HISTO: Fundamentals of Histology

Question 1

Where would you see these in acute appendicitis?

Answer 1

Neutrophils mean acute inflammation

Would be seen in the crypts in acute appendicitis (as below). Also in gastritis and mastitis.

Question 2

What are these cells and what are they associated with?

Answer 2

Lymphocytes and plasma cells - chronic inflammation and lymphomas. More plasma usually means lymphocytes // less is a plasma cell.

Question 3

What cells can be seen in this picture?

Answer 3

This is a picture of a crypt in colitis. The outside of the circular structure is mainly lymphocytes whereas the inside is neutrophils (recognised by the irregular nuceli). This signifies acute on chronic inflammation.

Question 4

What is seen in this slide of sheets of lymphocytes?

Answer 4

Lymphoma

Question 5

What is this cell? What are they associated with?

Answer 5

Eosinophil - bi-lobed nucleus and red granules.

Allergic reactions, parasitic infections (e.g. schistosomiasis), tumours e.g. Hodgkin’s disease.

Question 6

What is this?

Answer 6

Oesophagus with feline contractions. Due to eosinophil infiltration from an allergic reaction.

Question 7

Where are these cells commonly found?

Answer 7

In urticarial reactions e.g. skin. If you look at the biopsy of the skin then you will find these.

Question 8

What is this cell and what is it associated with?

Answer 8

Macrophages - associated with late acute inflammation (clean up after an infection), chronic inflammation (including granulomas*). They are also found in the alveoli.

*granulomas - macrophage groups

Question 9

What are these and which infection are they associated with?

Answer 9

Shown are sheets of epithelioid macrophages and some Langerhan’s cells (giant). They are found in TB as below in caseous lesions in the lung shown.

Question 10

What stain is shown?

Answer 10

Ziehl-Neelson stain for TB - phospholipid in the bacteria binds the red dye in the stain giving this colour.

Answer 11

Ontological classification - classified based on the cells that we think they came from.

Question 12

What is a carcinoma?

Answer 12

Tumour of epithelial cells - most common seen in practice

Question 13

Name 3 types of carcinomas.

Answer 13

1. Squamous cell carcinoms
2. Adenocarcinomas
3. Transitional cell carcinomas

Question 14

What is shown here?

Answer 14

Intercellular bridges in squamous cells.

Below is the zoomed out version shows keratin production which would be seen in a tumour.

Question 15

How can you recognise squamous cell carcinomas?(2)

Answer 15

Keratin production and intercellular bridges

Question 16

What do all adenocarcinomas have in common?

Answer 16

Mucin production and glands

Question 17

What type of cancer is this?

Answer 17

Squamous cell carcinoma - recognised by the big patches of keratin that they produce

Question 18

Name 5 sites of squamous cell carcinoma.

Answer 18

• Skin
• Head and neck
• Oesophagus
• Cervix
• Vagina
• Anus

Question 19

What is shown and what stain has been used?

Answer 19

Alcian blue stain - stains for mucin and highlights the goblet cells in the glandular epithelium of the large bowel

Question 20

What kind of tumour of the large bowel is this and how is it confirmed?

Answer 20

Nuclei are dark and there are irregular layers meaning that this is a tumour. Using an Alcian blue stain you can confirm that this is an adenocarcinoma as you can check for mucin production (as shown below).

Question 21

Name 5 sites of adenocarcinomas.

Answer 21

• Breast
• Lung
• Stomach
• Pancreas
• Colon

Question 23

Why are the cells dark?

Answer 23

They are pigmented cells or melanocytes

Question 24

What does this biopsy of a mole show?

Answer 24

Malignant melanoma - the cells are making melanin. But if it became very undifferentiated then the cells may stop making melanin.

Question 25

Which stain can be used for melanin?

Answer 25

Fontana stain

Question 26

What are the main 2 types of stains?

Answer 26

1. Histochemical - based on the chemical reaction between stain and component of the tissue. Product has a specific colour which is recognised. 2. Immunohistochemical - based on using an antigen to detect an antibody in the tissue but needs an additional detection mechanism to make this binding visible e.g. immunofluorescence

Question 27

Give an example of a classic histochemical stain.

Answer 27

Haematoxylin and eosin stain (H&E). Immunohistochemisry is more commonly used now.

Question 28

Which stain can be used to look at iron overload e.g. in the liver in haemochromatosis?

Answer 28

Prussian blue iron stain - used to highlight the brown in the slide below

Question 29

Which stain can be used to highlight the red parts of this glomerulus more brightly? Why is it used?

Answer 29

Congo red stain is used for staining amyloid - make sure that this is amyloid and not other tissue.

Question 30

If a Congo Red stain for amyloid has been done, what other test can be used to confirm the presence of amyloid?

Answer 30

Looking at the section under polarised light will produce apple green birefringence. Shows the glomerulus and blood vessels.

Question 31

Name 2 types of flags used in immunohistochemistry.

Answer 31

**Immunofluorescence** - goat anti-rabbit antibody will have a fluorescent tag on it which can be detected. **Immunoperoxidase** - instead of just the fluorescent tag you need to add an enzyme to produce the reaction for detection

Question 32

If you stain an undifferentiated tumour for cytokeratin, what type of tumour are you checking for?

Answer 32

CARCINOMA Cytokeratin is an epithelial marker.

Question 33

Why would you use the CD45 stain?

Answer 33

As a lymphoid marker

Question 34

What is this stain for? What type of stain is this? NB: it has been used to check for adenocarcinoma in a liver.

Answer 34

CK20 + is a marker. This stain is a mAb stain. If a similar stain called CK7 was used, and it was negative, you could deduce that this is a large bowel primary tumour which has metastasised to the liver.

Question 35

Which infections typically produce ulcers with cells with several nuceli?

Answer 35

**Typical of ALL Herpes virus infections** - clinically the most common one is herpes simplex but this can be confirmed by further staining with immunihistochemistry (monoclonal antibodies).