GI Pathology IV: Large Intestine

Question 1

True Diverticulum

Answer 1

Involves all 3 wall layers - Mekcel’s

Question 2

False Diverticulum

Answer 2

Only involves the mucosa and submucosa

Question 3

Diverticulitis

Answer 3

Inflammation of the diverticula that can cause pain

Question 4

Hernia

Answer 4

Serosal lined outputting of peritoneum - with loops of intestines trapped within the hernia sac

Question 5

What are the symptoms of ischemic bowel disease?

Answer 5

• Sudden severe abdominal pain
• Bloody diarrhea
• Tenderness
• Shock

Question 6

What is the pathogenesis of ischemic bowel disease?

Answer 6

Caused due to hypoxic injury and is worsened with the reperfusion injury

Question 7

Where is the ischemic bowel disease often the worst?

Answer 7

In water shed areas - furthest from circulation - splenic flexure

Question 8

What is the range of damage seen on the gross findings of ischemic bowel disease?

Answer 8

Can range from mucosal hemorrhage to transmural necrosis of the bowel wall

Question 9

Internal Hemorrhoids

Answer 9

They are above the pectinate line and are NOT painful

Question 10

External Hemorrhoids

Answer 10

Below the pectinate line and ARE painful

Question 11

Inflammatory Polyp (Solitary Rectal Ulcer Syndrome)

Answer 11

Sharp angle in the rectum undergoes recurrent abrasion and ulceration that leads to the formation of polyp.

Question 12

What is the histologic pattern seen with an inflammatory polyp?

Answer 12

Fibromuscular hyperplasia in the lamina propria with some inflammation present

Question 13

Juvenile Polyp

Answer 13

Most are found in children younger than 5 yrs and if solitary, then it is benign, if multiple then there is increased risk of adenocarcinoma

Question 14

Peutz-Jeghers Syndrome

Answer 14

Multiple benign hamartomas throughout the GI tract with hyper pigmentation of the lips, genitals and hands.

The polyps do NOT have malignant potential but patients are at increased risk of colorectal cancer.

Question 15

Hyperplastic Polyp

Answer 15

Asymptomatic. Look like adenomas with proliferation of mature goblet cells that pile up on each other giving it a serrated appearance.

Question 16

What are the types of Adenomatous Polyps?

Answer 16

• Sessile

- Pedunculated

Question 17

What is the histology of sessile adenomatous polyps?

Answer 17

Villous

Question 18

What is the histology of pendunculated adenomatous polyps?

Answer 18

Tubular

Question 19

Sessile Serrated Adenoma

Answer 19

Adenomatous polyp occurring predominantly in the right colon and has malignant potential

Question 20

Adenomatous Dysplasia

Answer 20

Neoplastic epithelium which lines the glands leading to disordered cells with or without mucin production and cells have increased N/C ratio

Question 21

What is the gene mutation in Familial Adenomatous Polyposis?

Answer 21

Autosomal dominant defect in APC gene on Ch5q21

Question 22

Gardner Syndrome

Answer 22

Autosomal dominant with polyps similar to FAP but with osteomas

Question 23

Turcots Syndrome

Answer 23

Intestinal adenomas with tumors of the CNS - most have APC mutations

Question 24

Hereditary Nonpolyposis Colorectal Cancer (Lynch Syndrome)

Answer 24

Autosomal dominant mutation of DNA mismatch repair genes that will have a lower number of polyps but with cancer occurring at younger ages than sporadic cancer

Question 25

What is the function of the APC gene?

Answer 25

APC is an inhibitor of B catenin and mutation in APC will cause B catenin to accumulate and active MYC and cyclin D1 leading to the promotion of proliferation

Question 26

What cancers do mutations in the DNA mismatch repair cause?

Answer 26

HNPCC

SSA

Question 27

What cancers do mutations in APC cause?

Answer 27

FAP

Sporadic CRC

Question 28

Right Sided CRC

Answer 28

Asymptomatic for a long period of time with signs of iron deficiency anemia from ulceration and blood loss

Question 29

One what side is the colon larger?

Answer 29

Right

Question 30

Left Sided CRC

Answer 30

The narrower lumen causes tumors that lead to bowel obstruction with possible blood in the stool

Question 31

What is the most common type of rectal cancer?

Answer 31

Adenocarcinoma

Question 32

What is the most common type of anal cancer?

Answer 32

Squamous Cell Carcinoma

Question 33

Acute Appendicitis

Answer 33

Obstruction from fecal matter leads to impair blood flow and bacterial contamination with transmural inflammation that leads to RLQ pain

Question 34

What is seen on histology of appendicitis?

Answer 34

Transmural inflammation full of neutrophils

Question 35

Mucocele

Answer 35

Benign dilatation of the lumen by mutinous secretions

Question 36

Mucinous Cystadenoma

Answer 36

Proliferation of benign neoplastic cells with dilatation of the lumen by mutinous material and it may rupture

Question 37

Mucinous Cystadenocarcinoma

Answer 37

Invasion of neoplastic cells

Question 38

Pseudomyxoma peritonei

Answer 38

Distention of the peritoneal cavity by the presence of semisolid mucin and epithelial mucin producing implants and/or malignant cells