Colon - Pathoma

Question 1

What developmental disorder is Hirschsprung disease associated with?

Answer 1

Down Syndrome

Question 2

What is the embryologic abnormality that causes Hirschsprung Disease?

Answer 2

congenital failure of ganglion cells to descend

Question 3

What causes Colonic Diverticula?

Answer 3

• Related to wall stress
  
  • associated with constipation and low fiber diet
  • commonly seen in older adults
  • Arise where vasa recta traverse musclularis propria ⇒ weak point in colonic wall
  • sigmoid colon is most common location

Question 4

What are the symptoms/complications of Colonic Diverticula?

Answer 4

• Sx: Usually asymptomatic
• Complications:
  
  • Rectal bleeding (hematochezia)
  • Diverticulitis
  • Fistula

Question 5

What is Angiodysplasia?

Answer 5

• Acquired malformation of mucosal and submucosal capillary beds

Question 6

Where does Angiodysplasia most commonly arise? Why?

Answer 6

• Cecum and Right Colon
  
  • due to high wall tension

Question 7

How does Angiodysplasia typically present?

Answer 7

Hematochezia in an older adult

Question 8

What is Hereditary Hemorrhagic Telangectasia?

Answer 8

• Autosomal dominant disorder resulting in thin-walled blood vessels
  
  • especially in the nasopharynx and GI tract
• Rupture presents as bleeding

Question 9

What is ischemic colitis?

Answer 9

ischemic damage to the colon

Question 10

Where does ischemic colitis most often occur?

Answer 10

Splenic flexure

Question 11

What is the most common cause of ischemic colitis?

Answer 11

Atherosclerosis of the Superior Mesenteric Artery

Question 12

How does Ischemic Colitis typically present?

Answer 12

• Postprandial pain and weight loss
  
  • increase energy requirements after meal
• Infarction presents as pain and bloody diarrhea

Question 13

What GI wall layers contribute to Colonic Polyps?

Answer 13

raised protrusions of colonic mucosa

Question 14

What is the most common type of Colonic Polyp?

Answer 14

Hyperplastic Polyp

Question 15

What causes Hyperplastic Polyps?

Answer 15

• due to hyperplasia of glands

Question 16

Where to hyperplastic polyps most commonly arise?

Answer 16

Left colon (rectosigmoid)

Question 17

Are hyperplastic polyps benign or malignant?

Answer 17

Benign, with no malignant potential

Question 18

What is the second most common type of colonic polyp?

Answer 18

Adenomatous polp

= neoplastic proliferation of glands

Question 19

Are adenomatous polyps benign or malignant?

Answer 19

• Benign, but premalignant
  
  • may progress to adenocarcinoma via the adenoma-carcinoma sequence

Question 20

What is the Adenoma-Carcinoma Sequence?

Answer 20

• APC mutations (sporadic or germline, chroms. 5) increase risk for formation of polyp
• KRAS mutations lead to mutation of polyp
• p53 mutations and increased expression of COX allow for progression to carcinoma

Question 21

What are the three key risk factors that tell you there is an increased theoretical risk of the progression from adenoma to carcinoma evaluated during colonoscopy?

Answer 21

• Risk for progression from adenoma to carcinoma
  
  • related to size >2cm
  • sessile growth (no stalk)
  • villous histology

Question 22

What is FAP?

Answer 22

• Autosomal dominant disorder → due to inherited APC mutation (chromosome 5)
  
  • characterized by 100’s to 1,000’s of adenomatous colonic polyps

Question 23

What is the prophylactic treatment for carcinoma in FAP patients?

Answer 23

Removal of colon and rectum

Question 24

What syndrome is associated with the combination of FAP + fibromatosis + osteomas?

Answer 24

Gardner Syndrome

(fibromatosis = non-neoplastic proliferation of fibroblasts that is destructive)

(osteoma = benign tumor of bone)

Question 25

What syndrome is associated with the combination of FAP + CNS tumors?

Answer 25

Turcot syndrome

(medulloblastoma and glial tumors)

Question 26

What is a Juvenile Polyp?

Answer 26

Sporadic hamartomatous benign polyp that arises in children (<5 yoa)

Question 27

How does a Juvenile polpy usually present?

Answer 27

Solitary rectal polyp that prolapses and bleeds

Question 28

Does Juvenile Polyposis (multiple juvenile polyps in the stomach and colon) increase the risk of cancer?

Answer 28

Yes!
Large numbers of juvenile polyps increases the risk of progression to carcinoma

Question 29

What syndrome is associated with hamartomatous polyps throughout the GI tract and mucocutaneous hyperpigmentation of the lips, oral mucosa, and genital skin?

Answer 29

Peutz-Jeghers Syndrome

Question 30

What is the inheritance pattern of Peutz-Jeghers Syndrome? Risk?

Answer 30

• Autosomal dominant
• Increased risk for colorectal, breast, and GYN cancer