Neoplastic Disease Flashcards
Neoplasms
Tumours result from genetic alterations (eg mutations) in cells, resulting in abnormal (neoplastic) growth
Cells escape permanently from normal growth regulatory mechanisms
‘Cancer’ refers to a malignant tumour or neoplasm
Classifications of neoplasms
Behavioural classifications
- benign or malignant
Histogenetic classifications; cell of origin
Precise classification of individual tumours is important for planning treatment
Benign tumours
Non invasive
Remain localised (don’t spread to other sites of body)
Slow growth rate
Close histological resemblance to parent tissue
Typically well circumscribed, often surrounded by a fibrous capsule
If they arise on an epithelial or mucosal surface they grow away form the surface as they cannot invade thereby creating an exophytic lesion
Can create large swelling
Tend to be encapsulated
Problems caused by benign tumours
Pressure on adjacent tissues
Obstruction to the flow of blood
Production of a hormone
Transformation into a malignant neoplasm
Anxiety for the patient
Malignant tumours
- invasive and thus capable of spreading directly or by metastasis
- relatively rapid growth
- variable histological resemblance to the parent tissue
- poorly circumscribed (cut lesion resembles a crab)
- malignant tumours on epithelial or mucosal surfaces cause a protrusion in the early stages, but eventually invade the underlying tissue - ulceration common
Effects of malignant tumours
Morbidity and mortality associated at be due to..
- pressure on / destruction of adjacent tissues
- formation of secondary tumours
- infection
- fracture of bones
- neuropathy
- immunosuppression
- haemorrhage, anaemia
- blood loss from ulcerated surfaces
- obstruction of flow
- production of a hormone
- weight loss
- anxiety pain
Invasion and spread of malignant tumours
Invasion
- reduced contact inhibition
- increased mobility
- matrix changes
- enzyme release
Local spread
- perineural; along perineural spaces
- sarcolemmal; along membranes of muscle
- pagetoid; spread within epithelium
Distance spread
- metastasis
Evolution path of a squamous cell carcinoma
Normal
Dysplasia - immature cells escape from basal layer
Carcinoma in situ - basement membrane intact
Invasion - erosion of basement membrane, tumour gains access to vascular channels
Metastasis - spread via lymphatic, secondary tumour in lymph node
Metastasis
The distant spread of a malignant tumour from its site of origin
Spread can occur by 3 main routes
- blood stream
- lymphatics
- across body cavities
Highly malignant tumours have a greater potential for metastasis
Certain metastasis like to go to certain sites eg brain, kidney
Dormancy; malignant cells spread but remain viable and non mit optic for years they can the start regrowth
Histogenetic classifications of tumours
- classification by cell of origin
- histologically determined
- degree of histological resemblance to parent tissue allows tumours to be graded
- histological grade correlates with clinical activity
Histogenesis
The specific cell of origin of an individual tumour - specifies tumour type and is incorporated into name given to tumour
Differentiation
- degree to which the tumour resembles histological lu its cell or tissue of origin
- the degree of differentiation of malignant tumours correlates strongly worth patient survauva (prognosis) and indicates the appropriate treatment
- grading of 123
- a well differentiated tumour more closely resembles the parent tissue than does a poorly differentiated tumour
Nomenclature of tumours
- all have suffic ‘oma’
- benign epithelial tumours are either papillomas or Adenomas
- benign connective tissue tumours have a prefix denoting the cell of origin
- malignant epithelial tumours are carcinomas
- malignant connective tissue tumours are sarcomas
Exceptions..
- tumours that defy accurate classifications are called anaplastic tumours
Staging of tumours
TNM classification
T-Tumour size
N=Degree of lymph node involvement
M=Extent of metastatic spread
This will affect how pt are managed
Carcinogenesis
- this is the process which results in the transformation of normal cells to neoplastic cells by casing permanent genetic alterations or mutations
- a carcinogen is an agent known or suspected to participate in the causation of tumours
- known or suspected carcinogens
Chemicals, viruses, (non)/ionising radiation, hormones, mycotoxins
