What is lymphoma?

What is Lymphoma

Lymphoma is a malignancy of the lymphatic system involving abnormal proliferation of lymphocytes (white blood cells) within lymph nodes and lymphoid tissues. 1

Main Classification

Lymphoma is divided into two major categories based on distinct pathologic and clinical features:

Hodgkin Lymphoma (HL)

• Accounts for approximately 10% of all lymphomas 2
• Characterized by the presence of Reed-Sternberg cells in an inflammatory background 1
• Two main subtypes exist:
  • Classical Hodgkin Lymphoma (CHL): Represents 95% of HL cases in Western countries 1, 3
  • Nodular Lymphocyte-Predominant Hodgkin Lymphoma (NLPHL): Represents 5% of HL cases, characterized by lymphocyte-predominant cells (sometimes called "popcorn cells") rather than Reed-Sternberg cells 1, 3

Non-Hodgkin Lymphoma (NHL)

• Accounts for approximately 90% of all lymphomas 2
• Most NHL (90%) are of B-cell origin, with the remainder being T-cell or natural killer (NK) cell types 2
• Diffuse large B-cell lymphoma (DLBCL) is the most common subtype, representing 30-40% of adult NHL 1, 3
• Other common subtypes include follicular lymphoma (22%), small lymphocytic lymphoma/chronic lymphocytic leukemia (6%), mantle cell lymphoma (6%), and MALT lymphoma (5%) 1

Epidemiology

• Bimodal age distribution: Most patients are diagnosed between ages 15-30 years, with a second peak in adults aged 55 years or older 1
• In 2020, an estimated 8,480 people were diagnosed with HL in the United States with 970 deaths 1
• NHL incidence has increased worldwide by approximately 30% in the 5 years prior to 2010 3, 4
• Slightly more men than women are diagnosed with HL 3

Clinical Presentation

Lymphoma typically presents as painless lymphadenopathy (enlarged lymph nodes) 5

Key clinical features include:

• Systemic "B symptoms" occur in more advanced disease: fever, unexplained weight loss >10% body weight, and drenching night sweats 1, 5
• T-cell lymphoblastic lymphoma (T-LBL) characteristically presents with a mediastinal mass and pleuro-pericardial effusions 6

Prognosis

HL is now curable in at least 80% of patients, with 5-year survival rates unmatched by any other cancer over the past 4 decades 1

• Aggressive lymphomas, while more dangerous if untreated, are more chemosensitive due to higher cell proliferation rates and are managed with curative intent 2
• Indolent lymphomas are largely incurable, requiring balance between quality of life and treatment toxicity 2

Important Clinical Considerations

Long-term follow-up after treatment completion is essential to monitor for potential late effects of therapy, including secondary cancers (lung, breast), cardiotoxicity, and neuropathy 1, 5

Patients require immunization with 13-valent pneumococcal conjugate vaccine followed by 23-valent pneumococcal polysaccharide vaccine at least 8 weeks later, as lymphoma causes immunosuppression 5