cellular pathology of cancer Flashcards
define metaplasia *
a REVERSIBLE change in which one adult cell type (usually epithelial) is replaced by another adult cell type
adaptive - cells sensitive to stress eg acid are replaced by cells that can cope
physiological example of metaplasia
cervix in puberty - go from columnar to squamous epithelium when exposed to acid of vagina
pathological example of metaplasia
barret’s oesophagus - squamous epithelium to columnar - because of change in pH - exposure to acid from acid reflux
respiratory columnar ciliated epithelium changes to squamous
definition of dysplasia *
an abnormal pattern of growth in which some of the cellular, architectural, molecular and genetic features are present that associate with cancer
but not invasive
pre-invasive stage with intact basement membrane
it is the step between normal cells and cancer
reversible
what can be seen in dysplasia *
more mitosis and abnormal mitosis
big nuclei
loss of architectural orientation - lose sequence from basement cells to maturing to keratinisation ie cells arent maturing in the normal way
loss of uniformity of individual cells
hyperchromatic nuclei - dark becasue contain more DNA
mitotic figures - abundant, abnormal and in places that they shouldnt be found
increased nuclear:cytoplasmic ratio - increase in size of nuclei but the cells dont get bigger - nuclei take up a greater proportion of the cell
enlarged nuclei
where is dysplasia common
cervix - HPV infection
bronchus - smoking
colon - ulcerative colitis
larynx - smoking
stomach - pernicious anaemia (chronic inflamm process)
oesophagus - acid reflux (have metaplasia, that progresses to dysplasia, which progressses to adenocarcinoma)
what is the difference between low and high grade dysplasia *
low - risk of progression is less, more likely ti be reversible
high - higher risk of invasion, closer to develop invasive cancer, nucleocytoplasmic ratio high so darker
what is a neoplasia, tumour or malignacy *
an abnormal, autonomous proliferation of cells, unresponsive to normal growth contriol mechanisms and persists even when whatever started the growth mechanism has stopped
(from yr1 - tumour is any mass forming lesion)
what are characteristics of benign tumour *
DO NOT INVADE/METASTISE - do not invade bv or spread - this is the functional characteristic
encapsulated - in fibrous capsule, easy to remove
usually well differentiated - look like tissue from where they come from
slowly growing - low mitotic rates
normal mitosess
(these are ways recognise benign tumours but dioesnt diagnose them as benign except for the 1st one)
benefit of tumour being benign *
easier to treat
treatment is 100% effective - no chance that it ahs spread
how would you test if a tumour had invaded tissue *
eg on chest - if you can move it, it is not attached to the skin/pec major =benign
when can a benign tumour be fatal *
in dangerous place eg meninges (if block frow between ventricles = hydrocephaly/increased intracranial pressure = death), or pit (press on important things like optic canal, also secrete hormones)
secretes something dangerous eg insulinoma (tumour of B cells)
gets infected eg bladder
ruptures eg liver adenoma - bleeds into the peritoneal cavity
bleeds - stomach (if presses on an artery which bleeds)
torts (twisted) - block blood supply - infarction eg ovarian cyst
characteristics of a mialignat tumour *
invades surrounding tissues
spreads to distant sites - via bv, nerve and lymphatics (if catch early might not have spread, doesnt mean that it is not malignant) prognosis depends on how far spread/invaded
no capsule
well to poorlyu differentiated
rapidly growing
abnormal mitoses
define metastasis *
a discontinuous growing colony of tumour cells, at distance from the primary cancer
in these cases local treatment is not enough
what determines metastasis *
lymphatic and vascular drainage of the site
lymph node involvement has a worse prognosis
eg colon - Dukes A = 90% - only in bowel wall, Dukes C = 30% - in lymph nodes
which lymph nodes to the testicles drain to
aortic
which nodes does the breast drain to
lateral - axillary
medial - internal mammary nodes
what is nuclear polymorphism *
when nuclei all look different from each other
how does nuclear cytoplasmic ratio change as cancer progresses *
gets worse from dysplasia to benign to malignant
features of well differentiated tumours *
a small number of mitosess
lack of nuclear polymorphism
relatively uniform nuclei
close resembalence to the corresponidning normal tissue
what does the suffix -oma mean *
benign
what is papilloma *
benign tumour on surface of epi
eg skin/bladder/colon
what is adenoma *
benign tumour of glandular epi
eg stomach, thyroid, colon, kidney, pit, pancreas, mucin, kidney, breast
define carcinoma *
a malignant tumour derived from epi
example of carcinoma *
squamous cell
adenocarcinoma - of glandular tissue
transitional cell - bladder
basal cell carcinoma - skin
how are carcinoma’s named *
have carcinoma
and before this - state what type of epi come from
examples of benign soft tissue tumours *
oestoma (pic)
lipoma - fat
chondroma - cartilage
leiomyoma - fat
define sarcoma *
a malignant tumour derived from connective tissue - mesenchymal cells
examples of sarcoma *
osteosarcoma - pic (see swelling and darker areas)
liposarcoma - rare but can occur
osteosarcoma
chondrosarcoma
striated muscle - rhabdomyosarcoma
leiomyosarcoma - sm
malignant peripheral nerve sheath tumour
feature of sarcoma *
larger nuclear:cytoplasmic
what are leukaemia and lymphoma *
tumours of white blood cells - they are different but can spread into each other
define leukaemia *
a malignant tumour of bone marrow derived cells that circulate in blood
define lymphoma *
a malignant tumor (even though called -oma) of lymphocytes that usually proliferate in lymph nodes
tissue based
eg lymph nodes, spleen, tonsils
exceptions of the -oma rule *
lymphoma
melanoma
define teratoma *
a tumour derived from germ cells, have the potentila to develop into tumours of all 3 germ layers - ectoderm, mesoderm, endoderm
totipotent so can differentiate into any type of tissue
occur mainly where you find germ cells ie ovaries and testes
can occur outside the gonads (Pituitary, pineal, mediastinum, sacrococcygeal areas)
image of mesoderm, endoderm teratoma
middle right - mesoderm
bottom L - endoderm (colonic)
bottom R - endoderm - bronchi
are teratomas benign or malignant *
male gonadal are all malignant
female gonadal are mainly benign `
image of female tertatoma &
benign ovarian teratoma - has cyst and hair growing in it
define a hamartoma *
localised overgrowth if cells and tissues native to the organ
cells are mature but architecturally are abnormal
common in children and should stop growing when they do
Common ones are haemangiomas (tumour of bv), bronchial hamartomas, Peutz-Jegher polyps in the gut.
eg bile duct or bronchial (in bronchial have cartilage, sm and epi like as normal just arranged differently)
image - bile duct - normal bile duct is round, abnormal is spikey
what are the criteria for assessing the differentiation of a malignant tumour *
evidence of normal function still present eg production of keratin (squamous cell), mucin (adenoma), bile (liver), hormones (endo)
eg image - top not glandular (random arrangement of cells), bottom looks like glandular tissue)
what is an anplastic carcinoma *
no differentiation
doesnt do anything any cells do
very agressive
describe TNM scale *
the grade of tumour describes its degree of differentiation
stage - how far it has spread - all malignant are locally invasive, stage asks how deep (into mucosa, submucosa, muscularis externa, adventitia, peritoneal cavity)
tumours of a higher grade tend to be of a higher stage
overall the stage is more important than grade in determining prognosis
TNM - tumour (how far invaded and size), nodes, metastasis
define carcinogen *
any substance that when exposed to living tissue may cause the production of cancer
5 morphological features that allow assessment for the differentiation of a tumour *
- number of mitoses
- nuclear polymorphism
- shape of nuclei
- resembalnce to normal tissue
- evidence of normal function
how can you get squamous carcinoma in lung when there is no normal squamous cells*
metaplasia occurs 1st - forming the sqaumous cells which then develop into sydplasia and invasive cancer
what does the screening test for cervical cancer look for *
moving away from looking for dysplasia - now looking for HPV genenomes associated with a higher risk
