Histopathology 1 - Fundamentals of histology

Question 1

What type of cell is predominant in the inflammatory process in acute appendicitis/gastritis/mastitis?

Answer 1

Neutrophilic inflammation

Question 2

What are the 4 main causes of eosinophilia?

Answer 2

1. Allergic reactions
2. Parasitic reactions
3. Tumous eg Hodgkin’s disease (not a neoplasm of eosinophils but a reaction to the neoplastic process)
4. Eosinophilic granulomatosis

Question 3

If ‘feline contractions’ are observed in the oesophagus, what is the pathology?

Answer 3

Eosinophilic oesophagitis - probably due to a food allergen (“asthma of the oesophagus”)

Question 4

Which cells are most associated with LATE acute inflammation as well as chronic inflammation (granulomas)

Answer 4

Macrophages

Question 5

What is a granuloma?

Answer 5

Organised collection of activated macrophages (ordinary macrophages are phagocytic but when activated, they are also secretory)

Question 6

What are the 2 most likely causes of granulomas?

Answer 6

Sarcoid
TB

Differentiate the two causes using the acid-fast Ziehl-Neelson stain

Question 7

What is a carcinoma?

Answer 7

Malignant tumour of epithlial cells

Question 8

What are the 2 key histological features of a squamous cell carcinoma?

Answer 8

Keratin production
Intercellular bridges

(Keratin production depends on location e.g. present in skin SCCs but probably not in oesophageal, cervical or lung etc.)

Question 9

What are the 2 key histological features of an adenocarcinoma?

Answer 9

Mucin production

Glands

Question 10

What is the basic principle of how immuno-histochemistry works?

Answer 10

Use an antibody to a particular antigen in a tumour or infectious agent and then use stains/detection systems that detect those antibodies

E.g. immunofluorescence, immunoperoxidase

Question 11

How do histochemical stains work?

Answer 11

Chemical reaction between chemicals added in the stain and the tissue that causes a change in colour

Question 12

What is used to stain amyloid?

Answer 12

Congo red stain

Question 13

How does amyloid appear under polarised light?

Answer 13

Apple green birefringeance

Question 14

Which polymorphs have a bilobed nucleus?

Answer 14

Eosinophils

Question 15

What is cytokeratin a marker of?

Answer 15

Epithelial cells - so can identify carcinomas

Different epitheliums will have different cytokeratin subtypes (e.g. CK20 or CK7) -> helps identify the primary tumour

Question 16

What is CD45 a marker of?

Answer 16

Lymphoid cells - so can identify lymphomas

Question 17

What stain can be used to detect melanin?

Answer 17

Fontana

Question 18

What stain can be used to detect iron (eg in haemachromatosis)?

Answer 18

Prussian Blue (think Prussia hated on both sides of IRON curtain)