Disorders Of Growth And Cancer Flashcards
What are cellular adaptations to stress?
- reversible changes in the number/size/type of cells in response to changes in their environment.
- physiological: responses of cells to normal stimulation by hormones or endogenous chemical mediators
- pathological: responses to stress that allow cells to modulate their structure/function to avoid/reduce injury
What is hypertrophy and its causes
- increase in size of cells/organ due to increased synthesis of structural proteins and organelles
- occurs when cells are incapable of dividing
- causes: increased functional demand, hormonal stimulation
What is hyperplasia and what causes it?
- increase in number of cells in an organ/tissue
- adaptive response in cells capable of replication
- physiological: hormonal/compensatory (eg. When a portion of tissue is removed/diseased)
- pathological: excessive hormonal/growth factor stimulation
What is atrophy and some causes?
- reduction in size/number of cells in organ/tissue due to decreased protein synthesis and increased protein degradation
- causes: loss of innervation, reduced blood supply, inadequate nutrition, decreased workload, loss of endocrine stimulation, ageing
What is metaplasia with an example?
- reversible change from one fully differentiated cell type into another
- adatpation that occurs when cells are sensitive to a particular stress and are replaced by cells which are better able to withstand the adverse environment
- eg. Normal ciliated columnar epithelial cells are replaced by stratified squamous epithelial cells in the respiratory epithelium of smokers
Define neoplasm
- new growth (abnormal)
- excessive uncoordinated growth compared to adjacent tissues
- persists even after cessation of causative stimuli
- usually the result of irreversible genetic change which is passed from one cell to its progeny
- can be classified according to biological behaviour (benign vs malignant) or tumour type, sub-type and site of origin
Describe features of benign neoplasms
- grows slowly without invading adjacent tissue or spreading to distant sites (localised)
- usually few cells undergoing cell division which appear normal
- well circumscribed due to lack of invasion
- small regular and uniform nuclei
Describe features of malignant neoplasms
- invades surrounding tissues and can spread to distant sites (metastasise) with faster growth rate
- numerous cells undergoing cell division including atypical cells
- not well circumscribed
- larger, pleomorphic nuclei with increased DNA content
- synonymous with cancer
Contrast benign vs malignant neoplasms in terms of histology, clinically, and treatment
Histologically: benign neoplasms resemble the tissue of origin whereas malignant neoplasms can differ from their tissue of origin
Clinically: benign neoplasms cause local effects and hormone secretions, whereas malignant neoplasms can additionally cause destruction, inappropriate hormone secretion and can be fatal
Treatment: benign neoplasms can be treated with local excision, whereas malignant neoplasms may require further therapy with radio/chemo/supportive care
Describe dysplasia
- form of neoplasia which begins as benign but can progress to malignant
- occurs typically in epithelial cells/melanocytes (surface cells)
- disordered growth where cells don’t differentiate fully but are contained by a basement membrane (non-invasive)
- cells appear with larger and darker nuclei
- can develop from a pre-existing condition or metaplasia
- can persist, regress or progress
Describe carcinoma in situ
- severe form of dysplasia
- full-thickness epithelial dysplasia from basement membrane to surface of epithelium (only epithelial neoplasms)
- if no more advanced than this stage then risk of metastasis is 0 due to lack of blood vessels and lymphatics in epithelium above the basement membrane
How are tumours typed and graded? What is the clinical significance of classifying tumours?
- tumour type = tissue type represented by tumour
- tumour grade = well differentiated (resembles identifiable tissue type) or undifferentiated (IHC may be needed)
- important for prognosis and predicted response to treatment
How are epithelial tumours named?
Benign = papilloma/adenoma
Malignant = carcinoma/adenocarcinoma
How are connective tissue tumours named?
Benign = Oma
Malignant = sarcoma
What are the different modes of cancer spread?
- local invasion (growth into surrounding tissue by direct expansion/invasion)
- lymphatic spread (common for spread of carcinomas)
- blood spread (common for sarcomas)
- transcoelomic (serosal) spread (usually stomach/ovary carcinomas)
