Histopathology 13 - Histopathology of Systemic Disease

Question 1

What can JCV infection in HIV positive patients lead to?

Answer 1

Progressive multifocal leukoencephalopathy

Question 2

What is the most common opportunistic infection in HIV positive patients?

Answer 2

CMV

Question 3

Which herpes virus causes kaposi sarcoma?

Answer 3

HHV8

Question 4

What is the main histological finding in sarcoidosis?

Answer 4

Non-caseating granulomas

Question 5

How does end-stage sarcoidosis appear on CXR?

Answer 5

‘Honeycomb’ lung

Question 6

What is a granuloma made up of?

Answer 6

Lymphoid cells and giant cells

Question 7

What colour does IgG4 stain when positive?

Answer 7

Brown

Question 8

Recall 3 diseases caused by IgG4 inflammation

Answer 8

Riedel thyroiditis
Autoimmune pancreatitis
Inflammatory pseudotumours

Question 9

What is the structure of amyloid?

Answer 9

Beta pleated sheet that forms non-branching fibrils

Question 10

What is the cause of AA amyloidosis?

Answer 10

Chronic inflammation

Question 11

Which conditions are particularly implicated in the development of AA amyloidosis?

Answer 11

Crohn’s

Rheumatoid arthritis

Question 12

What conditions can cause AL amyloidosis?

Answer 12

Myeloma

B cell neoplasms

Question 13

What is the link between transthyretin and amyloidosis?

Answer 13

Transthyretin mutation can –> cardiac amyloid

Question 14

What stain can be used for amyloid?

Answer 14

Congo red - gives green birefringence under polarised light

Question 15

What opportunistic infections are associated w/ HIV?

Answer 15

PCP
CMV
Candida
TB
Cryptococcus
Toxoplasma gondii
JC virus
Herpes
Cryptosporidium

Question 16

What tumours are associated w/ HIV?

Answer 16

Kaposi Sarcoma

Lymphoma (EBV, B cell)

Question 17

What CNS disease is associated w/ HIV?

Answer 17

Progressive multifocal leukencephalopathy

Question 18

What is the main feature of TB infection? what staining?

Answer 18

Caseating granulomas -

Ziehl-Neelsen stain reveals acid fast bacilli

Question 19

What is the main feature of sarcoidosis? - other features + diagnosis?

Answer 19

Non-caseating granulomas

Also causes:

• Erythema nodosum
• Increased levels of ACE and Ca in blood
• LATE STAGE = honeycomb lung

This is a diagnosis of exclusion

Question 20

What is IgG4 Related Disease caused by?

Answer 20

IgG4 antibody producing plasma cells

Question 21

What is amyloidosis? Where do they come from + which conditons

Answer 21

Deposition of abnormally folded proteins (can basically deposit anywhere causing a whole host of symptoms)

AA Amyloid (from serum amyloid A) - caused by chronic inflammatory states (eg. RA, UC, Crohns etc)

AL Amyloid (from light chains) - caused by multiple myeloma

Question 22

Staining for amyloidosis?

Answer 22

Congo Red dye causing apple green birefringence

Question 23

How can you differentiate between TB and sarcoid granulomas?​

Answer 23

TB = caseating​

Sarcoid = non-caseating​

Question 24

What is the difference between the pathology of AA and AL amyloidosis?​

Answer 24

AA = formed as a result of a chronic inflammatory state​

AL = formed from light chains in multiple myeloma