Flashcards in 18. Characteristic of tumours Deck (72)
Different malignancies show varied growth rates. What are slow-growing tumours associated with?
Different malignancies show varied growth rates. What are rapidly-growing tumours associated with?
Lethal within a short time
What is the definition of 'differentiation' in terms of tumours?
The extent that neoplastic cells resemble the corresponding normal parenchymal cells, morphologically and functionally
What are the characteristics of benign tumours in terms of differentiation?
- usually well-differentiated
- mitoses are rare
What are the characteristics of malignant neoplasms in terms of differentiation?
- wide range of parenchymal differentiation
- most exhibit morphologic alterations showing malignant nature
Do benign and malignant tumours look different histologically?
Well-differentiated malignant tumours and benign tumours can look very similar
What is anaplasia?
A condition whereby cells lose the morphological characteristics of mature cells
How are neoplasms comprised of poorly-differentiated cells described?
What condition is a "telltale sign of malignancy"
Neoplasms comprised of poorly-differentiated cells
What are some possible morphological changes in cells?
- abnormal nuclear morphology
- loss of polarity
- other changes
What is pleomorphism?
Describes variability in the size, shape and staining of cells and/or their nuclei. It is a feature characteristic of malignant neoplasms, and dysplasia
Give some examples of the huge differences shown in pleomorphism
- small cells with little differentiation
- large cells with one massive nucleus
- large cells with multinucleation
Cells can have abnormal nuclear morphology. Give some examples of this
- nuclei appear too large for the cell
- variability in nuclear shape
- chromatin distribution
- abnormally large nucleoli
In abnormal nuclear morphology, nuclei may appear too large for the cell that they are in. What is normal?
Normal nuclear to cytoplasmic ratio = 1:4 or 1:6
When abnormal, it can reach 1:!
In abnormal nuclear morphology, there can be variability in nuclear shape. Give examples
- making pictures (raisins, faces etc)
In abnormal nuclear morphology, there can be abnormal chromatin distribution. Give examples
- coarsely clumped
- along cell membrane
In abnormal nuclear morphology, there can be hyperchromatism. What does this look like?
What are mitoses an indication of and what are they seen in?
An indication of proliferation
Therefore seen in normal tissues with a rapid turnover and in hyperplasias
In malignancy, atypical bizzare mitotic figures are seen. Give examples
- tripolar division
- quadripolar division
- multiple spindles
What occurs in loss of polarity in cells?
- orientation of cells disturbed
- disorganised growth
In summary, what are the main characteristics of well differentiated tissues?
- closely resembles normal tissue or origin
- little or no evidence of anaplasia
- benign and occasional malignant
In summary, what are the main characteristics of poorly differentiated tissues?
- little resemblance to tissue of origin
- highly anaplastic appearance
In summary, what are the main characteristics of undifferentiated/anaplastic tissues?
- cannot be identified by morphology alone
- need molecular techniques
What is 'grade' in terms of tumour classification?
- closely related to differentiation/clinical behaviour
well differentiated = low grade/grade 1
moderately differentiate = intermediate/grade 2
poorly differentiated = high grade/grade 3
What is 'stage' in terms of classification of tumours?
A measure of prognostication/therapeutic decisions
Better differentiation = ?
Better retention of normal function
How can benign and well-differentiated carcinomas of the endocrine glands be detected?
They frequently secrete hormones characteristic of origin
Increased levels in the blood can be used to detect and to follow up tumours
How can changes in function of tumours give clinical clues?
- some tumours express foetal proteins not seen in adults
- some express proteins only normally found in other adult cells
Change in function of tumours can lead to paraneoplastic syndromes. For example, in bronchogenic carcinomas, what is released which leads to secondary effects on the body?
- parathyroid-like hormone