7. intro to cancer Flashcards
define NEOPLASIA (tumour):
abnormal mass of tissue with abnormal growth (exceeds and uncordinated), and which persists in the same excessive manner after the cessation of the stimulus which has evoked the change
- Benign or malignant
- When the stimulus (eg. Radiation) is taken away the cells continue to grow (autonomous growth)
define HYPERPLASIA:
increase in number of cells in a tissue caused by increased cell division
- proliferation of cells, but when the stimulus is taken away it stops proliferating
- not adaptive response like in muscles and nerve cells
- hormonal influences important
- appear as normal cells not cancer but can develop into cancer
define DIFFERENTIATION:
term to describe how different in appearance the cells of a tumour are to the cell type from which they are derived
Important in predicting the likely behaviour of a tumour
define anaplasia
cells with poor differentiation without morphological characteristics
characteristics of benign tumours
grow by expansion
compress adjacent tissue
do not infiltrate
stay at their site of origin and do not spread
characteristics of malignant tumours
grow by expansion and infiltration
compress and invade adjacent tissue
infiltrate
can spread to distant sites - metastasis
what type of cancer is usually fatal
secondary (spread to another part of body)
where do most tumours arise from
epithelia- first point of contact
ADENOMA:
benign tumours of glandular epithelium (colonic/ thyroid)
PAPILLOMA:
benign tumours of squamous and transitional epithelium (bladder)
CARCINOMA
malignant epithelial tumours
MESENCHYMAL TUMOURS:
embryonic connective)
Bone:
osteoma
osteosarcoma
Adipose tissue:
lipoma
liposarcoma
Cartilage benign, malignant
chondroma
chondrosarcoma
Smooth muscle
leiomyoma
leimyosarcoma
Strated muscle
rhabdomyoma
rhabdomyosarcoma
Teratomas
tumours of germ cells containing representatives from all 3 embryological germ cell layers
Embryonal tumours
derived from embryonic blast tissue
Gliomas:
glial cells of CNS
Melanoma
tumour of melanocytes, usually in skin
Lymphoma:
tumours of lymphoid tissue
Leukaemia
tumour of haemopoietic cells in bone marrow
Neuroendocrine tumour
tumours derived from neuroendocrine cells scattered in many sites
Kaposi’s sarcoma:
type of cancer that forms masses in the skin
Wilms tumour
type of kidney cancer
Cellular/ nuclei pleomorphism:
variation in size and shape of cells/ nuclei in a tumour
Nuclear Hyperchromatism:
very dark- staining nuclei due to increased nuclear DNA
High mitotic count:
increased numbers of cells in mitosis, including abnormal mitotic forms
DYSPLASIA:
abnormal cell structure due to:
- Loss of differentiation
- Pleomorphism
- Nuclear hyperchromatism
- High nucleus: cytoplasm
- High mitotic activity
CARCINOMA IN SITU
dysplasia in epithelium that does not show invasion across epithelial basement membrane (or intra-epithelial neoplasia)
characteristics of malignancy but no evidence of invasion
list four cytological criteria of a malignant tumour
Pleomorphism: cellular/ nuclear distinct forms
High nucleus: cytoplasm
Nuclear hyperchromatism
High mitotic count
Abnormal mitosis
non metastatic effect of tumours
effects on nervous system
weight loss, loss of appetite, fever, malaise and anaemia
- Cytokines are released from inflammatory cells due to presence of tumour
- Some tumours retain function of origin organ- if endocrine function- excess hormones may be secreted
- Some tumours can also secrete hormones (paraneoplastic syndrome) that can result in hypercalcemia, myopathy, malfunction of nerves or cerebellar ataxia
- These are due to autoantibodies generated to tumour cells which cross react with normal tissues and cause immune-mediated damage
Cachexia:
weight loss that cant be reversed by normal nutritional support
- Cachexia is a wasting syndrome
- Anorexia is loss of appetite sometimes associated with cancer cachexia
- Believed that chemicals released from the cancer into blood contributes to muscle and fat loss (increasing metabolism)
- Less able to respond to chemo
- Progressive weakness and death due to secondary infection (pneumonia)
main routes of metastatic spread of malignant tumours
lymphatics,
- When invades lumen of lymphatic, bits can break off and pass to the lymph nodes draining area
- Pass to the lymph node and trapped in the subcapsular sinus
- The tumour cells proliferate until the whole node is replaced by tumour
blood vessels (capillaries and small veins),
serosal surfaces
Common sites of blood borne metastasis:
Brain and CBF
Liver
Lung
Adrenals
Bone
UNDIFFERENTIATED or ANAPLASTIC TUMOUR
composed of cells which are so undifferentiated that their cell of origin is unknown
POORLY DIFFERENTIATED TUMOUR
composed of cells which bear little resemblance to the cell of origin, but just enough to enable the original cell type to be identified.
WELL - DIFFERENTIATED TUMOUR
is composed of cells which very closely resemble the cell of origin
