Session 8 - Neoplasm 1 Flashcards Preview

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Flashcards in Session 8 - Neoplasm 1 Deck (70):
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Define neoplasm

An abnormal growth of cells that persists after the initial stimuli is removed

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Define malignant neoplasm

Abnormal growth of cells which persists after the initial stimulus is removed AND invades the surrounding tissue with the potential to spread to distant sites

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Define tumour

Any clinically detectable lump or swelling

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A neoplasm is a type of...

Tumour

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A cancer is any...

Malignant neoplasm

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What is a metastasis?

A malignant neoplasm that has spread from its original site to a new contiguous (non-related) site

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Are tumours always neoplastic?

No, they can be either neoplastic of non-neoplastic

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Do neoplasms always form lumps?

No, some can be liquid tumours, eg leukaemia

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What is the original location of a neoplasm called?

Primary neoplasm

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What is a secondary site of a neoplasm?

The place to which the neoplasm has spread

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What is dysplasia?

A pre-neoplastic lesion in which cells show disordered tissue organisation and poor differentiation.

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What is the main difference between neoplasia and dysplasia?

Dysplasia is reversible, neoplasia is not

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How do benign neoplasm differ in behaviour from malignant?

Benign neoplasms are confined to the site of origin and do not produce metastases. Malignant neoplasms have the potential to metastasise

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How do benign tumours look to the naked eye?

Local confined area with an outer pushing margin which is regular

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When can benign tumours become dangerous?

When they are in areas which cannot compensate for them, or press against other structures eg the brain (space occupying lesion)

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How do malignant tumours appear to the naked eye

Irregular margins and shape with areas of necrosis and ulceration.

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Why does ulceration occur in malignant tumours?

Centre cannot get adequate blood supply and becomes necrotic, tumour breaks and necrotic tissue sloughs off with destruction of surface epithelial

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How do benign tumours appear microscopically?

Well differentiated without invasion

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How do malignant tumour appear microscopically?

Possible invasion of surrounding tissues/basement membrane. The differentiation can range from well to anaplastic.

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How do cells of a malignant neoplasm appear as the differentiation worsens?

Increased nuclear size and increased nuclear-cytoplasm ratio
Hyperchromasia
More mitotic figures with increased mitosis (sometimes abnormal)
Pleomorphism

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What is pleomorphism?

Cells which have increased variation in size and shape of cells and their nuclei, relative to each other.

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What does the term 'grade' indicate?

How differentiated the cells within a tumour are

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High grade tumours are...

Poorly differentiated

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Low grade tumours are...

Well differentiated

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What does the term anaplastic mean?

The cells of the tumour do not resemble any cell type.

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How does dysplasia lead to neoplasia?

The cell organisation and differentiation passes the pint of no return, ie it becomes irreversible

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What is an initiator?

Any mutagenic agent (intrinsic or extrinsic) which introduces a mutation into a cell

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What is a promoter?

Anyang which promotes the proliferation of the mutated population

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What is the end result of initiation and promotion?

An expanded monoclonal population of mutated cells

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Name some exogenous initiators

Chemicals
Infection
Radiation

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What is the advantage to neoplasm formation if there is an inherited/germline mutation?

The mutation does not have to occur from an external mutagenic agent, and thus initiation is skipped and the process can start at promotion

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What is progression?

The formation of a neoplasm from the expanded monoclonal population. Occurs by monoclonal cells acquiring another mutation, and this mutated cell being expanded forming a subpopulation. This process repeats several times (different amount required depending on where the neoplasm is)

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How is it possible to tell if a neoplasm is monoclonal in women?

All the cells in the tumour tissue would have the same isoenzyme of G6PD, in normal tissue there would be a patchwork of the isoenzymes dependant on the alleles in the woman.

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What is lyonisation?

Random inactivation of one allele during female embryogenesis

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In relation to neoplasms, what types of genes do genetic alterations usually effect?

Proto-oncogenes
Tumour-suppressor genes

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In relation to neoplasms, how are proto-oncogenes usually affected?

They are usually activated

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What effect does the activation of proto-oncogenes have and why?

It favours neoplasm formation as the genes effected are usually growth factors etc

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In relation to neoplasm formation, how are tumour-suppressor genes usually effected?

Both alleles are often deleted or inactivated

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How does deletion of tumour suppressor genes help neoplasm formation?

They normally suppress and control cellular proliferation and thus neoplasm formation. Without then there can be ku controlled proliferation

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Define carcinoma

A malignant neoplasm of epithelial origin

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Define adenocarcinoma

A malignant neoplasm of glandular epithelia

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What is meant by papilloma?

Finger-like projections

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What do most benign tumours end in?

-oma

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What do stromal malignant neoplasms end in?

-sarcoma

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What is meant by stromal?

Supporting tissues eg fibroblasts/smooth muscle

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What is mean by carcinoma-in-situ?

Carcinoma which hasn't invaded and passed the basement membrane

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What is a leukaemia?

A malignant neoplasms of white blood cells which are circulating or in the bone marrow

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What is meant by lymphoma?

A malignant neoplasm of the lymphocytes which have accumulated in the lymph nodes

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What are the four types of leukaemia?

Chronic lymphocytic leukaemia
Acute lymphocytic leukaemia
Chronic myeloid leukaemia
Acute myeloid leukaemia

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Chronic lymphocytic leukaemia is...

Accumulation of mature B cells which have escaped apoptosis and undergone cell-cycle arrest

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Acute lymphocytic leukaemia is...

Malignancy effecting b and t lymphocyte cell lines, arresting maturation and promoting uncontrolled proliferation of immature blast cells with marrow failure

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Chronic myeloid leukaemia is...

Uncontrolled proliferation of myeloid cells

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Acute myeloid leukaemia is...

Neoplastic proliferation of myeloid blast cells

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What is a leiomyoma?

Benign tumour of smooth muscle

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What is a leiomyosarcoma?

Malignant tumour of smooth muscle

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What is a fibroma?

Benign tumour of fibroblast cells

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What is a fibrosarcoma?

Malignant tumour of fibroblast cells

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What is a myeloma?

Malignant neoplasm of plasma cells

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What is a germline neoplasm?

A tumour of the ovary or testis

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Are tumours of the testis usually benign or malignant?

Malignant

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What two groups can malignant testis tumours be separated into?

Seminomas
Non-seminoma germ line teratoma

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What are teratomas?

Tumours which are comprised of a number of tissues not found at the site of origin and usually arise in germline cells eg testis and ovaries

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Where else, except testis and ovaries, can teratomas occur and why?

Anywhere along the midline due to embryonic rest in migration in the embryo during formation

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What are neuroendocrine tumours?

Tumours which arise from cells distributed throughout the body

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What is characteristic about tumours which end in -blastoma?

Formed from immature precursor cells and usually occur in children

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What is a polyp?

An abnormal growth projecting from the mucous membrane

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How can colon cancer present as an emergency?

Bowel perforation-> cancer erodes through mucus membrane which leads to peritonitis

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How does obstruction occur in colorectal cancer?

Tumour grows so large that it causes an obstruction as the lumen is narrowed

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Do benign or malignant colorectal tumours often cause occlusion of vessels?

Benign. Malignant tumours erode

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In what situation could a benign tumour cause sudden pain?

-If it outgrows it blood supply leading to infarction
-occlusion of a vessel
-if a pedunculated polyp becomes twisted, it will become infarcted