Morphologic, immunophenotypic, and molecular evaluation of bone marrow involvement in non-Hodgkin's lymphoma
P L Crotty1, B R Smith, G Tallini
1Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06520-8070, USA.
Insights
Diagnosing non-Hodgkin's lymphoma (NHL) marrow involvement uses morphology, flow cytometry (FCM), and PCR. FCM is superior for B-cell neoplasia, while PCR aids T-cell neoplasia diagnosis, detecting disease missed by morphology.
Area of Science:
- Hematology
- Oncology
- Molecular Diagnostics
Background:
- Marrow involvement diagnosis in non-Hodgkin's lymphoma (NHL) traditionally relies on morphology.
- Immunophenotyping by flow cytometry (FCM) and molecular techniques like polymerase chain reaction (PCR) are increasingly used to support diagnosis.
Purpose of the Study:
- To compare the diagnostic sensitivity of morphology, FCM, and PCR for detecting marrow involvement in NHL.
- To evaluate the utility of FCM and PCR in identifying clonality in B-cell and T-cell neoplasms.
Main Methods:
- Morphological assessment of bone marrow biopsies.
- Immunophenotyping by flow cytometry (FCM).
- Consensus primer polymerase chain reaction (PCR) for antigen receptor gene rearrangements.
Main Results:
- Concordance between FCM and PCR was observed in 78% of cases.
- FCM demonstrated higher sensitivity (97.5%) than PCR (67.5%) for B-cell neoplasia.
- PCR showed higher sensitivity (71.4%) than FCM (28.6%) for T-cell neoplasia.
- FCM and PCR detected clonality in the absence of morphologically apparent disease.
Conclusions:
- Morphology remains crucial for NHL marrow involvement evaluation.
- FCM is the preferred method for detecting clonality in B-cell neoplasms.
- PCR is a valuable adjunct for diagnosing marrow involvement in T-cell neoplasms, especially when morphology is inconclusive.
Abstract:
The diagnosis of marrow involvement in non-Hodgkin's lymphoma (NHL) relies on morphology with support from immunophenotyping by flow cytometry (FCM). We assessed the relative sensitivity of morphology, FCM, and consensus primer polymerase chain reaction (PCR) of antigen receptor genes in the detection of marrow involvement. In 78 of 100 (78%) cases, there was concordance between FCM and PCR. FCM detected more cases of clonality in B-cell neoplasia. There were 40 cases with objective evidence of involvement by B-cell neoplasia. In this group, FCM had a sensitivity of 97.5% (39 of 40); PCR had a sensitivity of 67.5% (27 of 40). In contrast, PCR had a sensitivity of 71.4%, and FCM a sensitivity of 28.6%, in T-cell neoplasia. In all 12 cases with involvement detected by biopsy, there was objective evidence of clonality. However, clonality was detected in four of seven patients with chronic lymphocytic leukemia and in five of eight patients with T-cell neoplasia in the absence of morphologically detectable disease. Clonality was identified in only one of seven patients with B-cell lymphoma in which the biopsy was interpreted as "suspicious but not diagnostic of involvement." We conclude that morphology remains of central importance in the evaluation of marrow involvement in NHL. We show that FCM and PCR identify involvement in the absence of morphologically apparent disease. In B-cell neoplasms, FCM remains the method of choice for the detection of clonality. PCR for T-cell receptor gene rearrangements may be an important adjunct to the diagnosis of marrow involvement in patients with T-cell neoplasms.
