A Comparison of Bone Marrow Flow Cytometry Findings and Bone Marrow Biopsy İmmunohistochemical Findings in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Methodological Study

Abstract

Introduction: The diagnosis of chronic lymphocytic leukemia/ small lymphocytic lymphoma (CLL/SLL), which also includes atypical forms, can be very difficult. The aim of this study is to compare immunohistochemical (IHC) and flow cytometric (FC) immunophenotyping methods in the CLL/SLL, the most common mature B-cell leukemia/lymphoma of adults, in bone marrow biopsy. In these two methods, it is to determine the minimum panels that can differentiate CLL/SLL from other mature B-cell leukemia/lymphomas. Material and Method: The study included 68 adult patients diagnosed with mature B cell leukemia/lymphoma. Final diagnoses were made on the basis of peripheral smear, bone marrow aspirate, bone marrow biopsy, IHC and FC analysis, clinical and genetic studies. Cell counts, final diagnosis and immunophenotyping were compared with both methods. Cytogenic findings were evaluated. The sensitivity, specificity, positive and negative predictive values of IHC and FC results for CLL/SLL were calculated. Results: CLL/SLL was diagnosed in 64.7% of the cases and non- CLL/SLL in 35.29% of the cases. The median age was 66.50 years, 69.18% male and 30.82% female. The diagnosis compatibility in FC and IHC was found to be highest in hairy cell leukemia/lymphoma with 100%, and in CLL/SLL with 90%. In other lymphomas, a definitive diagnosis could only be made with biopsy. Immunophenotyping made with CD23+CD43+CD5+LEF-1 in the bone marrow biopsy showed a sensitivity of 95.45% (range, 84.53-99.44%) and a specificity of 100.00% (range, 85.75-100.00%) for CLL/SLL. Immunophenotyping made with CD23+CD43+CD5+CD200+ in FC showed a sensitivity of 100.00% (range, 91.96-100.00%) and a specificity of 82.61% (range, 61.22-95.05%) for CLL/SLL. Conclusion: This was the most extensive study to have compared immunophenotyping in IHC and FC in bone marrow biopsies of mature B cell leukemia/lymphoma. The addition of LEF-1 to the CD23(+), CD43(+), CD5(+) panel in IHC and the addition of CD200 to the same panel in FC will be extremely helpful in the differential diagnosis of typical/atypical CLL/SLL from mature B cell leukemia/lymphoma.