Lymphoma and Infections

Infection and Lymphoma

• Infection with human T-cell lymphotropic virus type 1 in early childhood is strongly associated with adult T-cell leukemia/lymphoma.
• Gastric infection with Helicobacter pylori, a gram-negative bacteria, is associated with gastric MALT lymphomas.
• Hepatitis C virus is associated with splenic and nodal marginal zone lymphomas.

Pathology and Classification

• Non-Hodgkin lymphomas are neoplasms derived from the monoclonal proliferation of malignant B or T lymphocytes and their precursors.
• About 85% to 90% of NHLs in the United States are of B-cell origin.
• The classification of NHLs has evolved over the past five decades, with advances in immunology and genetics allowing for recognition of previously unrecognized subtypes.

WHO Classification

• WHO classification categorizes lymphoid malignancies into two major categories: B-cell lymphomas and T-cell (and natural killer cell) lymphomas.
• Precursor B- and T-Cell Neoplasms are categorized into two subtypes: Precursor B-lymphoblastic leukemia/lymphoma and Precursor T-lymphoblastic leukemia/lymphoma.

Lymph Nodes and Lymphoma

• Lymph nodes are small, BB-sized lymphoid organs that filter interstitial lymphatic fluid from the body's tissues.
• Lymph nodes provide an environment for the interaction of debris with antigen-presenting cells (APCs) and other immune cells.
• Lymphoma is cancer of the lymphatic system, arising from malignant transformation of immune cells.
• The primary cancerous cell of origin is the lymphocyte, often resulting in overlap between lymphomas and lymphoid leukemias.

Types of Lymphoma

• Hodgkin lymphoma is named after Thomas Hodgkin, who first described it in 1832.
• Hodgkin lymphoma is characterized by the presence of Reed-Sternberg cells.
• Non-Hodgkin lymphoma (NHL) is characterized by the presence of B- or T-cell lymphocyte markers.

Signs and Symptoms

• About 25% of patients present with fever, night sweats, and/or weight loss, known as B symptoms.
• Patients may also experience nonspecific symptoms including malaise, pruritus, fatigue, and development of pain after alcohol consumption.
• Most patients with Hodgkin lymphoma present with a painless, rubbery, enlarged lymph node in the supradiaphragmatic area.

Diagnosis, Staging, and Prognostic Factors

• Diagnostic and staging procedures are based on recommendations made at the Ann Arbor and Cotswolds conferences and new scientific advances.
• The diagnosis and pathologic classification of Hodgkin lymphoma can only be made by review of a biopsy by an expert hematopathologist.
• Routine laboratory tests, including complete blood count, complete metabolic panel, lactate dehydrogenase (LDH), and erythrocyte sedimentation rate (ESR), will be helpful in treatment planning and aid in prognosis.