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LEARNING OBJECTIVES
Upon completion of the chapter, the reader will be able to:
Discuss the underlying pathophysiologic mechanisms of the lymphomas and how they relate to presenting symptoms of the disease.
Differentiate the pathologic findings of Hodgkin lymphoma (HL), follicular indolent non-Hodgkin lymphoma (NHL), and diffuse aggressive NHL and how this information yields a specific diagnosis.
Describe the general staging criteria for the lymphomas and how it relates to prognosis; evaluate the role of the prognostic systems such as the International Prognostic Score for HL, the Follicular Lymphoma International Prognostic Index (IPI), and the IPI for diffuse, aggressive NHL.
Compare and contrast the treatment algorithms for early and advanced stage disease for HL.
Assess the role of autologous hematopoietic stem-cell transplantation for relapsed lymphomas.
Delineate the clinical course of follicular indolent and diffuse aggressive NHL and the implications for disease classification schemes and treatment goals.
Outline the general treatment approach to follicular indolent and diffuse aggressive NHL for localized and advanced disease.
Interpret the current role for monoclonal antibody therapy in NHL.
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The malignant lymphomas are a clonal disorder of hematopoiesis with the primary malignant cells consisting of lymphocytes of B-, T-, or natural killer (NK) cell origin. Lymphoma cells predominate in the lymph nodes; however, they can infiltrate lymphoid and nonlymphoid tissues, such as the bone marrow, central nervous system (CNS), gastrointestinal (GI) tract, liver, mediastinum, skin, and spleen. An overview of the lymph node regions typically involved in lymphomas is depicted in Figure 95–1. 
There are two broad classifications of lymphoma, Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), and both contain numerous histologic subtypes that are pathologically distinct disease entities.
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The clinical course varies widely among histologies of lymphoma. More aggressive subtypes are highly proliferating cells that require aggressive therapeutic intervention with chemotherapy, radiation therapy, or both. By contrast, certain subtypes of NHL are characterized by a disease course that flares and remits intermittently over a period of years regardless of treatment.
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EPIDEMIOLOGY AND ETIOLOGY
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Approximately 8830 new cases of HL were estimated to be diagnosed in the United States in 2021, with 960 deaths attributed to the disease.1 Broadly, HL is divided into two types, classical HL and nodular lymphocyte-predominate HL. Classical Hodgkin lymphoma makes up approximately 95% of HL cases and will be the focus of this chapter. The incidence of HL is bimodal, with peaks occurring in the third decade of life and in patients over 50.2 The precise cause of HL is unknown, ...