ABSTRACT
Introduction 281 Precursor B cell lymphoblastic lymphoma/leukemia 283 Definition 283 Synonyms 283 Epidemiology of spontaneous disease 283 Epidemiology of disease in genetically engineered mice 284 Histologic features 284 Immunologic features 284 Molecular features 285 Postulated cell of origin 285 Comments 285 Small B cell lymphoma/leukemia 285 Definition 285 Synonyms 285 Epidemiology of spontaneous disease 285 Epidemiology of disease in genetically engineered mice 285 Histologic features 285 Immunologic features 285 Molecular features 285 Postulated cell of origin 285 Comments 285 Splenic marginal zone B cell lymphoma 286 Definition 286 Synonyms 286 Epidemiology of spontaneous disease 286 Epidemiology of disease in genetically engineered mice 286 Histologic features 286 Immunologic features 286 Molecular features 286
Postulated cell of origin 286 Comments 286 Follicular B cell lymphoma 286 Definition 286 Synonyms 286 Epidemiology of spontaneous disease 287 Epidemiology of disease in genetically engineered mice 287 Histologic features 287 Immunologic features 287 Molecular features 287 Postulated cell of origin 287 Diffuse large B cell lymphoma 287 Definition 287 DLBCL – centroblastic 287 DLBCL – immunoblastic 288 DLBCL – histiocyte associated 288 DLBCL in genetically engineered mice 288 Diffuse high-grade blastic B cell lymphoma/leukemia 289 Definition 289 Synonyms 289 Epidemiology of spontaneous disease 289 Epidemiology of disease in genetically engineered mice 289 Histologic features 289 Immunologic features 289 Molecular features 290 Presumed cell of origin 290 Comments 290 Key points 290 References 290
The identification of T cells and B cells as subsets of lymphocytes readily distinguished by phenotype and function heralded a new era for the field of immunology. This milestone also marked the end of an epoch in which hematologic malignancies were categorized primarily on the basis of their cytology, histology, and clinical presentation. Classification
were gradually replaced by those emphasizing cell lineage and state of differentiation as defined by immunophenotyping. Identification of distinctive chromosomal abnormalities in metaphase spreads foresaw the wealth of molecular genetic approaches that now belong to the armamentarium of a modern department of human hematopathology. The sum of approaches to diagnosis provided by clinical features, morphology, immunophenotype, and genetic charac-
Organization (WHO) classification of human hematopoietic neoplasms,1 which has recently been updated.
