Utility of flow cytometry in subtyping composite and sequential lymphoma

Area of Science:

• Hematology
• Oncology
• Immunophenotyping

Background:

• Composite lymphoma (CL) and sequential lymphoma (SL) involve multiple distinct lymphoma variants.
• Previous studies on flow cytometry's utility in CL/SL are limited.

Purpose of the Study:

• To evaluate the utility of flow cytometry immunophenotyping in characterizing CL and SL.
• To define the role of flow cytometry in differentiating lymphoma subtypes within CL and SL cases.

Main Methods:

• Retrospective review of four CL/SL cases from two institutions.
• Morphological evaluation of H&E-stained tissue sections and subtyping using REAL criteria.
• Immunophenotyping using two-color flow cytometry and paraffin-section immunostains.

Main Results:

• Flow cytometry identified distinct monoclonal B-cell populations in Case 1 (follicle center and marginal zone CL).
• Case 2 demonstrated consistent CD5-/CD10-/CD19+/kappa+ cells in both lymphoplasmacytoid and Hodgkin's disease components.
• Distinct immunophenotypes were observed for the different lymphoma components in Cases 3 and 4, including T-cell and B-cell lymphomas.

Conclusions:

• Flow cytometry is a potentially useful adjunct for characterizing composite and sequential lymphomas.
• Immunophenotyping can help differentiate the distinct lymphoma components in CL and SL.
• Further studies are warranted to establish flow cytometry as a standard tool for CL/SL evaluation.