10.8 - Colon

Question 1

hirschsprung disease is associated with that syndrome?

Answer 1

down syndrome

Question 2

what is the cause of of hirschsprung disease?

Answer 2

due to congenital failure of ganglion cells to descend into myenteric and submucosal plexus

Question 3

hirschsprung disease is due to congenital failure of _____________ to descend into _________ and _________ plexus

Answer 3

• ganglion cells

- myenteric and submucosal

Question 4

the ganglion cells that fail to descend in hirschsprung disease are derived from ___________

Answer 4

neural crest cells

Question 5

where is the myenteric (auerbach) plexus located? what is its role?

Answer 5

• between inner circular and outer longitudinal muscle layers of muscularis propria
• regulates motility

Question 6

where is the submucosal (meissner) plexus located? what is its role?

Answer 6

• submucosa

- regulates blood flow, secretions, absorption

Question 7

what type of biopsy is necessary to diagnosis hirschsprung disease?

Answer 7

rectal SUCTION biopsy (to get submucosa)

Question 8

(false) colonic diverticula consist of outpouchings of ________ through the ______________

Answer 8

• submucosa

- muscularis propria

Question 9

generally, where do colonic diverticula arise?

Answer 9

where the vasa recta traverse the muscularis propria

Question 10

what part of the GI tract is the most common site of colonic diverticula?

Answer 10

sigmoid

Question 11

what are the 3 main complications of colonic diverticula?

Answer 11

• rectal bleeding
• diverticulitis
• fistula

Question 12

high stress in the left colon leads to _____________, whereas high stress in the right colon leads to ______________

Answer 12

• diverticula

- angiodysplasia

Question 13

what is angiodysplasia?

Answer 13

acquired malformation of mucosal and submucosal capillary beds

Question 14

what is the inheritance of hereditary hemorrhagic telangiectasia?

Answer 14

AD

Question 15

ischemic colitis is most often due to atherosclerosis of the ______________

Answer 15

SMA

Question 16

what are the two most common types of colonic polyps?

Answer 16

• hyperplastic

- adenomatous

Question 17

which type of colonic polyp shows a “serrated” appearance on microscopy?

Answer 17

hyperplastic

Question 18

where do hyperplastic polyps most often arise?

Answer 18

left colon (rectosigmoid)

Question 19

are hyperplastic polyps benign or malignant?

Answer 19

benign

Question 20

are adenomatous polyps benign or malignant?

Answer 20

benign but premalignant

Question 21

the adenoma-carcinoma sequence involves what genes (in order)?

Answer 21

APC - KRAS - p53

Question 22

which gene in the adenoma-carcinoma sequence is responsible for increased risk of formation of a polyp?

Answer 22

APC

Question 23

which gene in the adenoma-carcinoma sequence leads to formation of a polyp?

Answer 23

KRAS

Question 24

which gene in the adenoma-carcinoma sequence is responsible for progression to carcinoma?

Answer 24

p53

Question 25

APC is located on chromosome ____

Answer 25

5

Question 26

which medication can impede progression from adenoma to carcinoma in the adenoma-carcinoma sequence? why?

Answer 26

• aspirin

- decreased expression of COX, which allows for progression to carcinoma via p53

Question 27

what is the inheritance of FAP?

Answer 27

AD

Question 28

FAP is due to an inherited mutation of ____ on chromosome ____

Answer 28

APC on chromosome 5

Question 29

gardner syndrome consists of what constellation of conditions?

Answer 29

FAP plus fibromatosis and osteomas

Question 30

what is fibromatosis? where does it arise? with which syndrome is it associated?

Answer 30

• non-neoplastic proliferation of fibroblasts
• arises in retroperitoneum (desmoid)
• gardner syndrome

Question 31

turcot syndrome consists of what constellation of conditions?

Answer 31

FAP plus CNS tumors (medulloblastoma and glial tumors)

Question 32

• FAP
• fibromatosis
• osteomas

diagnosis?

Answer 32

gardner syndrome

Question 33

• FAP
• CNS tumors

diagnosis?

Answer 33

turcot syndrome

Question 34

• hamartomatous (benign) polyps throughout GI tract

- mucocutaneous hyperpigmentation on oral mucosa and genital skin

Answer 34

peutz-jeghers syndrome

Question 35

what is the inheritance of peutz-jegher syndrome?

Answer 35

AD

Question 36

HNPCC is due to inherited mutations in _______ enzymes?

Answer 36

DNA mismatch repair

Question 37

what are the 3 types of cancer that arise from HNPCC?

Answer 37

• colorectal
• ovarian
• endometrial

Question 38

how do left sided colon carcinomas appear? are these normally due to adenoma-carcinoma sequence or microsatellite instability?

Answer 38

• “napkin ring lesion”

- adenoma-carcinoma sequence

Question 39

how do right sided colon carcinomas appear? are these normally due to adenoma-carcinoma sequence or microsatellite instability?

Answer 39

• raised lesion

- microsatellite instability

Question 40

how do left sided colon carcinomas typically present?

Answer 40

• decreased stool caliber
• LLQ pain
• blood streaked stool

Question 41

how do right sided colon carcinomas typically present?

Answer 41

• iron deficiency anemia
• occult bleeding
• vague pain

Question 42

an older adult with iron deficiency anemia has _______________ until proven otherwise?

Answer 42

colorectal carcinoma

Question 43

• decreased stool caliber
• LLQ pain
• blood streaked stool

Answer 43

left sided colon carcinoma

Question 44

• iron deficiency anemia
• occult bleeding
• vague pain

Answer 44

right sided colon carcinoma

Question 45

what is the serum marker that is useful for assessing treatment response and detecting recurrence?

Answer 45

CEA

Question 46

is CEA useful for screening?

Answer 46

NO