Non-Hodgkin's lymphomas were separated from Hodgkin's disease by recognition of the Sternberg-Reed cells early in the twentieth century. The histologic classification for non-Hodgkin's lymphomas has been one of the most contentious issues in oncology. Imperfect morphologic systems were supplanted by imperfect immunologic systems, and poor reproducibility of diagnosis has hampered progress. In 1999, the World Health Organization (WHO) classification of lymphoid malignancies was devised through a process of consensus development among international leaders in hematopathology and clinical oncology. The WHO classification takes into account morphologic, clinical, immunologic, and genetic information and attempts to divide non-Hodgkin's lymphomas and other lymphoid malignancies. | Chapter 105. Malignancies of Lymphoid Cells Part 2 Non-Hodgkin s lymphomas were separated from Hodgkin s disease by recognition of the Sternberg-Reed cells early in the twentieth century. The histologic classification for non-Hodgkin s lymphomas has been one of the most contentious issues in oncology. Imperfect morphologic systems were supplanted by imperfect immunologic systems and poor reproducibility of diagnosis has hampered progress. In 1999 the World Health Organization WHO classification of lymphoid malignancies was devised through a process of consensus development among international leaders in hematopathology and clinical oncology. The WHO classification takes into account morphologic clinical immunologic and genetic information and attempts to divide non-Hodgkin s lymphomas and other lymphoid malignancies into clinical pathologic entities that have clinical and therapeutic relevance. This system is presented in Table 105-3. This system is clinically relevant and has a higher degree of diagnostic accuracy than those used previously. The possibilities for subdividing lymphoid malignancies are extensive. However Table 105-3 presents in bold those malignancies that occur in at least 1 of patients. Specific lymphoma subtypes will be dealt with in more detail below. Lymphomas associated with HIV infection are discussed in Chap. 182. Table 105-3 WHO Classification of Lymphoid Malignancies B Cell T Cell Hodgkin s Disease Precursor B neoplasm cell Precursor T neoplasm cell Nodular lymphocyte- predominant Hodgkin s disease Precursor lymphoblastic B Precursor lymphoblastic T leukemia lymphoma precursor B cell acute lymphoblastic leukemia lymphoma leukemia precursor T cell acute lymphoblastic leukemia Mature peripheral B cell neoplasms Mature peripheral T cell neoplasms Classical Hodgkin s disease B cell chronic lymphocytic leukemia small lymphocytic lymphoma T cell prolymphocytic leukemia Nodular sclerosis Hodgkin s disease B cell prolymphocytic leukemia T cell .
