> 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 drive
me
> into leaving Histology forever and seeking a lucrative highly paying
> successful career?
> I need help/advice/suggestions regarding handling breast specimens so that
> they are well preserved, easy to cut on the microtome, instead of
partially
> 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 the
> cassette without touching the sides, and cut them to 2mm in thickness. Of
> course, most times they are 4mm or more. They are then placed into
cassettes
> and held overnight in 10%NBF. They get put on the processor the next
evening.
> I tried alcoholic formalin, saw no difference. Large breast lymph nodes
are
> just as bad if not worse, raw in the centers. The small ones are usually
fixed
> 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
it,
I
> will be forever in your debt.
> Connie L. Probert
> Detroit, Michigan

Response from avenzano@cicv.inta.gov.ar

Dear Connie L. Probert: We usually deal with large pieces of tumors or other
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 secret
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
DVM-Pathology Group
INTA Castelar, Argentina