Now let us move to the
other major subtype
of lymphomas, non-Hodgkin's lymphomas. Not
a very imaginative title I am sure you would
agree for this very broad group of diseases.
Now there are many many different types of
malignant disease within this group of non-Hodgkin's
lymphoma. Around 85 percent of these are derived
from B lymphocytes whereas the remainder are
derived from T lymphocytes. These disorders
are actually increasing in incidence. We aren't
exactly sure why, but certainly infection
is . . . and trigger in some of these cases.
Now clinically this is quite an important
consideration in that we can divide this disorder
into a high-grade and low-grade disease.
What do I mean by that? Well, as you will see on
that list there. The high-grade disease is
more aggressive, but paradoxically quite curable.
Other lymphomas or low grade, they progress
slowly, but they are more difficult to cure.
It may recognize that is a similar phenotype
to leukemia where you have acute leukemias,
which are quite aggressive, but curable than
chronic leukemias, which are more slowly progressive,
but more difficult to cure.
The diagnosis of non-Hodgkin's lymphoma is
very similar to Hodgkin lymphoma needing history.
Examination and investigations and critical
biopsy of the lymph node. Again the immunohistochemistry
is important in defining the distribution
of T cells and B cells and the expression
of characteristic markers, which define the
subset of the disease. As we shall see, cytogenetic
and gene mutation analysis are becoming increasingly
important in lymphoma and I have showed two
examples there, the t(14:18) translocation
in follicular lymphoma and the MYD88 mutation
in the lymphoblastic lymphoma. CT and PET
scanning are very important to determine the
stage of disease and the response to therapy.
You will recognize on the right CT scan of
a patient with lymphoma and you will see on
the left side of that image, the lymphoid
mass just adjacent to the liver sitting above
Let us now look at some of the individual
subtypes of non-Hodgkin's lymphoma.
Let us start with high-grade aggressive non-Hodgkin
lymphoma. The most important subtype here
is Diffuse large B-cell Lymphoma DLBCL. Now
as with all non-Hodgkin lymphoma, this disease
may be present in lymph node tissue or sometimes
in other tissues in which case it goes under
the term of extranodal disease and that is
a common feature of non-Hodgkin's lymphomas
and not always so restricted to lymphoid tissue
as is Hodgkin lymphoma. The treatment for
Diffuse Large B-cell Lymphoma is with the
use of an anti-CD20 antibody together with
combination chemotherapy and that is a classic
regimen that is used R- or CHOP given in 1-3
cycles and indeed this is curative in the majority
of patients these days.