8. Neoplasms Flashcards
What is a neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed.
What is a malignant neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed and invades the surrounding tissue with potential to spread to distant sites.
What is a tumour?
Any clinically detectable lump or swelling.
What is a cancer?
A malignant neoplasm.
What is a metastasis?
A malignant neoplasm that has spread from its original site to a new non-contiguous site.
What are the primary and secondary site of a metastasis?
Primary - original site.
Secondary - place where it spreads to.
What is dysplasia?
A pre-neoplasmic alteration in which cells show disordered tissue organisation, this is reversible.
What is the key difference between benign and malignant neoplasms?
Benign neoplasms remain confined to their site of origin and do not produce metastases. Malignant neoplasms have the potential to metastasise.
Why are benign tumours rarely dangerous?
Because they grow in a confined local area and so have a pushing outer margin.
What is the outer margin and shape of malignant tumours?
Irregular.
How do malignant tumours cause necrosis and ulceration?
Necrosis by the tumour growing faster than the blood supply so ischaemic death.
Ulceration - irregular outline breaks epithelia.
How well differentiated are benign and malignant neoplasms?
Benign are well differentiated.
Malignant can be well differentiated or anaplastic - so poorly differentiated that they have no resemblance to any tissue.
What are some microscopic features of worsening differentiation?
Increasing nuclear size and nuclear to cytoplasmic ratio, increased nuclear staining (hyperchromasia), more mitotic figures and increasing variation in size and shape of cells and nuclei (pleomorphism).
What do grades indicate?
Levels of differentiation, high grade = poorly differentiated.
What is dysplasia?
Represents altered differentiation.
What percentage of cancer risk is down to environmental or extrinsic factors?
85%.