Hodgkin Lymphoma Classification-From Historical Concepts to Current Refinements

Area of Science:

• Hematopathology and Oncology
• Immunology and Molecular Biology

Background:

• The classification of Hodgkin lymphoma (HL) has evolved from purely histological observations to an integrated approach.
• Current HL classification incorporates morphological, immunophenotypic, molecular, and clinical features, as updated in the WHO 5th Edition.
• Hodgkin and Reed-Sternberg (HRS) cells are the diagnostic hallmark of classic HL (cHL), originating from B lymphocytes.

Purpose of the Study:

• To review the integrated classification system for Hodgkin lymphoma.
• To highlight the distinct features of classic HL subtypes and nodular lymphocyte-predominant HL (NLPHL).
• To emphasize the importance of HRS cell identification and the tumor microenvironment in HL.

Main Methods:

• Review of current classification systems for Hodgkin lymphoma.
• Integration of morphological, immunophenotypic, molecular, and clinical data.
• Analysis of Hodgkin and Reed-Sternberg (HRS) cell characteristics and the immune microenvironment.

Main Results:

• The integrated approach refines the diagnosis and understanding of HL subtypes, including cHL and NLPHL.
• Hodgkin and Reed-Sternberg (HRS) cells are critical diagnostic markers, distinct from typical B-cell phenotypes.
• HL is characterized by rare malignant cells, a high curability rate, and a significant immune cell microenvironment.

Conclusions:

• Accurate HL classification relies on a multidisciplinary approach integrating diverse pathological and clinical data.
• Understanding HL's unique cellular and microenvironmental features is crucial for diagnostic refinement and therapeutic guidance.
• Further exploration of immunologic and genetic biomarkers holds promise for improving HL classification, prognosis, and treatment.