Peripheral blood involvement in patients with follicular lymphoma: a rare disease manifestation associated with poor prognosis

Complete response using the EZH2 inhibitor tazemetostat against multiple relapsed follicular lymphoma in the leukemic phase

Though multiple relapses and serial shortening of remission is one of the characteristics of follicular lymphoma (FL), standard third- and later-line treatments with clear evidence have not yet been established. Tazemetostat, the first oral enhancer of zester homolog 2 (EZH2) inhibitor, showed a favorable clinical outcome and safety profile against relapsed mutant EZH2 FL in a clinical trial and was applied to this clinical setting. Peripheral blood involvement, known as the leukemic phase, was observed in approximately 10% of patients with FL and reported as a poor prognostic factor. However, because of the infrequency of EZH2-activating mutations, clinical data on tazemetostat against FL in the leukemic phase is lacking. Herein, we report a case of multiple relapsed FL in the leukemic phase for which tazemetostat was administered as a sixth-line treatment. Tazemetostat monotherapy showed a slow and sustained clinical efficacy in the leukemic phase as shown by nodal involvement. Circulating lymphoma cells gradually decreased and disappeared in counts after 4 months of treatment. However, circulating lymphoma cells were still detected by flow cytometry up to 6 months of treatment and finally undetected after 9 months. Extended-interval dosing of tazemetostat transformed a partial response into a complete response. Thus, tazemetostat is effective for the treatment of multiple relapsed FL in the leukemic phase.

Diagnosis, management and follow-up of follicular lymphoma: a consensus practice statement from the Australasian Lymphoma Alliance

Follicular lymphoma (FL) is the most common indolent non-Hodgkin lymphoma subtype, accounting for 15-20% of all lymphoma diagnoses. Although typically slow-growing and responsive to frontline therapies, advanced-stage FL remains incurable with current treatments and typically follows a chronic relapsing/remitting course with increasingly shorter responses to subsequent lines of therapy. Outcomes are highly variable; some patients experience prolonged first remissions that may approximate a 'functional cure'. By contrast, a significant minority of patients experience disease progression shortly after frontline treatment resulting in high rates of lymphoma-related mortality. Reflecting on the heterogeneous natural history of FL, clinical practice varies widely, particularly in controversial areas, including appropriate disease staging, selection of management strategies and duration of clinical follow-up. This position statement presents an evidence-based synthesis of the literature for application in Australasian practice.

Parallel testing of liquid biopsy (ctDNA) and tissue biopsy samples reveals a higher frequency of EZH2 mutations in follicular lymphoma

BACKGROUND

Recent genomic studies revealed enhancer of zeste homolog 2 (EZH2) gain-of-function mutations, representing novel therapeutic targets in follicular lymphoma (FL) in around one quarter of patients. However, these analyses relied on single-site tissue biopsies and did not investigate the spatial heterogeneity and temporal dynamics of these alterations.

OBJECTIVES

We aimed to perform a systematic analysis of EZH2 mutations using paired tissue (tumor biopsies [TB]) and liquid biopsies (LB) collected prior to treatment within the framework of a nationwide multicentric study.

METHODS

Pretreatment LB and TB samples were collected from 123 patients. Among these, 114 had paired TB and LB, with 39 patients characterized with paired diagnostic and relapse samples available. The EZH2 mutation status and allele burden were assessed using an in-house-designed, highly sensitive multiplex droplet digital PCR assay.

RESULTS

EZH2 mutation frequency was found to be 41.5% in the entire cohort. In patients with paired TB and LB samples, EZH2 mutations were identified in 37.8% of the patients with mutations exclusively found in 5.3% and 7.9% of TB and LB samples, respectively. EZH2 mutation status switch was documented in 35.9% of the patients with paired diagnostic and relapse samples. We also found that EZH2 wild-type clones may infiltrate the bone marrow more frequently compared to the EZH2 mutant ones.

CONCLUSION

The in-depth spatio-temporal analysis identified EZH2 mutations in a considerably higher proportion of patients than previously reported. This expands the subset of FL patients who most likely would benefit from EZH2 inhibitor therapy.

Interpreting flow cytometry with caution: A case report of follicular lymphoma in leukemic phase misdiagnosed as chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a subtype of mature B-cell proliferative neoplasms characterized by abnormally increasing lymphocytes in circulation. The diagnosis of CLL is usually established on peripheral blood analysis and typical flow cytometric immunophenotype rather than biopsy. In particular, the high RMH (Royal Marsden Hospital Scoring System for CLL) score of immunophenotype has a highly sensitive weight for diagnostic value. However, immunophenotyping by flow cytometry may also be misleading in specific clinical situations. Here, we report a case on admission with lymphadenopathy and lymphocytosis, misdiagnosed as chronic lymphocytic leukemia by flow cytometry initially but finally confirmed as follicular lymphoma (FL) in the leukemic phase via lymph node biopsy. Since FL in the leukemic phase is uncommon at the time of diagnosis and indicates a poorer prognosis of FL, such misdiagnosis is worthy of attention. It is also thought-provoking that there had been conflicts between immunophenotype of bone marrow and immunohistochemistry of lymph node. Our case report aims to remind clinicians’ awareness that the immunophenotyping by flow cytometric analysis needs to be interpreted with caution especially when the results cannot account for all of clinical features, and it is significant to make the right decision about when to conduct further examination including lymph node biopsy for avoiding misdiagnosis.

Peripheral Blood Involvement at Staging in Patients With Aggressive Peripheral T-Cell Lymphoma

INTRODUCTION

Peripheral T-Cell Lymphomas (PTCL) are a rare subgroup of lymphomas with a poor outcome.Traditional prognostic measures rely heavily on disease stage, and with the advent of targeted treatment, further stratificationcriteria are needed to guide treatment. To date, the impact of blood involvement at diagnosis on outcomes has not been assessed.

MATERIALS AND METHODS

We retrospectively reviewed blood involvement by flow cytometry at diagnosis in 102 consecutivelytreated patients who had flow cytometry data available at diagnosis. Of these, 78 patients with nodal subtypes were identified andstudied in this analysis.

RESULTS

Of 78 patients with nodal subtypes of PTCL who had flow data available at the time ofdiagnosis, circulating populations of malignant T cells matching those in the biopsied lymph nodes were found in 21 patients bymultiparameter flow cytometry. A positive flow cytometry was highly correlated with bone marrow involvement. The patientswith a negative flow cytometry had a trend toward a longer median PFS compared to those with a positive flow but there was noimpact on overall survival.

CONCLUSIONS

Circulating malignant tumor cells can be found in the peripheral blood in a subset ofpatients with aggressive nodal T-cell lymphomas, including peripheral t-cell lymphoma not otherwise specified andangioimmunoblastic T-cell lymphomas, and blood involvement is correlated with bone marrow involvement.

Leukemic High Grade B Cell Lymphoma is Associated With MYC Translocation, Double Hit/Triple Hit Status, Transformation, and CNS Disease Risk: The Mayo Clinic Experience

INTRODUCTION

Leukemic involvement in high grade B cell lymphoma (L-HGBL) is rare and has been sparsely described in the literature. We report our experience in a large single institution multicenter academic setting.

MATERIALS AND METHODS

Medical records of patients with HGBL who received care at Mayo Clinic between 2003 and 2020 were reviewed. L-HGBL was confirmed by peripheral blood smear and flow cytometry with corroboration from tissue and bone marrow biopsy findings.

RESULTS

Twenty patients met inclusion criteria. All patients had significant bone marrow involvement by HGBL. Leukemic involvement presented in 11 of 20 (55%) in the de novo and 9 of 20 (45%) in the relapsed setting. Seven of 20 patients had DLBCL, NOS, 6 of 20 had transformation (t-DLBCL), 3 of 20 had transformed double/triple hit lymphoma (t-DHL/THL), 2 of 20 had double hit lymphoma (DHL), and 2 of 20 had HGBL with intermediate features between DLBCL and Burkitt lymphoma. Nine of 15 patients had MYC translocation. Based on Hans criteria, 11 of 20 had germinal center B-cell (GCB) cell of origin (COO) and 9/20 had non-GCB COO. Five of 11 de novo patients experienced CNS relapse/progression. All de novo patients received anthracycline-based chemoimmunotherapy. Eighteen of 20 patients died of progressive disease. Median overall survival was significantly better in the de novo compared to relapsed group (8.9 months vs. 2.8 months, P = .01). COO, MYC status, DHL/THL status, HGBL subtype, or treatment group did not demonstrate a significant effect on overall survival.

CONCLUSION

L-HGBL carries a poor prognosis and is associated with MYC translocation, DHL/THL status, transformation, and high CNS risk. Novel therapeutic approaches are needed for L-HGBL.

Non-Hodgkin lymphoma mimicking acute leukemia: a report of six cases and review of the literature

Aggressive subtypes of non-Hodgkin lymphoma may uncommonly be referred to clinical oncologists for treatment of acute leukemia, due to an elevated or rapidly rising white blood cell count (WBC), with circulating neoplastic cells that morphologically resemble leukemic blasts seen in acute myeloid or lymphoblastic leukemia. We describe six cases of non-Hodgkin lymphoma that mimicked acute leukemia and were identified in the pathology records of the Brigham and Women's Hospital. The patients were older adults (mean age 70 years), who presented with leukocytosis (mean 79.7 × 10⁹/L) with circulating neoplastic cells (mean 57%), which mimicked leukemic blasts, thrombocytopenia, and anemia (4/6 patients). In each case, immunophenotypic analysis identified a population of mature B cells or mature T cells. We identified 15 additional cases of non-Hodgkin lymphoma in the literature that mimicked acute leukemia; considering all 21 cases, 11 had an appearance of acute lymphoblastic leukemia, 4 had an appearance of acute monocytic leukemia, and 6 had an appearance of acute leukemia unable to be further categorized. In general, patients exhibited poor overall survival. These cases illustrate the importance of comprehensive immunophenotypic analysis in the initial evaluation of hematolymphoid neoplasms, and that occasional cases of non-Hodgkin lymphomas can resemble acute leukemia at initial presentation.

Time for an individualized approach to first-line management of follicular lymphoma

Follicular lymphoma is a heterogeneous B-cell lymphoma both in presentation and at progression. For most patients it is a chronic, relapsing indolent disease with overall survival expectations now potentially beyond 20 years. However, in a significant minority (~20%) who experience early progression or histological transformation after treatment, the disease no longer has an indolent behavior. This review looks at the development of prognostic indices, staging and therapies for follicular lymphoma, identifying where the data can, and cannot, guide the multidisciplinary team to determine an individualized approach to first-line therapy. A nuanced patient- and disease-specific approach is necessary to maximize disease response and survival while minimizing therapeutic toxicity.

Follicular lymphoma: updates for pathologists

Follicular lymphoma (FL) is the most common indolent B-cell lymphoma and originates from germinal center B-cells (centrocytes and centroblasts) of the lymphoid follicle. Tumorigenesis is believed to initiate early in precursor B-cells in the bone marrow (BM) that acquire the t(14;18)(q32;q21). These cells later migrate to lymph nodes to continue their maturation through the germinal center reaction, at which time they acquire additional genetic and epigeneticabnormalities that promote lymphomagenesis. FLs are heterogeneous in terms of their clinicopathologic features. Most FLs are indolent and clinically characterized by peripheral lymphadenopathy with involvement of the spleen, BM, and peripheral blood in a substantial subset of patients, sometimes accompanied by constitutional symptoms and laboratory abnormalities. Diagnosis is established by the histopathologic identification of a B-cell proliferation usually distributed in an at least partially follicular pattern, typically, but not always, in a lymph node biopsy. The B-cell proliferation is biologically of germinal center cell origin, thus shows an expression of germinal center-associated antigens as detected by immunophenotyping. Although many cases of FLs are typical and histopathologic features are straightforward, the biologic and histopathologic variability of FL is wide, and an accurate diagnosis of FL over this disease spectrum requires knowledge of morphologic variants that can mimic other lymphomas, and rarely non-hematologic malignancies, clinically unique variants, and pitfalls in the interpretation of ancillary studies. The overall survival for most patients is prolonged, but relapses are frequent. The treatment landscape in FL now includes the application of immunotherapy and targeted therapy in addition to chemotherapy.

Low-Grade Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma

Primary splenic lymphoma (PSL) is a rare malignancy representing about 1% of all lymphoproliferative disorders, when using a strict definition that allows only involvement of spleen and hilar lymph nodes. In contrast, secondary low-grade B-cell lymphomas in the spleen, such as follicular lymphomas (FL), lymphoplasmacytic lymphoma and chronic lymphocytic leukemia/ small lymphocytic lymphoma, particularly as part of advanced stage disease, are more common. Indolent B cell lymphomas expressing CD10 almost always represent FL, which in its primary splenic form is the focus of this review. Primary splenic follicular lymphoma (PSFL) is exceedingly infrequent. This type of lymphoproliferative disorder is understudied and, in most cases, clinically characterized by splenomegaly or cytopenias related to hypersplenism. The diagnosis requires correlation of histopathology of spleen, blood and/or bone marrow with the correct immunophenotype (determined by flow cytometry and/or immunohistochemistry) and if necessary, additional molecular profiling. Management of this incurable disease is evolving, and splenectomy remains the mainstream treatment for stage I PSFL.

Lenalidomide triggers T-cell effector functions in vivo in patients with follicular lymphoma

The immunomodulatory drug lenalidomide is used in patients with follicular lymphoma (FL) with the aim of stimulating T-cell antitumor immune response. However, little is known about the effects of lenalidomide on T-cell biology in vivo in patients with FL. We thus undertook an extensive longitudinal immunologic study, including phenotypic, transcriptomic, and functional analyses, on 44 first-line and 27 relapsed/refractory patients enrolled in the GALEN trial (Obinutuzumab Combined With Lenalidomide for Relapsed or Refractory Follicular B-Cell Lymphoma) to test the efficacy of lenalidomide and obinutuzumab combination in patients with FL. Lenalidomide rapidly and transiently induced an activated T-cell phenotype, including HLA-DR, Tim-3, CD137, and programmed cell death protein 1 (PD-1) upregulation. Furthermore, sequential RNA-sequencing of sorted PD-1+ and PD-1- T-cell subsets revealed that lenalidomide triggered a strong enrichment for several gene signatures related to effector memory T-cell features, including proliferation, antigen receptor signaling, and immune synapse restoration; all were validated at the phenotypic level and with ex vivo functional assays. Correlative analyses pinpointed a negative clinical impact of high effector T-cell and regulatory T-cell percentages before and during treatment. Our findings bring new insight in lenalidomide mechanisms of action at work in vivo and will fuel a new rationale for the design of combination therapies.

Absolute B cell counts in blood predict long-term response in follicular lymphoma patients treated with rituximab without chemotherapy

Rituximab monotherapy is widely used for follicular lymphoma. However, there are no established predictors for response or response duration. We analyzed the long-term prognostic relevance of pre-treatment absolute blood counts of lymphocytes with subsets and monocytes in 265 follicular lymphoma patients, uniformly treated with rituximab without chemotherapy, in two Nordic Lymphoma Group trials. There were 265 previously untreated, stage II–IV follicular lymphoma patients with a median follow-up of over 10 years. Absolute B cell counts ≥ median (0.09 × 10⁹/L) were an independent predictor for shorter time to next treatment or death (multivariable analysis P = 0.010). In univariate analysis, absolute monocyte counts ≥ median (0.5 × 10⁹/L) did not correlate with time to next treatment or death, but with inferior overall survival (P = 0.034). Absolute T cell or T cell subset counts were not predictive for outcome. High absolute B cell counts, possibly reflecting circulating lymphoma cells, have an unfavorable impact on time to next treatment or death in patients treated with rituximab without chemotherapy.

Follicular Lymphoma: Recent and Emerging Therapies, Treatment Strategies, and Remaining Unmet Needs

Follicular lymphoma (FL) is a heterogeneous disease with varying prognosis owing to differences in clinical, laboratory, and disease parameters. Although generally considered incurable, prognosis for early- and advanced-stage disease has improved because of therapeutic advances, several of which have resulted from elucidation of the biologic and molecular basis of the disease. The choice of treatment for FL is highly dependent on patient and disease characteristics. Several tools are available for risk stratification, although limitations in their routine clinical use exist. For limited disease, treatment options include radiotherapy, rituximab monotherapy or combination regimens, and surveillance. Treatment of advanced disease is often determined by tumor burden, with surveillance or rituximab considered for low tumor burden and chemoimmunotherapy for high tumor burden disease. Treatment for relapsed or refractory disease is influenced by initial first-line therapy and the duration and quality of the response. Presently, there is no consensus for treatment of patients with early or multiply relapsed disease; however, numerous agents, combination regimens, and transplant options have demonstrated efficacy. Although the number of therapies available to treat FL has increased together with an improved understanding of the underlying biologic basis of disease, the best approach to select the most appropriate treatment strategy for an individual patient at a particular time continues to be elucidated. This review considers prognostication and the evolving treatment landscape of FL, including recent and emergent therapies as well as remaining unmet needs. IMPLICATIONS FOR PRACTICE: In follicular lymphoma, a personalized approach to management based on disease biology, patient characteristics, and other factors continues to emerge. However, application of current management requires an understanding of the available therapeutic options for first-line treatment and knowledge of current development in therapies for previously untreated and for relapsed or refractory disease. Thus, this work reviews for clinicians the contemporary data in follicular lymphoma, from advances in characterizing disease biology to current treatments and emerging novel therapies.

[Follicular lymphoma: An update]

Follicular lymphoma, the second most common lymphoma, is characterized by its slow growth and is often considered incurable in advanced stages. Progresses in biology have contributed to better understand the complex and successive mechanisms of development of this pathology, whose diagnosis is based on a lymph node biopsy. However, the prognosis of the patients is heterogeneous and several indexes have been proposed to identify groups of patients with a similar life expectancy, in order to guide the therapeutic choices. The treatment has been modified in the last 20 years by the emergence of anti-CD20 monoclonal antibodies which constitute, alone or in combination, of the cornerstone of therapeutic management. After staging using, in particular, 18-fluorodeoxyglucose positron emission tomography, the therapeutic strategy will be adapted for each patient, ranging from simple watchful waiting to a combination of chemotherapy and anti-CD20 antibodies. Relapses (which often require a new lymph node biopsy to eliminate a possible histological transformation into an aggressive lymphoma with poorer prognosis) remain common but are still accessible to effective therapeutic interventions. Thanks to these advances, the median life expectancy of patients with follicular lymphoma now exceeds 15 years.

Total metabolic tumor volume, circulating tumor cells, cell-free DNA: distinct prognostic value in follicular lymphoma

Outcomes for follicular lymphoma (FL) have greatly improved, but most patients will ultimately relapse. High total metabolic tumor volume (TMTV), computed from baseline ¹⁸F-fluorodeoxyglucose-positron emission tomography (PET), is associated with shorter progression-free survival (PFS), but circulating tumor cells (CTCs) and cell-free DNA (cfDNA) may also reflect tumor burden and be of prognostic value. The aim of our study was to correlate CTCs and cfDNA with TMTV in FL at diagnosis and to determine their prognostic values. We retrospectively analyzed 133 patients (with previously untreated FL and a baseline PET) from 2 cohorts with either a baseline plasma sample (n = 61) or a bcl2-JH-informative peripheral blood (PB) sample (n = 68). Quantification of circulating bcl2-JH⁺ cells and cfDNA was performed by droplet digital polymerase chain reaction. A significant correlation was found between TMTV and both CTCs (P < .0001) and cfDNA (P < .0001). With a median 48-month follow-up, 4-year PFS was lower in patients with TMTV > 510 cm³ (P = .0004), CTCs >0.0018 PB cells (P = .03), or cfDNA >2550 equivalent-genome/mL (P = .04). In comparison with TMTV alone, no additional prognostic information was obtained by measuring CTCs. In contrast, Cox multivariate analysis, including cfDNA and TMTV, showed that both cfDNA and TMTV remained predictive of outcome. In conclusion, CTCs and cfDNA correlate with TMTV in FL, and all 3 influence patient outcome. PFS was shorter for patients with high cfDNA and TMTV, suggesting that these parameters provide relevant information for tumor-tailored therapy.

A leukemic double-hit follicular lymphoma associated with a complex variant translocation, t(8;14;18)(q24;q32;q21), involving BCL2, MYC, and IGH

Double-hit lymphoma (DHL) is defined as lymphoma with concurrent BCL2 and MYC translocations. While the most common histological subtype of DHL is diffuse large B-cell lymphoma, the present patient had leukemic follicular lymphoma (FL). A 52-year-old man was admitted to our hospital due to general fatigue and cervical and inguinal lymph node swelling. The patient was leukemic and the pathological diagnosis of the inguinal lymph node was FL grade 1. Chromosomal analysis revealed a complex karyotype including a rare three-way translocation t(8;14;18)(q24;q32;q21) involving the BCL2, MYC, and IGH genes. Based on a combination of fluorescence in situ hybridization (FISH), using BCL2, MYC and IGH, and spectral karyotyping (SKY), the karyotype was interpreted as being the result of a multistep mechanism in which the precursor B-cell gained t(14;18) in the bone marrow and acquired a translocation between der(14)t(14;18) and chromosome 8 in the germinal center, resulting in t(8;14;18). The pathological diagnosis was consistently FL, not only at presentation but even after a second relapse. The patient responded well to standard chemotherapies but relapsed after a short remission. This patient is a unique case of leukemic DH-FL with t(8;14;18) that remained in FL even at a second relapse.

High-risk follicular lymphomas harbour more somatic mutations including those in the AID-motif

We investigated clinical and genetic characteristics of high-risk follicular lymphoma (FL), that lacked evidence of large cell transformation at diagnosis, in the rituximab era. First, we retrospectively analysed the clinical features of 100 patients with non-transformed FL that were consecutively treated with rituximab-containing therapies in a discovery cohort. The presence of either peripheral blood and/or bone involvement was associated with short progression-free survival. This was confirmed in a validation cohort of 66 FL patients. Then, whole exome sequencing was performed on randomly selected 5 high- and 9 standard-risk FL tumours. The most common mutational signature was a CG > TG substitution-enriched signature associated with spontaneous deamination of 5-methylcytosine at CpG, but mutations in WA and WRC(Y) motifs (so-called activation-induced cytidine deaminase (AID) motifs) were also enriched throughout the whole exome. We found clustered mutations in target sequences of AID in the IG and BCL2 loci. Importantly, high-risk FLs harboured more somatic mutations (mean 190 vs. 138, P = 0.04), including mutations in WA (33 vs. 22, P = 0.038), WRC (34 vs. 22, P = 0.016) and WRCY motifs (17 vs. 11, P = 0.004). These results suggest that genomic instability that allows for emergence of distinct mutations through AID activity underlies development of the high-risk FL phenotype.

Useful laboratory markers for the diagnosis of bone marrow involvement by malignant lymphoma

INTRODUCTION

This study aimed to investigate the effect of bone marrow involvement by malignant lymphoma (BMI) on laboratory data and to determine the useful laboratory markers for diagnosing BMI.

METHODS

We compared laboratory data between patients with and without BMI. We performed multivariate logistic regression and receiver operating characteristic (ROC) analyses to evaluate the diagnostic values of independent predictors.

RESULTS

In the BMI group, platelets in peripheral blood (PLT) and megakaryocyte count in bone marrow (MgK) were significantly lower than those in the non-BMI group (PLT, P < .0001; MgK, P = .0384). The rate of peripheral blood involvement by malignant lymphoma (PBI), red blood cell distribution width (RDW), D-dimer (DD), soluble interleukin-2 receptor (sIL2R), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) was significantly higher in the BMI group than in the non-BMI group (PBI, P < .0001; RDW, P = .0190; DD, P = .0006; sIL2R, P < .0001; AST, P = .0256; LDH, P = .0002). In multivariate analysis, PBI, PLT, sIL2R, and MgK levels were independent predictors of BMI.

CONCLUSION

PBI, PLT, sIL2R, and MgK may be the useful laboratory markers for BMI diagnosis.

[Leukemization of follicular lymphoma: The features of diagnostic and clinical course of a rare form of the disease]

AIM

To characterize a group of patients with follicular lymphoma (FL) with leukemization and to evaluate the efficiency of different therapy options (R-CHOP/R-FMC/high-dose chemotherapy (HDCT)).

SUBJECTS AND METHODS

18 (7.2%) out of 250 patients diagnosed with FL, who were examined and treated at the National Research Center for Hematology, Ministry of Health of the Russian Federation, were found to have leukemic FL (tumor cells in the peripheral blood smears were detected by cytology and flow cytofluorometry. Eight of the 18 patients had extranodal foci of involvement: lung, stomach, spleen, lumbar muscles, upper jaw, and vertebrae. Bone marrow was involved in 17 of the 18 patients. Tumor biopsy specimens displayed a morphological pattern of indolent FL in the majority of patients (10 of the 18 patients had cytological grade 1-2 tumors and 14 patients had a nodular or nodular-diffuse tumor growth pattern). The patients underwent R-CHOP/R-FMC) or HDCT cycles as first-line therapy, followed by autologous stem cell transplantation (auto-SCT).

RESULTS

The median follow-up was 66 months (range 12-217 months). The 5-year overall survival (OS) and progression-free survival (PFS) rates were 70% (10% SEM) and 35% (15% SEM), respectively. The median OS was not reached; the median PFS was 3 years.

CONCLUSION

Leukemic FL is characterized by low OS and PFS rates. The most effective chemotherapy regimens were R-CHOP, followed by HDCT and auto-SCT in first remission or R-FMC. These cycles can to a greater extent achieve a complete eradication of the bone marrow tumor clone. Due to the relapsing course of FL and the aggressiveness of leukemic FL, it is expedient to carry out auto-SCT in first remission.

Follicular Lymphoma: A Clinicopathological Analysis from a Tertiary Care Institute in Southern India

Introduction

Follicular lymphoma (FL) is an indolent lymphoproliferative disorder of B-cells with variable clinical behavior. It is the second most common subtype of Non-Hodgkin lymphoma in western countries but reported to have a lower incidence in Asia.

Materials and methods

Cases of FL diagnosed in the Department of Pathology of our Institute from January 2009 to June 2015 were included in the study. The clinicopathological parameters including staging, histological details, and immunohistochemical markers CD20, CD10 and BCL-2 were recorded in all the cases.

Results

Of the 497 cases of Non-Hodgkin Lymphoma reported during the study period, 36 (7.2%) cases were follicular lymphoma. The mean age was 50 years with male to female ratio of 3.2:1. Grade 1/2 was seen in 70% cases. 22 % cases had low grade with high proliferation index (Ki67 > 40%). Granulomatous response was seen in two cases. Diffuse large cell lymphoma component was present in four cases. Bone marrow involvement and peripheral blood spill were seen in 12 (37.5%) and six cases (18.8%) respectively. 72% cases were in stage 3 or 4.

Conclusion

The incidence of FL was lower in our study than other Indian studies. FL presented in the elderly, with male predominance and disseminated stage. The study highlights features of low grade with high proliferation index, granulomatous response, leukemic involvement, and transformation to high grade lymphoma.

Clinicopathological characteristics of follicular lymphoma with peripheral blood involvement

This study aimed to indicate patient outcomes and pathological characteristics of follicular lymphoma (FL) with peripheral blood (PB) involvement. Of 533 patients with FL, 56 (11%) had PB involvement. Of the patients treated with rituximab, 39 patients with PB involvement had significantly shorter progression-free survival than 107 patients with stage IV disease without PB involvement (p = 0.021), but the overall survival was not different (p = 0.804). The histopathology of the primary sites was usually nodal (95%) low-grade (86%) FL with IGH/BCL2 fusion (75%). Flow cytometric and immunohistochemical analyses revealed that the incidence of CD10 positivity was lower in the bone marrow (55% and 58%) and PB (41% and not available) than in the primary site (86% and 93%) (p = 0.004 and p = 0.0001, respectively). Therefore, even if small lymphoma cells in the bone marrow and PB are negative for CD10, FL cannot be ruled out.