Small B-cell Research Articles

Clinical Research in Africa: Collaborative Project between Senegal and France to Improve the Diagnosis and Therapeutic Management of Adult Lymphoma Patients

Background: Little is known about Non-Hodgkin Lymphoma (NHL) in Africa except for the high incidence of Burkitt lymphoma in children and the high association with HIV in Eastern Africa but not Western Africa. Difficulties including low access to health care, use of cytopuncture instead of nodal biopsy, cost of drugs and absence of supportive care lead to poor prognosis for NHL patients (pts) (overall response rate (ORR) <30%) (Diop et al., Bull Soc Patho Exo 2004). Meaningful lymphoma research cannot be conducted without accurate diagnosis (Naresh et al., Br J Hematol 2011). The Senegal Government has built a national anti-cancer program, focusing on prevention and improvement of diagnosis and treatment. A prospective single arm non-randomized phase 2 clinical trial was thus designed for adult pts with newly diagnosed diffuse large B-cell lymphoma (DLBCL) at Dakar (Senegal) University Hospital (DUH), in collaboration with Nancy (France) University Hospital (NUH). Methods: Histological results of suspected lymphoma in pts likely to be included in this trial are reported here. Only non-HIV adult patients were enrolled. A first histological study was performed in the pathology department of DUH. This included biopsies that were submitted to apposition before embedding. Hematoxylin and eosin staining was performed as well as immunohistochemistry (IHC). The panel used allowed to examine the expression of the following antigens: CD20, CD79a, CD3, CD5, CD23, cyclin D1, CD30, Bcl2, CD10 and Ki67. Biopsies were reviewed via an international telepathology platform using the i-Path software and retrospectively, in NUH Pathology department, by sending paraffin-embedded blocks on site. Findings: Between July 2018 and May 2022, 70 pts admitted with a clinical presentation suggestive of NHL were evaluated with a surgical biopsy, 31 of whom being confirmed with a diagnosis of DLBCL or equivalent as T-cell/histiocyte-rich large B cell LBCL, and thus eligible for the therapeutic trial. Median age of the 70 pts was 42 years old (18-70) and 32% were female. Other hematological diagnoses were Hodgkin lymphoma, small B-cell lymphoma, T-cell lymphoma, unclassed lymphoma and histiocytosis. There was no Burkitt lymphoma. Non-hematological diagnoses were achieved for 14 pts: lipoma, tuberculosis, reactive adenitis or metastasis of solid neoplasia. In nearly half of all cases, diagnosis was obtained without IHC, notably due to non-hematological diagnoses. In nearly half of all cases, the diagnosis was obtained without IHC. When IHC was used, CD20 and CD3 were mainly used to establish the diagnosis. The median time to obtain pathology results was 31 days. Thirty-one cases were diagnosed with the help of I-Path. Currently, 17 biopsies have been reviewed at NUH with diagnosis concordance in 71% of cases. The 5 inconsistent diagnoses were 2 NHL ultimately classified as adenocarcinoma, 1 reactive adenitis being in fact DLBCL and 2 T-cell/histiocyte-rich LBCL diagnosed as respectively DLBCL and small B-cell lymphoma. Interpretation: This is a large cohort of consecutive surgical biopsies performed in Senegal for lymphoma suspicion, showing the distribution of lymphoma in Western Africa and more interestingly, demonstrating that an accurate diagnosis is possible locally. The current hindrances in lymphoma diagnosis include basing treatment decisions on fine needle aspiration cytology in a large proportion of cases, poor quality histology or complete lack of IHC in cases where biopsies are performed, limited number of hematopathologists and lack of discussion between hematopathologists. In this study, systematic surgical biopsy, homogenous IHC staining procedures, electronic interaction between hematopathologists and retrospective review of biopsies have contributed to a huge improvement of the quality of diagnosis.

Hyperplasie lymphoïde folliculaire induite par la prise de dasatinib, une entité à connaître

Follicular lymphoid hyperplasia induced by dasatinib is an entity recently described. It is sometimes difficult to rule out the diagnostic of small B-cell lymphoma. Usually, the node is swollen, with follicular architecture conserved, composed by germinal centers with variable size and shape, with a hight number of mitoses and tingible bodies macrophages inside. Follicular lymphoid hyperplasia is isolated or associated with multiple reactive patterns. The immunohistochemical profil of germinal centers is CD20+, CD10+, BCL6+, BCL2-. Swollen node disappears in a short time after dasatinib discontinuation. Clinicians and pathologists need to be aware of this entity, so as not to avoid mistakenly suspect lymphoma when lymphadenopathy occurs in a patient with chronic myeloid leukemia treated with dasatinib.

A 69-YEAR-OLD MAN WITH HEAVY ASBESTOS EXPOSURE, DYSPNEA, AND PLEURAL SOFT-TISSUE THICKENING

A 69-YEAR-OLD MAN WITH HEAVY ASBESTOS EXPOSURE, DYSPNEA, AND PLEURAL SOFT-TISSUE THICKENING

Overexpression of interleukin-20 correlates with favourable prognosis in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma worldwide, accounting for about 40% of cases. The role of cytokines in the pathogenesis of lymphomas has been rarely addressed, although cytokines have a close immunological relationship with lymphocytes. We observed overexpression of interleukin (IL)-20 in reactive germinal centres (GCs) leading us to hypothesise that IL-20 may play a role in lymphomagenesis. In this study, we surveyed for IL-20 expression in various types of lymphoma and found that IL-20 was expressed most frequently in follicular lymphoma (94%), but also in Burkitt lymphoma (81%), mantle cell lymphoma (57%), nodal marginal zone lymphoma (56%), Hodgkin lymphomas (50%), small lymphocytic lymphoma (50%) and diffuse large B-cell lymphoma (DLBCL, 48%). IL-20 was not expressed in extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma), lymphoplasmacytic lymphoma, and plasmacytoma. T-cell lymphomas were largely negative for IL-20 expression, except for anaplastic large cell lymphoma (ALCL, 61%), which frequently expressed IL-20, especially in cutaneous ALCL, and showed an inverse association with ALK expression (p=0.024). We further tested IL-20 expression in another large cohort of DLBCL and found IL-20 expression more frequently in germinal centre B-cell (GCB) than in non-GCB subtype [16/26 (62%) versus 24/64 (38%), p=0.038]. In this cohort, IL-20 was associated with a lower rate of extranodal involvement (p=0.009), bone marrow involvement (p=0.040), and better overall survival (p=0.020). Mechanistically, IL-20 overexpression promoted G1 cell cycle arrest and subsequent apoptosis of DLBCL cells and vice versa invitro. We conclude that IL-20 may be involved in lymphomagenesis and may be useful as a prognostic marker in patients with DLBCL. In addition, IL-20 plays an inhibitory role in DLBCL growth, probably through cell cycle regulation.

Clinical Features Analysis and Survival Nomogram of Primary Small Intestinal Diffuse Large B-Cell Lymphoma

PurposeThis study aimed to analyze the clinical features and survival of primary small intestinal diffuse large B-cell lymphoma (PsI-DLBCL), and establish and independently validate a prognostic nomogram for individual risk prediction.Patients and methodsData for 24 patients from the Renmin Hospital of Wuhan University were used as an independent validation cohort, data for 1144 patients with PsI-DLBCL from the SEER database were randomly assigned to training (N=817) and internal validation (N=327) sets. The survival nomogram was constructed with the most significant factors associated with OS using Univariate and multivariate analyses on the training set. Decision curve analysis (DCA) was conducted. Internal validation was SEER validation set. Our cancer center cohort was used as an external validation set to further verify the survival nomogram.ResultsFive clinicopathological feature factors associated with OS of the training set yielded (age, marital status, Ann Arbor stage, surgery for primary site and chemotherapy), which were used to create a survival nomogram. Additionally, the calibration curves of the prognostic nomogram revealed good agreement between the predicted survival probabilities and the ground truth values. The stability of our survival nomogram was explained by internal and external validation data.ConclusionOur nomogram proposes the clinical and therapeutic factors affecting OS for patients with PsI-DLBCL. It shows that chemotherapy and surgery are beneficial to patients in the choice of treatment options. These results suggest that a survival nomogram may be better at predicting OS for PsI-DLBCL patients.

Relevance of Additional Immunohistochemical Markers in the Differential Diagnosis of Small B-Cell Lymphomas: A Case-Control Study

Objective:Clinical and pathological differential diagnosis of small B-cell lymphomas (SBCLs) is still controversial and may be difficult due to their overlapping morphology, phenotype, and differentiation to plasma cells. We aimed to examine the expression of the immune receptor translocation-associated protein 1 (IRTA1), myeloid cell nuclear differentiation antigen (MNDA), lymphoid enhancer-binding factor-1 (LEF1), and stathmin 1 (STMN1) markers in SBCL cases involving different sites that may have plasma cell differentiation.Materials and Methods:We studied 154 tissue samples with lymphoma involvement from 116 patients and evaluated the staining distribution of the markers. Expressions were evaluated in 21 chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), 7 follicular lymphoma (FL), 14 nodal marginal zone lymphoma, 17 extranodal marginal zone lymphoma, 55 splenic marginal zone lymphoma, 22 marginal zone lymphoma-not otherwise specified, and 18 lymphoplasmacytic lymphoma/Waldenström macroglobulinemia cases by immunohistochemistry.Results:The results confirmed that LEF1 was the most sensitive and specific marker for CLL/SLL and STMN1 was the most sensitive and specific marker for FL (p<0.001). MNDA and IRTA1 were useful markers to distinguish marginal zone lymphomas.Conclusion:Our results suggest that LEF1 for CLL/SLL and STMN1 for FL are reliable markers. LEF1, MNDA, STMN1, and IRTA1 are helpful with other routinely used immunohistochemical markers in a diagnostic algorithm considering their limitations.

Clinical outcome and Ki67 evaluation in dogs with nodal small cell B-cell lymphoma diagnosed by flow cytometry.

BackgroundNodal small cell B‐cell lymphoma subtypes in dogs cannot be distinguished by flow cytometry and information regarding treatment, prognosis, and outcome are limited.Hypothesis/ObjectivesObjectives were to describe outcome in dogs with nodal small cell B‐cell lymphoma diagnosed by flow cytometry and correlate clinical and laboratory data with survival. We hypothesized that B‐cell Ki67 expression measured by flow cytometry is associated with shorter progression free survival (PFS) and overall survival (OS).AnimalsForty‐nine dogs with nodal small cell B‐cell lymphoma, defined by >80% CD21+ B‐cells by flow cytometry and small‐sized B‐cells by forward scatter.MethodsRetrospective study reviewing treatment and outcome data extracted from medical records. Percentage of Ki67‐expressing B‐cells was measured by flow cytometry. Clinical, laboratory, and flow cytometry data were assessed for association with outcome.ResultsMedian percentage of B‐cell Ki67 was 41% (range, 3%‐97%). Median PFS was 119 days and median OS was 222 days (n = 49). Among cases treated with CHOP‐based chemotherapy (n = 32), median PFS was 70 days, median OS was 267 days, and 50% of cases achieved complete response. Low percentage of B‐cell Ki67 (≤11%) was associated with prolonged OS by univariable analysis. Greater age, substage B, high B‐cell CD25 expression and low B‐cell CD21 and class II major histocompatibility complex expression by flow cytometry were independently associated with shorter OS.Conclusions and Clinical ImportanceMost nodal small cell B‐cell lymphoma cases had aggressive disease. Low Ki67 expression can help identify cases with better prognosis. Age, substage, and flow cytometry variables are useful prognostic factors.

Clinical analysis of 20 cases of small B lymphocyte proliferative disease with t (14;19) (q32;q13)

Objective: The clinical characteristics and prognosis of 20 patients with small B-lymphocyte proliferative disease with t (14;19) (q32; q13) were analyzed to improve the understanding of such rare cases. Methods: The clinical data of 20 patients with t (14; 19) (q32; q13) small B lymphocyte proliferative disease treated in the First Affiliated Hospital of Nanjing Medical University from April 2013 to December 2020 were retrospectively collected and analyzed. Among them, 10 cases were chronic lymphocytic leukemia (CLL) and 10 cases were other small B-cell malignancies. Results: Among the 20 cases, 10 were male and 10 were female, and the median age at diagnosis was 53.5 (35-88) years old. All patients had absolute lymphocytosis, 19 patients had lymphadenopathy, and 10 patients had splenomegaly. With a median follow-up of 36 (4-163) months, three patients died, and 11 patients had a time to treatment (TTT) ≤12 months. Ten patients (50%) were accompanied by +12, two patients (2/17, 12%) were accompanied by 13q-. Moreover, we found that t (14;19) was associated with unmutated immunoglobulin heavy-chain variable (IGHV) somatic mutation (17/19, 89%) and a biased use of IGHV4-39 (7/17, 41%) was observed. Next-generation sequencing detected one or more gene mutations in 14 (14/17, 82%) cases and a total of 25 gene mutations had been revealed, of which the most frequent were NOTCH1 (35%) , followed by SF3B1 (24%) and KMT2D (18%) . For 10 CLL patients, five (50%) were defined as Rai Ⅲ/Binet C. It is noteworthy that among the 20 cases, two cases actually involved Richter transformation. Conclusions: Small B-cell malignant tumors with abnormal t (14; 19) show unique clinical biological characteristics, often accompanied by a variety of adverse prognostic factors, and tend to have an aggressive clinical course.

Molecular Mechanism of Pathogenesis and Treatment Strategies for AL Amyloidosis.

In amyloid light-chain (AL) amyloidosis, small B-cell clones (mostly plasma cell clones) present in the bone marrow proliferate and secrete unstable monoclonal free light chains (FLCs), which form amyloid fibrils that deposit in the interstitial tissue, resulting in organ injury and dysfunction. AL amyloidosis progresses much faster than other types of amyloidosis, with a slight delay in diagnosis leading to a marked exacerbation of cardiomyopathy. In some cases, the resulting heart failure is so severe that chemotherapy cannot be administered, and death sometimes occurs within a few months. To date, many clinical studies have focused on therapeutics, especially chemotherapy, to treat this disease. Because it is necessary to promptly lower FLC, the causative protein of amyloid, to achieve a hematological response, various anticancer agents targeting neoplastic plasma cells are used for the treatment of this disease. In addition, many basic studies using human specimens to elucidate the pathophysiology of AL have been conducted. Gene mutations associated with AL, the characteristics of amyloidogenic LC, and the structural specificity of amyloid fibrils have been clarified. Regarding the mechanism of cellular and tissue damage, the mass effect due to amyloid deposition, as well as the toxicity of pre-fibrillar LC, is gradually being elucidated. This review outlines the pathogenesis and treatment strategies for AL amyloidosis with respect to its molecular mechanisms.

Erythroderma as a Paraneoplastic Cutaneous Disorder in Mantle Cell Lymphoma: A Case Report and Literature Review of Molecular Insights into Physiopathology

Mantle Cell Lymphoma (MCL) is a lymphohematopoietic cancer of follicular origin and diffuse growth. It is a rare small B-cell lymphoma, with an incidence of 7-10% of all non-Hodgkin lymphomas, affecting adults (55-60 years), of which 80% are typically male. According to the World Health Organization guidelines, the diagnosis of MCL should be established based on morphological examination and immunophenotyping with detection of cyclin D1 resulting from the chromosomal translocation t(11;14)(q13;q32) of the CCND1 gene or SOX11 protein overexpression. Herein we present an infrequent clinical case of a female patient with MCL who presented erythroderma as a paraneoplastic cutaneous disorder. Moreover, we delved into the molecular insights of immune B-cell lymphocytic affections in this communication.

Mesangial proliferative glomerulonephritis with monoclonal immunoglobulin deposits: why nephrobiopsy is crucial

Proliferative glomerulonephritis (GN) with monoclonal immunoglobulin deposits (PGNMIDs) is a recently described entity among the spectrum of monoclonal gammopathy of renal significance (MGRS). The disease is renal limited and manifests in chronic glomerular disease, altered renal function and albuminuria, sometimes in the nephrotic range. Acute nephritic syndrome is rare. Until recently, in the absence of criteria for symptomatic haematological disease, patients with monoclonal Ig-related nephropathies often experienced difficulties in getting appropriate chemotherapy. Noticeable progress in management was achieved with the introduction of the concept of monoclonal gammopathy of renal significance, which distinguishes the situation of nephropathies induced by dangerous small B-cell clones from that of monoclonal gammopathy of undetermined significance (MGUS) that does not feature any end-organ damage. Monoclonal gammapathy of renal significance is not an independent kidney disease, not “chronic glomerulonephritis”, but a condition in which kidney damage is secondary to clonal B-cell proliferation. In other words, MGRS is a precancerous disease combined with chronic kidney disease that requires immediate treatment. Renal prognosis is poor, with progression to end stage renal disease in 25 % of patients within 30 months and frequent early recurrence on the renal allograft. However, recent studies indicate that clone-targeted chemotherapy may significantly improve renal outcomes, opening future perspectives for the management of this rare disease.

A novel diagnostic approach for the classification of small B-cell lymphoid neoplasms based on the NanoString platform

Small B-cell lymphoid neoplasms (SBCLNs) are a heterogeneous group of diseases characterized by malignant clonal proliferation of mature B-cells. However, the classification of SBCLNs remains a challenge, especially in cases where histopathological analysis is unavailable or those with atypical laboratory findings or equivocal pathologic data. In this study, gene expression profiling of 1039 samples from 27 gene expression omnibus (GEO) datasets was first investigated to select highly and differentially expressed genes among SBCLNs. Samples from 57 SBCLN cases and 102 nonmalignant control samples were used to train a classifier using the NanoString platform. The classifier was built by employing a cascade binary classification method based on the random forest algorithm with 35 refined gene signatures. Cases were successively classified as chronic lymphocytic leukemia/small lymphocytic lymphoma, conventional mantle cell lymphoma, follicular lymphoma, leukemic non-nodal mantle cell lymphoma, marginal zone lymphoma, lymphoplasmacytic lymphoma/Waldenström's macroglobulinemia, and other undetermined. The classifier algorithm was then validated using an independent cohort of 197 patients with SBCLNs. Under the distribution of our validation cohort, the overall sensitivity and specificity of proposed algorithm model were >95%, respectively, for all the cases with tumor cell content greater than 0.72. Combined with additional genetic aberrations including IGH-BCL2 translocation, MYD88 L265P mutation, and BRAF V600E mutation, the optimal sensitivity and specificity were respectively found at 0.88 and 0.98. In conclusion, the established algorithm demonstrated to be an effective and valuable ancillary diagnostic approach for the sub-classification and pathologic investigation of SBCLN in daily practice.

Research progress on epigenetics of small B-cell lymphoma.

Small B-cell lymphoma is the classification of B-cell chronic lymphoproliferative disorders that include chronic lymphocytic leukaemia/small lymphocytic lymphoma, follicular lymphoma, mantle cell lymphoma, marginal zone lymphoma, lymphoplasmacytic lymphoma/Waldenstrom macroglobulinemia. The clinical presentation is somewhat heterogeneous, and its occurrence and development mechanisms are not yet precise and may involve epigenetic changes. Epigenetic alterations mainly include DNA methylation, histone modification, and non-coding RNA, which are essential for genetic detection, early diagnosis, and assessment of treatment resistance in small B-cell lymphoma. As chronic lymphocytic leukemia/small lymphocytic lymphoma has already been reported in the literature, this article focuses on small B-cell lymphomas such as follicular lymphoma, mantle cell lymphoma, marginal zone lymphoma, and Waldenstrom macroglobulinemia. It discusses recent developments in epigenetic research to diagnose and treat this group of lymphomas. This review provides new ideas for the treatment and prognosis assessment of small B-cell lymphoma by exploring the connection between small B-cell lymphoma and epigenetics.

Myeloid nuclear differentiation antigen: an aid in differentiating lymphoplasmacytic lymphoma and splenic marginal zone lymphoma in bone marrow biopsies at presentation

The differential diagnosis between lymphoplasmacytic lymphoma (LPL) and marginal zone B-cell lymphoma, particularly splenic type (SMZL), can be challenging on onset of bone marrow biopsy (BMB) since morphology and phenotype are not specific and clinical features can overlap or be mildly developed at diagnosis. The LPL-specific L265P mutation in the MYD88 gene is not available in all laboratories, and genetic aberrancies identified in SMZL (del7q, mutations of NOTCH2 and KLF2) are seldom searched in routine practice. The study aim is to investigate the potential role of myeloid nuclear differentiation antigen (MNDA) expression in this specific differential diagnosis. We report MNDA reactivity in 559 patients with small B-cell lymphoma including bone marrow biopsies from 90 LPL and 91 SMZL cases. MYD88 p.Leu265Pro mutation status was assessed and confirmed as positive in 24 of 90 LPL cases, which served as the test set. MNDA staining was negative in 23 of 24 LPL cases in the test set (96%). In the 157 remaining cases (66 LPL, 91 SMZL), which served as the validation set, the MYD88 p.Leu265Pro mutation was unavailable and MNDA was more frequently expressed in SMZL (p<0.00001). In addition, immunohistochemical features more consistent with SMZL (i.e., presence of CD23+ follicular dendritic cell meshworks, polytypic plasma cells, DBA44 reactivity) were more often present in MNDA-positive cases (statistically significant for 2 such parameters). On the widest case series so far published focusing on LPL and SMZL immunohistochemical diagnosis at onset of BMB, we demonstrated that MNDA expression significantly support the diagnosis of SMZL. This observation may be of particular help in cases where the MYD88 p.Leu265Pro mutational status and/or SMZL-related genetic aberrations are unavailable.

Monitoring Patients with Light Chain (AL) Amyloidosis during and after Therapy: Response Assessment and Identification of Relapse

Light chain amyloidosis is a complex disease where a small B-cell clone produces a monoclonal immunoglobulin light chain that causes deposits and specific organ dysfunction. The available treatment strategies aim to reduce or eliminate amyloidogenic light chain production in order to avoid amyloid deposition and allow the repair of organ damage. An international effort allowed the definition of validated hematologic and organ response criteria based on biomarkers. Recently, new methods for the assessment of minimal residual disease were also proposed but still need international validation. Lastly, a joint effort is also required to accurately define relapse/progression criteria in order to apply timely therapeutic interventions. In this review, we describe the validated response criteria and report on the future direction for the definition of progression criteria in this disease.

Immunohistochemistry for LEF1 and SOX11 adds diagnostic specificity in small B-cell lymphomas

Lymphocyte enhancer-binding factor 1 (LEF1) and SRY-Box 11 (SOX11) are highly sensitive and specific for chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and mantle cell lymphoma (MCL) including the cyclin D1-negative subtype, respectively. We assessed the utility of these markers in a large cohort of small B-cell lymphomas (SBCLs) on varied sample types. Immunohistochemistry (IHC) was performed for LEF1 and SOX11 on 354 SBCLs (129 CLL/SLLs, 33 MCLs, 142 marginal zone lymphomas [MZLs]-nodal MZL [NMZL]: 40, extranodal MZL [ENMZL]: 28, splenic MZL [SMZL]: 74 cases-and 50 lymphoplasmacytic lymphomas [LPLs]/Waldenstrom macroglobulinemias [WMs]). Ninety-eight percent of CLL/SLLs were LEF1 positive. SOX11 showed good sensitivity (82%) and excellent specificity for MCL (99%), with only 2 of 142 MZLs (both SMZLs) showing SOX11 expression. The low sensitivity for SOX11 was on account of inclusion of 4 non-nodal cases. All 50 LPL/WMs were negative for both LEF1 and SOX11. The expression of SOX11 and LEF1 was not always mutually exclusive, as 2 confirmed MCLs expressed both markers. LEF1 and SOX11 have excellent utility as diagnostic markers especially for atypical CD5-positive SBCLs.

IGH/BCL2 Status Better Predicts Clinico-Pathological Behavior in Primary Splenic Follicular Lymphoma than Histological Grade and Other Molecular Markers.

Splenic lymphoma may be primary or secondary. Primary splenic lymphoma’s are rare and usually of follicular cell origin representing <1% of Non-Hodgkin’s Lymphoma’s. Most are secondary with 35% representing Marginal Cell sub-type with the rest being Diffuse Large B-Cell Lymphoma’s. Unlike the uniformly aggressive clinical course of Diffuse Large B-Cell Lymphoma’s, biological behavior of Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma remains less well defined. We present here a solitary splenic mass confirmed as Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma after a diagnostic splenectomy. Biopsy revealed monomorphic small lymphoid cells with low grade mitotic activity. Flow cytometry showed a lambda restricted population of B-Cells displaying dim CD19 and CD10. The cells were negative for CD5, CD11c, and CD103. FISH was negative for IGH/BCL2 fusion unlike nodal Follicular Lymphoma’s which are usually positive for this translocation. Evidence from this case and a review of literature support the finding that Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma is less likely to have the classic IGH-BCL2 fusion and the associated chromosomal 14;18 translocation. This profile is associated with less aggressive clinical behavior even when histopathology represents a high-grade pattern. In such cases splenectomy alone is adequate for localized disease when negative for IGH/BCL2 fusion regardless of histological grade.

A Review on Splenic Diffuse Red Pulp Small B-Cell Lymphoma.

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is a rare disease, representing <1% of all non-Hodgkin lymphomas (NHL). The most common clinical manifestations include splenomegaly, lymphocytosis, and hemocytopenia. A diagnosis of SDRPL can be challenging, as it shares multiple clinical and laboratory features with splenic marginal zone lymphoma (SMZL), hairy cell leukemia (HCL), and HCL variant (HCL-v). Obtaining splenic tissue remains the gold standard for diagnosis. In the cases where splenic tissue is not available, diagnosis can be established by a review of peripheral blood and bone marrow studies. SDRPL is characterized by a diffuse involvement of the splenic red pulp by monomorphous small-to-medium sized mature B lymphocytes effacing the white pulp. The characteristic immunophenotype is positive for CD20, DBA.44 (20 to 90%), and IgG, and typically negative for CD5, CD10, CD23, cyclin D1, CD43, annexin A1, CD11c, CD25, CD123, and CD138. The Ki-67 proliferative index is characteristically low. Cyclin D3 is expressed in the majority of SDRPL in contrast with other types of small B-cell lymphomas, thus facilitating the recognition of this disease. There is no standard treatment regimen for SDRPL. Initial treatment options include splenectomy, rituximab monotherapy, or a combination of both. Chemoimmunotherapy should be considered in patients with advanced disease at baseline or progression.

CD5-Negative, CD10-Negative Low-Grade B-Cell Lymphoproliferative Disorders of the Spleen.

CD5-negative, CD10-negative low-grade B-cell lymphoproliferative disorders (CD5-CD10-LPD) of the spleen comprise a fascinating group of indolent, neoplastic, mature B-cell proliferations that are essential to accurately identify but can be difficult to diagnose. They comprise the majority of B-cell LPDs primary to the spleen, commonly presenting with splenomegaly and co-involvement of peripheral blood and bone marrow, but with little to no involvement of lymph nodes. Splenic marginal zone lymphoma is one of the prototypical, best studied, and most frequently encountered CD5-CD10-LPD of the spleen and typically involves white pulp. In contrast, hairy cell leukemia, another well-studied CD5-CD10-LPD of the spleen, involves red pulp, as do the two less common entities comprising so-called splenic B-cell lymphoma/leukemia unclassifiable: splenic diffuse red pulp small B-cell lymphoma and hairy cell leukemia variant. Although not always encountered in the spleen, lymphoplasmacytic lymphoma, a B-cell lymphoproliferative disorder consisting of a dual population of both clonal B-cells and plasma cells and the frequent presence of the MYD88 L265P mutation, is another CD5-CD10-LPD that can be seen in the spleen. Distinction of these different entities is possible through careful evaluation of morphologic, immunophenotypic, cytogenetic, and molecular features, as well as peripheral blood and bone marrow specimens. A firm understanding of this group of low-grade B-cell lymphoproliferative disorders is necessary for accurate diagnosis leading to optimal patient management.

How to Diagnose and Treat CD5-Positive Lymphomas Involving the Spleen.

Patients with CD5-expressing lymphomas presenting with splenomegaly are frequently diagnosed with chronic lymphocytic leukemia. The most important differential diagnosis is mantle cell lymphoma, both in its classical and leukemic, non-nodal forms, given its prognostic and therapeutic implications. Other small B-cell neoplasms that frequently involve the spleen and occasionally express CD5 include the splenic marginal zone lymphoma, hairy cell leukemia and, rarely, lymphoplasmacytic lymphoma. The frequency of CD5 positivity depends in part on the sensitivity of the detection methods employed. Usually, a combination of morphological, immunophenotypic and molecular findings allows for a precise sub-classification of CD5-positive, low-grade B-cell lymphomas of the spleen. Some of these tumors may display a mixture of small and larger B cells, raising the possibility of more aggressive lymphomas, such as diffuse large B-cell lymphomas (DLBCL). Approximately 5–10% of DLBCL are CD5-positive and some may manifest as primary splenic lesions. When available, the morphology of DLBCL in the splenic tissue is distinctive and a leukemic picture is very rare. In conclusion, the appropriate morphological and clinical context assisted by flow cytometry panels and/or immunohistochemistry allows the differential diagnosis of CD5-positive, non-Hodgkin, B-cell lymphomas involving the spleen.