Re: Large mamary tissues
Large unfixed pieces of breat will not fix/process adequately in a normal
overnight schedule. Some compromises will have to be made in order to obtain
better sections. As you commented, getting the pathologist/intern to cut
smaller tissues is not easy, but often perseverence pays off. A second thing
you might try, is to "breadslice" the breast, ie make deep incisions(not all
the way through)from the subcut towards the skin, and pack the incisions
with either cottonwool or roller towel. This has the advantage of "wicking"
the fixative into the deeper aspects of the specimen. The breast is then
left overnight in an excess of formalin to fix.
A third option, that used to be used, and I mention this as an historical
note, is to place the cassettes in hot formalin in a 40-60deg oven. The
odour of formalin fumes comes to me now as I think about those eye-watering
Bone research unit
>From: Agustín Venzano
>To: HistoNet Server
>Subject: Large mamary tissues
>Date: Thu, 25 Apr 2002 14:25:34 -0300
> > Date: 22 Apr 2002 18:30:41 -0500
> > From: "Connie P."
> > Subject: Breast specimens
> > Could we please revisit my current nemesis, which is surely going to
> > into leaving Histology forever and seeking a lucrative highly paying
> > successful career?
> > I need help/advice/suggestions regarding handling breast specimens so
> > they are well preserved, easy to cut on the microtome, instead of
> > raw tissue which requires the cut and scoop method to obtain a slide.
> > I plead with the residents (1st yrs.) to trim them so that they fit in
> > cassette without touching the sides, and cut them to 2mm in thickness.
> > course, most times they are 4mm or more. They are then placed into
> > and held overnight in 10%NBF. They get put on the processor the next
> > I tried alcoholic formalin, saw no difference. Large breast lymph nodes
> > just as bad if not worse, raw in the centers. The small ones are usually
> > O.K. Does anyone have a tried and true method for handling large breast
> > specimens which works for them with few exceptions? If so, please share
> > will be forever in your debt.
> > Connie L. Probert
> > Detroit, Michigan
>Response from firstname.lastname@example.org
>Dear Connie L. Probert: We usually deal with large pieces of tumors or
>kind of tissues in our lab, and so far had no problem in processing. Small
>animals' mammary tumors are specially hard due to the presence of
>connective, catilaginous or even osseous tissue within them, our only
>is complete fixation. To achieve this one we follow up these two steps:
>1. We soak the entire tumor or a large part of it in 15 % saline formalin.
>2. The following day we trim the tumor into 3-4 mm. thick slices, putting
>these into plastic cassettes, which in turn are put into bottles full of a
>similar formalin solution. We leave these cassettes for a minimum of 12
>hours (Usually overnight) in the f.sol.
>3. We start up the authomatic processing of the samples.
>There's a very important aspect that should always be considered: Steps # 1
>and 2 are performed at room temperature or within a stove at 37 ºC during
>the cold season, but in no circumstances fixation is carried out below 25
>ºC, as cold temps. delay formalin penetration into the tissues. Another
>aspect that ought to be respected is to use a minimum tissue volume/15 %
>formalin solution volume ratio= 1/20 to ensure a proper fixation.
>I hope this will serve, sincerely yours
>Agustin Jose Venzano Halliburton
>INTA Castelar, Argentina
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