Intestinal polyps amd colorectal carcinoma

Question 1

What is a polyp?

Answer 1

An elevated mass lesion which protrudes to the lumen/surface.

Question 2

What is a true polyp?

Answer 2

A polyp that arises from the epithelium.

Question 3

What are the two main morphological types of polyps based on attachment?

Answer 3

Sessile (flat) and Pedunculated (on a stalk).

Question 4

What are the two main categories of true polyps based on neoplastic potential?

Answer 4

Non-neoplastic and Neoplastic.

Question 5

Name three types of non-neoplastic polyps.

Answer 5

Hyperplastic
Inflammatory
Hamartomatous

Question 6

What are the two main types of neoplastic polyps?

Answer 6

Benign (Adenoma) and Malignant (Carcinoma).

Question 7

What is the common age group for hyperplastic polyps?

Answer 7

60s-70s.

Question 8

What is the pathogenesis of hyperplastic polyps?

Answer 8

Delayed shedding of surface epithelial cells.

Question 9

Describe the macroscopic features of hyperplastic polyps.

Answer 9

Usually small (<5mm)

Question 10

What is a characteristic microscopic feature of hyperplastic polyps?

Answer 10

Glands may show a ‘serrated appearance’ towards the surface; no dysplasia.

Question 11

What are juvenile polyps?

Answer 11

Mucosal malformations (hamartomas)

Question 12

In which age group are juvenile polyps most commonly seen?

Answer 12

Children under 5 years old.

Question 13

Describe the macroscopic appearance of a juvenile polyp.

Answer 13

Rounded reddish polyp

Question 14

What is a key microscopic feature of juvenile polyps?

Answer 14

Cystically dilated glands containing mucin; no dysplasia.

Question 15

What is Juvenile Polyposis Syndrome?

Answer 15

An autosomal dominant inherited condition with multiple juvenile polyps and an elevated risk of colonic adenocarcinoma and other cancers.

Question 16

What are Peutz-Jegher polyps?

Answer 16

Hamartomatous polyps that can be single or multiple (associated with Peutz-Jegher syndrome).

Question 17

What is Peutz-Jegher syndrome?

Answer 17

An autosomal dominant syndrome characterized by multiple GI polyps

Question 18

Describe the macroscopic appearance of a Peutz-Jegher polyp.

Answer 18

Large

Question 19

What is a characteristic microscopic feature of Peutz-Jegher polyps?

Answer 19

A branching network of smooth muscle in the stroma of the polyp; glandular epithelium does not show dysplasia.

Question 20

What causes inflammatory pseudopolyps?

Answer 20

Chronic injury and healing.

Question 21

In what conditions are inflammatory pseudopolyps commonly seen?

Answer 21

Inflammatory bowel diseases

Question 22

What is an adenoma?

Answer 22

A neoplastic true polyp arising from epithelial proliferation

Question 23

Name the three types of adenomas according to gland architecture.

Answer 23

Tubular

Question 24

Which is the most common type of adenoma?

Answer 24

Tubular adenoma.

Question 25

Describe the typical macroscopic features of a tubular adenoma.

Answer 25

Typically small

Question 26

Describe the typical macroscopic features of a villous adenoma.

Answer 26

Larger (up to 10 cm)

Question 27

What are the microscopic features of dysplasia seen in adenomas?

Answer 27

Multilayered epithelium

Question 28

What factors determine the malignant potential of adenomas?

Answer 28

Polyp size (rare if <1 cm)

Question 29

What is Familial Adenomatous Polyposis (FAP) syndrome?

Answer 29

An autosomal dominant condition due to APC gene mutation

Question 30

What is the malignant potential in FAP?

Answer 30

100%

Question 31

What is the recommended management for FAP?

Answer 31

Prophylactic colectomy.

Question 32

What is a serrated adenoma?

Answer 32

Adenomas with prominent sawtoothed, distorted architecture in entire length of glands• Sessile or pedunculated• Dysplasia may be seen

Question 33

What are common clinical features of intestinal polyps?

Answer 33

Most are clinically silent; large polyps can cause occult bleeding

Question 34

What are the two main pathogenetic pathways for colorectal carcinoma (CRC)?

Answer 34

Adenoma-carcinoma sequence (APC-beta catenin pathway) and DNA repair gene mutation (microsatellite instability pathway).

Question 35

Briefly describe the adenoma-carcinoma sequence.

Answer 35

A multi-step process involving germline or somatic mutations (e.g.

Question 36

What is the role of the APC gene?

Answer 36

It's a tumor suppressor gene; its protein normally promotes degradation of β-catenin. Mutation leads to β-catenin accumulation and cell proliferation.

Question 37

What is the consequence of DNA mismatch repair gene mutations?

Answer 37

Allows mutations to accumulate in other cancer-causing genes.

Question 38

What is Microsatellite Instability (MSI) testing?

Answer 38

A genetic test for defective DNA repair.

Question 39

What is Lynch Syndrome (Hereditary Non-Polyposis Colorectal Cancer - HNPCC)?

Answer 39

An autosomal dominant syndrome due to inherited mutations in DNA repair genes Colonic cancers usually occur • At younger age • In right colon Uncommon cause of colorectal cancer, but commonest inherited syndrome of CRC

Question 40

List five major risk factors for colorectal carcinoma.

Answer 40

•Age: peaks at 60 to 70 years. .Personal History: of adenomas or previous colorectal cancer .Family History and Genetics: .Having frst-degree relatives with colorectal cancer or adenomas. •lnherited syndromes-such as Lynch syndrome (hereditary nonpolyposis colorectal cancer) and familial adenomatous polyposis (FAP). .Inflammatory Bowel Disease: ulcerative colitis and Crohn disease. •Dietary Factors: Diets high in fat and refined carbohydrates (red and processed or fried meats) and low in fruits,vegetables, and whole 'grains (fibre) have been linked to a higher risk. •Lifestyle Factors: Obesity, sedentary lifestyle, smoking, and heavy alcohol consumption. ‣ Metabolic Factors: Type 2 diabetes melltus.

Question 41

What percentage of colorectal carcinomas are sporadic APC gene mutation cancers?

Answer 41

Approximately 70-80%.Most

Question 42

What is the most common histological type of colorectal cancer?

Answer 42

Adenocarcinoma.

Question 43

What are common insidious symptoms of colorectal cancer?

Answer 43

Anemia,Abdominal cramps /discomfort,Blood in stool,Changes in bowel habits(constipation/diarrhea) Weight loss Insiduous onset of symptoms Asymptomatic for many years

Question 44

Where are colorectal cancers most frequently located?

Answer 44

Sigmoid colon and rectum.

Question 45

Name the three main macroscopic types of colorectal carcinoma.

Answer 45

Polypoid tumour Annular constricting tumour Malignant ulcer

Question 46

Describe a malignant ulcer in the colon.

Answer 46

Large ulcer Irregular shape•Raised edges•Necrotic, haemorrhagic base with tumour in the wall

Question 47

Describe an annular constricting carcinoma.

Answer 47

Circumferential diffuse thickening of the bowel wall napkin-ring’ constriction

Question 48

What are key microscopic features of adenocarcinoma of the colon?

Answer 48

Irregular-shaped glands invading stroma Well, moderately or poorly differentiated• Stroma –inflammation, desmoplasia (*)

Question 49

What is mucinous carcinoma of the colon?

Answer 49

A subtype where tumor cells are suspended in pools of extracellular mucin; associated with worse prognosis and Lynch syndrome.

Question 50

What is signet ring cell carcinoma of the colon?

Answer 50

A subtype where cells have intracellular mucin vacuoles pushing the nucleus to the periphery.

Question 51

How is colorectal cancer diagnosed and staged?

Answer 51

Radiology (CT/MRI)

Question 52

How does colorectal carcinoma spread?

Answer 52

Direct spread (to adjacent structures

Question 53

What is the primary prognostic indicator in colorectal carcinoma?

Answer 53

The STAGE (TNM).

Question 54

List three complications of colorectal carcinoma.

Answer 54

Obstruction