Benign and Malignant Tumours and Metastasis.

Question 1

What are the four main differences between benign and malignant tumours?

Answer 1

Invasion
Metastasis
Differentiation
Growth Pattern

Question 2

How do benign tumours differ from malignant tumours in relation to invasion?

Answer 2

Benign tumours do not invade adjacent tissue. Malignant tumours do and this often causes an immune response.

Question 3

How do benign tumours differ from malignant tumours in relation to metastasis?

Answer 3

Benign tumours do not metastasise. Malignant tumours have the capacity to but some are very slow to spread and can be diagnosed before this.

Question 4

What does differentiation refer to and how do benign tumours differ from malignant tumours in relation to differentiation?

Answer 4

This refers to how much the tumour cells resemble the cells of the tissue it is derived from. Tumour cells generally have larger nuclei (and so larger nuclei: cytoplasmic ratio) and more mitoses than normal as well as marked nuclear pleomorphism (variability in nuclear size and shape). Benign tumours tend to be more like the tissue it comes from as they are better differentiated.

Question 5

What does growth patterns refer to and how do benign tumours differ from malignant tumours in relation to growth patterns?

Answer 5

This means how much the architecture of the tumour resembles the architecture of the tissue it is derived from; tumours have a less well defined architecture than the tissue they are derived from -benign tumours retain the growth patterns of the tissue it came from

Question 6

Would a cytopathologist or a histopathologist be able to comment on the growth patterns of a tumour?

Answer 6

Histopathologists, as they look at tissues not individual cells and so can comment on the overall architecture of the tissue.

Question 7

How do we grade prostate cancer cells based on growth patterns and differentiation?

Answer 7

The Gleason Grading System (1 is good, 5B is worst)

Question 8

Can benign tumours become malignant?

Answer 8

Yes. Adenomas may develop into severe dysplasia which may progress into an adenocarinoma

Question 9

What are the different ways tumours can spread?

Answer 9

Direct extension
Haematogenous
Lymphatic
Transcoelomic
Perineural
Surgery

Question 10

What is direct extension?

Answer 10

When tumours spread into adjacent cells.

Question 11

What is haematogenous spread?

Answer 11

When tumours spread through the blood.

Question 12

What is lymphatic spread?

Answer 12

When tumours spread through the lymphatics to lymph nodes and beyond.

Question 13

What is transcoelomic spread?

Answer 13

When tumours spread through your coelomic cavities such as the peritoneal cavity, the pleural cavity, and the pericardial cavity.

Question 14

What is perineural spread?

Answer 14

When tumours spread through nerves.

Question 15

How can tumours spread through surgery?

Answer 15

If the surgeon isn’t careful when removing the cancer or in some rarer cases where people try to remove the cancer themselves.

Question 16

What is associated with direct extension of a tumour?

Answer 16

A stromal response including fibroblastic proliferation, vascular proliferation (angiogenesis) and an immune response.

Question 17

What blood vessels are usually invaded and why?

Answer 17

The blood vessels usually invaded are the venules and capillaries because they have thinner walls.
Most sarcoses metastasize first through the blood stream.

Question 18

The pattern of spread of a tumour that metastasises through the lymphatic system is dictated by what?

Answer 18

The pattern of spread is dictated by the normal lymphatic drainage of the organ in question.

Question 19

What cavity is especially vulnerable to tumour spread and why?

Answer 19

Peritoneal cavities have low resistance, are moist and are always moving which can dramatically increase the tumour spread.

Question 20

What sort of cancer spreads through the perineural route especially?

Answer 20

For liver cancers it is a very common way for it to spread as it is a low resistance pathway.

Question 21

How can we assess tumour spread?

Answer 21

1. Clinically - feeling a lump
2. Radiologically - CT scans, x-rays, etc.
3. Pathologically - Looking at the cell

Question 22

How do we stage tumours?

Answer 22

To stage tumours, we use the TNM system.
T = Tumour: the tumour size or extent of local invasion
N = Nodes: number of lymph nodes involved
M = Metastases: presence of distant metastases

Question 23

What does the grade of a tumour refer to?

Answer 23

Grade is how differentiated the tumour is.

Question 24

What does the stage of a tumour refer to?

Answer 24

Stage is how far the tumour has spread.

Question 25

The higher the grade/stage, the worse the prognosis. What is more important in determining prognosis?

Answer 25

The stage is more important in determining prognosis. The more it is spread the harder it is to remove. If it was a high grade but hasn't spread at all, it could be easily removed (e.g. basal cell carcinomas which rarely spread are much less dangerous).