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2.2 Cellular Pathology > Pigments and Minerals > Flashcards

Pigments and Minerals Flashcards

1
Q

Define what a pigment is

A

A pigment is a material that changes the colour or reflected or transmitted light as the result of wavelength-selective absorption

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2
Q

How are pigments defined in biology

A

Substances occurring in living matter that absorb visible light

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3
Q

Classify pigments

A

Endogenous

Exogenous

Artefact

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4
Q

Classify endogenous pigments

A

Haematogenous pigments

Non-haematogenous pigments

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5
Q

What are haematogenous pigments

A

Blood derived pigments

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6
Q

Give three examples of haematogenous pigments

A

Haemosiderins

Haemoglobin

Bile pigments

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7
Q

Give two examples of non-haematogenous pigments

A

Melanins

Lipofuscin

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8
Q

What are lipofuscins
(2)

A

Fine yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion.

It is considered to be one of the aging or “wear-and-tear” pigments

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9
Q

What are haemosiderins
(4)

A

Yellow or brown granules which normally appear intracellularly

Contain iron in the form of ferric hydroxide

Excessive in haemochromatosis

Deficient in anaemia

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10
Q

How can excess iron be dangerous in the body?
(3)

A

Excess iron absorption

Can’t excrete excess iron

Stores in the liver primarily and leads to fibrosis and cirrhosis

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11
Q

In your own words what are hemosiderins
(2)

A

Haemosiderins are iron-storage complexes

They are composed of partially digested ferritin and lysosomes

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12
Q

How does hemosiderin look on H&E

A

Brown deposits

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13
Q

What stain is used for hemosiderin (iron)?

A

Perls Prussian Blue

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14
Q

What are bile pigments
(2)

A

Bile is part of the breakdown product of rbcs
Bile appears browny on H&E but is more globular than iron

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15
Q

What stain is used for bile?

A

Fouchet’s Stain for Bile

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16
Q

How does Fouchet’s Stain for bile work?

A

Ferric chloride oxidises all bile pigment to green biliverdin

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17
Q

When would you see bile pigments
(2)

A

If there’s an obstruction in bile ducts ->bile will build up in hepatocytes

This is seen in fibrosis

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18
Q

Write a note on melanin
(6)

A

Found in the skin, brain, eye and hair

Different types, colours and amount in people

None in albinism, reduced amount in vitiligo

Associated with melanomas

Synthesised from tyrosine

Need to be able to identify malignant or benign processes

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19
Q

Write a note on melanin
(6)

A

Found in the skin, brain, eye and hair

Different types, colours and amount in people

None in albinism, reduced amount in vitiligo

Associated with melanomas

Synthesised from tyrosine

Need to be able to identify malignant or benign processes

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20
Q

How do we stain for melanin
(4)

A

An argentaffin reaction

Granules with melanin bind and reduce silver ions

Melanin is reduced by ferric ferricyanide

Then bleached with potassium permanganate

21
Q

What is an argentaffin

A

A cell which takes up silver e.g. melanin

22
Q

What do we do with a query melanoma

A

It will undergo immunohistochemistry

23
Q

List the steps in an argentaffin reaction for melanin
(3)

A

Granules with melanin bind and reduce silver ions (Masson Fontana)

Reduce ferric ferricyanide (Schmorls)

Bleach with potassium permanganate

24
Q

List the steps in an argentaffin reaction for melanin
(3)

A

Granules with melanin bind and reduce silver ions (Masson Fontana)

Reduce ferric ferricyanide (Schmorls)

Bleach with potassium permanganate

25
Q

List three different ways of carrying out immunostaining for melanomas

A

S100 protein in melanocytes and neural cells

HMB45 – antigen on melanosomes

Tyrosinase enzyme or Melan A

26
Q

Does an argentaffin reaction require a reducer?

A

NO

27
Q

Does an argentaffin reaction require a reducer?

A

NO

28
Q

What are the two types of silver reactions

A

Argentaffin reaction
Argyrophil reaction

29
Q

What molecular markers can be used for melanin

A

BRAF

V600E

30
Q

What stain is specific for melanin

A

Masson Fontana

31
Q

How does a melanoma appear on cytology

A

Brown coloured cells -> melanin in cells that shouldnt have melanin

32
Q

What is used to confirm the presence of melanocytes in cytology

A

Melan A -> carried out on body fluids where you wouldn’t expect to see melanocytes

33
Q

Write a note on lipofuscin
(7)

A

Wear and tear pigment

Yellow colour

Lysosomal

Intracytoplasmic

Found in brain, liver and heart

Lipid breakdown products

Associated storage disease - ceroid lipofuscinosin

34
Q

What histochemistry tests can be carried out for lipofuscin
(3)

A

Schmorls

Sudan Black B

Ziehl-Neelsen

35
Q

How does lipofuscin look on H&E

A

Redish brown

36
Q

What stain is most commonly used for lipofuscin

A

Schmorls

36
Q

What stain is most commonly used for lipofuscin

A

Schmorls

37
Q

How do exogenous pigments differ from endogenous pigments
(3)

A

They have no physiological functions

Gained by inhalation, ingestion, implantation etc

Most are classified as minerals and few are coloured

38
Q

Give two examples of exogenous pigments

A

Carbon in the air

Tattoo pigment in the skin

39
Q

Where can carbon be seen

A

Seen in the lung especially in dust cells -> lung macrophages

High amounts seen in people who live in industrial towns -> not seen often here

40
Q

Where can tattoo pigment be seen
(2)

A

Tattoo pigment seen in the skin

Can be mistaken for melanoma if deep e.g. close to the epidermis

41
Q

What causes artefact pigments

A

Due to chemical fixation -> less common today as we use buffered solutions

42
Q

Give an example of an artefact pigment

A

Formalin

43
Q

Write a note on formalin as a pigment
(3)

A

Brown pigment

Need to differentiate it from pathological pigments

Needs to be removed with picric alcohol

44
Q

Define minerals

A

Naturally occuring homogenous inorganic substances having a definite chemical composition and characteristic crystalline structure, colour and hardness

45
Q

Give three examples of minerals

A

Calcium

Copper

Iron

46
Q

Write a note on calcium

A

Constituents of bones and teeth in the form of calcium phosphate

47
Q

Write a note on calcium

A

Constituents of bones and teeth in the form of calcium phosphate

48
Q

Write a note on calcium

A

Constituents of bones and teeth in the form of calcium phosphate

2.2 Cellular Pathology (29 decks)

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