RE: Tissue processing - small biopsies

From:David Taylor Manager <DTMan@kingmower.com.au>

Dear Terry, Most of the endoscopy clinics in Adelaide are performed in
the AM. This gives us specimens sitting in formalin for at least 5 hours
which is enough to get fixation of 2-5 mm biopsies underway before
transfer to cassette. They then sit in formalin until the O/N processing
run starts. They then get processed in a Leica TP1050 which also has
formalin on it.
The use of foam may not be the best technique in the world but it's
relatively cheap, easy to use and has some great advantages. For
example, today we had one vet case consisting of 150 baby fish which
were placed between foam pads, 6 per cassette. They come out great in
H+E because the foam ensures the little buggers don't get all curled up.
The same can be said for prostate cores.
As far as the artefact is concerned, only those specimens that are to
large and probably should not be in foam will be affected. When a set of
levels is cut the sections will be deeper into the tissue and
superficial effect will disappear. Much the same as the large bits of
tissue a tired grumpy pathologist puts thru late at night. Next day the
cassette lid/ base imprint is trimmed off and sections cut.
The endoscopy type specimens we receive are usually between 2 and 5 mm,
well defined and we certainly do not discard any bits. If we receive
tiny tissue frags suspended in formalin, (usually from an FNA) I would
definitely do a centrifuged agar block.
By the way, we are a small private pathology lab in that we only do
Histo/ Cyto. Our workload is a mix of large surgical, smaller surgical
and GP cases as well as contract work for a veterinary pathology
company. We have large variations in workload (100-350+ blocks) which
causes the odd head-ache. David.

David Taylor
Laboratory Manager
Drs King & Mower
Adelaide, Australia
 

-----Original Message-----
From: Terry.Marshall@rgh-tr.trent.nhs.uk
[mailto:Terry.Marshall@rgh-tr.trent.nhs.uk]
Sent: Thursday, 2 August 2001 20:26
To: David Taylor Manager; histonet@pathology.swmed.edu
Subject: RE: Tissue processing - small biopsies


A few points of interest to me. 
I fail to understand how the presence of these typically triangular
defects can cause no problem. The very fact that they are in a foam pad
indicates that they are the smallest fragments, so how one can happily
discard a significant proportion of the available tissue, which is what
you are in effect doing, I know not. However, I don't want to exaggerate
the problem. I have been there (we use the damn things too) and know
that I can usually live with the artifact, but at the same time, one
must recognise it as less than satisfactory.

300 blocks a day - a small lab.?

I suppose for Oz community labs it is, but over here that would be the
work of a large  hospital.

I didn't know that (as you imply) there are different thickness' of foam
pad. I have used them in many labs, in 3 continents and all have looked
the same to me. Do tell us (all right then, me) more.

If your biopsies are fixed before processing, I congratulate you. Must
be the only private lab. in Oz to do so. In my experience it was a case
of "coming, ready or not". :-)

BTW, I am apprehensive regarding the carry over of reagent in sponges,
and indeed, the problem of the reagent fighting through a sponge full of
previous reagent to get its job done. I suppose the modern suck and blow
machines are helpful in that respect, but .......

Terry L Marshall
Histopathologist
Rotherham General Hospital, Yorkshire


Dear Terry, Yes there are a small percentage of biopsies which exhibit
the tiny triangular dents associated with being processed between biopsy
foam pads. Our 4 pathologist's have said that no it is not a problem.
The foam should be soaked in alcohol before poaring the specimen thru.
The foam pad should be designed to be used in tissue processing
cassettes, ie. not to thick. Most of our GE and gyne biopsies are fixed
before putting up. We are a small lab and do up to 30-40 biopsy
cassettes in a morning along with plenty of other tissue types, with up
to 300+ blocks for the day. David.

David Taylor
Laboratory Manager
Drs King & Mower
Adelaide, Australia
 

-----Original Message-----
From: Terry.Marshall@rgh-tr.trent.nhs.uk
[mailto:Terry.Marshall@rgh-tr.trent.nhs.uk]
Sent: Thursday, 2 August 2001 00:19
To: David Taylor Manager; histonet@pathology.swmed.edu
Subject: RE: Tissue processing - small biopsies


Let's get this straight David. You get no problems with foam artefact
you say. 
Do the pathologists? (You have not denied getting it, just having
problems with it).

Terry L Marshall
Histopathologist
Rotherham General Hospital, Yorkshire

I'm with Amos, agar/ gel is a pain. We use black foam biopsy pads and
train staff to embed properly. We have no problems

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