12 - Neoplasia 1 Flashcards
What is a neoplasm?
An abnormal growth of cells that persists after the internal stimulus is removed
What is a malignant neoplasm?
An abnormal growth of cells that persists after the internal stimulus is removed and invades surrounding tissue with potential to spead to distant sites
What is a tumour?
Any detectable lump or swelling, only cancer when it is a malginant neoplasm
What is a metastasis?
A malignant neoplasm that has spread from its original site to a new non-contigous site. The original site is the primary site and the place that it spread to is the secondary site
Is dysplasia a neoplasm?
No it is a pre-neoplastic alteration with disordered tissue structure, changes are reversible not irreversible like neoplasia
What are the differences between benign and malignant neoplasms macroscopically?
Malignant: irregular outer margin and shape, may have areas of necrosis and ulceration, have the potential to metastasise
Benign: grow in a confined local area so have a pushing outer margin, do not metastasise
What is the difference between benign and malignant neoplasms microscopically?
Benign: cells are like parent tissue so they are well differentiated
Malignant: can range from well to poorly differentiated, if not resemblance to any tissue they are called anaplastic
What happens to cells microscopically as differentiation worsens? i.e becomes malignant
- Increased nuclear size
- Increased nuclear to cytoplasmic ratio
- Increased nuclear staining (hyperchromasia)
- More mitotic figures
- Pleomorphism (increasing variation in size, shape and staining of cells and nuclei)
What does grading cancer refer to?
How differentiated the tumour is, the higher the grade the poorer the differentiation
How are different types of dysplasia classified?
- Dysplasia is reversible altered differentiation
- Mild, moderate and severe dysplasia, severe meaning worse differentiation and can lead to cancer
What is neoplasia caused by?
- Accumulations of mutations in somatic cells = PROGRESSION
- Initiators (mutagens) and Promoters (promote cell proliferation) induce mutations
- Need single initiator and prolonged promoter exposure to produce a mutant cell population
How do we know that neoplasms are monoclonal?
- In heterozygous females for G6PDH (x-linked) that codes for different isoenzymes
- In women, one X chromosome undergoes lyonisation, random in each cell
- In neoplastic tissue all of the cells produce the same isoenzyme, whether heat stable or labile, socome from same cell
Is a persons risk of cancer more down to intrinsic or extrinsic factors?
Migrating Japanese
What are some examples of initiators and promoters?
- Chemicals, infections, radiations and inherited mutations are initiators, some can also be promoters
What is progression, in terms of neoplasia?
When a neoplasm forms from a monoclonal population due to an accumulation of mutations in critical genes
In neoplasm, what are the two main types of genes that can affect their formation?
- Tumour supressor genes: normally supress neoplasm formation so when inactive neoplasm forms. recessive so both need mutating.
- (Proto) Onco-genes: abnormal activation favours neoplasm formation, dominant.
What are the general rules of naming neoplasms?
- Neoplasm’s site of origin
- If malignant or benign
- Type of tissue tumour forms
- Gross morphology (e.g cyst or papilloma)
What would be the suffix for a benign and malignant neoplasm?
Benign: -oma
Malignant: if epithelial -carcinoma (in-situ or invasive depending on basement membrane), if stromal -sarcoma
What type of neoplasms are leukaemia and lymphoma?
Leukaemia: malignant neoplasm of blood-forming cells arising in the bone marrow
Lymphoma: malignant neoplasms of lymphocyes, mainly in lymph nodes
What are germ cell neoplasms and -blastomas?
Germ cell: arise from pluripotent cells in the ovary or testis
Blastoma: occur mainly in children from immature precursor cells, e.g nephroblastoma
What is a papilloma?
- A papilloma is a benign epithelial tumor growing exophytically (outwardly projecting) in finger like projections
- Wart like growth on mucous membranes and skin
What are some of the different types of polyps?
Which type of cancer is most likely to form in the following organs:
- Bladder
- Bowel
- Skin
- Lung
- Breast
- Bladder: transitional cell carcinoma
- Bowel: adenocarcinoma
- Skin: squamous cell carcinoma, malignant melanoma, basal cell carcinoma
- Lung: adenocarcinoma, squamous cell carcinoma, small cell carcinoma
- Breast: adenocarcinoma
Which type of cancer is most likely to occur in the following organs:
- Prostate
- Brain
- Pancreas
- Uterus
- Oesophagus
- Stomach
- Thyroid
- Cervix
- Adenocarcinoma: prostate, pancreas, uterus, oesophagus, stomach, thyroid, cervix
- Squamous cell carcinoma: cervix, oesophagus
- Astrocytoma: brain
