| TERRY HAMBLIN |
If you present with a large lymph node,
whatever the eventual diagnosis, you
should first have a blood test. If the diagnosis is any sort of
lymphoma,
this may be apparent by finding a monoclonal population of lymphocytes
in the
blood. Sometimes a cast iron diagnosis can be made from the particular
pattern
of markers. This is usually true for CLL and mantle cell lymphoma, but
you
can't really distinguish between follicular lymphoma and marginal cell
lymphoma
from the markers, and diffuse large cell lymphoma only rarely spills
into
the blood. If you have the diagnosis of CLL then there is no need in
most cases
to take a lymph node.
Are there any circumstances when you do need to? Some cases have few if
any
cells in the blood, and these are usually called SLL, but it is
essentially
the same disease. Sometimes the nodes are inordinately large for the
white
count, or a lymph node might have rapidly enlarged so that the physician
will
suspect that there might be two diagnoses - CLL and diffuse large cell
lymphoma.
Or there may be a group of nodes that has not responded to therapy as
well
as the other nodes. I was once given a nasty surprise, when such a group
turned out to be harbouring an unsuspected malignant melanoma.
Nodes in the neck without a blood lymphocytosis present a special
problem
because an important cause is metastatic head and neck cancer. I always
get an
ENT opinion on these before biopsying them. Fine needle aspirate (FNA)
of neck
nodes has no place in the diagnosis of lymphoma, though it may be useful
to
detect carcinoma in a node. If possible a whole node should be taken,
though
with very large nodes or abdominal nodes that are being biopsied
remotely
under CAT scan guidance, we have to be content with only a portion of a
node.
Lymph node biopsy is not a job for a general surgeon. In 30 years I
referred
to only 2 surgeons who were experts in the field. The node should not be
put
in formalin, but sent fresh to the laboratory where it should be cut up
and
portioned out; some fixed for histology, some for cytogenetics and/or
FISH,
some dispersed for cell markers by Flow cytometry, some for RNA and DNA
extraction, and some frozen for future use.
Another major reason for a lymph node biopsy in CLL is for research. CLL
cells do not divide in the blood but in proliferation centers that are
in the
lymph nodes. In order to understand the disease it is necessary to study
these
proliferation centers, and for this we need lymph nodes. However, a
physician
should discuss with the patient about taking such a node, and the
patient
must recognise that he or she is volunteering to making a contribution
to
research. Biopsying some lymph nodes is more hazardous than others. The
neck is the
favored site. nodes in the armpit contain large amounts of fat, in the
groin
they are often reactive to infection. The neck however, is tiger country
with nerves waiting to be pranged. The facial nerve goes through the
parotid
gland, and that area is best avoided, just under the chin is the
submental nerve
that supplies the lower lip. That's why you need an expert surgeon who
is
used to operating in this area. Because the incision can follow the
folds of
the neck, there is often no scar. |
