Tumour Classification

Question 1

What suffix do most tumours share?

Which characteristics determine how they are named?

Answer 1

most have the suffix “oma”

they are classified by histological origin, whether they are benign or malignant and whether they are primary or secondary

Question 2

Why is naming tumours important?

Answer 2

1. it characterises the lesion’s behaviour
2. it determines prognosis
3. it outlines treatment options

Question 3

What are the 2 basic tissue types involved in histological classification?

Answer 3

epithelium:

this is tissue that lines surfaces

mesenchymal tissue:

• connective tissue (bones, ligaments, tendons, fat, cartilage)
• muscle
• nervous tissue
• marrow (haematological malignancies arise from different components that make up the blood cells)

Question 4

What are the 2 types of benign epithelial tumours?

Answer 4

papillomas or adenomas

this depends on whether the epithelium is either glandular/secretory or not

Question 5

What is an adenoma?

Answer 5

a benign epithelial tumour of glandular/secretory epithelium

Question 6

What is a papilloma?

Answer 6

a benign epithelial tumour or non-secretory/non-glandular epithelium

Question 7

How are papillomas classifed further?

Answer 7

by the cell type of origin

e.g. squamous cell papilloma, urothelial cell papilloma

Question 8

How are adenomas further classified?

Answer 8

by the glandular tissue of origin

e.g. colonic adenoma, thyroid adenoma

Question 9

What is the name for a malignant epithelial tumour?

Answer 9

carcinoma

Question 10

What is an adenocarcinoma?

Answer 10

a malignant epithelial tumour of glandular epithelium

they can arise from any glandular epithelium, but the organ needs to be specified

e.g. lung adenocarcinoma, colorectal adenocarcinoma

Question 12

How are carcinomas of non-glandular epithelium named?

Answer 12

based on the cell type that they have originated from

e.g. basal cell carcinoma, urothelial cell carcinoma

Question 13

What is meant by a carcinoma “in-situ”?

Answer 13

the carcinoma has not yet invaded through the basement membrane

invasion is preceded by dysplasia (disordered maturation and nuclear changes)

if no action is taken, the carcinoma will invade

Question 14

What are the following prefixes for benign mesencymal tumours?

Answer 14

the suffix is “oma”

e.g. tumour of bone would be osteoma

Question 15

What are the prefixes and suffix for malignant mesenchymal tumours?

Answer 15

the suffix is ‘sarcoma’

e.g. a malignant tumour of adipose tissue would be liposarcoma

Question 16

What are leiomyomas more commonly known as?

Answer 16

fibroids in the uterus

they are benign tumours of smooth muscle

Question 17

What is the proper name for a mole?

Answer 17

melanocytic naevus

it is a benign melanocytic lesion that has many sub-types

Question 18

What is a malignant melanoma?

Answer 18

it can be in-situ or invasive

it looks like a mole but is darker in colour and has a varying texture

Question 19

What is a mesothelioma?

Answer 19

a tumour of the pleura covering the lungs

it is always invasive (no benign counterpart) and nearly always fatal

Question 20

What are the 3 main types of CNS tumours?

Answer 20

1. tumours of the meninges (lining of the brain) - meningioma
2. tumours of glial cells - glioma
3. ptiuitary tumours

Question 21

How do neurones in the CNS form tumours?

Answer 21

neurones in the CNS rarely form tumours

tumours in the brain form from the glial cells (supportive cells)

In the PNS, neurones can form tumours

Question 22

How often do tumours metastasize to the brain?

Answer 22

may tumours metastasize to the brain but generally not vice versa

this is due to the blood-brain barrier

Question 23

Where are germ cells found?

Answer 23

germ cells make up the gonads (ovary and testis)

they are also found in the midline as primordial germ cells originate in the midline and then migrate to the gonads

Question 24

What are the 2 main types of germ cell tumours?

Answer 24

seminoma - originates from sperm cells in the testes

dysgerminoma - originates from oocytes

Question 25

How can a germ cell tumour be named based on differentiation?

Answer 25

1. yolk sac tumour
2. teratoma
3. choriocarcinoma (placental tumour)
4. embryonal carcinoma
5. mixed germ cell tumour

Question 26

What is significant about a teratoma?

Answer 26

it can differentiate into proper tissue types

there are often whole teeth or hairs within the tumour

there are many different tissue types found within the tumour

Question 27

What are blastomas?

What do they look like?

Answer 27

blastomas are paediatric (embryonal) tumours

they look like embryonal cells so are called small round blue cell tumours

Question 28

Why is it difficult to diagnose embryonal tumours just by looking at morphology?

Answer 28

tumours in children tend to look very similar and arise in similar locations

they all look like small round blue cells that form rosettes

genetic testing must be carried out to confirm diagnosis

Question 29

What are the 3 types of haematological malignancies and the cells that are involved?

Answer 29

leukaemias:

• originate from bone marrow or blood
• involves overgrowth of a certain type of white blood cell

lymphoma:

• overgrowth of lymphocytes within lymph nodes
• generally divided into Hodgkin’s and non-Hodgkin’s

myeloma:

tumour of plasma cells

Question 30

What is a harmartoma?

Answer 30

a benign tumour-like lesion

it is not neoplastic, it is just an overgrowth of tissue

wherever the tumour orignates from, they include a disorganised mixture of tissue types from that organ

Question 31

When can a hamartoma cause a problem?

Answer 31

if it starts to compress something

Question 32

What is a cyst?

Answer 32

a fluid-filled space lined by epithelium

this can be neoplastic and malignant, but is usually benign

Question 33

What is the difference between a primary and a secondary tumour?

Answer 33

primary:

this is where the tumour is located at the site of origin

secondary:

this is where the tumour is metastatic and has travelled to implant itself in a new location

Question 34

What happens if there is a case of an unknown primary tumour?

Answer 34

a tumour may be aggressive and malignant then the cells may not look like any particular type

immunohistochemistry is done to see which proteins are being expressed by the cells

Question 36

name the benign epithelial tumours

Answer 36

Question 37

name the malignant epithelial tumours

Answer 37

Question 38

name the benign mesenchymal tumours

Answer 38

Question 39

name the malignant mesenchymal tumours

Answer 39

Question 40

Answer 40

Question 41

Answer 41

Question 42

Answer 42

Question 43

Answer 43