risk of adenomas
10-50% risk of colon cancer
multiple juvenile polyps
What is peutz jeghers syndrome?
mutliple GI polyps
hyperigmentation of the mouth and fingers
increased risk of intussusception
increased risk of cancer of the pancreas, breast, lung, ovary, uterus
large and pedunculated, lots of goblet cells
What is cowden syndrome?
hamartomatous GI polyps
facial trichilemmomas, oral papillomas, acral keratoses
assoc risk of thyroid and breast cancer
polyps themselves no malig pot
What is cronkhite-canada?
GI hamartomatous polyps
ectodermal abnormalities (nail atrophy, alopecia)
What are inflammatory polyps?
pseudopolyps-regenerating mucosa adjacent to ulceration (seen in severe IBD)
What are lymphoid polyps?
mucosal bumps caused by intramucosal lymphoid follicles-normal
What are serrated polyps?
smooth protrusions of mucosa usally at the top of mucosal fold
serrated lamina nad increased numbers of goblet cells
hyperpastic or sessile
Which type of serrated polyp has malignant potential?
BRAF V600E mutations
What are adenomatous polyps? (adenomas)
Arise as a result of epithelial proliferative dysplasia
precursor lesions for adenocarcinoma
-tubular, villous, and tubulovillous adenoma
fourfold greater risk of developing adenomas among 1st deree relatives of pts w/ & risk of developing carcinoma
Where are most tubular adenomas found?
What are villous adenomas?
often large, sessile
older ppl in rectosigmoid
cancer invasion directly into colon wall
What is the only adequate treatment for an adenoma?
What is the most common colorectal cancer?
-usually in rectosigmoid
What are risk factors for colorectal cancer?
What is right sided colon cancer usually like?
fatique, weakness, iron deficiency anemia
polypoid eophytic lesions
What is left sided colon cancer usually like?
may be obstructive
occult bleeding, changes in bowel habit, abd discomfort
annular napkin ring constrictions
tend to be more infiltrative
What gene(s) are often inactived in adenoma carcinoma pathway?
if not inactivated APC B-catenin mutations
(leads to increased WNT signaling, decreased cell adhesion and increased cellular proliferation)
loss of p53 late
What is the depth of invasion for TIS-T4
TIS carcinoma in situ
T2 muscularis propria
T4 other organs/structures
What is the most important prognostic indicator of colorectal carcinoma?
Stage=T + M + N
Where does colon cancer like to spread?
lymph nodes, liver, lungs, bones
What is the major negative predictor of efficacy in EGFR moAB therapy?
BRAF mutation correlates with poor prognosis and lack of response
AD mutation of APC gene
>100 colonic adenomas
colon adenocarcinoma 100% of the time
What is gardner's syndrome?
adenomatous polyposis with osteomas, epidermoid cysts, desmoid tumros
What is turcot syndrome?
adenomatous polyposis with medulloblastoma
What is MAP?
aka MYH associated polyposis
hereditary colorectal cancer syndrome that has phenotypic overlap w/FAP
20-100 adenomatous polyps usually
due to mutations in MYH gene
presents older than FAP
What does MYH protein do?
DNA repair protein-base excision repair
repairs oxidation induced DNA damage by removing A mis-paired with G
What is lynch syndrome?
increased risk of colorectal & endometrial cancer in females (also SI, ureter, renal pelvis)
adenomas earlier than normal pop but in low nubers
microsatellite instability pathway, DNA mismatch repair genes busted
What is Muir Torre syndrome?
a lynch syndrome variant
associated wtih multiple sebaceaous adenomas, sebaceous carcinomas, and keratoacanthomas
What does microsatellite instability lead to?
accumulation of mutations in the genome
What do microsatellites serve as sensitve markers of?
mistmatch repair function
-typically microsatellites are shorter in tumor tissue
Is braf mutation seen in lynch syndrome?
What are the 2 main types of anal canal carcinoma?
What is the most common tumor of the appendx?
What is a mucinous cystadenoma/cystadenocarcinoma?
a mucous secreting epithelial tumor