In article <3538 at newsrv.uchc.edu>, rajan at newsrv.uchc.edu (T Rajan) writes:
>> In article <147559 at netnews.upenn.edu>, lally at biochem.dental.upenn.edu (Ned Lally) writes:
>> In article <gila005-090993204812 at right.dom.uab.edu>, gila005 at uabdpo.dpo.uab.edu (Steve Holland) writes:
>> |> In article <sspencer-090993151038 at ted.bocklabs.wisc.edu>,
>> |> sspencer at macc.wisc.edu (Stephan Spencer) wrote:
>> |> >
>> |> > I was wondering if someone could delineate the difference between a
>> |> > lymphoma and leukemia.
>> |> >
>> |> > Thanks..
>> |> >
>> |> > Stephan Spencer
>> |> > University of Wisconsin, Biochemistry
>> |> > sspencer at macc.wisc.edu>> |>
>> |> A leukemia is a tumor that produces abnormal white blood cells in the
>> |> bloodstream. A lymphoma is a tumor of the lymph nodes that causes
>> |> lymph nodes to expand, invade other organs, and cause lymphoid
>> |> tissue to appear where it should not. >
>> Leukemias are "tumors" of the bone marrow (blood forming cells), while lymphomas
>> are tumors of the lymphoid organs and lymphatics (effector cells). When tumor
>> cells are found in the circulating blood, by definition, it is leukemia.
>>>>>>>> ------------------------------------------------------------------------------
>>>> _/_/_/_/ _/_/_/_/ _/ _/ _/ _/ Edward T. Lally
>> _/ _/ _/ _/_/ _/ _/_/ _/ lally at biochem.dental.upenn.edu>> _/_/_/_/ _/_/_/ _/ _/ _/ _/ _/ _/ (215)898-5913|FAX(215)573-2050
>> _/ _/ _/ _/_/ _/ _/_/ The University of Pennsylvania
>> _/ _/_/_/_/ _/ _/ _/ _/
>>>> ------------------------------------------------------------------------------
>>> Leuk- is a prefix meaning "white"; the suffix -emia refers to blood. Leukemia
> is thus white blood - a large increase in white blood cells. While several
> conditions (such as acute infections) can give rise to significant elevations
> in white blood cell counts, numbers greater than 100,000/ml are almost always
> due to a malignant process. Most leukemias result from malignancies of the
> bone marrow (tumors of granulocytes give rise to (very common)"
> myelocytic leukemias", which can be acute or chronic;
> lymphocytic malignancies give rise to lymphocytic leukemias,which can also be
> acute or chronic; those
> of plasma cells give rise to the (rare) plasma cell leukemias; those of
> megakarycytes give rise to (extremely rare) megakaryocytic leukemias and so
> on). Lymphomas occassionly give rise to leukemias, usually very late in the
> course of the disease.
> Lymphomas are most certainly not tumors of lymphatics (effector
> cells),whatever that means. Tumors of lymphatics are rare and may be
> lymphangiomas (benign) or lymphangiosarcomas (malignant). Lymphomas are tumors
> of lymphocytic origin that give rise to a palpable mass - usually in a lymphmas
> are of cells other than lymphocytes but for historical reasons are still called
> lymphomas.
On rereading my posting, I realize that several lines were inadvertantly
deleted. The last few lines should have read something like this: Lymphomas
are tumors of (usually) lymphocytic origin that give rise to a mass - most
commonly originating in a lymph node. However, lymphomas can originate in any
organ (including the brain). in which case the lymphoma is called an
extra-nodal lymphoma. The diagnostic criterion for a lymphoma is a mass. Some
cells other than lymphocytes can give rise to a lymphoma, most notably those of
the reticuloendothelial system, which includes macrophages.
