Fundamentals of Histopathology Flashcards
Describe the basic histological markers of a neutrophil, and what kind of immune reaction they are found in.
Multi-lobular nucleus, and granular cells.
They are usually markers of acute inflammation
Describe the basic histological markers of a lymphocyte, and what kind of immune reaction they are found in.
Large nucleus, very little cytoplasm.
They are usually markers of chronic inflammation
Describe the basic histological markers of a eosinophils, and what kind of immune reaction they are found in.
Bi-lobular nucleus and red granules.
They are usually markers of either:
- Allergic reactions
- Parasitic infections
- Tumours (e.g. Hodgkin’s)
Describe the basic histological markers of a mast cell, and what kind of immune reaction they are found in.
Large granules
They are usually markers of allergic reactions
Describe the basic histological markers of a macrophage, and what kind of immune reaction they are found in.
Single nucleus, lots of cytoplasm
They are usually markers of:
- Late acute inflammation
- Chronic inflammation (granulomas)
What is a granuloma?
A collection of active macrophages, with a secretory element.
Found in infections (TB), inflammation (sarcoid) and cancer.
How are tumours classified?
Ontologically (by their cell origin)
What are carcinomas? Describe the three types. What stains can be used to identify these?
These are tumours originating from epithelial cells. They can be:
Squamous cell carcinomas
- Intercellular bridges
- Keratin production
- Cytokeratin stains can check for this type
Adenocarcinomas
- Glandular formation
- Mucin production
- Mucin stain can check for this type
Transitional cell carcinomas
- ‘Just look like TCC’
What are melanomas? What stain can be used to identify this?
Cancers originating from melanocytes. These tumours are pigmented, and produce melanin.
The Fontana stain checks for melanin production.
What are the two classes of stains used in histopathology? Give three examples of each
Histochemical stains:
- Ziehl-Nelson (TB, stains red)
- Prussian Blue (haemochromatosis, stains blue)
- Congo Red (amyloid, stains red - apple green under polarised light)
Immunohistochemical stains:
- Cytokeratin (to check for SCCs)
- CD45 (to check for lymphoid cells)
- Herpes Simples Ab (to check for specific Herpes viruses)
What is a histochemical stain? How does it work?
A stain that depends on a chemical reaction between itself and the different components of a cell
It will give a colour/other property to identify a positive result
What is an immunohistochemical stain? How does it work?
A stain that relies on an antibody to bind to a specific antigen. The antibody is bound to a form of detection.
The detection can be:
- Immunofluorescent (lights up)
- Immunoperoxidase (mixed with a substrate to cause a reaction)
