Lymphoma Oncology Basics

Lymphomas are a diverse group of malignant neoplasms arising from lymphocytes within the lymphatic system. The lymphatic system is a network of lymph nodes, lymphatic vessels, the spleen, thymus, tonsils, and bone marrow that functions as a critical component of the immune system. Lymphomas are broadly classified into two major categories: Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), which differ in their cellular origin, pathological features, clinical behavior, and treatment approach. Hodgkin lymphoma is characterized by the presence of the Reed-Sternberg cell, a large binucleated or multinucleated cell with prominent eosinophilic nucleoli that give it a distinctive owl-eye appearance on microscopy. Reed-Sternberg cells are derived from germinal center B lymphocytes that have undergone malignant transformation. These cells typically comprise only 1-2% of the tumor mass; the remainder consists of a reactive inflammatory infiltrate of normal T cells, B cells, macrophages, eosinophils, and fibrotic tissue. Hodgkin lymphoma has a bimodal age distribution with peaks in young adults (15-35 years) and older adults (over 55 years), and it typically spreads in a predictable, contiguous pattern from one lymph node group to adjacent...