Session 8 Lecture Notes Flashcards
What is the definition of a tumour?
Any detectable lump or swelling
What are the two types of tumours?
Non-neoplastic eg an abscess
Neoplastic eg cancer is a malignant neoplasm
What is the definition of metastasis?
A malignant neoplasm that has spread from its original site of origin (primary site) to a new site (secondary site)
What is the definition of dysplasia?
A pre-neoplastic alteration in which cells show disordered tissue organisation
It is different to neoplasm because it IS REVERSIBLE
What is the main difference between dysplasia and neoplasm?
Neoplastic cells are NOT reversible whereas the dysplasia cell changes ARE
Are benign neoplasms cancerous?
NO only malignant neoplasms are cancerous
What is the main difference between the activity of benign and malignant neoplasms?
Benign neoplasms are confined to their primary site of origin whereas malignant cells can metastasis to secondary sites
What is the difference macroscopically between benign and malignant neoplasms?
Benign = have a pushing outer margin Malignant = irregular outer margin and shape and may show necrosis and ulceration
What is the difference microscopically between benign and malignant neoplasms?
Benign = cells are well differentiated ie they closely resemble the parent tissue Malignant = cells range from well differentiated to poorly differentiated (anaplastic) ie they have no resemblance to target tissue
As cells become more poorly differentiated what 4 changes are seen?
- Increased nuclear size and nuclear to cytoplasmic ratio
- Increased nuclear staining (hyperchromasia)
- More mitotic figures
- Increased variation in size and shape of cells and nuclei (pleomorphism)
What is pleomorphism?
Cells that vary in size and shape as well as different nuclei appearances
What is hyperchromasia?
Darkly stained nuclei
Grade is used to indicate level of differentiation. Is a high grade well or poorly differentiated?
Low grade = well differentiated
High grade = poorly differentiated
The modified bloom richardson grading for breast cancer looks at which 3 factors?
- Tubules
- Mitosis
- Nuclear pleomorphism
What does in situ mean?
The tumour is above the basement membrane
Are the majority of mutations due to intrinsic or extrinsic factors?
Extrinsic factors (approximately 85%)
What 2 things are needed to cause mutation?
- Initiators (mutagenic agents)
2. Promotors (cause cell proliferation)
What is lyonisation?
This is X linked inactivation
One of the copies of the X chromosome in females is randomly inactivated to prevent double the amount of gene products being produced in women than men
Are neoplasms monoclonal and what does this mean?
Yes they are
They originate from a single founding cell
Initiator + Promotor + Progression = monoclonal cell population developing into a neoplasm
What genes are altered during neoplasm formation?
- Proto-oncogenes - they become abnormally activated to become oncogenes
- Tumour suppressor genes - they become abnormally inactivated so can’t prevent neoplasm formation
Are proto-oncogenes and tumour suppressor genes dominant or recessive alleles?
Proto-oncogenes = dominant
When one is activated (to become an oncogene) it drives proliferation
Tumour suppressor genes = recessive
Both have to be inactivated in order for them to stop functioning
What 2 types of carcinoma are there?
- In situ
- Invasive
In situ means the cancer has not penetrated the basement membrane whereas invasive it has
What would you call a benign vs malignant neoplasm in the bladder epithelium?
Benign = transitional cell papilloma Malignant = transitional cell carcinoma
What would you call a benign vs malignant neoplasm in the glandular epithelium?
Benign = adenoma Malignant = adenocarcinoma
What is a basal cell carcinoma?
A malignant neoplasm in the skin epithelium
Can lymphoid or haemopoeitic neoplasms be benign and malignant?
No - they are always considered malignant
Are germ cell neoplasms benign or malignant? What are they called?
Germ cells are found in the testis and ovaries In the testes they are MALIGNANT In the ovaries they are BENIGN Testis = malignant teratoma Ovaries = benign teratoma
What are blastomas?
Neoplasms that arise from immature precursor cells and mainly occur in children
What are the 3 stages in which a malignant neoplasm gets from a primary to secondary site?
- Grow and invade at primary site
- Enter a transport system and lodge at secondary site
- Grow at the secondary site to form a new tumour (colonisation)
Invasion into surrounding tissues by carcinomas requires 3 stages, what are they?
- Altered adhesion
- Stromal proteolysis
- Motility
What are the 3 ways in which stromal cells can reach distant sites?
- Travel through bloodstream
- Travel through lymphatic vessels
- Travel through fluid in body cavities (transcoelomic spread)
What are micrometastasis?
Surviving microscopic deposits of metastasis that fail to grow
What is tumour dormancy?
When a person harbours many micrometastases
Malignant neoplasms that travel in lymph vessels are likely to metastasis where?
In the lymph nodes
Malignant neoplasms that travel in the bloodstream are likely to metastasis where?
In the lung or liver as this is often the next capillary bed that they encounter
However it depends upon the cancer niche
What transport system do carcinomas vs sarcomas use when they metastasise?
Carcinomas = most often travel in the lymphatics Sarcomas = most often travel in the bloodstream (particularly liver, lungs, bone and brain)
Which neoplasms most frequently spread to the bone?
Breast, lung, kidneys, thyroid and prostrate cancer
What are paraneoplastic syndromes?
The indirect systemic effects of a neoplasm eg hormone secretion or increasing tumour burden
What are the 4 main local effects of a neoplasm?
- direct invasion and destruction of tissue
- ulceration at the surface leading to bleeding
- compression of adjacent structures
- blocking tubes and orifices
