Flashcards in Session 8 - Neoplasm 1 Deck (70):
An abnormal growth of cells that persists after the initial stimuli is removed
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
Any clinically detectable lump or swelling
A neoplasm is a type of...
A cancer is any...
What is a metastasis?
A malignant neoplasm that has spread from its original site to a new contiguous (non-related) site
Are tumours always neoplastic?
No, they can be either neoplastic of non-neoplastic
Do neoplasms always form lumps?
No, some can be liquid tumours, eg leukaemia
What is the original location of a neoplasm called?
What is a secondary site of a neoplasm?
The place to which the neoplasm has spread
What is dysplasia?
A pre-neoplastic lesion in which cells show disordered tissue organisation and poor differentiation.
What is the main difference between neoplasia and dysplasia?
Dysplasia is reversible, neoplasia is not
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
How do benign tumours look to the naked eye?
Local confined area with an outer pushing margin which is regular
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)
How do malignant tumours appear to the naked eye
Irregular margins and shape with areas of necrosis and ulceration.
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
How do benign tumours appear microscopically?
Well differentiated without invasion
How do malignant tumour appear microscopically?
Possible invasion of surrounding tissues/basement membrane. The differentiation can range from well to anaplastic.
How do cells of a malignant neoplasm appear as the differentiation worsens?
Increased nuclear size and increased nuclear-cytoplasm ratio
More mitotic figures with increased mitosis (sometimes abnormal)
What is pleomorphism?
Cells which have increased variation in size and shape of cells and their nuclei, relative to each other.
What does the term 'grade' indicate?
How differentiated the cells within a tumour are
High grade tumours are...
Low grade tumours are...
What does the term anaplastic mean?
The cells of the tumour do not resemble any cell type.
How does dysplasia lead to neoplasia?
The cell organisation and differentiation passes the pint of no return, ie it becomes irreversible
What is an initiator?
Any mutagenic agent (intrinsic or extrinsic) which introduces a mutation into a cell
What is a promoter?
Anyang which promotes the proliferation of the mutated population
What is the end result of initiation and promotion?
An expanded monoclonal population of mutated cells
Name some exogenous initiators
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
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)
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.
What is lyonisation?
Random inactivation of one allele during female embryogenesis
In relation to neoplasms, what types of genes do genetic alterations usually effect?
In relation to neoplasms, how are proto-oncogenes usually affected?
They are usually activated
What effect does the activation of proto-oncogenes have and why?
It favours neoplasm formation as the genes effected are usually growth factors etc
In relation to neoplasm formation, how are tumour-suppressor genes usually effected?
Both alleles are often deleted or inactivated
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
A malignant neoplasm of epithelial origin
A malignant neoplasm of glandular epithelia
What is meant by papilloma?
What do most benign tumours end in?
What do stromal malignant neoplasms end in?
What is meant by stromal?
Supporting tissues eg fibroblasts/smooth muscle
What is mean by carcinoma-in-situ?
Carcinoma which hasn't invaded and passed the basement membrane
What is a leukaemia?
A malignant neoplasms of white blood cells which are circulating or in the bone marrow
What is meant by lymphoma?
A malignant neoplasm of the lymphocytes which have accumulated in the lymph nodes
What are the four types of leukaemia?
Chronic lymphocytic leukaemia
Acute lymphocytic leukaemia
Chronic myeloid leukaemia
Acute myeloid leukaemia
Chronic lymphocytic leukaemia is...
Accumulation of mature B cells which have escaped apoptosis and undergone cell-cycle arrest
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
Chronic myeloid leukaemia is...
Uncontrolled proliferation of myeloid cells
Acute myeloid leukaemia is...
Neoplastic proliferation of myeloid blast cells
What is a leiomyoma?
Benign tumour of smooth muscle
What is a leiomyosarcoma?
Malignant tumour of smooth muscle
What is a fibroma?
Benign tumour of fibroblast cells
What is a fibrosarcoma?
Malignant tumour of fibroblast cells
What is a myeloma?
Malignant neoplasm of plasma cells
What is a germline neoplasm?
A tumour of the ovary or testis
Are tumours of the testis usually benign or malignant?
What two groups can malignant testis tumours be separated into?
Non-seminoma germ line teratoma
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
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
What are neuroendocrine tumours?
Tumours which arise from cells distributed throughout the body
What is characteristic about tumours which end in -blastoma?
Formed from immature precursor cells and usually occur in children
What is a polyp?
An abnormal growth projecting from the mucous membrane
How can colon cancer present as an emergency?
Bowel perforation-> cancer erodes through mucus membrane which leads to peritonitis
How does obstruction occur in colorectal cancer?
Tumour grows so large that it causes an obstruction as the lumen is narrowed
Do benign or malignant colorectal tumours often cause occlusion of vessels?
Benign. Malignant tumours erode