| SUSAN LECLAIR |
You have touched on a
difficult issue here. Traditionally the
differences between lymphoid diseases was determined by the
morphology of the cells and their location. The problem here is that
lymphocytes tend to look a lot alike and differentiation was
extremely difficult so that location became the major criteria.
Then, with the advent of flow cyometry analysis, it was possible to
separate similar looking cells on the basis of their cell markers
(e.g., CD20). But the problem then became that many of these now
called Mature (peripheral) B cell neoplasms have the some of the
same markers. It was about this time that straight line.
So it is possible for two different presentations to have at least
1-2 markers in common. What to do with them? Lately, lymphocyte
disorders have been studied with the add of genetic testing such as
PCR and FISH. With these tools, it is possible to identify the parts
of the cell's DNA that are abnormal. This is beginning to clear up
some of the overlaps in presentations and abnormal cell populations
but it is rather new and there are no absolute rules yet.
It is possible that a diagnosis might change two or three times as we
continue to look into and clarify the exact nature of the abnormality.
Just to let you know how difficult this is, I have listed here all of
the presentations that are now classified as Mature B cell neoplasms.
B cell CLL / SLL
B-cell Prolymphocytic leukemia
Burkitt's lymphoma / Burkitt's cell leukemia
Lymphoplasmacytic leukemia
Hairy Cell leukemia
Splenic marginal zone B-cell lymphoma
Extranodal marginal B cell lymphoma
Folllicular lymphoma
Mantle cell lymphoma
Diffuse large B - cell lymphoma
Plasma cell: myeloma/plasmacytoma |
|
TERRY HAMBLIN |
|
Small
lymphocytic lymphoma is how tissue histologists report
the lymph node or spleen picture of CLL. Some cases have
no leukemic cells in the blood so this is a valid
description, though it is often an early stage of CLL
and the cells appear in the blood eventually. However,
even where there are leukemic cells in the blood, the
histology of the lymph nodes is the same.
In
general SLL is treated in exactly the same way as CLL,
and there has even been a paper that says that it can be
divided into two types with mutated or unmutated VH
genes, just like CLL.
What
nobody knows is why in some cases there is no blood
phase of the disease.
There is
also a strange variety of the disease where the same
histology is seen in other tissues. Interesting sites
are the prostate and the orbit (the eye socket).
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TERRY HAMBLIN 17 April 2005 |
Confusion over
SLL
The term
CLL/SLL has been introduced but is easily misunderstood. What
hematologists called CLL based on the blood count picture, histologists
called SLL, based on the histology of the lymph node. Almost all cases
are diagnosed by hematologists, but a few cases have no lymphocytosis in
the blood and the disease is diagnosed by lymph node biopsy. Whatever
way it is diagnosed it is only one disease.
In occasional
cases the condition may appear to be stage 0 or I with only mild or no
lymph node enlargement in neck, groins or armpits, which are the area
examined for Rai or Binet staging. Nevertheless, some of these patients
have quite bad 'B' symptoms. In such patients it is important to look
for large lymph nodes at the back of the tummy (retroperitoneal nodes).
This requires CT scanning or ultrasound of the abdomen.
Peggy said her
husband had cleaved cells. This is quite unusual in CLL and it usually
means another type of lymphoma spilling out into the blood such as
mantle cell lymphoma (MCL) or follicular lymphoma (FL). It is very
important to get the right diagnosis (by lymphocyte markers). In MCL or
FL the usual prognostic factors, VH genes, CD38 and ZAP-70 do not have
the same implications. FISH may also be misleading. Trisomy 12, although
a common feature of CLL can also be seen occasionally in FL. |
