L18 - Characteristic of tumours

Question 1

What is the definition of ‘differentiation’ in terms of tumours?

Answer 1

The extent that neoplastic cells resemble the corresponding normal parenchymal cells, morphologically and functionally

Question 2

What are the characteristics of benign tumours in terms of differentiation?

Answer 2

• usually well-differentiated

- mitoses are rare

Question 3

What are the characteristics of malignant neoplasms in terms of differentiation?

Answer 3

• wide range of parenchymal differentiation

- most exhibit morphologic alterations showing malignant nature

Question 4

What is anaplasia?

Answer 4

Poorly-differentiated cells

A condition whereby cells lose the morphological characteristics of mature cells

Question 5

How are neoplasms comprised of poorly-differentiated cells described?

Answer 5

Anaplastic

Question 6

What condition is a “telltale sign of malignancy”

Answer 6

Anaplasia

Neoplasms comprised of poorly-differentiated cells

Question 7

What are some possible morphological changes in cells?

Answer 7

• pleomorphism
• abnormal nuclear morphology
• mitoses
• loss of polarity
• other changes

Question 8

What is pleomorphism?

Answer 8

Describes variability in the size, shape and staining of cells and/or their nuclei

Question 9

Give some examples of the huge differences shown in pleomorphism

Answer 9

• small cells with little differentiation
• large cells with one massive nucleus
• large cells with multinucleation

Question 10

Cells can have abnormal nuclear morphology. Give some examples of this

Answer 10

• nuclei appear too large for the cell
• variability in nuclear shape
• chromatin distribution
• hyperchromatism
• abnormally large nucleoli

Question 11

In abnormal nuclear morphology, there can be hyperchromatism. What does this look like?

Answer 11

Dark colour

Question 12

What are mitoses an indication of and what are they seen in?

Answer 12

An indication of proliferation

Therefore seen in normal tissues with a rapid turnover and in hyperplasias

Question 13

In malignancy, atypical bizzare mitotic figures are seen. Give examples

Answer 13

• tripolar division
• quadripolar division
• multiple spindles
  etc

Question 14

What occurs in loss of polarity in cells?

Answer 14

• orientation of cells disturbed

- disorganised growth

Question 15

what are characteristics of well differentiated tissues?

Answer 15

• closely resembles normal tissue or origin
• little or no evidence of anaplasia
• benign and occasional malignant

Question 16

what are the main characteristics of poorly differentiated tissues?

Answer 16

• little resemblance to tissue of origin

- highly anaplastic appearance

Question 17

what are characteristics of undifferentiated/anaplastic tissues?

Answer 17

• cannot be identified by morphology alone

- need molecular techniques

Question 18

what does a low grade refer to?

Answer 18

well differentiated = low grade/grade 1

moderately differentiate = intermediate/grade 2

poorly differentiated = high grade/grade 3

Question 19

What is ‘stage’ in terms of classification of tumours?

Answer 19

A measure of extent of disease [How far the tumour goes]

Question 20

Better differentiation = ?

Answer 20

Better retention of normal function

Question 21

How can benign and well-differentiated carcinomas of the endocrine glands be detected?

Answer 21

They frequently secrete hormones characteristic of origin

Increased levels in the blood can be used to detect and to follow up tumours

Question 22

Can benign tumours invade other areas of the body?

Answer 22

No, they are localised to their site of origin and cannot infiltrate, invade or metastasise

Question 23

What is encapsulation? (in terms of benign tumours)

Answer 23

The tumour grows in a contained area usually surrounded by a fibrous connective tissue capsule

Question 24

In benign tumours, what are the characteristics of the tissue plane?

Answer 24

• discrete, moveable
• easily palpable
• easily excised

Question 25

What is pseudoencapsulation?

Answer 25

Happens in slow-growing malignant tumours Looks like encapsulation but microscopically there are actually rows of cells penetrating the margin

Question 26

Do malignant tumours respect anatomical boundaries?

Answer 26

No Penetration of organ surfaces and skin

Question 27

Is surgical resection easy in malignant tumours?

Answer 27

No Requires resection of adjacent macroscopically normal tissue (margin)

Question 28

What is metastasis?

Answer 28

Spread of a tumour to sites physically discontinuous with the primary tumour

Question 29

What are the 3 pathways for metastasis?

Answer 29

- direct seeding - lymphatic spread - haematogenous spread

Question 30

What is direct seeding?

Answer 30

The neoplasm penetrates a natural open field without physical barriers

Question 31

In direct seeding, a neoplasm penetrates a natural open field without physical barriers. Give some examples of these

Answer 31

- peritoneal cavity - pleural cavity - pericardial space - subarachnoid space - joint spaces

Question 32

What is the most common pathway for metastasis?

Answer 32

Lymphatic spread

Question 33

Describe lymphatic spread

Answer 33

- lymphatic vessels at the tumour margins | - pattern of lymph node involvement follows the routes of lymphatic drainage

Question 34

What is haematogenous spread seen in?

Answer 34

Typical of sarcomas But also seen in carcinomas!

Question 35

Describe haematogenous spread

Answer 35

Bloodborne cells follow the venous flow drainage site of the neoplasm Often come to rest in the first encountered capillary bed

Question 36

In haematogneous spread, the cells often come to rest in the first encountered capillary bed, what is most frequently involved?

Answer 36

Liver (portal) Lungs (caval)

Question 37

In haemotogenous spread, why are veins involved?

Answer 37

They are more easily penetrated because they have thinner walls

Question 38

What is the stroma?

Answer 38

Connective tissue framework that neoplastic cells are embedded in

Question 39

What does the stroma provide?

Answer 39

- mechanical support - intercellular signalling - nutrition

Question 40

What is a desmoplastic reaction?

Answer 40

Fibrous stroma formation due to induction of connective tissue fibroblast proliferation by growth factors from the tumour cells

Question 41

What does the stroma contain? (in a desmoplastic reaction)

Answer 41

- cancer-associated fibroblasts - myofibroblasts (see puckering of skin) - blood vessels (blood to tumour) - lymphatics

Question 42

What are the clinical complications of tumours dependent on?

Answer 42

- location - cell of origin - behaviour

Question 43

In what general classifications can effects of tumours be?

Answer 43

- local - metabolic - due to metastases

Question 44

What are some LOCAL complications of tumours?

Answer 44

- compression | - destruction

Question 45

Compression is a local complication of tumours. Describe this

Answer 45

Displacement of adjacent tissue - benign eg. pituitary adenomas obliterate adjacent functioning pituitary tissue leading to hypopituitarism

Question 46

Destruction is a local complication of tumours. Describe this

Answer 46

Invasion Rapidly fatal is vital structures are invaded e.g. artery Mucosal surfaces - ulceration eg. GI - anaemia

Question 47

Give some non-specific METABOLIC complications of tumours

Answer 47

- cachexia - warburg effect - neuropathies - myopathies - venous thrombosis

Question 48

What is cachexia?

Answer 48

Profound weight-loss despite apparently adequate nutrition Tumour-derived humoral effects that interfere with protein metabolism

Question 49

what does a low grade refer to?

Answer 49

Poorly differentiated = high grade / grade 3

Question 50

what is the definition of cancer?

Answer 50

The uncontrolled growth of cells, which can invade and spread to distant sites of the body

Question 51

what is a neoplasm?

Answer 51

Lesion resulting from the autonomous growth or relatively autonomous abnormal growth of cells that persists in the absence of the initiating stimulus

Question 52

what is histogenesis?

Answer 52

The differentiation of cells into specialised tissues and organs during growth from undifferentiated cells

Question 53

what are the most common cancers in males?

Answer 53

lung; colon and rectum; prostate | lung most common

Question 54

what are the most common cancers in females?

Answer 54

lung; colon and rectum; breast | lung most common

Question 55

what is the definition of differentiation?

Answer 55

The extent that neoplastic cells resemble the corresponding normal parenchymal cells, morphologically and functionally

Question 56

how do you definite the rate of growth? (in relation to malignancy)

Answer 56

Doubling time of tumour cells; Fraction of tumour cell in replicative pool; Rate at which cells are shed or die