15. Characteristics of Tumours Flashcards Preview

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Flashcards in 15. Characteristics of Tumours Deck (26):

define cancer

the uncontrolled growth of cells, which can invade and spread to distant sites of the body


define tumour

an abnormal swelling


define neoplasm

a lesion resulting from the autonomous growth or relatively autonomous abnormal growth of cells that persists in the absence of the initiating stimulus


define anaplasia

lack of differentiation in neoplastic cells. this is a tell-tale sign of malignancy


define neoplasia

the presence or formation of new, abnormal growth of tissue


define histogenesis

the differentiation of cells into specialised tissues and organs during growth from undifferentiated cells


define differentiation in the context of tumours

the extent that neoplastic cells resemble the corresponding normal parenchymal cells, morphologically and functionally.
*well differentiated malignant tumours and benign tumours can look very similar


which cancers are most common in men and women?

men - lung, colorectal, prostate
women - lung, breast, colon, rectum


which cancer has the highest mortality in both sexes?

lung cancer, in both the sexes


on what basis are tumours characterised?

1. differentiation
2. rate of growth - in most cases, malignant tumours grow more rapidly than benign tumours, but this statement is not universal
3. local invasion
4. metastasis


what morphological changes can be observed in differentiation?

1. pleomorphism - variation in size and shape of nuclei, could be large cells with one massive nucleus, or a cell with multiple nuclei
2. abnormal nuclear morphology - coarsely clumped chromatin, hyperchromatism, abnormally large nucleoli
3. mitoses - an indication of proliferation, can be present physiologically. in malignancy, atypical, bizarre mitotic figures seen. tripolar, multipolar spindles
4. loss of polarity - disturbed orientation of cells, disorganised growth
5. other changes


what is grade?

a measure of how differentiated the tumour is. grade 1 - well differentiated
grade 3 - poorly differentiated


how does differentiation relate to the function of the cell?

better differentiation means better retention of normal function


how does cancer harm cells?



what differentiates benign tumour cells from cancer?

benign - cohesive expensive masses
localised to site of origin
no capacity to infiltrate, invade or metastasise


what is pseudo encapsulation in malignant tumours?

the tumour itself is slow growing, but microscopically, rows of cells can be seen penetrating the margin


what is metastasis correlated to?

lack of differentiation
local invasion
rapid growth
large size
but there are many exceptions


what are the pathways of metastasis?

1. direct seeding - neoplasm penetrates a natural open field without physical barriers
2. lymphatic spread
3. haematogenous spread


how do tumours spread using lymphatics?

tumours do not contain lymphatic channels but there may be some at the margins of tumours
pattern of lymph node involvement follows the routes of lymphatic drainage
determination of axillary node status determines the future course of disease and therapy
lymph node mets is most common


how to tumours spread through blood?

usually via veins, because they have tanner walls. often come to rest in the first encountered capillary bed. more common in sarcomas, but also seen in carcinomas
common sites - lungs and liver


what is the sentinel node?

first node in a regional lymphatic basin that receives lymph flow from the primary tumour. identified by a radiological tracer or a coloured dye


what is stroma?

connective tissue framework that neoplastic cells are embedded in


what is the function of storm?

1. mechanical support
2. intercellular signalling
3. nutrition


what is a desmoplastic reaction?

formation of fibrous storm due to induction of connective tissue fibroblast proliferation by growth factors from the tumour cells


what are the contents of stroma?

1. cancer associated fibroblasts
2. myofibroblasts
3. blood vessels
4. lymphocytic infiltrate


what are the clinical complications of storm?

dependent on the location, and can occur in both benign and malignant tumours