Neoplasia Flashcards
Define tumour
Mass or swelling
Define neoplasm
Abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the change
Define benign
neoplasm that is localised and cannot spread
Define malignant
Neoplasm that can invade and destroy adjacent structures and spread to distant sites
Define cancer
malignant neoplasm
Define metastasis
Spread of a cancer to a distant site
What are clinically irrelevant mutations?
Cells with irrelevant mutations do not dominate, since they have no survival advantage over the normal cells
How is a neoplasm formed?
Formed by the clonal expansion of a single precursor cell that has a survival advantage over its neighbour
What are the mutations like in pre-tumoural stage?
neoplastic mutations are present in the tissue, but they have not yet given rise to a tumour, therefore they are typically clinically silent
What are benign neoplasms and what can they cause?
Remain limited to the site of origin, show expansive growth and do not metastasize. Often clinically irrelevant but may cause…
- compression
- obstruction
- bleeding
- hormone secretion
- cosmetic effects
- progression to malignancy
What are seborrheoic keratosis’?
completely benign marks on the skin, commonly seen in the elderly, they cause cosmetic problems but the major issue with them is that Dr. sometimes can’t make a confident diagnosis and worry they could be malignant
Why are tubular adenomas of the colon with low grade dysplasia removed?
Though they are benign they are removed because there is a clear sequence from adenoma to adenocarcinoma
What is in situ neoplasia?
Some mutations give cells malignant capacity, the malignant phenotype comes to dominate the tissue, but so far the cells have not yet invaded the basement membrane
Considered “pre-cancerous”
Complete excision is curative
Often asymptomatic as does not form a mass
Important for screening programmes
What happens in cancer?
Cells with malignant phenotype invade local structures and spread through tissues (invasive malignancy)
malignant neoplasm - ability to invade and destroy adjacent tissues
Capacity to metastasise
What are the hallmarks of cancer?
sustaining proliferative potential Evading growth suppressors avoiding immune destruction enabling replicative immortality tumour promoting inflammation activating invasion and metastasis inducing angiogenesis genome instability and mutation resisting cell death deregulating cellular energetics
