Neoplasia 1

Question 1

Define neoplasm

Answer 1

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

Question 2

Define malignant neoplasm

Answer 2

An abnormal growth of cells that persists after the initial stimulus is removed and invades surrounding tissue with potential to spread to distant sites

Question 3

Define tumour

Answer 3

Any clinically detectable lump of swelling

Question 4

Define cancer

Answer 4

Any malignant neoplasm

Question 5

Define metastasis

Answer 5

Malignant neoplasm that has spread from its original site to a new non-contiguous site

Question 6

Define dysplasia

Answer 6

Pre-neoplastic alteration in which cells show disordered tissue organisation
Not neoplastic as reversible

Question 7

State an example of non-neoplastic tumour

Answer 7

Abscess, haematoma

Question 8

Compare benign and malignant tumours

Answer 8

Benign neoplasms confined to their site of origin and do not produce metastasis
To the naked eye - pushing outer margin which squashes and may damage surrounding tissue
May have inflammation and scarring
Granuloma tissue acts almost like a capsule
Under microscope -cells closely ensemble parent tissue
Well differentiated
Malignant neoplasms have the potential to metastasise
To the naked eye - irregular outer margin and shape and may show areas of necrosis and ulceration (if on surface)
In areas of ischaemia, necrosis can occur and grow faster than blood vessels can be induced
Under microscope - range from well to poorly differentiated
Well differentiated can also be malignant

Question 9

Define anaplasia

Answer 9

A condition of cells in which they have poor cellular differentiation, losing the morphological characteristics of mature cells and their orientation with respect to each other and to endothelial cells

Question 10

What cellular features occur with worsening differentiation

Answer 10

Increasing nuclear size and nuclear to cytoplasmic ratio
Increased nucleus staining (hypochromasia)
More mitotic figures
Increasing variation in size and shape of cells and nuclei (pleomorphism)

Question 11

How are neoplasms graded

Answer 11

Indicate differentiation, high grade being poorly differentiated and more aggressive tumours
Higher grades show lower survival rates

Question 12

Describe the effect of mutation on neoplasia

Answer 12

Mutation are caused by initiators and promoters
Initiators are mutagenic agents
Promotors cause cell proliferation
Promoter need to be given over prolonged time to form large population and for neoplasia to occur
Combination of initiators and promotors result in expanded, monoclonal population of mutant cells
Chemicals infections and radiation are the main initiators but some of these agents can also act as promotors
In some neoplasms, mutation can be inherited rather than from an external mutagenic agent
A neoplasm emerges from this monoclonal population through a process called progression, characterised by the accumulation of yet more mutations

Question 13

How do we know neoplasms are monoclonal

Answer 13

A collection of cells is monoclonal if they all originated from a single founding cell
Evidence comes from the study of X-linked gene for enzyme glucose-6-phosphate dehydrogenase (G6PD) in tumour tissue from women
Gene has several alleles encoding different isoenzymes
Early in female embryogenesis, one allele is randomly activated in each cell (lyonisation)
In heterozygous women that happen to have one allele encoding a heat stable isoenzyme and one a heat labile isoenzyme, normal tissues will be patchwork of each type
However, neoplastic tissues only express one isoenzyme indicating a monoclonal group of cells

Question 14

Understand which types of genes are involved in neoplasm

Answer 14

Genetic alterations affect proto-oncogenes and tumour suppressor genes
Proto-oncogenes become abnormally activated (oncogene), favouring neoplasm formation
May permanently activate receptor, permanently drive cell cycle
Dominant so only have to activate 2nd allele
Tumour suppressor genes, which normally suppress neoplasm formation, become inactivated
Recessive so have inactivate both alleles

Question 15

How are benign endothelial neoplasms named and give examples

Answer 15

End in -oma
Squamous papilloma - any tumor with finger-like projections
Eg. Skin, buccal mucosa
Transitional cell papilloma
Eg. Bladder mucosa
Adenoma - formed from glandular structures of epithelial
Eg. Adenomatous polyp of the colon
Connective tissue benign tumors
Eg. fibroma, lipoma, neuroma

Question 16

How are malignant neoplasms named

Answer 16

Malignant ones end in –carcinoma if it is an epithelial malignant neoplasm or –sarcoma if it is a stromal malignant neoplasm

Question 17

What is the difference between invasive and in-situ carcinoma

Answer 17

In-situ - no invasion of epithelial basement membrane

Invasive - penetrated through basement membrane

Question 18

What is leukaemia

Answer 18

Leukaemia is a malignant neoplasm of blood-forming cells arising in the bone marrow and then enter blood

Question 19

What are lymphomas

Answer 19

Lymphomas are malignant neoplasms of lymphocytes, mainly affecting lymph nodes
Hodgkins disease & non Hodgkins lymphoma

Question 20

Where do germ line neoplasms arise from and give examples

Answer 20

Germ cell neoplasms arise from pluripotent cells, mainly in the testis or ovary
Testis - malignant teratoma, seminoma (malignant neoplasm)
Ovary - benign teratoma = dermoid cyst

Question 21

Where do neuroendocrine neoplasms arise from

Answer 21

Neuroendocrine tumors arise from cells distributed throughout the body
Carcinoid tumors (various organs)
Phaeochromocytoma (adrenal glands)
Small cell carcinoma of bronchus

Question 22

What are -blastomas

Answer 22

Some neoplasms are called “-blastomas”, which occur mainly in children and are formed from immature precursor cells
Eg. nephroblastoma