Can a specifically-aimed pathologic classification overcome the difficulties in defining HIV-associated lymphomas?

Area of Science:

• Hematology
• Oncology
• Immunology

Background:

• High-grade B-cell lymphomas in HIV-infected patients display pleomorphic features, complicating classification using pre-AIDS epidemic non-Hodgkin's lymphoma (NHL) systems.
• Established classifications struggle to precisely define these lymphomas due to overlapping histologic subtypes.

Purpose of the Study:

• To investigate and categorize HIV-associated systemic lymphomas.
• To develop a more accurate pathological classification for HIV-associated lymphomas, addressing diagnostic difficulties.

Main Methods:

• Morphological and immunophenotypic investigation of 114 NHL and 25 Hodgkin's disease (HD) cases in HIV-infected patients over nine years.
• Adoption of the International Working Formulation (WF) for NHL, the updated Kiel Classification, and morphologic variants of high-grade B-cell NHL.
• Attempted pathological categorization based on recognition of "blastic" and "anaplastic" cell groups, incorporating pathogenetic aspects.

Main Results:

• A new pathological categorization of HIV-associated systemic lymphomas into "blastic" and "anaplastic" cell groups was proposed.
• This categorization aids in more accurate definition of subtypes like small non-cleaved cell (Burkitt) and immunoblastic lymphomas.
• Clear differentiation of "anaplastic" cell lymphomas, including anaplastic large cell (CD30/Ki-1+) lymphomas and potentially some HD cases, from polymorphic "blastic" cell lymphomas is emphasized.

Conclusions:

• The proposed categorization provides a more detailed histopathologic description of HIV-associated lymphomas.
• It facilitates diagnostic differentiation, particularly between "anaplastic" and immunoblastic lymphomas.
• This approach addresses the limitations of existing classifications for lymphomas in HIV-infected individuals.