Lecture 14 - Neoplasia 1 Flashcards
What is the definition of a Tumour?
Any clinical detectable lump or swelling
What is the definition of a neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed
What is oncology?
Study of tumours and neoplasms
Do tumours and neoplasms have a relationship with normal growth signals?
No they are independent of normal growth signals
What is Hyperplasia?
Increase in the number of cells
Is hyperplasia reversible?
Yes
Hyperplasia = reversible
What is Neoplasia?
Formation of an abnormal growth of cells
What is a Benign Neoplasm?
A neoplasm with gross and microscopic appearances that are considered to be innocent, implying that it will remain localised and will not spread to other sites
Describe the innocent appearance of a benign Neoplasm?
Nice smooth edges
Well circumscribed
Not looking likely it will spread
What is deemed as a Cancer?
A malignant neoplasm
What is the definition of a malignant neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed and invades surrounding tissue with the potential to spread to distant sites
What is the definition of a Metastasis?
Malignant neoplasm that has spread from its original site to a new non-contiguous site
What is meant be a new non-contiguous site for a metastasis?
No physical connection between the 2 tumours
What is Dysplasia?
A pre-neoplastic alteration in which the cells show disordered tissue organisation
Is dysplasia reversible?
Yes reversible
How can dysplasia look like neoplasia?
Hyperchromatic nuclei
High nuclear to cytoplasmic ratios
What are some examples of a non-neoplastic tumour?
Abcess
Haematoma
What is the difference between a primary malignant neoplasm and secondary metastasis?
The primary malignant neoplasm is the original neoplasm whereas the metastasis has spread from the primary neoplasm
What is the difference between the primary site and secondary site of malignant neoplasms?
Primary site = original site of malignant neoplasm
Secondary site = Place original neoplasm has spread to
What is the difference between benign and malignant neoplasms?
Benign = Remain confined to sit of origin, DO NOT METASTASISE
Malignant = Invade and CAN METASTASISE
What is coning?
When the intercranial pressure increases leading to the brainstem being forced through the foramen magnum leading to death
What is pleomorphism?
When cells and their nuclei have a varying size and shape
What is tumour burden?
The amount of cancer in the body
Higher tumour burden = increased fatigue and weight loss
How do benign tumours grow?
In a confined local area
Have a Pushing outer margin
Only dangerous when in certain locations
How do malignant tumours grow?
Irregular outer margin and shape
May have ulcerations and necrosis
Infiltration
What is meant by benign tumours having a pushing outer margin?
They appear to push tissue away/outwards rather than being invasive/infiltrative
Why can malignant tumours have centres of necrosis?
Rapid growth means that the centre cells don’t get enough nutrients and oxygen
What is the definition of differentiation?
Process of cells becoming different by growth or development to be specialised for a set function
What is the differentiation of a benign neoplasm like?
Well differentiated
Closely resemble the parent tissue
What is the differentiation like for a malignant neoplasm?
Ranges
The worse the malignant neoplasm gets the more poorly differentiated it becomes
Gets less and less similar to the parent tissue
What is the definition of anaplastic?
Cells with no resemblance to any tissue
How do very malignant poorly differentiated tissues appear?
Increased nuclear size
Increased nuclear to cytoplasm ratio
Hperchromasia (nuclei stain darker)
Abnormal mitotic figures (Looks like Merc logo)
Pleomorphism (Variation in size and shape of cells and nuclei)
How does a melonoma (skin neoplasm) appear?
Dermis has nests and clusters of epithelioid cells
Dark staining large nuceli
How do cell shapes differ between benign and malignant neoplasms?
Benign = Cells same throughout tumour, resemble tissue of origin
Malignant = Pleomorphic, less likely to resemble tissue of origin can have unexpected functions
What are the grades used to indicate the degrees of differentiation of a neoplasm? What do these grades mean?
Grade 1 - Well differentiated (resemble origin tissue)
Grade 2 - Moderately differentiated
Grade 3 - Poorly differentiated
What is Dysplasia?
Cells abnormally differentiate into different cell types and become disorganised
How is dysplasia classified?
Dependant on worsening differentiation
Mild
Moderate
Severe
Is dysplasia reversible?
Yes
What is Carcinoma in situ?
Full dysplasia affecting the full thickness of the epidermis
No cells have breached the basement membrane so isn’t an invasive cancer
What is an invasive carcinoma?
When cells breach the basement membrane
The dysplastic cells in a carcinoma have a potential to become an invasive carcinoma
What are the basic steps to developing a neoplasm?
Accumulated mutations in somatic cells (caused by initiator)
Promoters cause cell proliferation which propagates the genetic damage
Tumour forms from the colonial expansion of a single genetically damaged precursor cell
What causes the non-lethal genetic damage/mutations that lead to neoplasia?
Initiators/mutagenic agents
What are some chemical initiators for neoplasia?
Chemicals:
-Smoking
-Alcohol consumption
-Diet and obesity
Infectious agents:
-HPV
Radiation
Inherited mutations
What is the definition of progression?
When a single cell mutates and forms many cells (neoplasm) with the mutations
Step wise process of developing mutations which aid the cancer development (acquisition of more and more mutations)
If a young person has developed a neoplasm what should be done?
Investigate germ line mutations since its likely the person has inherited a defect that has affected a critical gene
What 4 regulated genes can be mutated leading to cancer?
Growth promoting proto-oncogenes
Growth inhibiting tumour suppressor genes
Genes that regulate programmed cell death (apoptosis)
Genes involved in DNA repair
What are proto-oncogenes?
Genes that participate at some level in driving cell proliferation
What are proto-oncogenes referred to as when they are abnormally stimulated?
Oncogenes
What are oncogenes?
Genes which favour neoplasm formation (excessive stimulation of growth, division and prevention of apoptosis)
What do Oncogenes produce?
Oncoprotiens
Why is a single mutation of a proto-oncogene so bad?
Oncogenes are dominant over normal proto-oncogenes
Only 1 allele needs to be damaged
What is the function of Tumour Suppressor Genes?
Makes proteins:
-Stop cell proliferation
-Repairs DNA
-Stimulate apoptosis in damaged cells
What happens if Tumour suppressor genes are mutated?
Loss of function so growth inhibition fails
How many alleles of the tumour suppressor gene needs to be mutated to cause failure of growth inhibition?
Both alleles
Usually what do the names of benign tumours end in?
-Oma
Usually what do the names of malignant tumours end in?
Carcinoma (epithelial)
Sarcoma (stromal)
Where can transitional cell papilloma occur?
Bladder mucosa
What is the name for a glandular benign neoplasm?
Adenoma
Where can squamous cell carcinoma form?
Skin
Larynx
Oesophagus
Lungs
…..
Where can transitional cell carcinoma happen?
Bladder, ureters
Where can adenocarinomas form?
Prostate
Breast
Pancreas
Oesophagus
Stomach
Lung
What is a benign smooth muscles neoplasm and malignant neoplasm?
Benign = Leiomyoma
Malignant = Leiomyosarcoma
What is a benign fibrous tissue neoplasm and malignant neoplasm?
Benign = Fibroma
Malignant = Fibrosarcoma
What is a benign bone neoplasm and malignant neoplasm?
Benign = Osteoma
Malignant = Osteosarcoma
What is a benign cartilage neoplasm and malignant neoplasm?
Benign = Chondroma
Malignant = Chondrosarcoma
What is a benign glial cell neoplasm and malignant neoplasm?
Benign = Glioma
Malignant = Malignant glioma
What is a Urinary Tract Epithelium benign neoplasm called?
Transitional cell papilloma
What is a Urinary Tract Epithelium malignant neoplasm called?
Transitional cell carcinoma
What is stroma/stromal tissue?
The supporting tissue that provides the framework for organs like glands, holds tissues in place like blood vessels and nerves
It’s a loose connective tissue
