Precise diagnosis of bone marrow infiltration in B-cell non-Hodgkin lymphoma: a multimodal molecular, morphologic, and immunohistochemical approach

Introduction
B-cell Non-Hodgkin lymphoma (B-NHL) commonly causes nodular bone marrow (BM) invasion, which makes it hard to diagnose. This study looks at how much more valuable it is to combine immunoglobulin heavy chain complementarity-determining region 3 clonality testing with morphology and immunohistochemistry (IHC) in identifying the difference between benign and malignant infiltrates.


Patients and methods
This study is a retrospective review of 52 BM biopsies performed on B-NHL patients between January and August 2024. Cases were classified by morphology/IHC (malignant, benign, or suspicious) and compared with PCR results.


Results
Morphology/IHC alone identified 36.5% (19/52) as malignant, 19.2% (10/52) as benign, and 44.2% (23/52) as suspicious. PCR confirmed clonality in 43% (10/23) of suspected cases, reclassifying more 15.4% (8/52) as malignant overall. Morphology/IHC exhibited 76.5% sensitivity but only 50% specificity compared with PCR.


Conclusion
Integrating PCR with morphology/IHC significantly improves diagnostic accuracy, particularly for indeterminate cases. This multimodal approach should be standardized in B-NHL BM evaluation.