Disorders Of Growth And Differentiation

Question 0

The more differentiated the tumour the better the prognosis. (True or false)

Answer 0

True

Question 1

Define differentiation.

Answer 1

Specialised morphology and function, distinguishes it from its parent cell. Qualitative change.

Question 2

Define anaplasia.

Answer 2

Lack of differentiation. Malignant transformation.

Question 3

Define pleomorphism.

Answer 3

Variation in size and shape. Low degree of differentiation.

Question 4

Is mitosis an indication of a tumours malignancy?

Answer 4

No. Only proliferation involves mitosis.

Question 5

What are the morphological changes of anaplasia?

Answer 5

Pleomorphism
Abundance of DNA
Mitosis (not necessarily an indication of malignancy)
Loss of polarity
Other: formation of giant tumour cells- eg Hodgkin’s lymphoma (Reed-Sternberg)

Question 6

Define neoplasm.

Answer 6

Abnormal mass growth of tissue. Growth exceeds and is uncoordinated with that of normal tissue. Continues in same excessive manner after cessation of the stimuli.

Question 7

What are the classification of a tumour?

Answer 7

Behavioural- benign or malignant

Histogenic- cell of origin

Question 8

Characteristics of benign tumour.

Answer 8

Non-invasive and remains localised.
Slow growth rate
Close histological resemblance to parent tissue.
Fibrous capsule that separates tumour from the host tissue, readily palpable and easy to remove.

Question 9

Characteristics of malignant tumours.

Answer 9

Hugh recurrent rate upon surgical intervention (microscopic transfer).
Invasive and capable of spreading directly or by metastasis.
Relatively slow growth rate.
Variable histological resemblance to parent tissue.

Question 10

Define metaplasia.

Answer 10

Reversible change in which one adult cell type is replaced by another cell type.
Adaptive substitution of cells that are sensitive to stress by cell types that are better able to withstand the adverse environment.
Associated with tissue damage, repair and regeneration.
If persistent can initiate malignant transformation.

Question 11

Define dysplasia.

Answer 11

Disordered growth. Loss of uniformity.
Often pre-neoplastic.
Does not necessarily progress to Cancer.
Exhibit pleomorphisms often contain hyperchromatic nuclei, abnormally large for cell size.

Question 12

Define metastasis

Answer 12

Tumour implants discontinuous with the primary tumour.

Question 13

What are the pathways if spread?

Answer 13

• direct seeding- of body cavities or surfaces
• lymphatic spread- secondary tumours in regional lymph nodes.
• haematogenous spread- by the blood stream,
• implantation- after operation- rare

Question 14

What is the molecular basis of carcinogenesis?

Answer 14

• non-lethal genetic damage
• formed by clinal expression of a single precursor cell that incurred genetic damage
• targets for genetic damage are the 4 classes of regulatory genes- growth producing oncogenes, tumour suppressor, apoptosis and DNA repair regulators.

Multi-step- requires both phenotypic and genetic levels