A22 - The general macro- and microscopic morphology of tumors. The increase in volume of tumor cells and tumoral proliferations

Question 1

Macroscopic tumours

Answer 1

Can be variable.
Depends on the tumour itself, the host tissue and the resistance of the host of the neoplasia

Question 2

Morphology of a microscopic tumour

Answer 2

We see two main parts of the tumour:

1. Tumour parenchyma

2. Stroma

Question 3

What is the tumour parenchyma?

Answer 3

It is a group of neoplastic cells.

The tumor parenchyma represents the tumor itself and defines the biological characteristics of the tumor tissue. It regulates the tumor stroma and promotes tumor progression.

Question 4

What is the tumour stroma?

Answer 4

It is the non-neoplastic component, and is the little nerves in the tumour

The stroma consists of the basement membrane, fibroblasts, extracellular matrix, immune cells (Lymphocytes and macrophages) and vasculature

In some cases the stroma will produce PDGF = Platelet degradable growth factors, which will produce collagen and we will see scirrhous or desmoplastic reaction = DESMOPLASIA

Question 5

What is it called if there is only one tumour? and of there are more tumours?

Answer 5

Soliter = There is only one tumour on the animals

Multiplex = There is more than one tumour

Question 6

What is recurrence of a tumour?

Answer 6

The tumour grows back after removal,

it DOES NOT mean that it is metastasis !!

Question 7

Colour of a tumour

Answer 7

Depens on several variables:

1. Blood content
2. Pigmentation
3. If blood present, is it old or new
4. Regressive changes = fatty infiltration, necrosis, calcification

Question 8

What is the extracellular matrix of the stroma?

Answer 8

It contains proteins and proteoglycans.
It can serve as a supporting tissue for the neoplasma, but also as an active storage of the growth function = Helping the neoplasm to survive and grow

Question 9

Tumour parenchyma of a maliagnant tumour

Answer 9

Malignant tumour = can invade other organs

Has several characterisitcs, and the ones that always should be described are:
1. Anisocytosis = Cell size
2. Anisokaryosis = Nuclear size
3. Pleomorphism = Shape

Question 9

Increase in volume of a tumour

Answer 9

Depends on several factors!
The growing of a tumour can stop for a long time, even years. Rarely, the tumours regress without any extrinsic factors

the increase in volume depends on:
1. The length of the proliferating tumour cells
2. The ratio of proliferating neoplastic cells
3. The rate of cell death

If the proliferation rate is high, the death rate is high and we see the growth of the tumour

Question 10

What does the growth of a tumour depend on?

Answer 10

1. Angiogenesis
2. Hormone dependency
3. Factors influencing the size of the stroma
4. The immune system of the patient