10.8 - Colon Flashcards
hirschsprung disease is associated with that syndrome?
down syndrome
what is the cause of of hirschsprung disease?
due to congenital failure of ganglion cells to descend into myenteric and submucosal plexus
hirschsprung disease is due to congenital failure of _____________ to descend into _________ and _________ plexus
- ganglion cells
- myenteric and submucosal
the ganglion cells that fail to descend in hirschsprung disease are derived from ___________
neural crest cells
where is the myenteric (auerbach) plexus located? what is its role?
- between inner circular and outer longitudinal muscle layers of muscularis propria
- regulates motility
where is the submucosal (meissner) plexus located? what is its role?
- submucosa
- regulates blood flow, secretions, absorption
what type of biopsy is necessary to diagnosis hirschsprung disease?
rectal SUCTION biopsy (to get submucosa)
(false) colonic diverticula consist of outpouchings of ________ through the ______________
- submucosa
- muscularis propria
generally, where do colonic diverticula arise?
where the vasa recta traverse the muscularis propria
what part of the GI tract is the most common site of colonic diverticula?
sigmoid
what are the 3 main complications of colonic diverticula?
- rectal bleeding
- diverticulitis
- fistula
high stress in the left colon leads to _____________, whereas high stress in the right colon leads to ______________
- diverticula
- angiodysplasia
what is angiodysplasia?
acquired malformation of mucosal and submucosal capillary beds
what is the inheritance of hereditary hemorrhagic telangiectasia?
AD
ischemic colitis is most often due to atherosclerosis of the ______________
SMA
what are the two most common types of colonic polyps?
- hyperplastic
- adenomatous
which type of colonic polyp shows a “serrated” appearance on microscopy?
hyperplastic
where do hyperplastic polyps most often arise?
left colon (rectosigmoid)
are hyperplastic polyps benign or malignant?
benign
are adenomatous polyps benign or malignant?
benign but premalignant
the adenoma-carcinoma sequence involves what genes (in order)?
APC - KRAS - p53
which gene in the adenoma-carcinoma sequence is responsible for increased risk of formation of a polyp?
APC
which gene in the adenoma-carcinoma sequence leads to formation of a polyp?
KRAS
which gene in the adenoma-carcinoma sequence is responsible for progression to carcinoma?
p53
APC is located on chromosome ____
5
which medication can impede progression from adenoma to carcinoma in the adenoma-carcinoma sequence? why?
- aspirin
- decreased expression of COX, which allows for progression to carcinoma via p53
what is the inheritance of FAP?
AD
FAP is due to an inherited mutation of ____ on chromosome ____
APC on chromosome 5
gardner syndrome consists of what constellation of conditions?
FAP plus fibromatosis and osteomas
what is fibromatosis? where does it arise? with which syndrome is it associated?
- non-neoplastic proliferation of fibroblasts
- arises in retroperitoneum (desmoid)
- gardner syndrome
turcot syndrome consists of what constellation of conditions?
FAP plus CNS tumors (medulloblastoma and glial tumors)
- FAP
- fibromatosis
- osteomas
diagnosis?
gardner syndrome
- FAP
- CNS tumors
diagnosis?
turcot syndrome
- hamartomatous (benign) polyps throughout GI tract
- mucocutaneous hyperpigmentation on oral mucosa and genital skin
peutz-jeghers syndrome
what is the inheritance of peutz-jegher syndrome?
AD
HNPCC is due to inherited mutations in _______ enzymes?
DNA mismatch repair
what are the 3 types of cancer that arise from HNPCC?
- colorectal
- ovarian
- endometrial
how do left sided colon carcinomas appear? are these normally due to adenoma-carcinoma sequence or microsatellite instability?
- “napkin ring lesion”
- adenoma-carcinoma sequence
how do right sided colon carcinomas appear? are these normally due to adenoma-carcinoma sequence or microsatellite instability?
- raised lesion
- microsatellite instability
how do left sided colon carcinomas typically present?
- decreased stool caliber
- LLQ pain
- blood streaked stool
how do right sided colon carcinomas typically present?
- iron deficiency anemia
- occult bleeding
- vague pain
an older adult with iron deficiency anemia has _______________ until proven otherwise?
colorectal carcinoma
- decreased stool caliber
- LLQ pain
- blood streaked stool
left sided colon carcinoma
- iron deficiency anemia
- occult bleeding
- vague pain
right sided colon carcinoma
what is the serum marker that is useful for assessing treatment response and detecting recurrence?
CEA
is CEA useful for screening?
NO
