Neoplasms Flashcards
What is a neoplasm?
Is composed of cells that grow in a poorly regulated manner.
There is a failure of the normal mechanisms that control cellular proliferation
What is Anaplasia?
Totally undifferentiated neoplastic parenchyma
Biochemically, anaplastic cells resemble other anaplastic cells more than they do their tissue of origin.
What is Hamartoma?
Is a benign, focal malformation that resembles a neoplasm in the tissue of its origin. This is not a malignant tumour, and it grows at the same rate as the surrounding tissues. It is composed of tissue elements normally found at that site, but which are growing in a disorganized mass.
What are the 2 types of neoplasm?
Benign
Malignant
What is a benign neoplasm?
The margins of the tumour are well defined
The neoplasm only grow locally
Tend to have a good prognosis
Cells are not cancerous and won’t spread
What is a Malignant neoplasm?
Margins of the tumor are poorly defined
The neoplastic cells grow into, and destroy the surrounding tissues
A major cause of mortality
Cells are cancerous and can spread to other organs
How do neoplastic cells form?
Normally,
following cell division from a stem cell or precursor cell, normal cells will assume a specific function > known as differentiation.
Neoplastic Cells however,
will fail to achieve a highly differentiated state (seen in histology).
How do benign neoplasms cells change?
These cells are differentiated, but correspond fairly closely from which cells they were derived.
This can mean that functional attributes (from the original tissue) may remain e.g. a benign tumour still secretes hormones which has endocrinological effects.
What are Well Differentiated Malignant Neoplasm?
the neoplastic cells closely resemble the original tissues.
What are Poorly Differentiated Malignant Neoplasm?
the neoplastic cells show only a passing resemblance to the original tissues.
What are Anaplastic Malignant Neoplasm?
Not possible to identify the cell origin on a morphological observation.
Do benign tumours grow fast or slow?
Slow
Do benign tumours compress local tissues?
Yes
What is the growth of a malignant tumour?
Most significant > growth is not confined to one space, and grows into adjacent tissues, termed invasion.
As they invade local tissues, cause damage & destruction.
Most sinister property, of a malignant tumour is when the primary tumour becomes detached and moves to another part of the body
this is called METASTASES.
Just like the primary, metastases will grow into local tissue and cause tissue destruction.
If neoplastic cells are to grow, they must obtain what?
adequate nutrient by developing an adequate set of support tissues
In particular, they require an adequate vascular supply.
The ability for a tumour to induce and maintain a vascular supply is a key factor in its growth.
Growth of a Neoplasm is determined by different factors. What are they?
Vascularity
& therefore the adequacy of nutrient supply to the tumour
If cell proliferation exceeds cell death
Primary malignancy can metastasize in 4 main ways. What are they?
Local Invasion
Lymphatic spread
Vascular Spread
Transcoelomic Spread
What is local invasion?
most common pattern; spread of tumour into adjacent tissue. Can also spread along natural tissue planes e.g. nerves
What is lymphatic spread?
Frequently will spread via draining lymphatic vessels & are conducted to local lymph nodes where they grow as secondary tumours.
What is Vascular spread?
Tumour can spread via the veins draining the primary lesion.
GI tumours are frequently conducted via the portal vein, giving rise to mets in the liver.
Tumor cells that enter systemic veins most frequently spread to the lung, bone marrow, brain & adrenal glands.
What is Transcoelomic Spread?
Primary tumors in the abdominal cavity or the thorax can spread directly across coelomic spaces e.g. the peritoneal or pleural cavities.
True or False. Neoplastic Cells have to acquire special attributes to invade & metastasize.
True
Within a primary tumor, it is likely that only a proportion of cells acquire these attributes by developing additional genetic mutations as part of their further abnormalities in cell growth.
To grow through the basement membrane into the extracellular matrix & then enter a vessel
neoplastic cells must express surface molecules for adhesion.
To grow into adjacent tissues & vessels,
they must be able to be motile and capable of migration
Once the neoplastic cell is anchored to the basement membrane,
it secretes enzymes which are able to degrade extracellular matrix this appears to be an important factor in metastasis.
