15. Characteristics of Tumours

Question 1

define cancer

Answer 1

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

Question 2

define tumour

Answer 2

an abnormal swelling

Question 3

define neoplasm

Answer 3

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

Question 4

define anaplasia

Answer 4

lack of differentiation in neoplastic cells. this is a tell-tale sign of malignancy

Question 5

define neoplasia

Answer 5

the presence or formation of new, abnormal growth of tissue

Question 6

define histogenesis

Answer 6

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

Question 7

define differentiation in the context of tumours

Answer 7

the extent that neoplastic cells resemble the corresponding normal parenchymal cells, morphologically and functionally.
*well differentiated malignant tumours and benign tumours can look very similar

Question 8

which cancers are most common in men and women?

Answer 8

men - lung, colorectal, prostate

women - lung, breast, colon, rectum

Question 9

which cancer has the highest mortality in both sexes?

Answer 9

lung cancer, in both the sexes

Question 10

on what basis are tumours characterised?

Answer 10

1. differentiation
2. rate of growth - in most cases, malignant tumours grow more rapidly than benign tumours, but this statement is not universal
3. local invasion
4. metastasis

Question 11

what morphological changes can be observed in differentiation?

Answer 11

1. pleomorphism - variation in size and shape of nuclei, could be large cells with one massive nucleus, or a cell with multiple nuclei
2. abnormal nuclear morphology - coarsely clumped chromatin, hyperchromatism, abnormally large nucleoli
3. mitoses - an indication of proliferation, can be present physiologically. in malignancy, atypical, bizarre mitotic figures seen. tripolar, multipolar spindles
4. loss of polarity - disturbed orientation of cells, disorganised growth
5. other changes

Question 12

what is grade?

Answer 12

a measure of how differentiated the tumour is. grade 1 - well differentiated
grade 3 - poorly differentiated

Question 13

how does differentiation relate to the function of the cell?

Answer 13

better differentiation means better retention of normal function

Question 14

how does cancer harm cells?

Answer 14

infiltration
invasion
destruction

Question 15

what differentiates benign tumour cells from cancer?

Answer 15

benign - cohesive expensive masses
localised to site of origin
no capacity to infiltrate, invade or metastasise

Question 16

what is pseudo encapsulation in malignant tumours?

Answer 16

the tumour itself is slow growing, but microscopically, rows of cells can be seen penetrating the margin

Question 17

what is metastasis correlated to?

Answer 17

lack of differentiation
local invasion
rapid growth
large size 
but there are many exceptions

Question 18

what are the pathways of metastasis?

Answer 18

1. direct seeding - neoplasm penetrates a natural open field without physical barriers
2. lymphatic spread
3. haematogenous spread

Question 19

how do tumours spread using lymphatics?

Answer 19

tumours do not contain lymphatic channels but there may be some at the margins of tumours
pattern of lymph node involvement follows the routes of lymphatic drainage
determination of axillary node status determines the future course of disease and therapy
lymph node mets is most common

Question 20

how to tumours spread through blood?

Answer 20

usually via veins, because they have tanner walls. often come to rest in the first encountered capillary bed. more common in sarcomas, but also seen in carcinomas
common sites - lungs and liver

Question 21

what is the sentinel node?

Answer 21

first node in a regional lymphatic basin that receives lymph flow from the primary tumour. identified by a radiological tracer or a coloured dye

Question 22

what is stroma?

Answer 22

connective tissue framework that neoplastic cells are embedded in

Question 23

what is the function of storm?

Answer 23

1. mechanical support
2. intercellular signalling
3. nutrition

Question 24

what is a desmoplastic reaction?

Answer 24

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

Question 25

what are the contents of stroma?

Answer 25

1. cancer associated fibroblasts
2. myofibroblasts
3. blood vessels
4. lymphocytic infiltrate

Question 26

what are the clinical complications of storm?

Answer 26

dependent on the location, and can occur in both benign and malignant tumours