Controlled and uncontrolled DOG Flashcards
'’Controlled’’ disorders of growth can be divided into:
- Congenital (agenesis, aplasia and hypoplasia)
2. Acquired (atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia)
Disorders of growth fall into 2 major groups:
- Controlled (non-neoplastic) = process lies under normal controls (does not mean it is beneficial to the animal)
- Uncontrolled (neoplastic) = cells proliferate without the constraint of normal cellular controls and usually fail to reach full differentiation. Result in tumours, neoplasma and are irreversible.
What is a tumour?
An abnormal mass.
What is a neoplasm?
'’New growth’’. Any new and abnormal growth in which cell multiplication is uncontrolled and progressive.
What are the main types of controlled alterations in cell growth?
- Hypertrophy (increase in cell size)
- Atrophy (decrease in cell size, often also involves a decrease in cell number)
- Hyperplasia (increase in cell number, implies cells involved are capable of mitotic division)
- Metaplasia (replacement of one cell type to another
- Dysplasia (epithelial tissue - proliferation of cells, disorderly arrangement rather than an orderly progression from immature basal cells through intermediate cell types to the mature fully differentiated cells near the surface-> pre-neoplastic)
What is anaplasia?
Loss of differentiation of adult cells i.e. an irreversible alteration toward a more primitive (embryonic) morphology. Reversion to a lower level of differentiation. (Anaplastic)
Benign =
not malignant, favourable for recovery
Malignant =
tending to become progressively worse, leading to death.
What does the term metastasis mean?
The transfer of disease from one site in the body to another not directly connected to it. Most commonly either haematogenously or via the lymphatics. Often used in the setting of neoplasia, however, can also describe the spread of infectious diseases.
What does the term pleiomorphism mean?
Variation in size and shape. e.g. some cells may be extremely large with large nuclei while others of the same cell type may be small with small hyperchromatic nuclei. There may be a change in nuclear shape and there may be prominent and multiple nucleioli present. . Nuclear: cytoplasm may approach 1:1 (normal 1:4)
How are neoplasms classified?
- Cell of origin
2. Behaviour
What is the name ‘stroma’ given to?
Supporting CT and blood vessels (neoplastic cells often stimulate stroma)
What is the most important feature of a neoplasm?
its BEHAVIOUR.
List some gross features of Benign Neoplasms:
- well circumscribed borders
- dont metastasize
- may have ulceration due to trauma e.g. knocking a lump
- growth is slow
- Maybe within a capsule
- Compression of surrounding tissue
- NOT fixed to surrounding tissue
List some gross features of Malignant Neoplasms:
- invasive borders
- may metastasize
- more often you see ulceration due to trauma or invasion
- Common to have haemorrhage or necrosis
- No capsule
- Grow fast
- Compress surrounding tissue
and often fixed to/invasion of surrounding tissue
What are the common routes of metastases?
- Exfoliation & Implantation
- Haematogenous Spread
- Lymphatic Spread
What is meant by the term ‘grading’?
Looking at cell features/mitotic rate, how much they look like normal tissue cells (use microscopic pathology table to gauge) - uses case series
What is meant by the term ‘staging’
(Extent of disease). How much has it spread to different tissue? BM, lymphatics, other organs? (disadvantage is that it has already happened - metastasis)
What is the name of a tumour with cells of lymphoid origin?
Lymphosarcoma (when a solid neoplasm); Leukaemia (when in blood)
What is the name of a malignant tumour of melanocytes?
Malignant melanoma (or melanosarcoma)
List 3 direct effects that a tumour may have on surrounding tissue?
- distortion
- blockage of secretions/ excretions
- scarring
- atrophy
- pain
List 3 systemic effects that a tumour may have on a host?
- Metastasis
- Cachexia
- Anaemia
- Infarction
- Paraneoplastic syndromes (hormones)