Assessment of bone marrow involvement in non-Hodgkin’s lymphomas: comparison between histology and flow cytometry

Utility of leukocyte-associated immunoglobulin-like receptor-1 (CD305) in flow cytometric detection of minimal bone marrow involvement by B-cell non-Hodgkin lymphoma

Multicolor flow cytometry (MFC) is crucial in detecting occult or minimal bone marrow (BM) involvement by non-Hodgkin lymphomas (NHL), which may not be detected using trephine biopsy or imaging studies. Detection of low-level BM involvement can be challenging without definite immunophenotypic aberrancies. We studied the utility of CD305 in MFC detection of minimal BM involvement by B-NHL, especially in the absence of aberrancies by commonly used markers. The study included 1084 consecutive BM samples submitted for the staging of B-NHLs (excluding CLL) over two years. Samples were studied for morphological, immunophenotypic, and histopathological assessment. MFC studies were performed using 10-13 color MFC, including CD305-antibody (clone, DX26). Minimal BM involvement was defined with a cutoff of ≤10% lymphoma cells in viable cells on MFC assessment. Of 1084, 148 samples revealed overt morphological involvement by B-NHL and were excluded from analysis. BM samples of 172/936 patients were morphologically negative but revealed involvement using MFC independently. Corresponding trephine biopsy involvement was detected in only 79/172 (45.9%) patients. On MFC, 23/172 samples showed BM involvement with >10% lymphoma cells, and 149/172 (86.6%) samples revealed minimal involvement. In 54/149 (36.24%) samples, lymphoma cells were detected only with aberrant loss of CD305 expression. In 78 of the remaining 95 samples (82.1%), it provided an immunophenotypic aberrancy addition to other markers and supported the results. CD305 is a highly useful marker in the flow cytometric assessment of minimal BM involvement by B-NHL. MFC is a superior modality to trephine biopsy in detecting low-level BM involvement.

Aberrant expression of CD54 detected by flow cytometry is a characteristic of B-lymphoma cells in bone marrow specimens

Background

Flow cytometry (FC) is a popular method to detect bone marrow (BM) involvement in patients with B-cell non-Hodgkin lymphoma (B-NHL). The majority of screen panels of FC still rely on finding monoclonal B-cells, e.g., B-cells with immunoglobin (Ig) light-chain restriction, which has many limitations. Therefore, exploring new markers is warranted.

Methods

A total of 52 cases of B-NHL with BM involvement were collected. The median age was 60 years. Out of these 52 cases, 34 were male, and 18 were female. A 10-color FC panel was used to detect the expression of CD54 on lymphoma cells. The expression of CD54 was calculated as the mean fluorescence index ratio (MFIR) and was described as the mean ± standard error of the mean (SEM).

Results

Up to 18/52 (34.62%) of BM specimens abnormally expressed an increased level of CD54, including 1/10 cases of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), 9/13 cases of mantle cell lymphoma (MCL), 2/14 cases of follicular lymphoma (FL), 5/9 cases of marginal zone lymphoma (MZL), and 1/3 cases of high-grade B-NHL (HG B-NHL). The expression level of CD54 was significantly increased in MCL cases (53.41 ± 11.04) compared with CLL/SLL cases (11.66 ± 2.79) and FL cases (13.49 ± 2.81). The lowest percentage of CD54-positive B-cells attained 0.13%. In 5/9 cases of MZL and 1/3 cases of HG B-NHL, increased expression of CD54 was the only abnormal immunophenotype detected besides Ig light-chain restriction. No aberrant CD54 expression was identified by FC in lymphoplasmacytic lymphoma (LPL) (0/2) and Burkitt lymphoma (BL) (0/1) cases. Aberrant expression of CD54 was not related to plasma cell differentiation.

Conclusion

Lymphoma cells, especially in MCL and MZL cases, frequently show increased expression of CD54. Such aberrant expression is not related to plasma cell differentiation. We highly recommend adding CD54 to the FC screening panel to detect BM involvement in patients with B-NHL.

Bone Marrow Involvement by Aggressive B Cell Lymphoma Undetected by Aspirate Immunophenotyping

Staging for newly diagnosed lymphoma is an essential diagnostic step aimed at not only estimating prognosis but also refining the ensuing therapeutic pathway. Bone marrow is routinely sampled for this reason. Morphological assessment of the bone marrow aspirate and biopsy remains the gold standard approach. Nonetheless, ancillary testing such as aspirate immunophenotyping is also used with the aim to increase sensitivity and add diagnostic utility, e.g., to provide proof of clonality. Both of these techniques are fraught with shortcomings and concordance is often not perfect. Cases of infiltrative lymphoma identified by morphology, and not detected by flow cytometry highlights the dangers of over reliance on aspirate immunophenotyping. Under sampling, disintegration, fibrosis and hemodilution are but some causes of a false negative flow result. Therefore, neither technique is sufficient in isolation. In this submission, a case of such a discrepancy is presented as an introduction for review of literature that highlights this phenomenon.

CD43 in the malignant flow cytometry laboratory in 2020

Objectives: CD43 can be useful in routine flow cytometry. We conducted a systematic review aiming to describe when CD43 is used by flow cytometry in malignant hematology and to determine its value in these settings. Methods: Systematic review of MEDLINE (search 'CD43' AND 'flow cytometry,' starting in 2010). Results: Twenty-one of 103 entries retrieved were included in this systematic review. CD43 is used in three settings: 1) in the classification of mature B cell lymphoproliferative disorders, 2) as part of a strategy to quantify residual disease in chronic lymphocytic leukemia (CLL) and 3) to help classify CD10-positive B cell populations. In this section, the published data is summarized, the clinical usefulness in each of these settings is evaluated and illustrative cases are shown. Conclusion: CD43 has a growing role in the diagnosis and management of B cell malignancies; it has become essential for the classification of B cell lymphoproliferative disorders and may be of help in the differential diagnosis of CD10-positive lymphomas by FC. It is also required for optimal quantification of CLL residual disease, which will soon be used to guide therapeutic decisions.

Systematic review of staging bone marrow involvement in B cell lymphoma by flow cytometry

The clinical relevance of flow cytometry (FC)-based bone marrow involvement (BMI) in B cell non-Hodgkin lymphoma (B-NHL) is not well established. We conducted a systematic review of MEDLINE regarding the use of FC to establish BMI in B-NHL to determine the prevalence of BMI by FC, to understand the interrelation between FC and bone marrow biopsy (BMB), and to explore the prognostic impact of BMI by FC. Relevant exclusion criteria included publication before 2010. Eleven publications (of 18 screened) were included, with 2803 patients involved. Relevant methodological details were often unreported. The prevalence of BMI by FC varied based on histological subtypes included. The median kappa agreement between BMB and FC was 0.68 and the type of discordance (FC+/BMB- vs. FC-/BMB+) was highly variable across studies. Only 4 studies (all in diffuse large B cell lymphoma) assessed the prognostic impact of BMI by FC. Two found a worse prognosis for patients with FC+/BMB- than those without BMI. To conclude, studies assessing BMI by FC are retrospective, of low methodological quality and with heterogeneous findings.

High proportion of anergic B cells in the bone marrow defined phenotypically by CD21(-/low)/CD38- expression predicts poor survival in diffuse large B cell lymphoma

Background

Diffuse large B cell lymphoma (DLBCL) is the commonest lymphoma that is highly aggressive where one-third of the patients relapse despite effective treatment. Interaction between the lymphoma cells and the non-clonal immune cells within the bone marrow microenvironment is thought to play a critical role in the pathogenesis of DLBCL.

Methods

We used flow cytometry to characterize the proportion of B cell subpopulations in the bone marrow (N = 47) and peripheral blood (N = 54) of 75 DLBCL patients at diagnosis and study their impact on survival.

Results

Anergic B cells in the bone marrow (BM), characterized as having CD21(−/low)/CD38- expression, influenced survival with high numbers (defined as > 13.9%) being associated with significantly shorter overall survival (59.7 months vs 113.6 months, p = 0.0038). Interestingly, low numbers of anergic B cells in the BM (defined as ≤13.9%) was associated with germinal center B cell type of DLBCL (p = 0.0354) that is known to have superior rates of survival when compared to activated B cell type. Finally, Cox regression analysis in our cohort of patients established that the inferior prognosis of having high numbers of anergic B cells in the bone marrow was independent of the established Revised International Prognostic Index (R-IPI) score.

Conclusions

High proportion of anergic B cells in the BM characterized by CD21(−/low)/CD38- expression predicts poor survival outcomes in DLBCL.

Diagnostic and Clinical Impact of Staging 18F-FDG PET/CT in Mantle-Cell Lymphoma: A Two-Center Experience

INTRODUCTION

The diagnostic accuracy of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in staging mantle-cell lymphoma has not yet investigated. The aim of this 2-center retrospective study was to investigate the utility of ¹⁸F-FDG PET/CT in assessing nodal, splenic, bone marrow (BM), and gastrointestinal (GI) disease compared to CT, BM, and GI endoscopy; and to assess its clinical impact.

PATIENTS AND METHODS

One hundred twenty-two patients with histologically proven mantle-cell lymphoma were included. PET/CT BM findings were considered positive if isolated/multiple focal uptake in the BM not explained by benign findings and/or diffuse BM uptake higher than liver with/without focal uptakes were present. PET/CT findings were considered positive for GI involvement in the presence of isolated/multiple focal uptake in the GI organ.

RESULTS

All patients had positive PET/CT showing the presence of at least one hypermetabolic lesion, with the exception of one case. PET/CT results, compared to CT, detected more nodal and/or splenic lesions in 26 patients. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT for BM were 52%, 98%, 97%, 65%, and 74%; for GI 64%, 91%, 69%, 90%, and 85%; and for GI excluding diabetic patients, 78%, 92%, 72%, 94%, and 89%. PET/CT permitted upstaging of 21 cases and downstaging of 2.

CONCLUSION

¹⁸F-FDG PET/CT showed excellent detection rate in nodal and splenic disease-a rate better than CT. For BM and GI evaluation, in order to reach good accuracy, the selection of patients and the use of specific criteria for evaluation of these organs seems to be crucial. Moreover, PET/CT altered the management and therapeutic approach in about 20% of patients.

Follicular Lymphoma Diagnostic Caveats and Updates

CONTEXT.—

Follicular lymphoma is a common small B-cell lymphoma, likely to be encountered by any practicing pathologist, regardless of specialty. Although the features of typical follicular lymphoma are well known and in most instances easily identifiable, there are lesser-appreciated morphologic appearances that can raise alternative diagnostic possibilities. The limited tissue available in core needle biopsies can make it additionally challenging to thoroughly evaluate those features in the context of architecture. Furthermore, ancillary testing including immunohistochemistry and molecular/genetic analysis do not always show classic findings and may pose additional challenges to interpretation.

OBJECTIVES.—

To review the morphologic features of follicular lymphoma with a discussion of morphologic variants and mimics; to discuss pitfalls of ancillary testing and provide the practicing pathologist with an appropriate context for interpretation of immunohistochemical and molecular/genetic studies when follicular lymphoma is part of the differential diagnosis; and to propose diagnostic strategies when there is limited tissue for evaluation.

DATA SOURCES.—

We used examples of follicular lymphoma from our institution as well as a review of the literature, with a focus on the diagnostic aspects that are broadly relevant to a general pathology practice.

CONCLUSIONS.—

Follicular lymphoma can occasionally present with atypical morphologic, immunohistochemical, or molecular/genetic features. In particular, those findings can be difficult to interpret in the setting of a limited tissue sample. Awareness of those possibilities will help guide the pathologist to a more accurate and precise diagnosis.

Positron Emission Tomography-based Analysis Can Accurately Predict Bone Marrow Involvement With Mantle Cell Lymphoma

INTRODUCTION

Mantle cell lymphoma (MCL) is a rare subtype of non-Hodgkin lymphoma and requires both bone marrow biopsy and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) to correctly stage the disease at diagnosis. However, accurate identification of bone marrow involvement by lymphoma on FDG PET/CT scans has not been previously demonstrated. We hypothesized that a voxel-based analysis of the iliac bones on the FDG PET/CT scan might provide insight into bone marrow involvement.

PATIENTS AND METHODS

A retrospective cohort study of patients with a diagnosis of MCL who had undergone both single iliac bone marrow biopsy and FDG-PET/CT scan from 1 study site were included in the development phase (n = 10). An additional 12 patients from a second institution were included in the validation phase. Using a semiautomated workflow, a voxel-based data set of FDG uptake within the bilateral iliac bones was captured for each patient. In the development phase, empirical receiver operating characteristic curves for each data set were fit. We then identified the standardized uptake value (SUV) threshold cutpoints at which the sensitivity and specificity were optimized to 100%. In the validation phase, we evaluated the performance of these candidate SUV threshold cutpoints in 15 additional patients from a second institution.

RESULTS

We found that 1 cutpoint, > 38% of voxels with activity < 0.95, outperformed all the other candidate cutpoints, correctly classifying all patients except for 1 (overall sensitivity, 100%; specificity, 87.5%).

CONCLUSION

The ability to correctly identify bone marrow involvement using FDG PET/CT-based voxel analysis provides promise as a novel noninvasive method of accurate staging.

Assessment of bone marrow involvement in patients with lymphoma: report on a consensus meeting of the Korean Society of Hematology Lymphoma Working Party

In September 2011, the Korean Society of Hematology Lymphoma Working Party held a nationwide conference to establish a consensus for assessing bone marrow (BM) involvement in patients with lymphoma. At this conference, many clinicians, hematopathologists, and diagnostic hematologists discussed various topics for a uniform consensus in the evaluation process to determine whether the BM is involved. Now that the discussion has matured sufficiently to be published, we herein describe the consensus reached and limitations in current methods for assessing BM involvement in patients with lymphoma.

[Diffuse large B-cell lymphoma with monoclonal immunoglobulin secretion]

AIM

to provide the clinical characteristics of patients with diffuse large B-cell lymphoma (DLBCL) with monoclonal immunoglobulin secretion and to evaluate the efficiency of intensified mNHL-BFM-90 or R-DA-EPOCH/R-HMA therapy programs in patients with Ig-secreting DLBCL.

SUBJECTS AND METHODS

A clinical trial was conducted in 93 patients with newly diagnosed DLBCL, among whom 21 (22.6%) were found to have monoclonal immunoglobulin secretion.

RESULTS

Ig-secreting DLBCL is shown to be characterized by bone marrow involvement (p<0.001), as well as generalized injury (Ann Arbor Stage 4) and a high risk in accordance with the international prognostic index (p=0.001 and p=0.026, respectively). Analysis of overall and event-free survival rates has indicated that the patients have a poor prognosis versus those with non-Ig-secreting DLBCL and poor prognostic factors even when implementing intensified therapy programs, such as mNHL-BFM-90 or R-DA-EPOCH/R-HMA ones.

CONCLUSION

The investigation has demonstrated that there is a high association of the secretion of monoclonal paraproteins with bone marrow involvement in DLBCL (p<0.001). The intensified therapy using the mNHL-BFM-90 and R-DA-EPOCH/R-HMA programs involving autologous hematopoietic stem cell transplantation also permits the patients with Ig-secreting DLBCL to achieve long-term sustained remissions in not all cases.

Laboratory Test Utilization Management: General Principles and Applications in Hematopathology

As the cost of health care continues to rise and reimbursement rates decrease, there is a growing demand and need to cut overall costs, enhance quality of services, and maintain as a top priority the needs and safety of the patient. In this article, we provide an introduction to test utilization and outline a general approach to creating an efficient, cost-effective test utilization strategy. We also present and discuss 2 test utilization algorithms that are evidence-based and may be of clinical utility as we move toward the future of doing the necessary tests at the right time.

Bone marrow flow cytometry in staging of patients with B-cell non-Hodgkin lymphoma

Background

Bone marrow biopsies are routinely performed for staging patients with B-cell non-Hodgkin lymphoma (NHL). In addition to histomorphological studies, ancillary tools may be needed for accurate diagnosis. We investigated the clinical utility of multiparameter flow cytometric examination of bone marrow aspirates.

Methods

A total of 248 bone marrow specimens from 232 patients diagnosed with B-cell NHL were examined. Monoclonal antibodies directed against CD19, CD20, CD10 (or CD5), and κ and λ immunoglobulins were used. Multi-stage sequential gating was performed to select specific cells of interest, and the results were compared with bone marrow histology.

Results

The concordance rate between histomorphology and flow cytometry was 91.5% (n=227). Eight cases (3.2%) were detected by flow cytometry alone and were missed by histomorphology analysis, and 6 of these 8 cases showed minimal bone marrow involvement (0.09-2.2%). The diagnosis in these cases included large cell lymphoma (n=3), mantle cell lymphoma (n=3), and mucosa-associated lymphoid tissue (MALT) lymphoma (n=2). Thirteen cases were histopathologically positive and immunophenotypically negative, and the diagnoses in these cases included diffuse large cell lymphoma (n=7), T-cell/histiocyte-rich large B-cell lymphoma (n=2), anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma (n=1), follicular lymphoma (n=1), MALT lymphoma (n=1), and unclassifiable lymphoma (n=1).

Conclusions

Multi-color flow cytometry can be a useful method for assessing bone marrow in staging NHL and also plays a complementary role, especially in detecting small numbers of lymphoma cells.

Prognostic value of bone marrow involvement by clonal immunoglobulin gene rearrangements in follicular lymphoma

Aims

We aimed to evaluate the prognostic value of routine use of PCR amplification of immunoglobulin gene rearrangements in bone marrow (BM) staging in patients with follicular lymphoma (FL).

Methods

Clonal rearrangements were assessed by immunoglobulin heavy and light-chain gene rearrangement analysis in BM aspirates from 96 patients diagnosed with FL and related to morphological detection of BM involvement in biopsies. In 71 patients, results were also compared with concurrent flow cytometry analysis.

Results

BM involvement was detected by PCR in 34.4% (33/96) of patients. The presence of clonal rearrangements by PCR was associated with advanced clinical stage (I–III vs IV; p<0.001), high FL International Prognostic Index (FLIPI) score (0–1, 2 vs ≥3; p=0.003), and detection of BM involvement by morphology and flow cytometry analysis (p<0.001 for both). PCR-positive patients had a significantly poorer survival than PCR-negative patients (p=0.001, log-rank test). Thirteen patients positive by PCR but without morphologically detectable BM involvement, had significantly poorer survival than patients with negative morphology and negative PCR result (p=0.002). The poor survival associated with BM involvement by PCR was independent of the FLIPI score (p=0.007, Cox regression). BM involvement by morphology or flow cytometry did not show a significant impact on survival.

Conclusions

Our results showed that routine use of PCR-based clonality analysis significantly improved the prognostic impact of BM staging in patients with FL. BM involvement by PCR was also an independent adverse prognostic factor.

A quality improvement assessment of multiple, concurrent flow cytometry analyses at a tertiary care center

INTRODUCTION

The utility of flow cytometry (FC) in diagnosis and staging of hematologic malignancy is controversial. Often, multiple specimens from the same patient are processed concurrently for FC analyses, alongside tissue for histomorphologic diagnosis.

METHODS

To assess the diagnostic utility of multiple, concurrent FC analyses, a 10-year retrospective review of cases with ≥2 concurrent specimens (from the same patient) submitted for FC was conducted. Light microscopic (LM) diagnoses were compared to FC findings, and the contribution of FC results to final diagnoses was examined.

RESULTS

Of 4058 specimens (predominantly lymph nodes, bone marrows, and oropharyngeal tissues) submitted for FC analyses, 129 (3.2%) represented cases with multiple (average: 2.19) concurrent FC analyses. All were accompanied by tissues and/or aspirates for LM examination. In 115 (89.1%) cases, multiple FC analyses were performed prior to morphologic examination. In 87.0% of those cases, ≥1 FC result(s) aligned with LM findings. In 15 (13.0%) cases where FC results differed from morphologic diagnoses, 86.7% (13/15) failed to detect an abnormal cell population by FC in the presence of a hematologic malignancy by LM. In one case (0.9%), FC detected a lymphoma, without morphologic evidence by LM.

CONCLUSIONS

Overall, multipart FC failed to demonstrate a significant contribution in initial diagnoses of hematologic malignancies compared with analysis of a single specimen.

Low-grade B-cell lymphoma presenting primarily in the bone marrow

Cases of low-grade B-cell lymphoma presenting primarily in the bone marrow are rare, and its clinicopathology remains unclear. We retrospectively examined patients with low-grade B-cell lymphoma presenting primarily in the bone marrow. Fourteen patients met the inclusion criteria, including 5 with lymphoplasmacytic lymphoma (LPL), 3 with chronic lymphocytic leukemia/small lymphocytic lymphoma, 2 with follicular lymphoma (FL), and 4 with low-grade B-cell lymphoma not otherwise specified (LGBCL-NOS). The median age was 69.5 years (range, 42-89 years), and a slight male predominance was noted (9 men and 5 women, 1.8: 1). Immunohistochemically, all cases were positive for CD20. One case was positive for CD138. Both cases of FL were positive for CD10 and B-cell lymphoma 2 (BCL-2), and immunoglobulin heavy locus (IgH)/B-cell lymphoma 2 rearrangement was observed by fluorescence in situ hybridization. The myeloid differentiation primary response gene (88) leucine to proline mutation was observed in 3 of 5 LPL, 1 of 2 FL, and 2 of 4 LGBCL-NOS patients. Paraproteinemia was observed in 10 patients; IgM and IgG paraproteinemia were observed in 6 and 3 patients, respectively. In this patient series, 3 patients had died at a median follow-up of 36.5 months; the cause of death of 1 LPL patient was malignant lymphoma itself. Thus, low-grade B-cell lymphoma presenting primarily in the bone marrow has various subtypes, and approximately one-third of the patients had LGBCL-NOS. The immunophenotypic features and myeloid differentiation primary response gene (88) leucine to proline mutation data of LGBCL-NOS suggested that some cases present with characteristics similar to those of LPL or marginal zone lymphoma.

Clinical significance of cytogenetic aberrations in bone marrow of patients with diffuse large B-cell lymphoma: prognostic significance and relevance to histologic involvement

Background

Although knowledge of the genetics of diffuse large B-cell lymphoma (DLBCL) has been increasing, little is known about the characteristics and prognostic significance of cytogenetic abnormalities and the clinical utility of cytogenetic studies performed on bone marrow (BM) specimens. To investigate the significance of isolated cytogenetic aberrations in the absence of histologic BM involvement, we assessed the implication of cytogenetic staging and prognostic stratification by a retrospective multicenter analysis of newly diagnosed DLBCL patients.

Methods

We analyzed cytogenetic and clinical data from 1585 DLBCL patients whose BM aspirates had been subjected to conventional karyotyping for staging. If available, interphase fluorescence in situ hybridization (FISH) data were also collected from patients.

Results

Histologic BM involvement were found in 259/1585 (16.3%) patients and chromosomal abnormalities were detected in 192 (12.1%) patients (54 patients with single abnormalities and 138 patients with 2 or more abnormalities). Isolated cytogenetic aberrations (2 or more abnormalities) without histologic involvement were found in 21 patients (1.3%). Two or more cytogenetic abnormalities were associated with inferior overall survival (OS) compared with a normal karyotype or single abnormality in both patients with histologic BM involvement (5-year OS, 16.5% vs. 52.7%; P < 0.001) and those without BM involvement (31.8% vs. 66.5%; P < 0.001). This result demonstrated that BM cytogenetic results have a significant prognostic impact that is independent of BM histology. The following abnormalities were most frequently observed: rearrangements involving 14q32, 19q13, 19p13, 1p, 3q27, and 8q24; del(6q); dup(1q); and trisomy 18. In univariate analysis, several specific abnormalities including abnormalities at 16q22-q24, 6p21-p25, 12q22-q24, and -17 were associated with poor prognosis. Multivariate analyses performed for patients who had either chromosomal abnormalities or histologic BM involvement, revealed IPI high risk, ≥ 2 cytogenetic abnormalities, and several specific chromosomal abnormalities, including abnormalities at 19p13, 12q22-q24, 8q24, and 19q13 were significantly associated with a worse prognosis.

Conclusions

We suggest that isolated cytogenetic aberrations can be regarded as BM involvement and cytogenetic evaluation of BM improves staging accuracy along with prognostic information for DLBCL patients.