Pathology of the Colorectal Carcinoma

Question 1

What is a polyp?

Answer 1

A protrusion above an epithelial surface

Question 2

Is a polyp benign or malignant?

Answer 2

Can be either

Question 3

What are some examples of benign epithelial polyps

Answer 3

Neoplastic (adenoma inflammatory IBD)

Hamartomatous (juvenile polyp )

Question 4

What is a type of malignant epithelial polyp?

Answer 4

Polypoid (adenocarcinomas or carcinoid polyps

Question 5

What are the 3 different types of macroscopic

Answer 5

Pedunculated
Sessile
Flat

Question 6

Describe pedunculated polyps

Answer 6

Hangs on a long stalk form the mucosa and is mushroom like- easy to remove

Question 7

Describe sessile polyps

Answer 7

Carpet like - difficult to cut out as over a longer area

Question 8

What is dysplastic epithelial lining

Answer 8

Epithelium that has failed to mature

Question 9

Describe adenomas of the colon

Answer 9

Benign tumours which are not invasive and have the potential to develop into cancers

Question 10

How can we reduce the risk of cancer?

Answer 10

Screen the colon and remove all adenomas

Question 11

What are the 3 different microscopic architecture variability

Answer 11

Tubullovillous (tree like)
Tubular (large circles)
Villous (Finger like projections)

Question 12

What are all adenomas?

Answer 12

Dysplastic

Question 13

What can happen if adenomas are left?

Answer 13

They can lead to cancer

Question 14

Describe the adeoma-carcinoma sequence

Answer 14

Normal mucosa,
adenoma (dysplastic)
Adenocarcinoma (invasive)

Question 15

Why must all adenomas be removed?

How is this done?

Answer 15

Because they are all premalignant

Either done endoscopically or surgically

Question 16

Do all colorectal adenomas have the same molecular genetic origins?

Answer 16

No

Question 17

What causes the variation in colorectal adenomas

Answer 17

separate pathways for injerited tumours

Sparate pathways for serrated adenomas

Question 18

What is the primary treatment in most cases of adenocarinoma of the large bowel

Answer 18

Surgery

Question 19

How is the tumour staged?

Answer 19

Endoscopic biopsy sent to pathology

Question 20

Why are gland cells formed?

Answer 20

They are derived from stem cells which give rise to large colonic crypts which still contain traces of normality

Question 21

How does cancer spread to the serosal fat?

Answer 21

Invades through the muscle

Question 22

How do we stage colorectal carcinoma

Answer 22

Using Duke’s staging

Question 23

What are the 3 stages of Duke’s staging?

Answer 23

Dukes A: Confined by muscularis propria
Dukes B: Through muscularis propria
Dukes C: Metastatic to lymph nodes

Question 24

Where are most colorectal carcinomas found?

Answer 24

75% Left side (rectum,sigmoid descending)

25% Right side (Caecum, ascending)

Question 25

What are the common presentations of left sided colorectal carcinomas?

Answer 25

Blood PR, Altered bowel habit and obstruction

Question 26

What are the common presentations of right sided colorectal carcinomas

Answer 26

Anaemia, weight loss | No PR bleeding

Question 27

Why do some tumours appear to be glistening?

Answer 27

Due to the mucous which is produced from the tumour

Question 28

What might be affected by local invasion

Answer 28

Mesorectum, peritoneum, other organs such as the bladder, ovary or prostate, uterus or vagina

Question 29

What might be affected by lymphatic spread

Answer 29

Mesenteric nodes

Question 30

What might be affected by haematogenous

Answer 30

Liver, distant sites

Question 31

Where is the most common site of metastases from colorectal cancer and why?

Answer 31

Liver | Due to the hepatic portal system

Question 32

What are the two types of inherited cancer syndromes?

Answer 32

Heriditary Non Polyposis Coli (HNPCC) | Familial Adenomatous Polyposis (FAP)

Question 33

How many polyps are present in HNPCC

Answer 33

<100

Question 34

How many polyps are present in FAP

Answer 34

>100 polyps

Question 35

Describe the genetics of HNPCC FAP

Answer 35

Autosomal dominant

Question 36

What may be required for patients in FAP

Answer 36

removal of the colon and rectum at a young age

Question 37

Describe the onset for HNPCC and FAP

Answer 37

HNPCC - Late | FAP - Early

Question 38

What causes HNPCC

Answer 38

Defect in DNA mismatch repair

Question 39

What causes FAP

Answer 39

Defect in tumour supression

Question 40

Where do HNPCC tumours arise

Answer 40

Right side

Question 41

Where do FAP tumours arise

Answer 41

Throughout the entire colon

Question 42

What is HNPCC associated with

Answer 42

Gatric and endometrial carcinoma

Question 43

What is FAP associated with?

Answer 43

Desmoid tumours and thyroid carcinoma