I've never done it on pancreas, but I'll let you know about how it
is handled on melanin and argentaffin cells. I'm going to guess that
might will be similar to the staining of argentaffin cells. (See 5th
paragraph)

Fontana-Masson (F-M) is one of those silver stains that you have to
check, to see 
if it's done yet. Usually for us, 1 hour is enough time to see
positivity in 
melanocytes and most melanomas. Some melanomas needs longer time in the
silver. 
Some poorly and un-differentiated melanomas as well as some amelonotic
melanomas 
never pick up the silver. Longer time (up to 2 hours) may be needed to
stain 
intestinal argentaffin cells and argentaffinic carcinoid tumors.

We do the gold chloride until the background is clear. This is usually
a 0.2% solution, and takes us about 10 - 20 seconds. Similar to doing
the
gold chloride on a GMS for fungus. 1 minute in 5% sodium thiosulfate
seems 
to work for us, but it won't hurt anything if you go for 5 minutes.

Now, I have a question. Why F-M on a pancreas? 

I don't remember any argentaffin cells in a pancreas. I've used
argyrophilic stains 
like Grimelius, Sevier-Munger or Churukian-Schenk (our preference) to
demonstrate 
alpha cells (glucagon). We've used aldehyde fuchsin to demonstrate beta
cells (insulin). 
Mallory trichrome stains alpha cells red and beta cells blue. The acinar
cells stain with
phloxine, PTAH, and PAS variable. The ductal epithelium stains with
alcian blue.

Now we use immuno stains, like NSE, chromagranin and synaptophysin, if
memory serves me correctly.
Or glucagon, insulin or gastrin.

So why F-M? What type of tumor are they suspecting? Something
non-pancreatic?

Just wondering.

Hope this helps.

Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073


kkdulany@UNMC.EDU wrote:
> 
> On Monday I have to do the Fontana-Masson stain and I haven't done it in a long
> time.  I checked the AFIP manual and the Sheehan book, and the timing is very
> different in each book.  For instance the AFIP says to stain in the silver soln.
> for 1 hour, and Sheehan says two hours.
> Also thegold chloride ranges from 2 to 3  minutes in Sheehan to 10 minutes in
> the AFIP. Hypo times range from 1 minute to 5 minutes.  Does anyone do this
> stain routinely enough to give me some guidelines?     I am doing this on
> pancrea tumors if that makes any difference. Thanks for any help you can give
> me.
> Karen Dulany HTL
> Eppley Institute for Cancer Research
> Omaha, NE