As the pathologist inventor of tissue-tek I have been "fighting" fatty
tissue all of my LONG professional life. You are correct that the BEST
of all answers is for the PA or pathologist to cut tissue sections 2-3mm
thick. It helps to use COLD/refrigerated fatty tissue for this purpose
(much like the butcher slices "leaf lard" to place on the surface of an
expensive tenderloin!). A VERY sharp knife/blade is also helpful.
After designing the original tissue-tek cassette with metal covers and
round holes, I designed cassettes with an increased number of
rectangular holes in both the bottoms and tops, and then the cassettes
with attached covers were added by Lab Tek to eliminate the cleaning of
These changes DID NOT eliminate problems in processing FATTY tissue
because the circulation of processing fluids was not materially
improved. Finally, and with a particular concern for processing fatty
tissue.....I invented TurbOflow cassettes to increase the circulation of
processing fluids with a turbine-like "swish" movement thru the side
walls of the cassette. This has helped somewhat in the processing of
breast and other fatty tissues because of the increased flow across the
cassette contained tissues.
HOWEVER....nothing is better than a 2-3mm thick tissue sample placed in
the processing cassette by the PA or Pathologist....or Resident in
I have been PREACHING this same sermon for more than 50 years and
not all have been listening.
Good Luck and Kindest regards.
CSO McCormick Scientific
[mailto:email@example.com] On Behalf Of Orr,
Sent: Tuesday, May 29, 2007 8:09 AM
Subject: [Histonet] processing fatty tissue
Date: Fri, 25 May 2007 22:57:59 EDT
Subject: [Histonet] processing of fatty tissue samples
Hi, what is everyone doing in histo land when it comes to processing
We now keep a processor dedicated to (fatty) breast tissue. We do also
run fatty tissue with this same process.
You can check out the CAP guidelines for Breast tissue that may help
with your process.
We first had to decide if our fatty tissues were either partially
fixed, partially cleared or a portion of both.
Each time we had unacceptable tissue we would troubleshoot back the
whole way to the OR.
Our problem ended up as a combination of our Gross Staff (residents and
PA's) submitting thicker pieces, cramming cassettes and not enough
We decided our fixation time was appropriate and well within the CAP
So we added more time in our 100% alcohols (you'll need to decide if you
should add more time or change reagents more frequently or add an
additional container of 100%)
We also adjusted the processing schedule and added a third station of
Our VIP has 4 paraffin baths and we use all of them with varied times.
We now have excellent results with this set up. ~A simple reminder
every hour on the hour to the Gross Room to "keep the tissue thin" helps
everything run smoothly! (LOL)
It is a great help for us to have the capability to separate our tissues
in this manner with several processors.
Becky Orr CLA,HT(ASCP)QIHC
Assistant Manager, Anatomic Pathology
Evanston Northwestern Healthcare
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