Neoplasia Flashcards
Describe a neoplastic tumour.
A focal, purposeless overgrowth of one cellular component.
Some tumours are driven by normal genes which are expressed inappropriately. What are they?
Oncogenes
proto-oncogenes in a normal cell
Some tumours are triggered by the loss of normal genes. What are they?
Tumour suppressor genes
What is dysplasia?
Disordered tissue organisation which can be pre-neoplastic.
Change is reversible, cells have altered differentiation.
What is neoplasia?
A new growth which persists after the initial stimulus is removed.
What is a carcinoma?
A malignant epithelial tumour
What is carcinogenesis?
Production of cancer
What is a blastoma?
Poorly differentiated cell of embryonic type, tend to be very aggressive.
Mainly seen in children.
What is a benign tumour that arises from a gland called?
Adenoma
What is a benign tumour which arises from a gland and contains cavities?
Cystadenoma
What is a club-shaped tumour dangling from a surface?
Polyp
What is a sessile polyp?
A polyp which lacks a stalk
What is an adenomatous polyp?
A polyp which contains glandular growth.
What is a papilloma?
An outgrowth from an epithelial surface with long, thin branches.
What is a malignant tumour that arises from a gland?
Adenocarcinoma
What is a benign tumour arising from fibroblasts?
Fibroma
What is a benign tumour arising from bone?
Osteoma
What is a benign tumour arising from fat cells?
Lipoma
What is a benign tumour arising from cartilage?
Chondroma
What is a benign tumour arising from blood vessels?
Haemangioma
What is a benign tumour arising from lymphatic vessels?
Lymphangioma
What is a malignant tumour arising from bone marrow?
Myeloma
Are lymphomas benign or malignant?
Malignant
What is a benign tumour arising from smooth muscle?
Leiomyoma
What is a malignant tumour arising from smooth muscle?
Leiomyosarcoma
What is a malignant tumour arising from striated muscle?
Rhabdomyosarcoma
What is a benign tumour arising from striated muscle?
Rhabdomyoma
What is a tumour of neurons?
Ganglioneuroma
What is a malignant glial tumour?
Glioblastoma
What is a pleomorphic adenoma of salivary glands?
Benign tumour in the salivary glands which contains mixtures of epithelium, connective tissue and cartilage.
What is a fibroadenoma of the breast?
A benign tumour in the breast which contains glands and connective tissue
Why can teratomas contain material that is found anywhere in the body?
They are derived from cells which are so primitive (germ line cells) that they can produce all three embryonic leaflets.
What is a hamartoma?
A lump of tissue belonging to the organ in which it is found but has been wrongly assembled in the course of development.
Are present at birth and grow with the person.
What is a choristoma?
Ectopic tissue.
Lumps of normal tissue which doesn’t belong in the organ where the lump is found.
What properties do tumour cells share with embryonic and foetal cells?
They tend to grow quickly and are immature
What is anaplasia?
Cells which don’t have the morphological characteristics of a normal cell.
What is tumour progression?
Tumours becoming gradually more poorly differentiated in their life.
What are the features of a rapidly dividing cell seen microscopically?
More cytoplasmic basophilia due to increased RNA
Nucleoli increased in size and number
Mitoses increased and mitotic figures may be abnormal
How can mitotic figures be a measure of malignancy?
The number is proportional to the rate of growth and therefore aggressiveness of the tumour.
What is atypia?
Structural abnormality. Tends to parallel the degree of aggressiveness.
Size and shape of the cell is abnormal, nucleus is large and the secretions become irregular.
What are the behavioural changes in malignant cells?
Immortality
Loss of anchorage dependency
Loss of contact inhibition
Decreased requirement for growth factors as they supply their own
What are the functional changes in malignant cells?
Mobility - allows invasion and gives them the potential to move to another site.
Decreased adhesion between cells which plays a role in invasion
Tendency to shed surface molecules.
- Collagenase helps the cells invade through the ECM
- Tissue factor may lead to exaggerated clotting.
How can surface-related changes to malignant cells assist in diagnosis or treatment of a cancer?
Some of the surface molecules which are shed can be found in the blood and are known as tumour markers.
They are useful for diagnosing a particular malignancy or monitoring response to a treatment.
How and where do ulcerated tumours tend to develop?
Tend to arise from a bacterially contaminated surface such as the skin.
In the gut this is thought to be secondary to bacterial infection and digestive enzymes. The surface of the tumour is eroded by friction, then colonised by bacteria which causes a non-healing ulcer.
An ulcer with a raised edge strongly suggests an ulcerated tumour rather than a non-neoplastic ulcer.
What is scirrhous carcinomas?
A tumour with lots of connective tissue stroma. They are firm or hard.
Describe the cut surface of most tumours.
Most are white
Foci of necrosis common in malignant tumours
Large spaces filled with cysts suggest the tumour is epithelial.
What do you look at to find where a tumour has arisen from?
Identifying features for a specific cell type
If the tumour has lost all differentiation they can still be recognised by a specific antibodies.
What do you look at to determine how aggressive a tumour is?
Cellular abnormalities - lack of differentiation, cytologic atypia, pleomorphism
Architectural atypia - abnormal cellular pattern, infiltration
What are the secondary changes that can be seen in a tumour?
Ulceration
Necrosis (seen in the centre of tumours, more common in malignancy)
Calcification (seen in dead cells/necrotic masses)
Tortion (seen in pedunculated tumours, results in red infarct)
Give an example of a cell other than a tumour cell which is able to invade tissues.
Trophoblasts - invade the uterine wall
Leukocytes - invade tissues in inflammation
What is a metastasis?
A secondary tumour which has arisen from detached, transported cells.
Through what channels are metastases able to travel to a new site?
Blood
Lymph
Fluid in tissue spaces
Are metastases able to metastasise?
Yes
Why are metastases the most lethal expression of malignancies?
Greatly increase the disease burden
What are microscopic metastases and which cancers are most likely to produce them before excision?
Non-clinical, dormant metastases.
Breast cancer/malignant melanoma
Which vessels do metastases most commonly permeate?
Capillaries or veins (have very thin walls)
Which cancer is most likely to invade a large vein and grow through it?
Renal cell carcinoma
Where do tumours in organs which are drained by the portal system metastasise to?
Liver
What is the seed and soil model for tumours which metastasise?
The ‘seed’ is the tumour type, and the ‘soil’ is the tissue in which it embeds. Certain types of tumour have a preferential ‘soil’, yet the reason for this is yet unknown.
Where do breast carcinomas tend to metastasise to?
Lymphatics
Skeleton
Where do bronchial carcinomas tend to metastasise to?
Adrenal glands
What are Kruckenburg tumours?
Bilateral mesenteric tumours of the ovaries
Why are the lungs a common site for the metastases of many tumours?
They are the first large capillary bed after entry into the veins.
What is a common location for carcinomas to metastasise to, but is very rare for sarcomas?
Lymphatics
exception: rhabdomyosarcomas
Describe peau d’orange and why it occurs.
Carcinomas of the breast permeate the lymphatics of the overylying skin, causing the skin to become oedematous and puckered.
If lymph nodes near a tumour are swollen, what could be the cause if it has not metastasised?
Secondary to antigens and irritants which leach out of a tumour (especially if necrotic, ulcerated or infected).
Draining lymph nodes can then undergo hyperplasia.
How can seeding of a metastasis into the peritoneum cause ascites?
Fluid accumulation secondary to factors produced by tumours which cause leaking of fluid from the peritoneal membrane
OR
Secondary to fluid leaking from the surface of the tumour