GI Neoplasia II

Question 1

Molecular association?

Answer 1

KRAS mutation

(Serrated lumens = hyperplastic polyp)

Question 2

List some factors associated with DECREASED risk of CRC

Answer 2

High calcium, folate, fiber, postmenopausal HRT, selenium, vegetable and fruit-heavy diet, ASA/NSAID use

Question 3

Inheritance pattern of FAP?

Answer 3

AD

(Inherit loss of one APC allele)

Question 4

Left or right CRC: frank bleeding

Answer 4

Left

Question 5

Biopsy of the associated GI lesion would reveal:

Answer 5

Hamartomas = mass of tissue indigenous to site

(Peutz-Jehgers syndrome = colonic hamartomas + oral hyperpigmentation)

Question 6

A 75 year old patient had a polypoid adenocarcinoma surgically removed 5 years ago. He now presents with occult bleeding and anemia. First step in management?

Answer 6

CEA to monitor for recurrence

Question 7

Dx?

Answer 7

Tubular adenoma

(Notice the pedunculated mass with crowded, hyperchromatic glands)

Question 8

How can this present?

Answer 8

Single rectal polyp in kid; can prolapse out of anus

(Juvenile/retention polyp = large cystic spaces/dilated glands

Question 9

Left or right CRC: tenesmus

Answer 9

Left

(Feeling of incomplete emptying)

Question 10

List some factors associated with INCREASED risk of CRC

Answer 10

Age, Fhx, lack of physical activity, low fiber/high fat diet, obesity, consumption of red meat, smoking, EtOH

Question 11

This finding is associated with:

Answer 11

FAP

(Multiple retinal pigmented areas)

Question 12

Left or right CRC: occult bleeding

Answer 12

Right

Question 13

What does CRC look like on barium enema?

Answer 13

Apple core lesion

Question 14

Treatment options for CRC

Answer 14

1. If localized to head of polyp = endoscopic polypectomy
2. Surgery
3. If node positive = surgery

Question 15

Left or right CRC: polypoid carcinoma

Answer 15

Right

Question 16

A 40 year old whose mother died of CRC at age 45 wants to undergo a colonoscopy, which is normal. A year later she presents with weight loss, anemia, and occult fecal blood. First step in management?

Answer 16

Screening for microsatellite mutations + check for ovarian, endometrial, urinary, and gastric cancers

(Development of CRC without polyps [indicated by normal colonoscopy] + Fhx of CRC <50 yo indicates HNPCC, which is caused by microsatellite instability, more associated with right sided CRC; also has increased risk of the above listed cancers)

Question 17

Which is heritable: oncogene or tumor suppressor gene abnormalities?

Answer 17

Tumor suppressor genes

(Oncogenes usually turned on via enviornmental stimuli)

Question 18

Left or right CRC: obstruction

Answer 18

Left

Question 19

Describe the adenoma-carcinoma sequence

Answer 19

Polyp to dysplasia to adenocarcinoma to invasive cancer

Question 20

An 80 year old patient presents with fever, hematachezia, and abdominal pain. On physical exam, you notice several splinter hemorrhages and oral mucosal petechiae. Cause?

Answer 20

Strep bovis endocarditis caused by CRC

Question 21

Dx?

Answer 21

Villous adenoma

(Tall glands, crowded cells)

Question 22

Left or right CRC: anemia

Answer 22

Right

Question 23

When does FAP present? Most common lesion?

Answer 23

2-3 decade (AD so in adulthood)

Adenomatous polyp (they have >100 so 100% chance of developing CRC if colectomy not performed)

Question 24

Mutation of FAP? Of HNPCC?

Answer 24

FAP = loss of APC

HNPCC = mutation in DNA mismatch repair enzymes (microsatellite)

Question 25

Why must patients avoid red meat before doing a fecal occult blood test?

Answer 25

Red meat contains myoglobin, which also has peroxidase activity, so it can catalyze oxidation of guaiac by peroxide like heme

Question 26

Left or right CRC: annular carcinoma

Answer 26

Left

Question 27

Left or right CRC: microsatellite instability

Answer 27

Right

Question 28

Left or right CRC: adenoma carcinoma sequence

Answer 28

Left