What Is A Neoplasm? Flashcards
What is a neoplasm?
An abnormal growth of cells that persist after the initial stimulus is removed
What is the definition of a maglignant neoplasm?
An abnormal growth of cells that persists after the stimulus is removed and invades surrounding tissue with potential to spread to distant sites
What is a tumour?
Any clinically detectable lump or swelling (may or may not be cancer)
What is cancer?
Any malignant neoplasm
What is a metastasis?
A malignant neoplasm that has spread from its original site to a new non-contiguous site
(Original site-primary site, place of spread- secondary site)
What is dysplasia?
A pre-neoplastic alteration in which cells show disordered tissues organisation.
Can also represent altered differentiation. Mild, moderate and sever dysplasia indicates worsening differentiation.
Dysplasia is reversible- is a pre-neoplastic change
Why is dysplasia not neoplastic?
Because the change is reversible
If a neoplasm metastasises can it be malignant?
Yes, malignant neoplasms have the potential to metastasise whereas benign neoplasms remain confined to their site of origin
How do benign neoplasms appear macroscopically?
Grow in a confined local area and so pushing outer margin. There is often a regular outer margin and shape and are easier to remove
What does a malignant tumour look like macroscopically?
They have an irregular outer margin and shape and may show areas of necrosis (if the tumour is growing faster than angiogenesis can occur) and ulceration (if on a surface).
How does a benign neoplasm look microscopically?
Has cells that closely resemble the parent tissue (they are well differentiated)
How does a malignant tumour appear microscopically?
Range from well to poorly differentiated. You would need to look for other features
What type of cells are called anaplastic?
Cells with no resemblance to any tissue (usually used in regards to a malignant neoplasm)
How is ‘grade’ used as a term for neoplasms?
It is used to indicate differentiation, high grade being poorly differentiated
What are initiators and promoters in terms of neoplasm? And what relevance do they have?
Initiators- mutagenic agents causing mutations (ie chemicals, infections and radiation, some of these can also act as promoters). In some neoplasms mutation can be inherited rather than from an external mutagenic agent.
Promoters- cause cell proliferation
You need both and for a prolonged period of time in order to develop an expanded monoclonal population of mutant cells which will go through ‘progression’ to develop into a neoplasm. Either or will not do it.
They must come in a specific order too!
How does a neoplasm emerge from a monoclonal population?
Through a process called progression- characterised by the accumulation of yet more mutations
What makes a neoplasm monoclonal?
All the cells have all originated from a single founding cell.
What are two examples of important genes that can be affected by genetic alterations?
Proto-oncogenes and tumour suppressor genes
What do proto-oncogenes become when they’re abnormally active? What do these favour?
Oncogenes
Favour neoplasm formation
How might a tumour suppressor gene mutation lead to a neoplasm formation?
This gene normally suppresses growth and then when a mutation occurs it can become inactivated and thus uncontrolled growth of cells can occur
What happens to cells as differentiation of the individual cells becomes worse?
Increasing nuclear size and nuclear to cytoplasmic ratio,
Increased nuclear staining (hyperchromasia), more Mitotic figures and increasing variation in size and shape of cells and nuclei
What is pleomorphism?
Increasing variation in size and shape of cells an nuclei
How do we know neoplasms are monoclonal?
There was a study conducted looking at the gene coding for the enzyme: G6PD, in tumour tissue of women.
**unfinished cue card
How do you name a benign neoplasm of the mesenchymal tissue?
Prefix + -oma
How do you name a malignant neoplasm of the mesenchymal tissue?
Prefix + -sarcoma
Name two cancers that are of the mesenchymal tissue but do not follow the normal nomenclature of neoplasms
Leukaemia: malignant neoplasm of blood-forming cells arising in the bone marrow
Lymphoma: malignant neoplasms of lymphocytes, mainly affecting lymph nodes
*both always malignant
What is mesenchymal tissue, what does it include?
Connective tissue, blood or lymphatic
How do you name a benign glandular neoplasm of the epithelial tissue?
____ adenoma
How do you name a benign finger like neoplasm of the epithelial tissue?
____ papilloma
How do you name a malignant neoplasm of epithelial tissue?
____ carcinoma
What two types of carcinomas can you get and what do they mean?
In-situ: no invasion through the epithelial basement membrane
Invasive: penetrated through basement membrane
Where would you normally find an adenoma?
In the lumen of an organ
Ie Pituitary adenomas
Where would you normally find a papilloma?
In stratified squamous epithelium
Eg intraductal papilloma (neoplasm of the breast duct)
What is a myeloma?
Malignant neoplasms of plasma cells
Why are some neoplasms called ‘-blastomas’?
They are those that are formed from immature precursor cells and occur mainly in children
Eg nephroblastoma
