LECTURE - Uncommon Stains: Pigments & Minerals

Question 1

exogenous pigments

Answer 1

• artifactual or from the environment
• most common are:
  tattoos
  carbon (lung from smoking or living in urban setting)
  silica (lung)
  asbestos (lung)

Question 2

this is the main cause of mesothelioma

Answer 2

chrysotile asbestos exposure = serious form of lung cancer

Question 3

T or F. Mesothelioma has a long latency period

Answer 3

T; 6-12 mos

Question 4

this was the most common cause of workplace death since 2007

Answer 4

mesothelioma epidemic

asbestosis is 4th most common

Question 5

prognosis of mesothelioma

Answer 5

6-12 months but long latency period so took a while to make connection

Question 6

which stain can we use to say that it is definitively say it is asbestos

Answer 6

iron stain

- protein that coats asbestos will stain with iron = turns iron a nice bright blue

Question 7

endogenous pigments

Answer 7

within the body

• melanin
• lipofuscin = wear and tear pigment = brownish on H&E

Question 8

melanin stain

Answer 8

• Masson Fontana Silver stain
• melanin is an Argentaffin substance = capable of reducing silver on its own
• bleaching with strong oxidizers to confirm melanin

Question 9

what does silver look like when it is reduced and overlaid with gold?

Answer 9

black

Question 10

histology is used to show overabundance of this

Answer 10

iron

• hemochromatosis
• brown colour with H&E but not that distinct

Question 11

Perls Prussian Blue for iron

Answer 11

• HCl releases iron from hemosiderin
• ferric chloride reacts with potassium ferrocyanide to form ferric ferrocyanide = brilliant blue
• neutral red counterstain

Question 12

copper

Answer 12

• trace element
• Wilson’s disease, inherited defect/deficiency of ceruloplasmin (carrier protein of copper; copper accumulates)
• copper accumulation in liver but spills to brain skin, eyes = Kayser Fleischer rings = bronze colour
• Rhodanine method = binds specifically w copper = red/orange in colour

Question 13

calcium

Answer 13

• deposits in certain diseases
• hypercalcemia of malignancy = deposit in kidney
• method = Von Kossa
• principle is metallic substitution = silver will get substituted for calcium
• light or hydroquinone reduces silver (reducing agent)