Bone Marrow Immunohistochemistry and Flow Cytometry in the Diagnosis of Malignant Hematologic Diseases With Emphasis on Lymphomas: A Comparative Retrospective Study.

We aim to evaluate the degree of agreement between immunohistochemistry (IHC) and flow cytometry (FC) in the diagnosis of malignant hematologic diseases, mainly lymphomas. A total of 260 bone marrow biopsies, 255 bone marrow aspirates, and 5 other suspensions of 260 patients used for diagnosis of a hematologic malignancy between 2009 and 2012 with both, IHC and FC, were retrospectively analyzed. Overall there is a substantial degree of agreement (κ=0.69) between IHC and FC. Chronic lymphocytic leukemia/small lymphocytic lymphoma, mature T-cell neoplasms, acute leukemias, and myelodysplastic syndromes had the highest concurrence rates (>80%). In nonconcordant cases, an IHC provided diagnosis in 25.4%, and an FC in 4.6%. Lymphomas were diagnosed by an IHC only in 51% of the cases. Both methods have good concurrence rates and are complementary. An IHC has the advantage of combining markers, morphology, and tissue immunoarchitecture, which is beneficial in the diagnosis of lymphomas. An FC is required in leukemias as it is faster and plays an important role in minimal residual disease.