Neoplasia 1 Flashcards
What is a neoplasm?
An abnormal growth of cells that persists after the stimulus has been removed
What is a malignant neoplasm?
An abnormal growth of cells that persists after the stimulus has been removed AND invades surrounding tissue with the potential to spread to distal sites
What is a tumour?
Any clinically detectable lump or swelling
What is a metastasis?
Malignant neoplasm that has spread from its original site to a new non-contigous site
What is dysplasia?
A pre-neoplastic alteration to cells which shows disordered tissue organisation
It is REVERSIBLE
How do benign and malignant neoplasms show different behaviour?
Benign tumours: grow in a confined area and do not produce metastasis
Malignant neoplasms: have the potential to metastasise
How do benign and malignant neoplasms differ to the naked eye?
Benign tumours- grow in a confined area and push out an outer margin
Malignant tumours- irregular outer margin and shape. May show areas of necrosis and ulceration
How do benign neoplasms look under the microscope?
- Well differentiated
- closely resemble the parent tissue
How do malignant neoplasms look under the microscope?
Malignant neoplasms can be well differentiated, Moderately differentiated or poorly differentiated
What are cells that bear no resemblance to any tissue called?
Anaplastic
How do cells change with worsening differentiation?
- increased nuclear size
- increased nuclear to cytoplasm ratio
- increased nuclear staining
- more mitotic figures
- increased variation in size and shape of cells and nuclei
What is pleomorphism?
increased variation in size and shape of cells and nuclei
How does neoplasia occur?
Accumulated mutations in somatic cells
What 2 things are needed for neoplasia to occur?
- A mutagenic initiator
- Promoters that cause cell proliferation
What are monoclonal neoplasms?
A collection of cells that all originate from a single founding cell
How can you determine if a neoplasm is monoclonal using glucose-6-phospate dehydrogenase?
- There are different alleles encoding different isoenzymes of G6PD
- In lyonisation, one allele is randomly inactivated in each cell which will give a patchwork of each cell type
- In neoplasms, all cells will only express one isoenzyme which indicates they are neoplastic
What is a carcinoma?
A malignant neoplasm of epithelial origin
What is a sarcoma?
A malignant neoplasm of stromal cells (connective tissue)
What is the difference between in situ and invasive carcinomas?
In situ- don’t invade through epithelial basement membranes
Invasive- penetrate the basement membrane
What is leukaemia?
A malignant neoplasm of blood forming cells arising in bone marrow
What is lymphoma?
A malignant neoplasm of lymphocytes, mainly affecting lymph nodes
What is myeloma?
A malignant neoplasm of plasma cells
What is a germ cell neoplasm?
Neoplasm arising from pluripotent cells, mainly in the testes and ovaries
What do prominent nucleoli in biopsies indicate?
A high rate of DNA transcription
