Neoplasia Flashcards
What is a neoplasm? Compared to hyperplasia or regeneration?
Neoplasm is an abnormal growth that continues to proliferate in the absence of a stimulus. Both hyperplasia and regeneration have a stimulus (growth factor) - and stop on removal of this stimulus
What is a malignant neoplasm?
An abnormal growth that invades surrounding tissue with potential to spread to distant sites
What is the difference between a neoplasm, tumour and cancer?
A tumour is any growth- detectable lump or swelling
A neoplasm is a type of tumour
Cancer is a malignant neoplasm
Why is dysplasia not neoplastic?
Because it is reversible. It has the potential to become neoplastic and malignant - and often is pre-neoplastic
What are the macroscopic differences between a benign tumour and malignant tumour and why?
Benign - usually defined outer margin and refined to a local area - smoother
Malignant - usually rough outer edges - may have necrosis/ulceration
Why might malignant tumours show necrosis?
Because some areas of the tumour may not have angiogenesis - necrosis. Or tumour is growing faster than angiogenesis can provide blood supply - necrosis.
Does a well differentiated neoplasm always mean it is benign?
No some malignant neoplasms are well differentiated. But benign neoplasms are always well differentiated.
Can malignant tumours be any of: poorly, moderately and well differentiated?
Yes
What is an anaplastic tissue?
One that has no resemblance to any tissue
Which 4 microscopic features correlate with a poor differentiated tissue?
- Mitosis seen (sometimes abnormal forms - aneuploidy)
- Cellular and nuclear size size variation
- Nuclear hyperchromasia
- Increased nuclear:cytoplasm ratio
What is nuclear hyperchromasia?
Nucleus stains more deeply than normal
What is pleomorphism?
Variation in size and shape of cells and nuclei
Is high grade tumour poorly or well differentiated?
High grade tumour is poorly differentiated
Does grade of cancer correlated with prognosis? What 3 factors do clinicians look at in the cell when grading a breast cancer for example (think microscopic features)?
Yes - grade 3 much less survival, and grade 2 less survival than 1.
Look at 1) Amount of tubules 2) Mitotic figures 3) Nuclear pleomorphism - then Grade either 1, 2, 3 depending on how differentiated the malignant neoplasm is.
Is a carcinoma in situ a reversible growth?
No. Once a growth goes from dysplasia to carcinoma in situ it is irreversible.
When looking at skin dysplasia - what is reduced keratin evidence of?
Reduced differentiation —> dysplasia —> often preceded malignant tumour. Dysplasia is characterised by abnormal differentiation.
When does an in situ tumour become an invasive tumour?
When it breaks through the basement membrane
Are most cancers initiated by intrinsic or extrinsic risk factors?
85% are extrinsic risk factors, 15% thought to be genetic. Get information by looking at ethnic migrant groups and comparing.
What are initiators and promotors? What is the relevance of them?
Initiators are mutagens that can cause cancer, promotors cause the cell proliferation. You need an initiator followed by prolonged promotor exposure to proliferate.
How does a monoclonal pre-neoplastic growth become polyclonal? What is this process termed? Are mutagens intrinsic/extrinsic/both?
Accumulation of more mutagens - called progression. Mutagens can be both intrinsic and extrinsic
What is the definition of monoclonal?
A group of cells that are originated from the same founding cell.
What is lyonisation?
X-linked inactivation of one allele in every female cell. Occurs in early embryogenesis.
What are oncogenes compared to proto-oncogenes?
Porto-Oncogenes are normal genes that code for proteins involved in cell growth. When photo-oncogenes become abnormally activated they become oncogenes.
