Lecture 10 - The Pathology of Cancer: Classifications of Neoplasms

Question 1

Why is an understanding of cancer pathology important?

Answer 1

1. Explains how cancers present clinically

2. Histopathological assessment importmnt for: diagnosis, prognosis and treatment

Question 2

What is the definition of neoplasia?

Answer 2

A neoplasm is a mass of cells that:

• have undergone an irrerversible change from normality
• proliferate in an uncoordinated manner
• are partially or completely independent of the factors which control normal cell growth

Question 3

In what four ways can neoplasms be classified?

Answer 3

1. behaviour
2. histogenesis
3. histological
4. functional

Question 4

Malignant neoplasms have the capacity for:
1.
2.

Answer 4

1. local invasion into surrounding tissue

2. spread to distant sites to form secondary deposits. Metastases occur via lymph of homogenous

Question 5

What does staging tell us?

Answer 5

extend of spread (local or distant)

Question 6

Describe the generic TNM system for staging

Answer 6

T = tumour
N = nodes
M = metastasis

Question 7

Where do most malignant neoplasms originate from?

Where do most benign neoplasms originate from?

Answer 7

epithelia

mesenchymal tissues

Question 8

Give 2 examples of haemato-lymphoid neoplasms

Give 2 examples of germ cell neoplasms

Answer 8

lymphoma, leukaemia

teratomas, seminoma

Question 9

What is differentiation?

Answer 9

Differentiation is the degree to which a neoplasm histologically resembles its tissue of origin
e.g benign neoplasms = always well differentiated
malignant neoplasms = differentiation variable

Question 10

What is grading?

Describe grade 1, 2 and 3

Answer 10

Grading is a term used to describe the degree of differentiation
1 = well differentiated
2 = moderately differentiated
3 = poorly differentiated

Question 11

Grading has implications for …

Answer 11

prognosis and treatment

e.g. well-differentiated prostate cancer can be managed conservatively

Question 12

Some malignant tumours are so poorly differentiated the tis is impossible to determine their histogenesis. These are called ……

Answer 12

anaplastic neoplasms

Question 13

Classification of common neoplasms table

Answer 13

see lecture

Question 14

What are the three histological subtypes of thyroid carcinoma?
Why are cancers classified in this way?

Answer 14

papillary
follicular
anaplastic
Differnt behaviour and prognosis according to histological subtype

Question 15

Describe functional classification?

Answer 15

• classification according to substances produced

- endocrine neoplasms secreting secreting functionally active hormones e.g. insulinoma, prolactinoma

Question 16

What are teratomas?

Where can they occur?

Answer 16

neoplasms derived from embryonic germ cells
have the capacity to form representatievves of all 3 germ cell layers
- ovaries - usually benign
- testes - usually malignant
- midline structures - behaviour variable

Question 17

In what 5 ways can benign and malignant be compared?

Answer 17

1. essential differences
2. gross appearance
3. microscopic features
4. growth characteristics
5. effects on host

Question 18

In what 5 ways can benign and malignant be compared?

Answer 18

1. essential differences
2. gross appearance
3. microscopic features
4. growth characteristics
5. effects on host

Question 19

What are the essential differences between benign and malignant neoplasms?

Answer 19

invasion –> malignant

metastates –> malignant

Question 20

What aspects of gross appearance can be compared?

Answer 20

shape 
- well circumsized vs irregular 
Size 
- generally smaller vs generally larger
Haemorrhage
- unusual vs common 
Ulceration
- unusual vs common 
Necrosis 
- unusual vs common

Question 21

What aspects of microscopic features can be compared?

Answer 21

nuclear size 
- normal vs enlarged 
nucleoli
- small/inconspicuous vs prominent 
pleomorphism 
- absent vs often marked 
mitoses
- infrequent vs frequent (may be atypical)
differentiation 
- good vs variable

Question 22

What is pleomorphism?

Answer 22

tissue arrangement and loss of polarity

Question 23

What are uterine leimyomas often known by?

Are they benign or malignant?

Answer 23

uterine fibroids
benign
well circumscribed/well differentiated

Question 24

How can they be compared in terms of growth characteristics?

Answer 24

speed
- slow vs rapid
spontaneuous arrest
- common vs rare

Question 25

How can the effects of host be compared?

Answer 25

mechanical pressure
- yes vs yes
invasion
- no vs yes (may damage vital structures)
metastasis
- no vs yes (common cause of death)
paraneoplastic syndromes
- no vs yes (neurological, haematological, endocrine, immunological
death
- very uncommon vs frequent (if untreated)