Histochemistry in Disease Diagnosis Flashcards
Write about the liver biopsy
(5)
Its a small core/s of tissue
Used for the investigation of liver disease
Used to confirm a suspected clinical diagnosis
Used to establish extend of liver disease/monitor disease progression
Used to investigate malignancy (primary or metastatic)
Might be investigating a hepatocellular carcinoma -> usually investigating metastasis
Explain how a liver biopsy would be taken
(5)
Biopsy taken with a small gauge needle
Biopsy put in small pot of formalin
Need to be careful not to snap the tissue
Might see fatty change, inflammation etc
Are there any nests of malignancy?
What stains are often carried out on liver biopsies
H&E
Masson Trichrome -> looking for fibrosis
Gordon and Sweet’s silver stain
What is fibrosis
Fatty change intracellular in hepatocytes
Why might a silver stain be used on liver biopsies
Staining for reticulin
What might cause tissue alteration in liver biopsy
Infections e.g. Hep C or Hep B or parasites
Alcohol
Drugs
Metabolic issues
Autoimmune conditions
Haemachromatosis
Wilson’s disease
Malignancy
Why would we stain for alpha-1-antitrypsin
(3)
A deficiency in an enzyme causes deposition of AAT in the liver
We use Diastase and PAS to stain for AA1
The Diastase digests the glycogen so we can see the PAS positive material left
This is often seen in paediatric hospitals as it is a metabolic disease that affects neonates
How do we stain for Wilson;s disease
Rubeanic acid stain
How do we stain for Wilson;s disease
Rubeanic acid stain
How do we investigate malignancy in liver
(5)
H+E for morphology
Use IHC to confirm if malignancy is primary or metastatic
Use IHC to confirm if hepatocellular or cholangiocarcinoma
90% of liver cancer is metastatic
If metastatic need to identify cell or origin -> need IHC panel
Why might a renal biopsy be taken
(3)
Only done in specialised hospitals with a renal clinic
Only taken on clinical suspicion of renal disease -> usually diagnostic imaging is done first
suspicion of glomerulonephritis, nephropathy, chronic kidney disease
How do we process renal biopsies?
(3)
Need to determine if we have the structure we need for staining in the biopsy e.g. we need glomeruli if looking for glomerulonephritis
Biopsies usually come in fresh on moistened gauze in a petri dish
There are three different processes:
- Light microscopy - FFPE
- Fluorescent microscopy - frozen section
- Electron microscopy - resin
How do we examine glomeruli
(3)
Stain for basement membrane
Can use silver -> sensitise basement membrane then apply the silver
Look for alterations e.g. thickening or projections -> tramlines in the basement membrane
How do we examine nephronopathy?
(4)
Membranous staining
Look for projections
Fluorescence -> granular appearance
Normally linear stain in basement membrane in fluorescence
How would you be able to diagnose membranoproliferative glomerulonephritis
Tram tracking
Double layer of basement membrane
How do we investigate amyloidosis
Congo red
Fluorescence -> apple-green biorefringence
What are the main components of the GIT?
Salivary glands
Oesophageal biopsy
Gastric biopsy
Small intestine
Large intestine
What do we stain for in the GIT
Mucins
Infections
Where are salivary glands usually investigated and how is this done
Head and Neck clinic
Mucin stains applied -> glandular structures with mucins
What stains do we use to investigate H. pylori?
(2)
Warthin Starry
Giemsa
Describe how H. pylori is investigated
Bacteria seen on surface of epithelium or upper layer of glandular cells, might be seen in crypts
When is histochemistry used in cytopathology
(3)
Infections such as PCP, TB or fungi
Mucins such as mucin secreting adenocarcinoma
Amyloid
How is PCP investigated?
Pneumocystis jirovecii
Bronchiole washes or brushings
Grocott’s silver
How is TB investigated
ZN stain
Why would we see adenocarcinomas in cytology
If you don’t have enough cells for immunohistochemistry
Could get a resection but this would take time
What are signet cells
Adenocarcinoma of the stomach
Characteristic vaculation of cells
Nucleus gets pushed to one end of the cell
Can stain for mucin to confirm as mucin secreting carcinoma
Write about histochemistry in malignancy
(7)
Alterations to cell/tissue components
- mucins
- connective tissue alteration
- amyloid
Assessment of invasion
- basement membrane
Immunohistochemistry utilised more for specific protein and biomarker of prognosis and therapeutics
Quality Control and Trouble-shooting
(6)
Good control material
- know positive tissues for specific entities
Check each slide and control
- Quality of tissue section
- Quality of stain
Trouble-shoot
- slide/tissue sections/control
- protocols
- reagents
Write about control in the lab
Need control material that is positive for the component your staining for
Need to check all of each test slides and the controls
Some labs will cut a control onto the same slide as the test -> usually pathologists do this and prefer this -> they have something to compare against
Need to be able to trouble shoot issues -> need to be able to identify issues and why they happened e.g. is there an issue with microtomy
Give some examples of protocols
Have you done everything in order
If using automated stainer -> are the times correct
Are the protocols still valid
Check your reagent
Check stock control
If making up reagent have you use the right components and concentrations
