[Histonet] Re: processing

Robert Richmond RSRICHMOND <@t> aol.com
Wed Nov 14 12:32:57 CST 2007

Neutral buffered formalin is the prescribed fixative for breast tissue
.for the USA's FDA approved HER2 immunostaining procedure.

Neutral buffered formalin is a quite adequate fixative for fatty
breast tissue as long as you do two things:

1. The pathologist has to cut the damn tissue thin enough, and not
overload the cassettes. I'm appalled at the number of pathologists who
are unable or unwilling to do this. I think this detail is
particularly important for manual processing (such as our
correspondent in Russia describes), though probably no one now working
in the USA remembers this technique, since the Technicon processor
came into use in the early 1930's - probably the most revolutionary
change in surgical pathology in the 20th century, with the possible
exception of the cryostat (refrigerated microtome) in the early

2. Breast tissue needs to fix overnight. This prolonged fixation is
also prescribed by the FDA for the HER2 IHC. You have to sympathize a
lot with the patient's anxiety about the outcome of her biopsy, but
she needs the right diagnosis, not the fast diagnosis. Pathologists
need to remind their surgeons of this delay from time to time (so I
learned from Bill Shelley of blest memory, my first teacher in
surgical pathology, at Johns Hopkins around 1970).

Unfortunately, the commercial labs we compete with are bound by none
of these injunctions - they can promise you the moon and then moon you

On another topic today, Mark Adam Tarango in Las Vegas refers to my
advocacy of Diff-Quik II as "old school". Does that make me feel old!,
since I set the technique up in a number of labs in the early 1990's.
When this old boy was in school, Helicobacter (let alone staining it)
lay even further in the future than the CT scanner.

Bob Richmond
Samurai Pathologist
Knoxville TN

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