Tumour classification and behaviour Flashcards
(36 cards)
What processes is cellular proliferation important for?
Embryogenesis, normal tissue homeostasis, healing and repair, response to increases demand.
What is a labile tissue?
The cells divide regularly and rapidly and spend little time in G0. eg the skin, gut and bone marrow.
What is a stable tissue?
The cells that show little division. eg. the liver
What are perninant cells?
Those which never or very rarely divide, ege neurons or the myoceridiocycles.
What is metoplasia?
The replacement of one normally differentiated tissue type with another, normally in response to a change in the environmental stimuli.
Define a tumour?
An abnormal mass of tissue formed by excessive proliferation of cells as a result of an irreversible genetic change which is passed from one tumour cell to its progeny.
How is a tumour classified?
By its biological behavior and the cells type from which the tumour has arisen (histogenesis or differentiation).
What are the four main pathways a tumour can spread by?
Local, lymphatic, blood and transcoelomic.
Describe local spread.
Cells insinuate themselves between adjacent normal cells and invade along tissue planes, even if the tumour appears grossly well-defined. Dense collagenous tissues such as fascia or periosteum tend to act as a barrier to some extent.
Which cancers can spread via the lymphatics?
Carcinomas, early event. eg breast cancer patient have palpable axillary lymph nodes. Melanomas and sarcomas rarely spread via the lymphatics.
How to cancers spread from the lymphatics to the blood?
Via the thoracic duct
Which cancers spread by the blood?
Sarcomas, early event, mostly to the lungs. Carcinomas but normally after the lymphatics, an expection is renal carcinoma as it spreads along the renal vein and sometimes the inferior vena cava. Bowel tumours spread via the mesenteric veins to the liver but initially to the mesenteric lymph nodes.
Which cancers can spread blood to bone?
Many carcinomas, usually to the spine through the pre-vertebral venous plexus.
Is spread by the arteries common? Why?
No, the walls are to thick. Some cases of lung cancer can but may initially be via the pulmonary veins.
What is transcoelomic spread and some examples?
Spread across the body cavity. Intra-abdominal tumours like ovarian carcinoma. Krukenberg tumours spread from gastric carcinoma to both ovaries. Rare in both melanomas and sarcomas.
How, is it thought, do cells lodge in a site of metastases?
Via mutated surface receptors like CD44. Similarly to normal lymphatic circulation.
What are the clinical effects of benign tumours?
palpable lumps, pressure or expansion effecting adjacent tissues (like blocking a hallow viscus), effects due to the substances produced (eg endocrine hormones causinf hyperthyrodism due to a thyroid tumour).
Whats are the local effects of a malignant tumour?
Palpable mass (grows rapidly and may be painful), carincomas often ulcerate and bleed as they outgrow the bloody supply, Can cause iron-deficiency anaemia. Carcinomas of a hollow viscus many cause stenosis or complete obstruction.
What are the metastatic effects of a malignant tumour?
Multiple metastases masses have similar effects as the primary mass, but as there are more the outcome is more severe.
What are the non-metastatic effects of a malignant tumour?
Wasting (cachetic). weight and appetite loos, feeling unwell. Anaemia and febrile (have a fever). Normally due to the increas in cytokines eg IL-1 and TNF.
What are paraneoplastic syndromes and what causes them in metastatic cancers?
Separate diseases which arise as a consequence of cancer, often due to inappropriate generation of hormones. e.g. the secretion of ADH in small-cell carcinoma of the lung will cause dilutional hyponatraemia. PTHrP produced by many carcinomas leads to hypercalcemia (behaves like PTH and activates osteoclasts).
Where can cancer cells easily be found for cytology diagnosis?
Urine, sputum, fluid from the pleural cavity or peritoneum.
Which methods are used to diagnosis cancer?
Clinical, radiological, biochemical and cytology.
What is the difference between a cancers grade and its stage?
The grade is its basic biological nature and the stage describes the extend of its development.
