Flow cytometry in the bone marrow staging of mature B-cell neoplasms
A Stacchini1, A Demurtas, L Godio
1Flow Cytometry Unit, Molinette Hospital, Turin, Italy. astacchini@molinette.piemonte.it
Insights
Flow cytometry (FC) and morphology agree on bone marrow involvement in most B-cell lymphomas. However, FC is more sensitive for minimal disease, though its clinical relevance in staging B-non-Hodgkin
Area of Science:
- Hematology
- Oncology
- Immunology
Background:
- Flow cytometric (FC) analysis of bone marrow is common in hematolymphoid disorders.
- Its role in staging B-non-Hodgkin's lymphoma (B-NHL) and B-cell lymphoproliferative diseases requires definition.
Purpose of the Study:
- To objectively evaluate the utility of FC in detecting bone marrow involvement in B-cell malignant neoplasms.
- To compare the diagnostic performance of FC with traditional morphologic examination.
Main Methods:
- Retrospective analysis of 54 staging and 156 restaging bone marrow biopsies and aspirates from 185 patients.
- Independent review of morphologic examination and FC results to assess bone marrow involvement.
Main Results:
- Morphology and FC results agreed in 83.8% of cases (176/210).
- Discrepancies occurred in 14.2% (30/210), with morphology positive in 11.9% (25/210) and FC negative.
- FC detected bone marrow involvement in 2.4% (5/210) of histologically negative biopsies.
Conclusions:
- Neither morphology nor FC alone is sufficient for detecting all bone marrow involvement in B-lymphoid neoplasms.
- FC is more sensitive than histology for minimal B-NHL disease (<5% neoplastic infiltrates).
- The clinical significance of FC-detected minimal disease in lymphoma staging needs further investigation.
Background:
Even though flow cytometric (FC) analysis of bone marrow aspirates is often performed in hematolymphoid disorders at diagnosis and during disease monitoring, its role has not been defined during the staging of B-non-Hodgkin's lymphoma (B-NHL) and B-cell lymphoproliferative diseases. The goal of this study was to provide an objective evaluation of how FC might help in the detection of bone marrow involvement by the different types of B-cell malignant neoplasms.
Methods:
Fifty-four staging and 156 restaging bone marrow biopsies and bone marrow aspirates, obtained from 185 consecutive patients, were analyzed retrospectively. The results of the morphologic examination and FC were reviewed independently, and their ability to detect bone marrow involvement was compared.
Results:
FC and morphology agreed in 176 cases (83.8%), i.e., both showed 77 positive cases and 99 negative ones. Discrepant results were obtained in 30 cases (14.2%) in which morphologic examination showed 25 (11.9%) positive cases, whereas FC showed no evidence of disease. FC detected involvement in five cases (2.4%) in the presence of a histologically negative bone marrow biopsy. All morphologically undetermined bone marrow cases (four) were negative by FC.
Conclusions:
Neither morphologic examination nor FC alone is adequate for the detection of all cases of B-lymphoid neoplasm bone marrow involvement. FC failed to detect bone marrow involvement in those B-NHL cases having focal paratrabecular infiltration, but proved to be more sensitive than histology in detecting small clonal B-cells in B-NHL, which demonstrated fewer than 5% neoplastic infiltrates. The clinical relevance of minimal disease detected by FC alone needs further evaluation because staging of lymphomas currently is based only on morphologic data.
