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SUMMARY
This chapter outlines the category of preneoplastic and neoplastic lymphocyte and plasma cell disorders. It introduces a framework for evaluating neoplastic lymphocyte and plasma cell disorders, outlines clinical syndromes associated with such disorders, and guides the reader to the chapters in the text that discuss each of these disorders in greater detail.
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Lymphocyte and plasma cell malignancies present a broad spectrum of different morphologic features and clinical syndromes (Table 1–1). Lymphocyte neoplasms can originate from cells that are at a stage prior to T- and B-lymphocyte differentiation from a primitive stem cell or from cells at stages of maturation after stem cell differentiation. For example, acute lymphoblastic leukemias arise from an early lymphoid progenitor cell that may give rise to cells with either B- or T-cell phenotypes (Chap. 2), whereas chronic lymphocytic leukemia arises from a more mature B-lymphocyte progenitor (Chap. 3) and myeloma from progenitors at even later stages of B-lymphocyte maturation (Chap. 18). Disorders of lymphoid progenitors may result in a broad spectrum of lymphocytic diseases, such as B- or T-cell lymphomas (Chaps. 9 and 15), hairy cell leukemia (Chap. 4), prolymphocytic leukemia (Chap. 3), natural killer cell large granular lymphocytic leukemia (Chap. 5),1 myeloma, and plasmacytoma (Chap. 18). Hodgkin lymphoma also is derived from a neoplastic B cell that has highly mutated immunoglobulin genes that are no longer expressed as protein (Chap. 8).
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