Lecture 24; Tumours of the colon

Question 1

What are the benign and malignant cancer of the bowel?

Answer 1

Benign tumours; Mostly polyps

Malignant tumours; Mainly adenocarcinomas

Question 2

What is a polyp?

Answer 2

A circumscribed growth or tumour which projects above the surrounding mucosae

Question 3

How is the nature of polyps determined? and what can it be?

Answer 3

Biopsy

Non neoplastic polyp
or
Neoplastic polyps - adenomas

Question 4

What are the potential non-neoplastic polyps;

Answer 4

Hyperplastic polyps

Inflammatory polyps

Question 5

Write some notes on hyperplastic polyps;

Answer 5

Benign (non-neoplastic)
Usually asymptomatic
Do NOT have malignant potential
3-6mm, common

Question 6

Write some notes on inflammatory polyps;

Answer 6

Seen in IBD, overgrowth

Theyre benign, psuedopolyps

Question 7

What are neoplastic polyps-adenomas? and some notes on presenting population

Answer 7

Adenomas, epithelial proliferation with variable degrees of dysplasia

• Benign polyps WITH malignant potential
• Mostly 50+
• Familial predisposition

Question 8

What is the pathology of neoplastic polyps- Adenomas?

Answer 8

3 Main types;

Tubular adenomas
- Most common, tubular glands
Villous adenomas
- Villous projections
Tubulovillous adenomas
- Mixture of above

Question 9

Whats the clinical presentation of neoplastic polyps-adenomas?

Answer 9

Most asymptomatic, found co-incidentally
May bleed, or produce mucosal discharge

IF larger;

• Altered bowel habit
• Obstruction

Question 10

Describe the adenoma to carcinoma sequence;

Answer 10

Benign
- Hyper-proliferation
= Adenoma polyp
(small->large with growth)
- Severe dysplasia (pre-cancerous, abnormal growth and metabolism)

Malignant

• Severe dysplasia can become adenocarcinoma
• Then can become invasive (cancer)

Look at slide 18 if confused

Question 11

What is the main risk for neoplastic polyps?

Answer 11

Main risk is size of polyps

Question 12

What is the progression of growth from hyperproliferative patch to malignant cancer associated with?

Answer 12

Changes in morphology and aquisition of many mutations (lots of genetic changes and expressive changes along the way)

Question 13

Where can colorectal cancer occur?

Answer 13

Between the ceacum and the rectum

Question 14

Write some notes on colorectal presentation;

Answer 14

Peaks between 60-70
If young case, then considered familial
Males more likely for rectal cancer

Question 15

Whats the pathology of colorectal cancer?

Answer 15

• Adenocarcinoma
• Variable differentiation

Extra note for fun; can have central necrotic area as it can outgrow blood supply)

Question 16

What is used for the staging of colorectal cancer?

Answer 16

TNM system

T = Extent of invasion in bowel wall (Thickness)
N = Number of lymph nodes involved (Number)
M = Metastatic disease present or not (Metastasis)

Prognosis determined by stage of tumour and tailors treatment plans

T1-4

Question 17

What are the clinical features of colorectal cancer?

Answer 17

Abdo pain, mucous discharge, PR bleeding, change in bowel habit, bowel obstruction

RHS = iron deficiency due to occult bleeding (cant see / unoticed)

Spread to regional nodes….
Consitutional symptoms = weight loss, malaise

Think about locations and implications

Question 18

What is familial polypois syndrome? inheritance pattern?

Answer 18

Group of inherited polypois syndromes
- Autosomal dominant

Predispotion to malignant transformations (adenomas) in colon etc

Question 19

What is familial adenomatous polyposis?

Answer 19

Multiple adenomas in colon and elsewhere of gut - Most tubular adenomas

Heaps and heaps of polyps. Predisposed to malignant transformations.

Question 20

Write some notes on familial adenomatous polyposis;

Answer 20

• Usually evident in adolescence
• LOTS OF POLYPS
• Transforms into cancer
• Autosomal dominant
• Prophylatic colectomy

Question 21

Write some notes on hereditary nonpolyposis colorectal cancer? (HNPCC)

Answer 21

• Autosomal dominant inheritance
• Progress adenoma to carcinoma but no increase in polyps
• Due to inherited mutation in DNA mismatch repair gene

Regular screening and polyp removed.

Question 22

What are the two types of familial colorectal cancer?

Answer 22

1) Familial adenomatous polyposis (A polyposis syndrome)

2) Hereditary nonpolyposis colorectal cancer