Characteristics of tumours Flashcards
define cancer
uncontrolled growth of cells which can invade and spread to distant sites in the body.
define tumour
abnormal swelling
define neoplasm
lesion resulting from autonomous growth or relatively autonomous growth of cells that persist in the absence of the initiating stimulus.
define histogenesis
The differentiation of cells into specialised tissues and organs during growth from undifferentiated cells (3 primary germ layers)
Are tumours categorised histogenically
Yes
what is the tumour name given to epithelial cell tumours
carcinoma.
what is the tumour name given to connective tissue tumours
Sarcomas
what is the tumour name given to lymphoid/haematopoietc organs
lymphomas, leukaemias
define differentiation in terms of tumours.
The extent that neoplastic cells resemble the corresponding normal parenchymal cells, morphologically and functionally
what are the typical features of benign tumours
well differentiated and mitoses are rare.
what are the typical features of malignant tumours
wide-range of parenchymal differentiation.
Most exhibit morphologic alterations showing malignant nature.
Well-differentiated malignant tumours and benign tumours can look very similar
define anaplasia
Neoplasms, which have poorly differentiated cells
what morphological changes take place in tumours
pleomorphism- shape and size.
abnormal nuclear morphology
mitoses
loss of polarity
are pleomorphisms extremely variable in different tumours and cells
Yes
what changes can cause abnormal nuclear morphology in tumour cells.
nuclei become large
nuclear to cytoplasmic ratio can reach 1:1.
variability in nuclear shape
Chromatin distribution- coarsely clumped or along the cell membrane.
hyperchromatism- dark in colour and large nucleoli.
are mitosis seen in normal tissue
Yes- especially in cells with a high turnover
what is different about mitoses which are sen in cancer cells
◦ Tripolar
◦ Quadripolar
◦ Multipolar spindles
Lot more proliferation occurring.
what does loss of polarity result in
Orientation of cells disturbed
Disorganised growth
what are the 4 categories of differentiation of the tumour cells.
Well differentiated
Moderately differentiated
Poorly differentiated
Undifferentiated / anaplastic
define grade
related to differentiation / clinical behaviour
well differentiated tumours-lowgrade
poorly differentiated tumours high grade.
define stage
A measure of prognostication / therapeutic decisions
why are well differentiated tumours better than poor differentiated tumours, an what glands commonly display this
Better differentiation = better retention of normal function
endocrine glands.
define paraneoplastic syndromes
caused by substances that are secreted by a benign tumor, a malignant (cancerous) tumor, or a malignant tumor’s metastases. The disturbances caused by paraneoplastic syndromes occur in body organs at sites that are distant or remote from the primary or metastatic tumors.
what paraneoplastic features do bronchogenic carcinomas show.
◦ Corticotropin
◦ Parathyroid-like hormone
◦ Insulin
◦ Glucagon
are benign tumours encapsulated
YES- within a rim of compressed fibrous tissue.
are benign tumours palpable and easily excised
Yes.
Are malignant tumours encapsulated
Yes-Pseudo encapsulation
define metastases
“Spread of a tumour to sites physically discontinuous with the primary tumour”
can benign tumours metastases
No
what characteristics predispose a tumour to being metastatic
◦ Lack of differentiation
◦ Local invasion
◦ Rapid growth
◦ Large size
what are the 3 methods by which metastases can happen and which is most common
direct seeding
lymphatic spread- common
haematogenous spread.
what is direct seeding metastases
Neoplasm penetrates a natural open field without physical barriers
what is lymphatic spread metastases.
Most common pathway
Tumours do not contain lymphatic channels
Lymphatic vessels at the tumour margins
what is haematogenous spread of metastases
via blood
does the pattern of lymph node involvement follow lymph node drainage
Yes
define sentinel node
The first node in a regional lymphatic basin that receives lymph flow from the primary tumour
how is the sentinel node identified.
Injection of radiolabelled tracers/coloured dyes
what are the uses of regional nodes
Effective barriers to further tumour dissemination.
Cells arrest within node and then can be destroyed by a tumour-specific immune response.
Not every enlarged node has cancer in it -Drainage of tumour cell debris and tumour antigens induces reactive change in nodes
which type of tumour is more commonly spread haemoatogneously
sarcomas
which type of blood vessel is commonly used in haematogneously spread and why
Veins more easily penetrated
-Thinner walls
are benign tumours slow growing of fast growing
slow
are malignant tumour slow or fact growing
fast
do bengin tumours locally invade
no
define stroma
connective tissue framework that neoplastic cells are embedded in.
Provides: mechanical support, intracellular signalling and nutrition
define desmoplastic reaction
fibrous stroma formation due to induction of connective tissue fibroblast proliferation by growth factors from the tumour cells
what does the stroma provide
Provides: mechanical support, intracellular signalling and nutrition
what does the stroma contain
cancer-associated fibroblasts
myofibroblasts
blood vessels
lymphocytic infiltrate
what are local complications of tumours
compression- displacement of adjacent tissues
destruction- invasion of blood vessels and mucosal surfaces.
what are the metabolic complications of tumours
well differentiated tumours retain normal function
Number of cells exceeds normal organ
over function of the cells
Non specific metabolic effects of tumours
cachexia- weight loss Warburg effect- produces energy by high rates of glycolysis with fermentation of lactic acid neuropathies myopathies venous thrombosis.
