Morphologic and Immunologic Terms for Lymphomas
Maryalice Stetler-Stevenson (stetler@box-s.nih.gov)
Thu, 9 Jan 1997 15:49:56 -0400
At the risk of starting a long dialog of limited scientific value,
I feel that I must address Ken Ault's comments. The current classification
of lymphoid neoplasms, the REAL classification, is designed to group
lymphoproliferative disorders into categories that represent biological
entities (Blood 84:1361-1392, 1994). They are not based upon "subjective"
morphology. The diagnostic categories are based upon immunophenotypic and
genotypic criteria as well as morphology. Mantle cell lymphoma has a
characteristic morphology, immunophenotype and t(11;14). It also has a
clinical prognosis that is distinct from other low grade B-cell neoplasms.
It is not a subjective morphological diagnosis. Any good hematopathologist
can diagnose a typical mantle cell lymphoma. Follicular lymphoma is even
easier and again not only has morphologic, immunophenotypic and genotypic
criteria but there is also an associated clinical prognosis. Follicular
lymphoma is a disease that we know a lot about, not a subjective
morphological classification.
The problem comes with those gray cases which are not typical for
anything and the state of the art is such that we can't give an accurate
diagnosis and must give a best guess. Another problem is that
hematopathology is very difficult and requires extensive experience.
General Surgical Pathologists trying to sign out a difficult
hematopathology case may give the impression that the morphological
evaluation is subjective. However, when you sit with a truly great
Hematopathologist, such as Elaine Jaffe, the subjectivity is removed and
the science of the process revealed. Bad Morphology is the same as bad
flow.
Maryalice
>
> I have been "listening" to the discussion about the
>confusion between terms like "follicular lymphoma" and
>specific immunophenotypes with interest because this is a
>topic of interest to me for many years. At the risk of
>offending some of my good friends on this list I would like to
>add my two cents to the discussion and maybe expand it
>somewhat.
> I think that we are all gratified that the continual evolution in
>lymphoma classification has begun to utilize
>immunophenotypic descriptions more and more - this is long
>overdue. However, we must remember that all of the
>historical classifications, especially those including such
>terms as "follicular", "mantle", etc. are based on (highly
>subjective in my view) morphology. We now seem to be in a
>transition phase between morphologic descriptions and
>immunophenotypic and genetic definitions of these diseases.
> We are asking for a lot of confusion, and we are doing
>ourselves a disservice, if we keep trying to align morphologic
>descriptions with specific immunophenotypes.
> In my view, it is especially unfortunate when we create new
>disease entities based not upon clinical criteria but upon
>variations in our own classification systems. For example:
>is a CD10 positive follicular lymphoma a different disease
>than CD10 negative follicular lymphoma? We shouldn't
>mistake a failure of our multiple classification systems for
>new diseases!
> This may a lengthy restatement of the obvious, but I needed
>to say it - and I feel better now!
> Ken Ault
>
Maryalice Stetler-Stevenson
Director Flow Cytometry Unit
Laboratory of Pathology, NCI, NIH