Neoplasm Flashcards
What is a neoplasm
neoplasm is, “!n abnormal growth of cells that persists after the initial stimulus is removed”; For malignant neoplasms the definition needs extending: “an abnormal growth of cells that persists after the initial stimulus is removed AND invades surrounding tissue with potential to spread to distant sites”
What is a tumour
A tumour is any clinically detectable lump or swelling. A neoplasm is just one type of tumour
What is a cancer
A cancer is any malignant neoplasm
What is a metastasis
A metastasis is a malignant neoplasm that has spread from its original site to a new non-contiguous site. The original 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 cells show disordered tissue organisation. It is not neoplastic because the change is reversible.
What is the different between benign and malignant neoplasms?
BENIGN AND MALIGNANT NEOPLASMS SHOW DIFFERENT BEHAVIOUR: Benign neoplasms remain confined to their site of origin and do not produce metastases. Malignant neoplasms have the potential to metastasise.
Why are benign tumours rarely dangerous?
BENIGN AND. MALIGNANT NEOPLASMS APPEAR DIFFERENT 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 are rarely dangerous. Malignant tumours have an irregular outer margin and shape and may show areas of necrosis and ulceration (if on a surface)
How do neoplasms look under the miscroscope?
1.5 UNDER THE MICROSCOPE NEOPLASMS SHOW VARYING DEGREES OF DIFFERENTIATION: A benign neoplasm has cells that closely resemble the parent tissue, i.e. they are well differentiated. Malignant neoplasms range from well to poorly differentiated. Cells with no resemblance to any tissue are called anaplastic.
What are hyperchromasia and pleomorphism?
With worsening differentiation individual cells have 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, which is called pleomorphism.
What does grade mean?
Clinicians use the term grade to indicate differentiation, high grade being poorly differentiated. Ow grade = well differentiated Eg. 1-tubules 2-mitosis 3-nuclear pleomorphism
What does dysplasia Indicate?
Dysplasia also represents altered differentiation. Mild, moderate and severe dysplasia indicates worsening differentiation
What is neoplasia caused by?
1.6 NEOPLASIA IS CAUSED BY ACCUMULATED MUTATIONS IN SOMATIC CELLS:
The mutations are caused by initiators, which are mutagenic agents, and promoters, which cause cell proliferation.
What do initiators and promoters cause?
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.
What is progression?
A neoplasm emerges from this monoclonal population through a process called progression, characterised by the accumulation of yet more mutations. See Neoplasia Lecture 3
New mutations - cause new expansions
When we get enough mutations that cause dysreulated autonomous growth - neoplasm
We need initiation, promotion, and progression to make a cancer
What are protooncognees and oncogenes
Pathway taht impinges on the cell cycle. The genes that are important In cancer are genes involved in such pathways. Eg a gene coding for a receptor in thei pathway
Normal gene = protooncogene
Abnormally activated to drive proliferation = oncogene
