Colorectal Stuff

Question 1

What is Mut Y Homolog-Associated polyposis?

Answer 1

uniquely autosomal recessive colorectal condition.
Patient has less polyps (but still at least 10 adenomas) than FAP but can still have duodenal adenomas and desmoid tumors. Attenuated polyps.

Question 2

FAP:
What inheritance, gene and chromosome?
Lots of polyps but where are the benign ones?
What is the prophylactic treatment?
MCC of death after prophylactic surgery?
2nd MCC of Death after prophylactic surgery? Tx?
What other surveillance is needed after Total Colectomy?

Answer 2

• FAP is autosomal dominant for APC gene mutation on chromosome 5q
• The Stomach polyps are benign
• total proctocolectomy with ileoanal anastomosis is most optimal. Eliminates lifelong surveillance.
• MCC of death after total colectomy is from periampullary tumors.
• Second MCC of death after total colectomy is desmoid tumors (bland fibrous neoplasm, with local infiltration)
• Desmoid tumors respond to tamoxifen, NSAIDS, or Sulindac
• Can get duodenal polyps so need EGD q1-2 years with side-viewing scope

Question 3

Presentation of Turcot Syndrome?

Answer 3

Colorectal polyps + CNS tumors, 2/3 have APC mutation.

Question 4

Peutz-Jeghers syndrome: 
What is mutated?
Presentation?
Prophylactic surgery?
Surveillance?

Answer 4

• STK11
• hamartomatous polyps, mucocutaneous pigmentation, sertoli cells.
• DON’T take out the colon prophylactically. Increased risk of extra colonic cancers.
• Colonoscopies every 2 years.

Question 5

Cowden Syndrome,
What is mutated?
Presentation?

Answer 5

-PTEN tumor suppressor
-Macrocephaly, trichilemmomas, and tumors of breast, thyroid, uterus, and skin. Variable polyps.
Hamartomas composed of all 3 germ layers.

Question 6

Muir-Torre Syndrome presentation?

Answer 6

Muir-Torre syndrome has sebaceous gland tumors and visceral cancer, usually colorectal cancer

Question 7

Juvenile polyposis mutation and presentation?

Answer 7

• SMAD4

- juvenile non-adenomatous polyps, early age colorectal cancer

Question 8

Gardner syndrome presentation?

Answer 8

abdominal desmoid tumors, osteomas (usually in the head), and sebaceous cysts

Question 9

Lynch syndrome types, risks, surveillance?

Answer 9

Lynch syndrome 1 – colon cancer
AD inheritance but 20% are sporadic
Lynch syndrome 2 – colon cancer + endometrial, ovarian, gastric cancers
-Surveillance
Colonoscopy @ 20 yo every 1-3 years
Transvaginal US @ 20-25 every year
-Prophylactic resection includes total abdominal colectomy with ileorectal anastomosis + TAH + BSO

Question 10

Micro satellite tumor cause in sporadic tumors?

What about in Lynch syndrome?

Answer 10

• MSI tumors in 15% of sporadic colorectal cancer result from the hypermethylation of the MLH 1 gene promoter.
• MSI tumors in Lynch syndrome are caused by germline mutations in MLH 1, MSH 2, MSH 6, and PMS2.