Department of Pathology, State University of New York at Stony Brook |
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EIGHTY-five percent of
non-Hodgkin's lymphomas originate from B-cells. This origin is inferrable
in most cases from: |
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You can see some diagrams of normal lymphocyte
maturation and the lymphoma equivalents to these stage.
The following table contrasts features of low and higher grade lymphomas (note that "higher grade" entries apply to most of the intermediate grade and all the high grade categories in the Working Formulation): |
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It is, however, a paradox of all lymphomas that the indolent, low grade lymphomas permit long survivals but are virtually uncurable and may not be treated initially. On the other hand, the higher grade lymphomas are often rapidly deadly, but all patients are treated and some respond even to the point of complete cure. Behind this paradox is the observation that both chemotherapy and radiotherapy target rapidly dividing cells. For some lymphomas, such as small non-cleaved cell lymphoma, the cell of derivation is unknown or controversial. Other lymphomas start by resembling their cell of origin but subsequently dedifferentiate. For example, follicular center cell lymphomas may grow diffusely, belying their origin from cells that grow in follicles. In such cases their follicular nature must be inferred from softer evidence, such as the presence of characteristic small-cleaved follicular center cells, certain antigens such as CD10, or the characteristic t(14;18) BCL-2 gene rearrangement. Also, many low-grade lymphomas tend to progress to higher grade disease. In Richter's transformation, for example, small lymphocytic lymphoma promotes itself to diffuse large cell lymphoma. Immuno- and Genophenotype:
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