Neoplasia 1 Flashcards
What is a neoplasm?
A neoplasm is “an abnormal growth of cells that persists after the initial stimulus is removed”
What is a malignant neoplasm?
“An abnormal growth of cells that persisits after the initial stimulus has been removed and invades surrounding tissue with potential to spread to distant sites.”
Define Tumour
Any detectable lump or swelling - can be non-neoplastic or neoplastic.
Define cancer
A cancer is any malignant neoplasm
What is a metastasis?
A malignant neoplasm that has spread from it’s origional site to a new non-contiguous site.
What is the difference between a primary and secondary tumour?
The origional location is the primary site and the place to which it has spread is a secondary site.
What is dysplasia?
Dysplasia is a pre-neoplastic alteration in which cels show disordered tissue organisation. It is not neoplastic because the change is reversible.
What are the differences in behaviour between benign and malignant neoplasms?
Benign neoplasms remain confined to their sites of origin and do not porduce matastases. Malignant neoplasms have the potential to metastasise.
-e.g. The teacher who developed fascination of child pornography because of a tumour that was pressing onto his brain.
What are the differences between benign and malignant neoplasms to the naked eye?
Benign tumours grow in a confined local area and so have a pushing outer margin. This is why they are so rarely dangerous.
Malignant tumours have an irregular outer margin and shape and mau show areas od necrosis and ulceration (if on a surface)
How do you descibe the varying degress of differentiation of benign and malignant tumours?
A benign neoplasm has cells that closely resemble parent tissue (well differentiated)
Malignant neoplasms range from well to poorly differentiated. Cells with no resemblance to any tissue are called anaplastic
With worsening differentiation, what microscopic features are shown?
- Increasing nuclear size
- Increasing nucelar to cytoplasmic ratio
- Increased nucear staining (hyperchromasia)
- More mitotic figues
- Increasing variation in size and shape of cells and nuclei (pleomorphism)
What does the term ‘grade’ mean?
Clinitians use the term grade to indicate differentiation, high grade being poorly differentiated.
Generally, the higher the grade the worse the outcome.
Other than being a pre-neoplastic alteration, what else is dysplasia?
This represents altered differentiation.
Dysplasia is reversible but still abnormal growth.
Not inevitable, but might, lead to carcinoma in tissue.
The more severe the displasia (mild to moderate to severe) indicates worsening differentiation.
What causes neoplasia?
Neoplasia is caused by accumulated mutations in somatic cells.
85% of the cancer risk is due to environment or extrinsic factors.
How does cancer occur?
The mutations are caused by initiators, which are mutagenic agents and promoters which cause cell proliferation.
In combination initiators and promoters result in an expanded, monoclonal population of mutant cells. Chemicals, infections and radiation are the main initiators but some of these agents can also act as promoters. In some neoplasms, mutations can be inherited rather than from an external mutagenic agent.
A neoplasm emerges from this monoclonal population through a process called progression, characteried by the accumulation of yet more mutations.
