Flashcards in MoD Session 8 Deck (140):
What is neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed
What does cell growth become in neoplasm?
How is neoplasm distinguished from inflammation clinically?
Neoplasm is cold to touch
When would neoplasm not cause a lump?
What is malignant neoplasm?
An abnormal growth of cells that persists after the initial stimulus is removed and which invades surrounding tissue w/potential to spread to distant sites
What must be present in cells to cause neoplasia?
What is a tumour?
Any clinically detectable lump or swelling
What two types of tumour can form?
What two types of neoplastic tumour are there?
What is metastasis?
Malignant neoplasm that has spread from its original location to a new non-contiguous site
Why might removal of a primary malignant neoplasm not prevent spread of cancer?
Each secondary tumour has the potential to spread
Is tumour formation reversible?
What is dysplasia?
Pre-neoplastic alteration in which cells show disordered tissue organisation
Is dysplasia reversible?
How are benign neoplasms characterised?
Remain confined to site of origin
Do not produce metastases
Create a pseudocapsule
What does the danger of a benign neoplasm depend on?
What tissue it is pressing on
What characteristics do malignant neoplasms display?
Irregular outer margin and shape
Can show ulceration in centre due to inadequate blood supply formation
Have the potential to metastasise
What do the cells of a benign neoplasm closely resemble?
How can the cells in a malignant neoplasm vary?
From well to poorly differentiated
What term is used to describe cells with no resemblance to any tissue?
What examines tissue cells ex situ so there is no architecture surrounding them?
How do poorly differentiated cells compare to sell differentiated cells?
What is pleomorphism?
Variance in cell and nuclei size and shape
How may mitotic figures appear in poorly differentiated cells?
May be abnormal
How is the grading of neoplasm determined?
Grade 1-3 with decreased differentiation with each stage
What happens to mortality with each increase in neoplasm grade?
It increases by 40%
What indicates worsening differentiation?
Mild --> moderate --> severe dysplasia
At what point does dysplasia become neoplasia?
When the worsening differentiation becomes irreversible
How long can the development of dysplasia into neoplasia take?
What three aspects does the Modified Bloom Richardson grading for breast cancer examine?
What percentage of cancer risk is extrinsic?
What change is seen in skin which has undergone reversible dysplasia?
Decreased specialisation causing loss of keratin
What change is seen in skin which has undergone irreversible dysplasia?
What causes neoplasia?
Accumulated mutations in somatic cells
How are the 10 million opportunities for somatic cell mutation per second dealt with to prevent neoplasia?
What causes a cell to enter G0?
What two things are needed to cause neoplasia?
What are the main initiatiors of neoplasm which can also act as promoters?
What causes early onset of cancer by skipping the initiator/promoter step of neoplasm?
Inheritance of a germline mutation
What is progression?
Formation of a neoplasm by accumulating more mutations by subclonal expansion
What causes heterogenous cells to be present within a neoplasm?
Is a neoplasm formed from progression monoclonal?
Yes, from same founding cells
What is a monoclonal tumour?
Tumour which originates from a single founding cell
What can be studied to identify monoclonal tumours?
How are different alleles of G6PD gene switched off during female embryogenesis?
Randomly by lyonisation
What expression of G6PD izoenzyme is seen in normal tissue?
Patchwork of cells expressing both heat stable and heat labile isoenzymes
What isoenzyme expression of G6PD is seen in neoplastic tissue?
Either only maternal or paternal isoenzyme expressed
What genetic alteration occurs in proto-oncogenes which favours neoplasm formation?
Abnormally activated oncogenes
Why does abnormal activation of a proto-oncogene only need activation of one allele?
It is positively acting
What is the effect of abnormal activation of proto-oncogenes?
Abnormally pushes cell through cell cycle
What happens to tumour suppressor genes to favour neoplasm formation?
Inactivation of growth factor
Inactivation of receptors
Why is deletion of both alleles of tumour suppressor genes needed to cause neoplasia formation?
Alleles have an inhibitory function
What words with the suffix -oma are not neoplasms?
What suffix do neoplastic blood disorders have?
What are the two types of benign epithelial tumour?
What are papillomas?
Benign non-glandular/non-secretory epithelial tumours
What do adenomas consist of?
What prefixes the papilloma/adenoma in benign epithelial tumours?
Name of specific cell type origin
What is a carcinoma?
A non-glandular malignant epithelial tumour
What is an adenocarcinoma?
A glandular malignant epithelial tumour
What is also included in malignant epithelial tumour names in addition to carcinoma/adenocarcinoma?
Name of tissue of origin - type of epithelial cell
What is the difference between in-situ and invasive carcinoma?
In-situ = no basement membrane penetration
Invasive = penetrated basement membrane
What are the four names of benign epithelial tumours?
Squamous cell papilloma
Transitional cell papilloma
Basal cell papilloma
What are the four names of malignant epithelial tumours?
Squamous cell carcinoma
Transitional cell carcinoma
Basal cell carcinoma
What are the eight types of benign mesenchymal tumours?
What is a leiomyoma?
Benign smooth muscle tumour
What is a rhabdomyoma?
Benign striated muscle tumour
What are the eight types of malignant mesenchymal tumours?
What is a cyst?
Fluid-filled space lined by epithelium
Are cysts neoplasms?
Some are, some are not
What five types of cyst are there?
What is Burkitt's lymphoma?
B-cell lymphoma associated w/Epstein-Barr virus and malaria
Where is Burkitt's lymphoma endemic?
Certain parts of Africa
What is Ewing's sarcoma?
Malignant tumour of bone of uncertain histiogenesis
What is Hodgkin's lymphoma?
Malignant lymphoma characterised by the presence of Reed-Sternberg cells
What is Kaposi's sarcoma?
Malignant neoplasm derived from vascular endothelium
What is Kaposi's sarcoma commonly associated with?
What are harmatomas?
Tumour-like lesions lacking autonomy of true neoplasm
What are teratomas?
Neoplasms forming cells representing all 3 germ layers
Where are teratomas most common?
How does the presence of teratoma in the ovaries compare to that in the testes?
Ovaries - usually benign
Testes - usually malignant
Why does a retinoblastoma form?
Where does a retinoblastoma arise?
In the eye
Where does a nephroblastoma/Wilms' tumour arise?
In the kidney
Where does a neuroblastoma arise where it can mature into a harmless, benign ganglioneuroma?
Where do hepatoblastomas arise?
In the liver
What do mixed tumours exhibit?
Characteristic combination of cell types e.g. mixed parotid/fibroadenoma of breast
What is a neuroendocrine tumour?
Cells scattered diffusely in various epithelial tissues form hormone or carcinoid tumours
What is a carcinoid neuroendocrine tumour?
A neuroendocrine tumour which does not secrete a peptide hormone
Where are embryonal tumour almost exclusively seen?
What do embryonal tumours have histiological resemblance to?
Embryonic form of organ
What types of tumour are embryonal?
What is the name given to a normal gene that is expressed inappropriately?
Give four characteristics of malignant tumours.
Atypical - cells are structurally and functionally abnormal in varying degrees
What is transformation in neoplasia?
Change of a normal cell to a malignant cell
What can be said about the nature of blastomas?
Tend to be very aggressive
What is the name of a club-shaped tumour dangling from a surface by means of a stalk?
What do type of tissue do polyps grow out of?
What are sessile polyps?
Polyps that lack a stalk
What is the name given to an outgrowth from an epithelial surface which has long thin branches and resembles a cauliflower in cross-section?
Is myeloma malignant or benign?
In what type of tissue is it very unlikely to see a benign tumour?
What is odd about a ganglioneuroma?
It is a tumour of neurones which are meant to be non-dividing cells
What is a glioblastoma?
Malignant glial tumour
Where do tetaromas tend to arise?
Along the midline - base of the skull, anterior mediastinum, along aorta, in gonads
How do harmatomas develop during growth?
Present at birth and grow with the person
Where does the lump of tissue found in a harmatoma belong?
To the organ in which the lump was found
What are choristomas/ectopic tissue?
Lumps of normal tissue that do not belong in the organ where they are found
What is the likely method by which tumours contain cells which are less differentiated?
Contain undifferentiated stem cells whose progeny fail to mature
Why do tumour cells have increased cytoplasmic basophilia?
Increased RNA therefore more active protein synthesis
Why can the number of mitoses be used as a measure of malignancy?
Their number is proportional to the rate of growth
What tends to parallel the degree of aggressiveness?
What causes a signet ring cell?
Abnormal mucus secretion causing it to be retained as a large droplet that distends the cell
Why might cells be seen floating in mucus in malignant cells?
Abnormal mucus secretion due to atypia
What properties do malignant cells possess?
Loss of anchorage dependence
Loss of contact inhibition
Decreased requirement for growth factors
Why do malignant cells have decreased requirement for growth factors?
They supply their own by autocrine secretion
How do cancer cells move around, allowing their invasion?
Between which cells is decreased adhesion seen in malignant cells?
How can a tendency of malignant cells to shed surface molecules such as proteins, glycoproteins and enzymes help malignant cells to function?
Shedding enzymes e.g. collegenase helps them to invade through ECM
Tissue factor exaggerates clotting
How can surface molecules shed by malignant cells be useful clinically?
Some are found in blood (tumour markers) and can be used for diagnosis
What two components do all tumours consist of?
How do some benign tumours develop a fibrous capsule?
Laid down by surrounding tissues as a response to pressure
Why can some benign tumours such as fibroadenoma of the breast be 'shelled out' through a clear cut cleavage plane with little surrounding tissue?
They are surrounded by a fibrous capsule
What must be removed with malignant tumours?
What type of tumours tend to become ulcerated?
Those that arise from a bacteria only containing tend surface
What is the formation of an ulcerated tumour in the gut thought to be secondary to?
Bacterial infection and digestive enzymes
How is a non-healing ulcer formed on a tumour?
Surface eroded by friction --> colonised by bacteria --> ulcer
What does an ulcer with a raised/rolled edge strongly suggest?
Ulcerated tumour rather than non-neoplastic ulcer
What is any ulcer on the skin present for more than 3-4 weeks a suspect for?
What are scirrhous carcinomas?
Tumours with lots of connective tissue stroma
How do melanomas, angiomas, hepatoma and most other tumours appear on cross section?
Melanomas = black
Angiomas = red with blood
Hepatomas = green with bile
Most others = white
What do foci of necrosis correlate with in malignant tumours where they are more commonly seen?
How can BV within the stroma of a tumour arise?
Incorporated by growing tumour
Newly developed by angiogenesis
How are tumour cells that are so undifferentiated they have lost identifying structural features recognised?
Usually retain some cell-specific antigen that can be recognised by a specific antibody
What secondary changes are seen in tumours?
When is necrosis seen in tumours?
Secondary to ischaemia in the centre of tumour
Can be due to impaired blood flow by high tissue pressures in the centre of the tumour
When is calcification of a tumour seen?
In dead cells or necrotic masses
What is used in breast screening by mammography to identify malignancy?
Calcification of tumours
What is torsion?
An accident seen in benign or malignant pedunculated tumours