week 5- histopathology and cytopathology Flashcards
what is histopathology
study of changes in tissue associated with disease
what is cytopathology
study of changes in cells associated with disease
What is the difference between histology and histopathology?
Histology is the study of tissues in general.
Histopathology is the study of tissues associated with disease.
What is the difference between cytology and cytopathology?
Cytology is the study of cells in general.
Cytopathology is the study of cells associated with disease.
what is histopathology and cytopatholgy used for
screening
diagnosis
treatment
determining prognosis
what is screening used for
- highlight abnormalities in asymptomatic patients
- benefits must outweigh harm
- bowel/ breast cancer
- cervical screening
what does diagnosis used for
- look for abnormal cells
- signs of inflammation
- used alongside medical history and other methods
SLIDE 8-11
What is histopathology in brief?
- the tissue sample is enclosed within paraffin wax
- the paraffin wax block is cut into thin sections
- Section placed on microscope slide
- Slide is stained with dyes and then examined
- results sent to requesting clinician to follow up
what is histology process
- receipt/ booking in
- fixation
- dissection
- processing
- embedding
- microtomy
- staining
- immunohistochemistry
what is receipt/ booking in
specimen is taken from GP surgery, outpatient clinic or during surgery
it is labelled with atleast 3 forms of ID and pot and request form should match
what is fixation
often samples are stored and sent in formaldehyde
pre-filled pots and buckets are provided to drop sample in
samples may be frozen (study proteins)
- immunofluorescence
- biopsies for enzyme studies
what is formaldehyde - related to fixation
it preserves tissue, prevents autolysis, kills bacteria and viruses, forms cross-links with proteins thus preserving them
it is the most common fixative
What are artefacts - related to fixation
Artefacts are structures in a histological section that has come from outside sources.
Can result from ice crystals, insufficient / over fixation.
what is dissection
-transfer pieces of tissue into cassettes
- technique depends on sample size:
small- no dissection needed
intermediate/large - representative piece taken
what is processing
- dehydrate tissue and infiltrate with molten paraffin wax
-often automated- up to 600 cassettes per run (rapid processing= same-day diagnosis) - reagents: alcohol, xylene and paraffin
what is embedding
- transfer tissue to wax block
- paraffin embedding machine
- samples picked ip from plastic cassette and soaked in liquid paraffin, then arranged in the middle of the mould
What is sample orientation - related to embedding?
The way you cut the paraffin wax with the tissue inside
what is microtomy
- thin section of tissue from the wax block is sliced and mounted onto microscope slide
- use a microtome
- 3-4 microns (0.003-0.004 mm)
what is staining
- haematoxylin and eosin
- depth of colour related to time spent in dyes as well as structures
what is haemotoxylin
basic (alkali) dye which stains acidic structures such as DNA purple
what is eosin
acidic dye and stains basic structures pink
what is immunohistochemistry (ICH)
determines the location of an antigen in tissue using antigen
secondary antibody linked to enzyme
What things are important about the process of fixation in immunohistochemistry - IHC
- The fixation must be optimised
- If the sample is fixated too little or too much, it can lose signal
what is immunofluorescence (IF) - direct
- rapid single- step staining
- no signal amplification
- antibodies can be from the same host, so long as have different fluorophore
what is immunofluorescence (IF) - indirect
- 2 step protocol
- signal amplified
- requires primary antibodies from different hosts
- can work out cheaper
Describe how immunofluorescence is used when you have multiple targets?
It is used to assess the colocalisation ( 2 or more different targets in the same physical area) of antigens in tissue and cells
It is faster as you can look for multiple antigens in one sample
How is histopathology used to detect cervical cancer/
Screening reduces incidence/mortality of cervical cancer by detecting and potentially pre cancerous areas of the cervix
How is the cervix tested to detect cervical cancer?
- call and recall
- sample takers and primary care
- cytology and histology labs
- colposcopy
How are abnormal cells detected in the cervix using Histopathology
The abnormal cells are detected using immunohistochemistry process
What is neoplasia and dysplasia?
Neoplasia - new growth
Dysplasia - abnormal growth
What are the stages of cervical cancer
CIN1
CIN2
CIN3
CIN4
What happens in CIN1?
Only slightly abnormal cells
Usually caused by HPV infection
Isn’t camcer but can progress to cancer
Usually goes away on its own
It’s aka low-grade dysplasia
What happens in CIN2?
Moderately abnormal cells
Usually caused by HPV infection
Still not cancer but can progress to cancer
Treated by cryotherapy, laser therapy
It’s aka high grade/moderate dysplasia
What happens in CIN3?
Severely abnormal cells
Usually caused by HPV infection
Still not cancer yet but can become cancer if it isn’t treated
Treated by cryo/laser therapy, LEEP to remove abnormal tissue
It’s aka high grade/severe dysplasia
What happens in CIN4?
This is when it becomes a cancer, it is known as invasive carcinoma
What is a colposcopy/
it is a procedure used to examine the cervix
What happens during a colposcopy and what do the results show/
Acetic acid is applied - normal areas won’t stain, abnormal cell growth will appear white
Iodine can be applied - abnormal cell growth areas won’t stain, normal cells will appear brown - this is because iodine is taken up by normal cells with high glycogen
What is Large Loop Exercision of the Transformation Zone (LLETZ)
It is a treatment that can prevent the development of cervical cancer.
CIN is removed with a clear margin
What is breast cancer screening?
It consists of a mammogram (low dose X ray)
Detects cancers too small to see or feel
What are the lobules and ducts?
(anatomy of the breast)
Lobules - the glandular tissue that produces milk
Ducts - deliver milk to be expelled
Cancer can form in the lobules/lobes and the ducts
What is the histology of ducts/lobules??????
What are the different types of breast lumps
Lipoma - benign cancer, composed of adipose cells
Fibroadenoma - benign cancer, epithelial and stroll
Carcinoma - in the ducts/glands, malignant cancer, genetic 60+
Phyllodes tumour - usually benign, stromal origin
Cyst
Fat necrosis
What is the histopathology like in a carcinoma?
You can see a loss of myoepithelial layer
Using IHC you can see there is a negative/reduced stain for p63
what is p63 and what does it mean if there’s a reduced/negative stain for it?
p63 is involved in cellular differentiation - therefore, if there is reduced amounts it shows there is no differentiation — cancer cells are usually not differentiated !!!!!!!!!!!!!!!!!
How is a diagnosis made?
You need a multi-disciplinary team meeting consisting of:
pathologists
surgeons
radiographers
Oncology nurses
MDT coordinator
You need all the input from these people to make a diagnosis
What are the 3 assessments of testing for breast cancer?
Physical examination
Scan
Biopsy
Why are biopsies useful?
Because they give information about the stage that the tumour is in
What are the disadvantage of histopathology?
It requires fragments of tissue
Retrieving the tissue is invasive - may cause bleeding/trauma
More expensive
Longer procedure
Learn Histopathology V cytopath
What is exfoliative cytology?
This is where cells are shed by the body - via sputum, urine, other secretions
Or where cells are manually scraped/brushed - via a smear, skin scraped from inside nose/mouth
What is aspiration cytology?
It uses a fine needle aspiration to take cells from swelling/lumps/cysts/nodules etc
Commonly used to test for cancer
How is cytopathology of the urinary system carried out?
What are other sources in the body used to take out cells for cytopathological uses?
Pleural body cavities - lungs, trachea
Pericardial body cavities - heart, liver
Peritoneal body cavities - stomach, live etc
What is immunocytochemistry?
What are targets for immunoCYTOchemistry?
Cytoplasmic
Nuclear
Membrane
Lipids
Proteins
Learn more about immunocytochemistry
What is apoptosis?
Programmed cell death
What is necrosis?
Uncontrolled cell death resulting from injury/infection
What is a urinary cast/
Small cylindrical structures generated by distal convoluted tubules in the kidney
They are found in the urine when you have certain diseases
What are the types of urinary casts and what do they show?
Epithelial cast - shows there is a sign of damage to tubule cells in the kidney
\White b blood cell cast - shows a sign of infection/inflammation
Granular cast - shows degenerated cellular material
Red blood cell cast - Shows there is a small amount of bleeding in the kidney
CHECK DIAGRAM ON PP
What is Strongyloides stercoralis/
It is a nematode that can infect human
KNOW WHAT A NEMATODE LOOKS LIKE
