[A] 1.70 The general macro- and microscopic morphology of tumors. The increase in volume of tumor cells and tumoral proliferations

Question 1

Macroscopic morphology: Overview

Answer 1

• Very variable
• Background:
  
  • Characteristics of neoplastic tissue (Metastatic predisposition)
  • Acquired characteristics (Neoplasia resistance)

Question 2

Macroscopic morphology: Forms

Answer 2

• Nodular/tuberous form
• Plain form
• Fungous form
• Papillar form
• Arborescens form
• Pedunculated form
• Annular form
• Cystous/cystic form
• Gelatinous form

Question 3

Macroscopic form type

Answer 3

Nodular/tuberous form

Question 4

Macroscopic form type

Answer 4

Plain form

Question 5

Macroscopic form type

Answer 5

Fungous form

Question 6

Macroscopic form type

Answer 6

Papillar form

Question 7

Macroscopic form type

Answer 7

Arborescens form

Question 8

Macroscopic form type

Answer 8

Pedunculated

Question 9

Macroscopic form type

Answer 9

Annular

Question 10

Macroscopic form type

Answer 10

Cystous/cystic form

Question 11

Macroscopic form type

Answer 11

Gelatinous form

Question 12

Macroscopic morphology: Description

Answer 12

1. Benign/malignant
2. Solitary (unicentric -) or multiplex (multicentric tumourigenesis)
3. Reccurance (Does it grow back after removal)
4. None of the above is metastasis

Question 13

Simultaneous neoplasia can be…

Answer 13

• Occur at the same time or after each other
• In the same animal

Question 14

Colour of the tumour: Dependent on

Answer 14

• The tissue of origin
• Influence of:
  
  • Blood content
  • Pigmentation
  • Fresh/older bleeding
  • Regressive changes

Question 15

Microscopic morphology of tumour: Two main parts

Answer 15

• Stroma - Non-neoplastic component
• Tumour parenchyma: All neoplastic cells

Question 16

Stroma

Answer 16

• Extracellular matrix (collagen fibres, proteoglycans)
• Vessels
• Tumour-infiltrating inflammatory cells (Lymphocytes, macrophages)
• Other cellular elements: Fibroblasts, myofibroblasts, endothelial cells

Question 17

Desmoplasia

Answer 17

1. Tumour cell PDGF production →
2. Stromal fibroblast → Collagen

Scirrhous/Desmoplastic reaction

Question 18

Extracellular matrix of neoplasia

Answer 18

• Proteins & Proteoglycans
  
  • Passive supporting function
  • Active binding
  • Storage function (GF)

Question 19

Tumour parenchyma

Answer 19

Cells of a malignant tumour - Less differentiated

• High variability
• Nuclear variability
• Cytoplasm

Question 20

Tumour parenchyma: High variability under the microscope

Answer 20

• Cell size: Anisocytosis
• Nuclear size: Anisokaryosis
• Shape: Pleomorphism (multinucleated giant cells)

Question 21

Tumour parenchyma: Nuclear variability under the microscope

Answer 21

• Karyomegaly: Large nucleus
• Multinucleation
• Hyperchomasia: Increased DNA content
• Prominent nucleolus/nucleoli
• Mitotic figures

Question 22

Tumour parenchyma: Cytoplasm under the microscope

Answer 22

• Basophilia: Increased ribosomes due to fast growth rate
• Loss of functional parts (Cilia, pigment)

Question 23

Increase in volume of tumour cells & tumour proliferations: Overview

Answer 23

• Constant growing is one of the most important properties
  
  • But with varying speeds - Can stop for years
• Tumours can regress without extrinsic environmental effect (rare)

Question 24

Duplication of the volume of a tumour depends on…

Answer 24

• Length of cell life-cycle
• Ratio of proliferating neoplastic cells
• Rate of cell death

Question 25

Give the order of the cell cycle

Answer 25

1. G₀ = Resting cell 2. G₁ = Before DNA synthesis 3. S = Synthesis of DNA 4. G₂ = Premitotic phase 5. M = Mitosis

Question 26

Cell cycle: Without extrinsic stimulation

Answer 26

Cell cycle cannot leave the G₀ phase

Question 27

Cell cycle: DNA damage

Answer 27

1. Cell cycle stops at G₁/S & G₂/M (controlled by tumour suppressor _p53_) 2. DNA repair or apoptosis, senescence

Question 28

Because some neoplastic cells won't react to extrinsic/extrinsic signals...

Answer 28

1. The G₀ phase doesn't occur 2. Don't express functional _p53_ protein 3. Cell-cycle becomes continuous 4. Progressive accumulation of mutations Telomerase reactivation → Ø Senescence → Immortalisation

Question 29

Apoptosis: Methods

Answer 29

* Chromatin marginalisation * Nuclear condensation & fragmentation * Cell shrinkage

Question 30

Size of tumour

Answer 30

* 1, 000, 000 cells = 1mg/1mm³ (1 Million cells) * (Divided 20 times) * 1, 000, 000, 000, 000 cells = 1kg (1 trillion cells) * (Divided 40 times)

Question 31

Even with the most modern imaging technology it is hard to detect neoplasia smaller than...

Answer 31

1mm³ * _Latency_ = Existing but not expressing anything * At the time of diagnosis, the tumour has already divided 20-30 times

Question 32

Most neoplastic cells are in which cell phase?

Answer 32

G₀

Question 33

Rate of tumour growth is dependent on...

Answer 33

* Angiogenesis * Secondary changes in substance * Microenvironmental relationship, patient's immune reaction * Hormone dependency * Factors influencing the size of stroma