Cancer (Bowel Focus) Flashcards
What is neoplasia?
An abnormal mass of tissue that results when cells divide more than they should do or do not die when they should
Can be benign or malignant
Benign neoplasia
Don’t invade, resemble normal tissue, exophytic growth, near normal nucleus, slow growth rate, rarely cause necrosis, often encapsulated in tissue
Malignant neoplasia
invade tissue, variable but poor resemblance to tissue, endophytic growth, enlarged nuclear:cytoplasmic ratio, fast growth rate, necrosis is common, poorly defined border
Basement membrane invasion
Benign tumors never invade, malignant tumors always invade basement membrane
Differentiation to normal tissue
Benign: well-differentiated and closely resemble tissue
Malignant: poorly differentiated and does not resemble tissue, causes destruction of adjacent tissue
Normal bowel tissue
Can see ducts, connective tissue, epithelia
Malignant tumor bowel tissue
low grade malignant: can still see some ducts and epithelia
high grade malignant: everything is completely destroyed and doesn’t resemble old normal tissue
Benign growth
Grow outwards, exophytic growth
Makes them unable to invade and spread through surrounding tissue
Malignant growth
endophytic growth, grow inwards
Invade and spread through surrounding tissue
Get into vascular tissue (vascular permeation)
Benign nucleus morphology
normal nucleus size
Malignant nucleus morphology
nucleus increases in size and causes increased nuclear:cytoplasm ratio
More DNA replication means larger nucleus and more aggressive tumor
Benign growth rate
Grow slowly
Malignant growth rate
Grow quickly
Benign necrosis
Does not cause cell death, low necrosis level
Malignant necrosis
Causes cell death, higher levels of necrosis
Benign border
Well defined, circumscribed border
cannot invade surrounding tissue, so they grow into a space and are confined by that space
Malignant border
poorly-defined, irregular border
invade through surrounding tissue and so are not confined by a space
Tumor classifications
Tumours can be classified based on the tissue type that they originate from (histogenic classification)
Papilloma
A benign tumour arising in epithelial tissue that grows exophytically (outwards)
Adenoma
A benign tumour arising in glandular tissue e.g. stomach mucosa, small intestine, colon
Carcinoma
A malignant tumour arising in epithelial tissue
Adenocarcinoma
A malignant tumour arising in glandular tissue
Sarcoma
A tumour arising in connective or other non-epithelial tissue e.g. blood vessels, nerves, cartilage
Prostate cancer
Most common in men
Breast cancer
Most common in women
Anatomical classification
tumors can be classified by location as well as histogenic
Burkitt’s lymphoma definition
cancer of B cells and affects the lymphatic system
Burkitt’s lymphoma cause
associated with the EBV virus and with malaria
Burkitt’s lymphoma epidemiology
Endemic in central africa
Burkitt’s lymphoma symptoms
causes rapid and severe swelling of the lymph nodes in the face and neck.
Ewing sarcoma
ulcerating cancer of the bone, which usually affects teenagers and young adults.
Hodgkin’s Lymphoma
characterised by the presence of a certain type of cell called Reed-Sternberg cells. These are large cells which contain more than one nucleus.
Blastoma
tumours of blast cells (a type of stem cell)
Stem cells
More active in younger children
Ability to differentiate into other types of cells
Types of blastomas
Retinoblastoma, Nephroblastoma, Neuroblastoma
Retinoblastoma
Affects the eye
Nephroblastoma
Affects the kidney
Neuroblastoma
Affects the brain
Harmatoma
affect connective tissue, and cause cells in the connective tissue to grow larger as the patient grows
Not true neoplasm, since they don’t create new tissue; cells just grow larger
Don’t cause symptoms but are detected on scans and look like any other tumor
Endocrine tumor
Originate from hormone producing tissue
Tumors generally cause excessive production of hormones
Insulomas
Tumor in pancreatic cells that produce insulin
Causes excess production of insulin
Cyst
A cyst is a fluid filled space that is lined by epithelium
Cyst causes
parasites, trauma.
Some malignant tumours
Teratoma
a tumour of an egg or sperm cell.
Egg and sperm cells have the ability to differentiate and grow into any part of the body
causes this differentiation and growth to go out of control and therefore results in a tumour which grows body parts
Detachment of tumor cells
Lose expression of cadherin molecules and become easily able to separate from other cells
Movement of tumor cells through tissue
tumor cells have mutations which mean they secrete proteolytic enzymes (metalloproteinases) which break down the surrounding connective tissue so they are able to move through it.
Depends on level of proteolytic enzyme inhibitors:
Cartilage and intervertebral discs: high levels so harder for tumor travel
Blood vessels and nerves: low levels so easier for tumor travel
epithelial-mesenchymal transition
normally, epithelial cells tend to not want to move very much. Whereas mesenchymal cells (the cells that make up connective tissue) tend to naturally want to move around a bit more
malignant epithelial cells have a mutation which means that they start expressing proteins that are usually produced by mesenchymal cells
