RE: [Histonet] Black pigment on Bronch Lavages

From:"Marshall Terry Dr, Consultant Histopathologist"

Carbon is neither refractile nor birefringent.
Nothing becomes refractile simply by looking at it through crossed polarizers.
To appreciate refractility (better) you need to either close the sub-stage diaphragm or lower the condenser.
BTW, asbestos fibres may be birefringent, but they are so small when dispersed in lung, that this is no way of detection, because they are simply too small to see with a light microscope, by any means. The asbestos bodies are of course, haemosiderin encrustations.

Dr Terry L Marshall, B.A.(Law), M.B.,Ch.B.,F.R.C.Path
 Consultant Pathologist
 Rotherham General Hospital
 South Yorkshire

-----Original Message-----
From: []
Sent: 30 October 2003 21:03
Subject: RE: [Histonet] Black pigment on Bronch Lavages

As our pathologist was explaining his problem to me while we looked at the slide in particular under his microscope, he said that Carbon was not the item in question as it does not become refractile when he polarizes/darkfield his microscope (to be honest he was whizzing objectives and filters so fast I could barely follow him!).  I know carbon is very common in lung, but to my eye as well, it is too fine and regular to resemble the stuff I usually see. 

-----Original Message-----
From: []
Sent: Wednesday, October 29, 2003 3:31 PM
Subject: Re: [Histonet] Black pigment on Bronch Lavages

dear kathy, how have you ruled out carbon, as this is so common. peter h. dohan, md

-----Original Message-----
Sent: Oct 29, 2003 1:30 PM
Subject: [Histonet] Black pigment on Bronch Lavages

One of our pathologists and myself have been trying to identify some black intracellular pigmentation in a bronch lavage.  We have ruled out carbon, and bleaching the section did not work, therefore is not melanin.  It is a very fine dark black pigment and appears quite uniform in shape and size.  Our pathologist is thinking that it is lead (the patient is a long time professional painter), but lead stains are negative.  My other thought is aluminum deposits but have not yet stained for this.
I am hoping someone on the "Net"  may have some idea of what this may be, and if there is a method for demonstrating it.
Thanks very much in advance!
Kathy Johnston
Tech II - Special Stains
Anatomic Pathology - FMC
Calgary Laboratory Services
1403-29 Street NW
Calgary AB, Canada T2N 2T9
403-290-4093 fax

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