[Histonet] GI biopsies

[Michelle Bell]

Paula,
Is this a new occurrence or has always been a problem?
I would suggest you first determine if the folds are present after microtomy before staining.  You should be able to view the folds on your paraffin sections.  It is possible that the tissue is lifting, especially if you feel there are no folds present when you pick up the sections.  If you can’t see the folds before staining, then the tissue is lifting during staining.  This can be caused by a slide oven not hot enough or not long enough in The slide oven.  It can also be that your water pressure is too high. It can also be that your slides are not adhesive enough.

If you’re seeing the wrinkles prior to staining, then the alcohol may help.

________________________________
From: Paula via Histonet <histonet at lists.utsouthwestern.edu>
Sent: Wednesday, February 11, 2026 2:46:56 PM
To: histonet at lists.utsouthwestern.edu <histonet at lists.utsouthwestern.edu>
Subject: [Histonet] GI biopsies

Dear Colleagues,

I’m reaching out to the group to ask for input regarding microscopic folds
in GI biopsy sections.  I’m hoping for some “tricks of the trade”
suggestions.

In our lab, sections appear flat and well-relaxed on the water bath with no
visible gross folds. However, after H&E staining, the pathologist identifies
epithelial microfolds in small GI biopsies (esophagus, stomach, colon).
These are not visible before staining and are occurring across multiple
techs.

We currently use Leica Paraplast Plus (polymer-enhanced paraffin). We have
reviewed and optimized:

• Embedding orientation (flat, mucosa aligned)
• Water bath temperature and float time
• Blade angle and cutting speed
• Section thickness (4 µm)



Despite this, we continue to see post-stain microfolding.

For those of you who cut a high volume of GI biopsies:

·        Have you found certain paraffins perform better (e.g., low-melt,
non-polymer)?

·        Do you run a different water bath temperature specifically for GI?

·        Any “tricks of the trade” for minimizing epithelial compression
that aren’t in the textbooks?

I would greatly appreciate any practical advice or shared experience. Thank
you in advance for your insights.

Best regards,
Paula Lucas
Histology Laboratory/BioPath Medical Group





We are doing a lot more GI cases, and we’re experiencing complaints from the
pathologist about folds.  There are microscopic and are interfering with
taking images.



Can someone recommend tricks to the trade of minimizing these folds in the
sections?



Thank you in advance,

Paula

BioPath Medical Group

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