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Different malignancies show varied growth rates. What are slow-growing tumours associated with?

Long survival


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?

Poorly-differentiated cells

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?

- pleomorphism
- abnormal nuclear morphology
- mitoses
- 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
- hyperchromatism
- 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

- irregular
- 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?

Dark colour


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?

- corticotropin
- parathyroid-like hormone
- insulin
- glucagon
- others


What are the general differences between cancer and benign tumours in terms of local invasion?

Cancer =
- infiltration
- invasion
- destruction

Benign =
- cohesive expansile masses
- localised to site of origin
- no capacity to infiltrate, invade or metastasise