ABSTRACT
This chapter focuses on the pathology and pathobiology of selected aggressive B-cell and T/natural killer-cell lymphomas. The World Health Organization Classification of Neoplasms of the Hematopoietic and Lymphoid Tissues represents the first true worldwide consensus classification of hematological malignancies. There are several lymphomas that virtually always present in extranodal sites, and appear to correspond to normal lymphoid cells specific for extranodal immunological reactions. Extranodal aggressive B-cell neoplasms comprise, Burkitt’s lymphoma, and lymphomatoid granulomatosis. Three common variants have been distinguished: centroblastic, immunoblastic, and anaplastic. Many patients with extranodal involvement are asymptomatic, but when symptoms are present they are highly dependent on the site of involvement. Plasmablastic lymphoma (PBL) is a diffuse proliferation of neoplastic cells, most of which resemble B immunoblasts morphologically but plasma cells immunophenotypically. The frequent association between PBL and human immunodeficiency virus infection suggests that immunodeficiency predisposes to the development of PBL.
