Session 8 Neoplasms

Question 1

What’s a neoplasm?

Answer 1

An abnormal growth of cells that persists after the initial stimulus is removed

If malignant, persists after stimulus is removed and invades surrounding tissue with the potential to spread to distant sites

Question 2

What is dysplasia?

Answer 2

A pre neoplastic alteration in which cells show disordered tissue organisation

Question 3

How is a tumour, neoplasm and cancer linked?

Answer 3

Neoplasm = a type of tumour (a detectable bump/swelling)

Any malignant neoplasm - cancer

Question 4

How do benign and malignant tumours differ in their affects?

Answer 4

Benign = affect the area they are confined too and don’t metastasis

Malignant = potential to metastasis

Question 5

How would neoplasms that are benign/malignant appear different to the naked eye?

Answer 5

Benign = confined area, have a pushing outer margin

Malignant = irregular outer margin and shape and may show areas of necrosis and ulceration if on a surface

Question 6

What occurs with worsening differentiation to cells?

Answer 6

Increase nuclear size and nuclear to cytoplasmic ratio
Increased nuclear staining = hyperchromasia
Increasing variation in size and shape of cells = pleomorphism

Question 7

What’s an anaplastic cell?

Answer 7

Has no resemblance to an tissue. A poorly differentiated cell - usually a malignant neoplasm.

Benign cells are well differentiated.
The term grade can be used to indicate differentiation, high grade being poorly differentiated.

Question 8

What’s dysplasia?

Answer 8

Shows altered differentiation. Can be mild, moderate or severe.

Question 9

What causes cell mutations and neoplasia?

Answer 9

Initiators = mutagenic agents

Promoters = cause cell proliferation

Get a monoclonal population of mutant cells

Question 10

How do we know neoplasms are monoclonal?

Answer 10

A collection of cells are monoclonal if they all originated from a single founding cells

Question 11

What genes are particularly affected by mutations?

Answer 11

Porto oncogenes = from oncogenes, proto oncogenes favour neoplasm formation
Tumour suppressor genes = normally suppress neoplasm formation, become inactive

Question 12

What are

• leukaemia
• lymphomas
• myeloma

Answer 12

Leukaemia = blood neoplasm
Lymphoma = lymphocyte and lymph node neoplasm 
Myeloma = neoplasm of plasma cells 

All malignant

Question 13

How do neuroendocrine tumours arise?

Answer 13

From cells distributed throughout the body

Question 14

How do malignant cells get from a primary to secondary site?

Answer 14

1) grow and invade primary site
2) enter a transport system and lodge at secondary site
3) grow at secondary site to form a new tumour = colonisation

Question 15

What alterations are required for the invasion by malignant cells?

Answer 15

proteolysis
Motility
adhesion

• a reduction in E Cadherin expression is required for altered adhesion
• this involves changes in integrin expression is needed
• cell must degrade membrane and stroma to invade
• need altered expression of proteases = matrix metalloproteinases MMP
• malignant cells take over non neoplastic cells = form a niche, with stroma, fibroblasts, endothelial cells and inflammatory cells
• normal cells provide growth factors

Question 16

How do malignant neoplasms transport to distant sites?

Answer 16

Blood vessels
Lymphatic vessels
Fluid in body cavities e.g pleura, peritoneal, pericardial and brain ventricles, which is known as transcoelomic spread.

Question 17

How does a clinical metastasis occur and how can it fail?

Answer 17

Secondary site malignant cells must grow = colonisation

Colonisation = greatest barrier to metastasis and cells may die or fail to grow into clinically detectable tumours
Surviving deposits that fail to grow = micrometastases, which lie dormant. If they grow, neoplasm relapses.

Question 18

What determines the site of a secondary tumour?

Answer 18

1) regional drainage of blood, lymph or coelomic fluid. If lymph, to lymph nodes. If coelomic fluid, to other areas in coelomic space or adjacent organs. If blood, to next capillary bed.
2) due to interactions between malignant cells and the local tumour niche at the secondary site

Question 19

How do carcinomas and sarcomas differ in their spread?

Answer 19

Carcinomas = via lymph and then to blood borne distant sites. Common sites are lung, bone, liver and brain.

Sarcomas = blood stream

Question 20

How is one malignancy more likely to spread than another?

Answer 20

The bigger, the more likely to spread and more aggressive

Question 21

What are paraneoplastic syndromes? Give examples

Answer 21

Tumour burden - number of cells
Hormones - secretion
Miscellaneous effects

Paraneoplastic syndromes - triggered by an altered immune response. Involve nonmetastatic systemic effects that accompany malignant disease.

Question 22

What are the local effects of neoplasms?

Answer 22

1) Direct invasion and destruction of normal tissue
2) Ulceration at surface leading to bleeding
3) Compression of adjacent structures
4) Blocking tubes/orifices

Question 23

What are the systemic effects of neoplasms?

Answer 23

Increased tumour burden

• parasitic effect on host
• tumour + secreted cytokines cause reduced appetite, weight loss, malaise, immunosuppressed, thrombosis

Hormones
- produce hormones we don’t need.

Miscellaneous effects
- neuropathic affecting brain and peripheral nerves, skin problems e.g pruritis and abnormal pigmentation, fever, finger clubbing and myositis.