Question 1

Which of the following best describes the pigment seen in the first image (blackened lung tissue)?

Accepted Answer

Exogenous pigment, specifically carbon (anthracosis)

Question 2

The second image shows a liver with nodular changes. Which condition is most likely represented, and what pigment accumulation is commonly associated with this disease?

Accepted Answer

Haemochromatosis; accumulation of haemosiderin

Question 3

In the third image (histology slides), which pathological process is most likely occurring in the liver tissue on the right?

Accepted Answer

Biliary infarction due to obstructive jaundice

Question 4

Which pigment is demonstrated in the fifth image (brown granules in ganglion cells), and what is its clinical significance?

Accepted Answer

Lipofuscin; marker of cellular aging and oxidative stress

Question 5

The sixth image shows melanin-containing basal cells. Which histochemical stain is most appropriate for demonstrating melanin?

Accepted Answer

Masson Fontana

Question 6

Which pigment is responsible for the dark brown coloration seen in the seventh image (melanin-laden macrophages/lymphocytes in melanoma)?

Accepted Answer

Melanin

Question 7

The eighth image shows a blue pigment powder. Which histochemical reaction produces this pigment, and what does it detect?

Accepted Answer

Perls' Prussian Blue reaction; detects ferric iron (Fe3+)

Question 8

A patient presents with skin hyperpigmentation and diabetes mellitus (see image 10). Which inherited disorder is most likely, and what is the primary pigment involved?

Accepted Answer

Haemochromatosis; haemosiderin

Question 9

Which histochemical stain is used to demonstrate haemosiderin in tissue sections, as seen in images 11-14?

Accepted Answer

Perls' Prussian Blue

Question 10

What is the main difference between haemosiderosis and haemochromatosis?

Accepted Answer

Haemosiderosis is acquired and less toxic, iron stored in reticuloendothelial cells; haemochromatosis is inherited, iron stored in parenchymal cells and is more toxic

Question 11

Which pigment is demonstrated by the Von Kossa method, and what is a limitation of this technique?

Accepted Answer

Calcium; not specific, can also stain other minerals

Question 12

Which pigment is associated with Wilson's disease and what histochemical stains can be used to demonstrate it?

Accepted Answer

Copper; Shikata Orcein, Rubeanic acid, Rhodanine

Question 13

Which type of microscope is required to visualize birefringent urate crystals in gout, and what is the principle behind its operation?

Accepted Answer

Polarising microscope; detects rotation of polarised light by birefringent material

Question 14

Which pigment is most commonly found in the lungs of urban dwellers and smokers, and how is it identified histologically?

Accepted Answer

Carbon (anthracosis); identified by site and morphology, not by histochemical stain

Question 15

Which fixative is best for preserving lipids in tissue sections for histochemistry, and what is a major limitation of traditional wax sectioning?

Accepted Answer

Osmium tetroxide; fixes and blackens lipids, but is uncommon

Question 16

Which dye is used in the lysochrome method to stain neutral fats, and what is the principle behind this staining?

Accepted Answer

Sudan Black B; dye is soluble in lipids but insoluble in aqueous solvents

Question 17

A patient with repeated blood transfusions develops iron overload. Which pigment accumulates, and where is it primarily stored?

Accepted Answer

Haemosiderin; reticuloendothelial system (spleen, Kupffer cells)

Question 18

Which lipid storage disorder is characterized by accumulation of lipids in the kidney and can be demonstrated by Oil Red O staining?

Accepted Answer

Fabry disease

Question 19

Which of the following equations correctly represents the chemical reaction in Perls' Prussian Blue method for ferric iron detection?

Accepted Answer

$$4Fe^{3+} + 3$$[$$Fe^{2+}(CN)_6$$]^{4-} \rightarrow $$Fe_4$$[Fe(CN)_6]_3$$ (Prussian Blue)

Pigments and Lipids: Histochemistry and Pathological Significance

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