Hodgkin Lymphoma

Basics

Description

B lineage malignant lymphoid neoplasm. Typically presents with painless lymphadenopathy, often cervical (70–80%) or supraclavicular (25%). Mediastinal mass present in 50%. Constitutional symptoms (e.g., fatigue, fever, night sweats, weight loss, cough, pruritus) may or may not be present. Constitutional symptoms sometimes precede development of lymphadenopathy.

Epidemiology

  • Represents 7% of childhood cancer
  • 11.7 cases/million/y age <20 years
  • Most common cancer for ages 15 to 19 years
  • Rarely seen in children age <5 years
  • M > F age <15 years
  • F > M age 15 to 19 years
  • Bimodal age distribution in adults: early peak mid/late 20s; late peak > age >50 years

Risk Factors

  • Few known risk factors include the following:
    • Immune deficiency (e.g., HIV infection)
    • Autoimmune disorders
    • Lower socioeconomic status for childhood form (age 14 years or younger)
    • Higher socioeconomic status for young adult form
  • Decreased risk if
    • Multiple older siblings
    • Exposure to common infections in preschool

Genetics

  • Familial Hodgkin lymphoma (HL) rare, accounting for 4.5% of cases
  • Familial cases may reflect
    • Genetic influences, including inherited immunodeficiency states
    • Environmental factors
    • Exposure to viruses

Pathophysiology

  • Reed-Sternberg cells, a clonal population of large binucleate cells arising from B cells, are the malignant cells in HL. Surface antigen expression includes CD30 but not CD20.
  • Only 1% of cells in involved nodes are Reed-Sternberg cells and morphologic variants; the rest are inflammatory cells: lymphocytes, macrophages, fibroblasts, plasma cells, eosinophils.
  • Two clinically distinct subtypes of HL recognized:
    • Classical HL (90–95% of cases)
      • Nodular sclerosing
      • Mixed cellularity
      • Lymphocyte depleted
      • Lymphocyte rich
    • Nodular lymphocyte predominant (5–10% of cases; treated differently from classical HL. See National Comprehensive Cancer Network (NCCN) guidelines for treatment recommendations.)

Etiology

  • Cause unknown
  • Association between Epstein-Barr virus (EBV) infection and HL: 20–50% of patients with classical HL have monoclonal or oligoclonal proliferation of EBV-infected cells.

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