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AbstractMonoclonal gammopathy has been reported to interfere with several laboratory measurement results. We investigated potential interference in monoclonal gammopathy on immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations using three different routine chemistry instruments: Alinity (Abbott Laboratories), Cobas 8000 (Roche Diagnostics) and Optilite (Binding Site) at the Department of Clinical Biochemistry, Aalborg University Hospital, Denmark. Blood samples collected from 216 patients with known monoclonal gammopathy were analyzed on Alinity, Cobas and Optilite. Diagnoses were ascertained from clinical records. Scatter plots with Passing-Bablok regression were used to investigate associations between concentrations of IgA, IgG and IgM measured with each of the different instruments. Furthermore, comparison of IgG analyses on Alinity, Optilite and Cobas according to monoclonal IgM concentration was explored with Bland-Altman plots. A total of 81 patients were identified with IgM type monoclonal gammopathy and 8 of these patients (10%) had analytical interference as reflected by more than 25% decrease in the level of IgG measured on Alinity as compared to Optilite and Cobas. All blood samples with interference on IgG measurement using Alinity were from patients with lymphoplasmacytic lymphoma/Waldenströms macroglobulinemia and all of them had monoclonal IgM concentrations above 10 g/L. This study identified a source of interference from IgM monoclonal gammopathy on IgG measurement performed using Alinity. The interferences caused falsely low results of IgG which is important to recognize to ensure proper patient management. [ABSTRACT FROM AUTHOR]

Purpose of Review: Waldenström macroglobulinemia is a rare non-Hodgkin lymphoma (NHL) characterized by lymphoplasmacytic bone marrow infiltration associated with an immunoglobulin M (IgM) monoclonal gammopathy. Over the past two decades, a number of important novel therapies have emerged for the treatment of relapsed and refractory (R/R) WM. The purpose of this review is to discuss these novel agents. Recent Findings: Chemoimmunotherapy which formed the basis treatment for R/R WM is slowly being replaced by novel targeted agents. These therapies, including Bruton's tyrosine kinase inhibitors, proteasome inhibitors, and B-cell lymphoma 2 inhibitors, have widened the landscape of management. Emerging therapies currently under investigation, such as bispecific T-cell engagers, chimeric antigen T-cell receptor therapy, and novel small molecule inhibitors, have additionally shown the potential to improve response and survival. Summary: The treatment of R/R WM has greatly evolved, in large part due to a greater understanding of the biology of WM, and the evaluation of novel targeted agents in the basket trials of NHL, showing early activity in the small WM cohorts. Combination regimens with these established and emerging novel therapies have the potential to further improve disease control and induce higher rates of deep responses. Strategies aimed at altering the disease trajectory would require randomized controlled trials to provide relevant data on optimal integration and sequencing of more effective and tolerable regimens earlier in the disease course. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM) is a chronic B-cell lymphoproliferative disorder characterized by lymphoplasmacytic cell overgrowth in the bone marrow and increased secretion of IgM immunoglobulins into the serum. Patients with WM have a variety of clinical outcomes, including long-term survival but inevitable recurrence. Recent advances in disease knowledge, including molecular and genetic principles with the discovery of MYD88 and CXCR4 mutations, have rapidly increased patient-tolerable treatment options. WM patients may benefit from chemotherapy regimens that include rituximab-based regimens, alkylating drugs, proteasome inhibitors, monoclonal antibodies, and drugs targeting Bruton tyrosine kinase inhibitors. In light of these advancements, patients can now receive treatment customized to their specific clinical characteristics, focusing on enhancing the depth and durability of their response while limiting the adverse effects. Despite the rapidly developing therapeutic armament against WM, a lack of high-quality evidence from extensive phase 3 trials remains a significant challenge in the research. We believe clinical outcomes will keep improving when new medicines are introduced while preserving efficacy and minimizing toxicity. [ABSTRACT FROM AUTHOR]

Lymphoplasmacytic lymphoma (LPL) is a relatively rare form of indolent B-cell non-Hodgkin’s lymphoma, termed Waldenström’s macroglobulinaemia (WM) in the presence of an IgM paraprotein. Although traditionally treated with combination chemoimmunotherapy, the management is evolving in the era of targeted molecular therapies including Bruton’s tyrosine kinase inhibitors (BTKi). However, intolerance and refractoriness to BTKi mean newer agents are required, and the prognosis of so-called quadruple-refractory patients is poor. BCL2 is an anti-apoptotic, pro-survival protein that promotes lymphoma cell survival. Inhibition of BCL2 using first-in-class agent venetoclax has already altered the treatment paradigm in other conditions, including chronic lymphocytic leukaemia (CLL). In-vivo inhibition of BCL2 has been shown to lead to apoptosis of LPL/WM cells. Five studies have published results on the use of BCL2 inhibitors in WM to date, including oblimersen sodium, venetoclax, and sonrotoclax. Fixed-duration venetoclax resulted in high response rates, but many patients relapsed following the completion of therapy. The combination of venetoclax with ibrutinib resulted in higher and relatively deep response rates, but unexpected deaths due to ventricular events mean this combination cannot be explored. Two pivotal trials are currently evaluating the use of fixed-duration venetoclax, either in combination with rituximab or pirtobrutinib, whereas another multi-arm study is studying the use of continuous sonrotoclax monotherapy for R/R WM or in fixed-duration combination with Zanubrutinib for treatment-naïve patients. The potential role of BCL2 inhibitors in WM/LPL remains under study, with many hopeful that they may provide an additional chemotherapy-free oral alternative for patients requiring treatment. In an indolent condition with existing effective treatment regimens, including CIT and cBTKi, cost-effectiveness and toxicity profile will be key, although an additional treatment modality for quadruple-refractory patients with limited treatment options is urgently required.

Waldenström macroglobulinaemia (WM) is a unique, cluster of differentiation (CD) 20+ B‐cell malignancy, with a characteristic immunoglobulin M‐secreting lymphoplasmacytic bone marrow infiltrate that is bolstered by a highly supportive microenvironment, including upregulated programmed death 1 expression. However, the impact of checkpoint inhibition in WM is unclear.Commentary on: Kothari et al. PembroWM: A phase II trial to investigate the safety and efficacy of rituximab and pembrolizumab in relapsed/refractory Waldenström's macroglobulinaemia. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19706. [ABSTRACT FROM AUTHOR]

The B cell receptor (BCR) signaling pathway plays a crucial role in B cell development and contributes to the pathogenesis of B cell neoplasms. In B cell malignancies, the BCR is constitutively active through both ligand-dependent and ligand-independent mechanisms, resulting in continuous Bruton tyrosine kinase (BTK) signaling activation, which provides a survival and proliferation advantage to the neoplastic clone. Among B cell malignancies, those in which the most significant results were obtained by treatment with BTK inhibitors (BTKi) include chronic lymphocytic leukemia, mantle cell lymphoma, lymphoplasmacytic lymphoma, and diffuse large B cell lymphoma. Covalent BTKi (namely ibrutinib, acalabrutinib, and zanubrutinib) functions by irreversibly blocking BTK through covalent binding to the cysteine residue 481 (Cys-481) in the ATP-binding domain. Despite the high efficacy and safety of BTKi treatment, a significant fraction of patients affected by B cell malignancies who are treated with these drugs experience disease relapse. Several mechanisms of resistance to covalent BTKi, including Cys-481 mutations of BTK, have been investigated in B cell malignancies. Non-covalent BTKi, such as pirtobrutinib, have been developed and proven effective in patients carrying both Cys-481-mutated and unmutated BTK. Moreover, targeting BTK with proteolysis-targeting chimeras (PROTACs) represents a promising strategy to overcome resistance to BTKi in B cell neoplasms. [ABSTRACT FROM AUTHOR]

Lymphoplasmacytic lymphoma (LPL) is a rare variant of non‐Hodgkin lymphoma, accounting for <1% of cases. Skin involvement in LPL is quite rare—accounting for approximately 5% of extramedullary disease—and includes a variety of clinical morphologies, such as erythematous‐to‐violaceous plaques, violaceous nodules or tumors, and ulceration at various anatomical sites. Herein, we report the case of a 45‐year‐old Korean woman who presented with generalized erythematous indurated plaques and pendulous skin growths, which were asymptomatic, with marked diffuse infiltration of lymphocytes and plasma cells in the dermis. Immunohistochemical studies revealed that the lymphoid cells expressed CD3, CD79a, and cytoplasmic IgG, but lacked CD10 and IgM. Moreover, kappa light chain restriction and monoclonal immunoglobulin heavy chain gene rearrangement were observed. Upon further workup, lymphoma involvement was reported in multiple lymph nodes, including those in the cervical and axillary regions. This case shows a unique form of cutaneous LPL clinically presenting as acquired cutis laxa, emphasizing the dermatologists' need to be vigilant for variant forms of this disease. [ABSTRACT FROM AUTHOR]

Lymphoplasmacytic lymphoma often needs to be differentiated from other B-cell lymphomas with plasmacytic differentiation, especially marginal zone cell lymphoma. Molecular detection of MYD88 p.L265P hotspot mutation supports the diagnosis of lymphoplasmacytic lymphoma since it is seen in about 90% of such lymphoma, which is much higher than other B-cell lymphomas. MYD88 p.L265P is a gain-of-function mutation that enhances the activity of the NF-κB signaling pathway and therefore drives lymphomagenesis. Other mutations in MYD88 are rarely reported. This study aims to report an unusual MYD88 in-frame deletion in an aggressive lymphoplasmacytic neoplasm. This is an IgM-positive, CD5- and CD10-negative mature B-cell lymphoma with prominent plasmacytic differentiation and aggressive features. The clinical and pathologic findings were most consistent with lymphoplasmacytic lymphoma. Next-generation sequencing identified an unusual MYD88 in-frame deletion in the absence of the hotpot p.L265P mutation. Other concurrent pathogenic mutations also include truncating mutations of TRAF3, which is a negative regulator of the NF-κB signaling pathway, and a missense mutation of TP53. Karyotype analysis showed complex karyotypes, including chromosome 6q deletion. By searching literature and online cancer databases, we identified only 8 other mature B-cell lymphomas with MYD88 in-frame deletions, but none of them was diagnosed with lymphoplasmacytic lymphoma. Recognizing such in-frame deletions is necessary to help understand the mutational spectrum of MYD88 in B-cell lymphomas. It remains to be further investigated whether such MYD88 in-frame deletions are also overrepresented in lymphoplasmacytic lymphoma among other B-cell lymphomas. [ABSTRACT FROM AUTHOR]

We performed a molecular analysis of formalin-fixed paraffin embedded and decalcified bone marrow trephine biopsies of 41 patients with a B-cell disorder with lymphoplasmacytic differentiation to enable a more precise diagnosis and to describe potentially prognostic and therapeutic relevant mutations. Analysis was performed with a commercially available next-generation sequencing (NGS) lymphoma panel (Lymphoma Solution, SophiaGenetics). Results were correlated with clinical and pathological parameters. Our group covered a spectrum of B-cell disorders with plasmacytic differentiation ranging from Waldenstroem's macroglobulinemia (WM), to small-B-cell lymphomas with plasmacytic differentiation (SBCL-PC) to IgM myeloma (MM). The most helpful diagnostic criteria included morphology and immuno-phenotype as a prerequisite for the interpretation of molecular analysis. MYD88 mutation was present in nearly all WM, but also in 50% of SBCL-PCs, while MM were consistently negative. Driver mutations, such as TP53, were already detectable early in the course of the respective diseases indicating a higher risk of progression, transformation, and reduced progression-free survival. In addition, we report on a novel BIRC3 frameshift mutation in one case of a progressive WM. Our data indicate that patients with LPL/WM might benefit from thorough pathological work-up and detailed molecular analysis in terms of precise diagnosis and targeted treatment allocation. [ABSTRACT FROM AUTHOR]

Background: Waldenstroms macroglobulinemia (WM) or Lymphoplasmacytic lymphoma is a rare B cell lymphoproliferative malignancy characterized by serum monoclonal immunoglobulin M (IgM) protein and lymphoplasmacytic infiltration in the bone marrow. Patients usually present in their seventh decade with symptoms related to the infiltration of the marrow or the effects of monoclonal IgM in the blood. Objective: Was to study the clinical characteristics and treatment outcome of patients diagnosed with WM. Materials and methods: This is a retrospective analysis of 26 cases of WM treated at a tertiary cancer centre. Results: WM constituted 0.68% of our nonHodgkin's lymphoma. The median age at presentation was 67 years with a male to female ratio of 2:1. Four patients had lymphadenopathy, six had splenomegaly and four patients had evidence of hyper viscosity. All patients had IgM paraproteinemia, the M band was IgM-kappa in 19 patients and IgM-lambda in seven patients. All patients had a histopathological confirmation. According to IPSS-WM, 12 patients each were in the intermediate and high risk group and 2 in the low risk group. Among the 26 patients, 20 patients received upfront treatment and four patients were kept under observation. The indications for treatment were cytopenia in ten patients, constitutional symptoms in five, hyper viscosity in four and symptomatic lymphadenopathy in one patient. Sixteen patients received rituximab-based chemotherapy. Four patients with features with hyper viscosity underwent plasmapheresis. The three year progression free survival and overall survival were 69.4% and 78 % respectively. Conclusions: WM is a low grade B cell lymphoproliferative disorder having an indolent course and do not require treatment for prolonged period. Diagnosis is challenging due to lack of distinct diagnostic features. Rituximab containing regimens are the standard of care. Newer targeted treatment options may improve the outcome of this incurable disease. [ABSTRACT FROM AUTHOR]

Introduction: Bing-Neel syndrome (BNS) is a rare and heterogenous manifestation of Waldenström macroglobulinemia (WM) involving central nervous system (CNS) infiltration by malignant lymphoplasmacytic cells. Efforts to standardize diagnostic criteria have improved in recent years, as have treatment options including the use of the Bruton tyrosine kinase inhibitor (BTKI) ibrutinib. Case Presentation: Here, we present the case of a 70-year-old male with a remote history of WM previously treated with bendamustine and rituximab, who presented to medical attention with several months of left-sided weakness, headache, and ataxia. Brain magnetic resonance imaging revealed numerous enhancing masses in the bilateral cerebral hemispheres, inferior medulla, and upper cervical spine. Laboratory studies showed serum IgM lambda monoclonal gammopathy and elevated free serum kappa and lambda light chains, while cerebrospinal fluid flow cytometry revealed CD19+ B cells. Stereotactic brain biopsy of a right frontal brain lesion was consistent with lymphoplasmacytic lymphoma, confirmed by a positive MYD88 L265P mutation. He received ibrutinib 420 mg orally daily, and this resulted in appreciable clinical and radiologic responses, which have persisted over a 31-month period. Conclusion: The advent of molecularly targeted agents and novel therapies for WM has provided patients and clinicians with additional therapeutic options. The use of BTK inhibitors with their high-level CNS penetrance, in particular, offers a novel way to treat BNS and improve patient overall survival while maintaining a high level of quality of life. We discuss the importance of MYD88 L265P testing in the context of BNS as well as the expanding role of BTKIs in treating this disease.

Waldenström macroglobulinemia (WM) rarely leads to pulmonary embolism. Due to its low incidence, the underlying pathophysiology, prognosis, and optimal treatment remain largely unexplored and uninvestigated. In this study, a patient with a double-clonal WM, a rare subtype, presented with pulmonary embolism. The patient had a small number of plasma cells without morphological abnormalities, and an effective therapeutic response was observed. Nonetheless, the clinical prognosis requires a long-term follow-up.

Introduction: Waldenström macroglobulinemia (WM) represents a subset of lymphoplasmacytic lymphoma (LPL) with the immunoglobulin (Ig)M paraprotein. MYD88 L265P and CXCR4 mutations are common mutations in WM patients, and mutations in ARID1A and KMT2D (MLL2) have also been reported. However, little information has been accumulated on genetic changes in LPL with other paraproteins like IgG. Methods: We therefore aimed to evaluate genetic differences between WM and LPL with non-IgM paraprotein (non-IgM-type LPL) using targeted next-generation sequencing (NGS) in 20 Japanese patients (10 with WM, 10 with non-IgM-type LPL). Results: Mutations were detected in ARID1A (10%), CXCR4 (20%), MYD88 (90%), and KMT2D (0%) for WM patients and in ARID1A (10%), CXCR4 (20%), MYD88 (70%), and KMT2D (10%) for non-IgM-type LPL patients. No significant differences were identified. No mutations were detected in NOTCH2, PRDM1, CD274 (PD-L1), PDCD1LG2 (PD-L2), RAG2, MYBBP1A, TP53, or CD79B. Discussion: Mutant allele frequency in MYD88 L265P did not differ significantly between WM and non-IgM-type LPL. Most mutations detected by NGS were subclonal following MYD88 L265P, although one non-IgM-type LPL patient harbored only CXCR4 S338X mutation. Our NGS analyses reveal genetic characteristics in LPL patients and suggest genetic similarities between these two subsets of LPL, WM and non-IgM-type. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM) is a rare, non-Hodgkin lymphoma that remains incurable. Rituximab, an anti-CD20 monoclonal antibody has been the cornerstone of treatment against WM, and its combination with an alkylator, bendamustine, achieves durable remission in treatment-naive patients with symptomatic WM. However, novel “druggable” targets that have been identified within the clonal lymphoplasmacytic cells in WM have resulted in a rapid development of targeted therapies in both the frontline and relapsed and refractory (R/R) settings. Several agents directed against the known targets have shown promising efficacy, with mostly manageable toxicities. The class of Bruton’s tyrosine kinase (BTK) inhibitors has transformed the therapeutic landscape for patients with WM, given their convenient oral dosing and strong efficacy, with high rates of attainment of very good partial response (VGPR). The tolerability of the next-generation BTK inhibitors appears to be superior to that of the first-in-class agent, ibrutinib. Targeted therapies from other classes have also demonstrated efficacy in both single-agent and combination regimens. Inhibitors of proteasome BCL-2, mTOR and PI-3 kinase have demonstrated efficacy in WM. Emerging therapies under investigation will continue to further shape the management paradigm, especially in the R/R setting. These include bispecific antibodies, radiotherapeutic agents and chimeric antigen receptor T-cell (CART) cell therapies. This review outlines the current literature and future direction of targeted therapies in WM.

The B cell receptor (BCR) signaling pathway plays a crucial role in B cell development and contributes to the pathogenesis of B cell neoplasms. In B cell malignancies, the BCR is constitutively active through both ligand-dependent and ligand-independent mechanisms, resulting in continuous Bruton tyrosine kinase (BTK) signaling activation, which provides a survival and proliferation advantage to the neoplastic clone. Among B cell malignancies, those in which the most significant results were obtained by treatment with BTK inhibitors (BTKi) include chronic lymphocytic leukemia, mantle cell lymphoma, lymphoplasmacytic lymphoma, and diffuse large B cell lymphoma. Covalent BTKi (namely ibrutinib, acalabrutinib, and zanubrutinib) functions by irreversibly blocking BTK through covalent binding to the cysteine residue 481 (Cys-481) in the ATP-binding domain. Despite the high efficacy and safety of BTKi treatment, a significant fraction of patients affected by B cell malignancies who are treated with these drugs experience disease relapse. Several mechanisms of resistance to covalent BTKi, including Cys-481 mutations of BTK, have been investigated in B cell malignancies. Non-covalent BTKi, such as pirtobrutinib, have been developed and proven effective in patients carrying both Cys-481-mutated and unmutated BTK. Moreover, targeting BTK with proteolysis-targeting chimeras (PROTACs) represents a promising strategy to overcome resistance to BTKi in B cell neoplasms.

Lymphoplasmacytic lymphoma (LPL) is a neoplasm of small B lymphocytes, plasmacytoid lymphocytes and plasma cells usually involving the bone marrow (BM). A subset of LPL which is associated with IgM monoclonal gammopathy is called Waldenstrom's macroglobulinaemia (WM), and usually requires therapeutic intervention when a patient becomes symptomatic (Bone Marrow failure characterised by cytopenia or hyperviscosity syndrome). Here, we report the case of an 80-year-old female with clinically unsuspected WM who initially presented to the Emergency Department (ED) with nausea and vomiting. The patients' gastrointestinal symptoms subsequently settled and was awaiting discharge. Non-specific, borderline size significant lymph nodes on CT chest was the only substantial past medical history. The diagnosis of WM was made after the Biochemistry Biomedical Scientist (BMS) detected the presence of a Type I monoclonal cryoglobulin. A potential cryoprecipitate was suspected when repeated 'clotting' error flags occurred during routine laboratory analyses; the sample aspiration difficulties being attributed to the viscous nature of the sample. The investigation of inaccessible low volume lymphadenopathy in the elderly should include serum protein electrophoresis and immunoglobulins as this may have established an earlier diagnosis in this case. The application of good scientific principles informed the laboratory investigation and resulted in the identification of a large IgM monoclonal cryoglobulin that prompted further appropriate investigations resulting in the diagnosis of WM. This case also highlights the importance of good communication between the laboratory and clinical staff. [ABSTRACT FROM AUTHOR]

Objectives To summarize the conclusions of the 2021 Society for Hematopathology/European Association for Haematopathology workshop regarding transformations of marginal zone lymphoma (MZL) and lymphoplasmacytic lymphoma (LPL). Methods Nineteen cases were submitted to this portion of the workshop. Additional studies were performed in cases with sufficient material. Results Cases included splenic MZL (n = 4), splenic diffuse red pulp small B-cell lymphoma (n = 2), nodal MZL (n = 4), extranodal MZL (n = 1), and LPL (n = 8). The most common transformation was to diffuse large B-cell lymphoma (DLBCL), but others included classic Hodgkin lymphoma, high-grade B-cell lymphomas with MYC and BCL6 rearrangements, plasmablastic lymphoma, and plasma cell leukemia. Two splenic MZLs with transformation to DLBCL contained t(14;19)(q32;q13.3) IGH::BCL3 rearrangements in both samples. Paired sequencing studies in 5 MZLs with transformation to clonally related DLBCL identified a variety of mutations and gene fusions at the time of transformation, including CARD11, IGH::MYC, NOTCH2, P2RY8, TBLX1X1, and IGH::CD274. Conclusions Marginal zone lymphoma and LPL may undergo a variety of transformation events, most commonly to DLBCL, which is usually, although not always, directly clonally related to the underlying low-grade lymphoma. Multiparameter analysis including broad-based sequencing studies can assist in the diagnosis and classification of these uncommon cases. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM) is a rare, non-Hodgkin lymphoma that remains incurable. Rituximab, an anti-CD20 monoclonal antibody has been the cornerstone of treatment against WM, and its combination with an alkylator, bendamustine, achieves durable remission in treatment-naive patients with symptomatic WM. However, novel "druggable" targets that have been identified within the clonal lymphoplasmacytic cells in WM have resulted in a rapid development of targeted therapies in both the frontline and relapsed and refractory (R/R) settings. Several agents directed against the known targets have shown promising efficacy, with mostly manageable toxicities. The class of Bruton's tyrosine kinase (BTK) inhibitors has transformed the therapeutic landscape for patients with WM, given their convenient oral dosing and strong efficacy, with high rates of attainment of very good partial response (VGPR). The tolerability of the next-generation BTK inhibitors appears to be superior to that of the first-in-class agent, ibrutinib. Targeted therapies from other classes have also demonstrated efficacy in both single-agent and combination regimens. Inhibitors of proteasome BCL-2, mTOR and PI-3 kinase have demonstrated efficacy in WM. Emerging therapies under investigation will continue to further shape the management paradigm, especially in the R/R setting. These include bispecific antibodies, radiotherapeutic agents and chimeric antigen receptor T-cell (CART) cell therapies. This review outlines the current literature and future direction of targeted therapies in WM. [ABSTRACT FROM AUTHOR]

Abstract Background Waldenström macroglobulinemia is a rare hematological malignancy and is the most common diagnosis in patients with hyperviscosity syndrome. Bilateral central retinal vein occlusion as an initial presentation of hyperviscosity syndrome in Waldenström macroglobulinemia is rare. Case presentation A 42-year-old Nepalese male presented with sudden-onset bilateral painless blurring of vision. Fundus examination revealed bilateral, diffusely dilated, tortuous retinal veins and intraretinal deep blot hemorrhages in all four quadrants of the retina in both eyes; features of bilateral central retinal vein occlusion. Serum electrophoresis showed hypoalbuminemia with an immunoglobulin M kappa monoclonal spike. Bone marrow picture and immunohistochemistry analysis were suggestive of lymphoplasmacytic lymphoma. The patient received systemic therapy for Waldenström macroglobulinemia, along with intravitreal bevacizumab. Conclusion Adequate hydration, plasmapheresis, and a combination of bortezomib, dexamethasone, and rituximab regimen as a systemic therapy may represent an ideal choice for patients with hyperviscosity in Waldenström macroglobulinemia.

Waldenström macroglobulinemia (WM) is a rare lymphoplasmacytic disorder characterized by an IgM paraprotein. The clinical presentation of WM varies and can include common manifestations such as anemia and hyperviscosity, in addition to less common features such as cryoglobulinemia, IgM-related neuropathy, and immunoglobulin light chain (AL) amyloidosis. Amyloidosis is a protein-folding disorder in which vital organ damage occurs due to the accumulation of misfolded protein aggregates. The most common type of amyloidosis in patients with an IgM paraprotein is AL amyloidosis, although other types of amyloidosis may occur. IgM-related amyloidosis has distinct clinical features when compared with other subtypes of AL amyloidosis. This review highlights the diagnostic criteria of IgM-related AL amyloidosis, as well as the clinical characteristics and treatment options for this disorder.

Bing–Neel syndrome (BNS) is a rare neurological complication of Waldenström macroglobulinaemia. We highlight key issues in clinical presentation, diagnosis, and treatment while focusing on new and emerging therapies available for patients diagnosed with BNS. It is anticipated that further development of Bruton Tyrosine Kinase (BTK) inhibitors and less toxic chemoimmunotherapies will improve treatment delivery and response.

Abstract Lymphoplasmacytic lymphoma (LPL) and marginal zone lymphoma (MZL) frequently infiltrate the bone marrow with similar histologic and immunohistochemical characteristics posing diagnostic problems. Bone marrow biopsy specimens from 25 LPL and 16 MZL have been studied, correlating with clinical, laboratory parameters and the MYD88_p.L265P mutation. Paratrabecular and interstitial infiltration pattern, serum IgM paraprotein levels, and MYD88_p.L265P mutation were significantly more frequent in LPL. Nodular or intrasinusoidal pattern with lymphocytosis and splenomegaly were associated with MZL diagnosis. Different clinical and histological parameters should be collected when LPL or MZL is suspected in bone marrow biopsy specimens.

Abstract Waldenström macroglobulinemia (WM) is a rare, incurable low grade lymphoma following a relapsing trajectory. Management strategies have evolved with the introduction of targeted therapy including new classes of Bruton tyrosine kinase inhibitor (BTKi). Treatment may however be limited particularly at relapse by a lack of drug availability and tolerability. We assessed the real‐world efficacy and tolerability of bortezomib‐containing regimens in patients with WM at frontline and relapse including those with prior BTKi resistance. Forty‐one patients were identified with 44 bortezomib‐containing regimens administered (n = 12 frontline, n = 32 relapse). Of patients treated at relapse, the median prior lines of therapy was 3 (range 1–7). 24% (10/41) of the cohort were refractory or intolerant to BTKi prior to bortezomib delivery. The median follow‐up after bortezomib administration was 34 months (range 0‐131). Overall response rate was 88%; 2‐year overall survival and progression‐free survival were 90% (95% confidence interval [CI] 73–96) and 76% (95% CI 55–87), respectively. Median time‐to‐next‐treatment was 66 months. Neuropathy (grade 1–2) occurred in 24% (8/34) and did not result in treatment cessation in any case. Gastrointestinal disturbance occurred in 7% (3/41). Treatment discontinuations were rare (1/44; 2%), suggesting a manageable safety profile. Major response rate was comparable in those with prior BTKi compared with those without (75% [6/8] vs 84% [27/32], p = 0.61). Bortezomib should be considered as a treatment modality particularly in those who are refractory to BTKi.

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Simple Summary: Waldenström's macroglobulinemia is a lymphoproliferative disorder rarely described in veterinary medicine. According to the human classification of hematopoietic tumors, this disease is defined as a subtype of lymphoplasmacytic lymphoma with bone marrow involvement and monoclonal gammopathy of IgM type. Cytopathology is a convenient and accurate diagnostic procedure to diagnose lymphoma in dogs. However, ancillary techniques, such as PCR for antigen receptor rearrangement, flow cytometry, immunohistochemistry, and histology, are usually required to fully characterize the grade and phenotype, especially in ambiguous cases. Immunosecretory lymphoproliferative disorders result from malignant clonal expansion of B-cells and are usually characterized by hyperglobulinemia, although normoglobulinemia can also occur, hypoglobulinemia being rarer. Monoclonal gammopathy can be suspected on serum protein electrophoresis as it usually migrates as a narrow peak in the γ or β fractions, but immunofixation is required for confirmation and characterization. This case report describes clinicopathologic features, diagnosis, treatment, and the outcome of Waldenström's macroglobulinemia in a 2-year-old neutered female Small Munsterlander dog with atypical bimorphic plasmacytoid differentiation and unusual M-protein migration on serum protein electrophoresis. A 2-year-old neutered female Small Munsterlander dog was presented for an insect bite. Physical examination revealed a poor body condition, a peripheral lymphadenomegaly, and suspected splenomegaly. A complete blood count (Sysmex XN-V) revealed marked leukocytosis with lymphocytosis and abnormal dot plots. An abnormal monomorphic lymphoid population and marked rouleaux formation were noted on the blood smear. Lymph node aspirates contained an atypical bimorphic population of lymphocytes, either with a plasmacytoid or a blastic appearance. This double population was also found in the spleen, liver, bone marrow, tonsils, and other tissues. Peripheral blood and lymph node clonality assays revealed clonal BCR gene rearrangement. Flow cytometry revealed a mixed population of small-sized B-cells (CD79a+ CD21+ MHCII+) and medium-sized B-cells (CD79a+ CD21− MHCII−) in lymph nodes and a dominant population of small-sized mature B-cells (CD21+ MHCII+) in peripheral blood. Though normoproteinemic, serum protein electrophoresis revealed an increased α2-globulin fraction with an atypical restricted peak, identified as monoclonal IgM by immunofixation. Urine protein immunofixation revealed a Bence-Jones proteinuria. A diagnosis of Waldenström's macroglobulinemia was made. Chemotherapy was initiated, but the dog was euthanized 12 months after the initial presentation due to marked clinical degradation. [ABSTRACT FROM AUTHOR]

Shashank Cingam,1 Surbhi Sidana2 1Division of Hematology and Oncology, University of New Mexico Comprehensive Cancer Center, Albuquerque, NM, 87102, USA; 2Division of BMT and Cell Therapy, Stanford University School of Medicine, Stanford, CA, 94305, USACorrespondence: Surbhi Sidana, Division of Blood and Marrow Transplant and Cellular Therapy, Stanford University School of Medicine, 300 Pasteur Drive, Room H0101c, Stanford, CA, 94305, USA, Tel +650 498-6000, Fax +650 725-3321, Email Surbhi.sidana@stanford.eduAbstract: Waldenström’s Macroglobulinemia (WM) is a clonal B-lymphocyte neoplasm characterized by the presence of IgM monoclonal protein and ≥ 10% bone marrow involvement with lymphoplasmacytic cells. Several mature B-cell and plasma cell disorders can potentially produce monoclonal IgM immunoglobulin and hence, careful consideration of the differential diagnosis is vital. Clinico-pathological features, immunophenotype, and MYD88 mutation status help distinguish WM from other plasma cell and lymphoproliferative disorders. Treatment is only indicated in patients symptomatic from adenopathy or organomegaly, neuropathy, hyper viscosity, cryoglobulinemia, cold agglutinin disease, cytopenia’s or amyloidosis. Alkylators (cyclophosphamide, bendamustine) in combination with anti-CD20 antibodies and novel targeted agents including Bruton tyrosine kinase (BTK) inhibitors like ibrutinib are the mainstay of frontline treatment in symptomatic WM.Keywords: Waldenström’s Macroglobulinemia, lymphoplasmacytic lymphoma, WM, LPL

Background: Waldenström macroglobulinemia is a rare hematological malignancy and is the most common diagnosis in patients with hyperviscosity syndrome. Bilateral central retinal vein occlusion as an initial presentation of hyperviscosity syndrome in Waldenström macroglobulinemia is rare. Case presentation: A 42-year-old Nepalese male presented with sudden-onset bilateral painless blurring of vision. Fundus examination revealed bilateral, diffusely dilated, tortuous retinal veins and intraretinal deep blot hemorrhages in all four quadrants of the retina in both eyes; features of bilateral central retinal vein occlusion. Serum electrophoresis showed hypoalbuminemia with an immunoglobulin M kappa monoclonal spike. Bone marrow picture and immunohistochemistry analysis were suggestive of lymphoplasmacytic lymphoma. The patient received systemic therapy for Waldenström macroglobulinemia, along with intravitreal bevacizumab. Conclusion: Adequate hydration, plasmapheresis, and a combination of bortezomib, dexamethasone, and rituximab regimen as a systemic therapy may represent an ideal choice for patients with hyperviscosity in Waldenström macroglobulinemia. [ABSTRACT FROM AUTHOR]

Introduction: Bing-Neel syndrome (BNS) is a rare and heterogenous manifestation of Waldenström macroglobulinemia (WM) involving central nervous system (CNS) infiltration by malignant lymphoplasmacytic cells. Efforts to standardize diagnostic criteria have improved in recent years, as have treatment options including the use of the Bruton tyrosine kinase inhibitor (BTKI) ibrutinib. Case Presentation: Here, we present the case of a 70-year-old male with a remote history of WM previously treated with bendamustine and rituximab, who presented to medical attention with several months of left-sided weakness, headache, and ataxia. Brain magnetic resonance imaging revealed numerous enhancing masses in the bilateral cerebral hemispheres, inferior medulla, and upper cervical spine. Laboratory studies showed serum IgM lambda monoclonal gammopathy and elevated free serum kappa and lambda light chains, while cerebrospinal fluid flow cytometry revealed CD19+ B cells. Stereotactic brain biopsy of a right frontal brain lesion was consistent with lymphoplasmacytic lymphoma, confirmed by a positive MYD88 L265P mutation. He received ibrutinib 420 mg orally daily, and this resulted in appreciable clinical and radiologic responses, which have persisted over a 31-month period. Conclusion: The advent of molecularly targeted agents and novel therapies for WM has provided patients and clinicians with additional therapeutic options. The use of BTK inhibitors with their high-level CNS penetrance, in particular, offers a novel way to treat BNS and improve patient overall survival while maintaining a high level of quality of life. We discuss the importance of MYD88 L265P testing in the context of BNS as well as the expanding role of BTKIs in treating this disease. [ABSTRACT FROM AUTHOR]

Plasma cell neoplasms including multiple myeloma (MM) and related terminally differentiated B-cell neoplasms are characterized by secretion of monoclonal immunoglobulin and stepwise development from a preneoplastic clonal B and/or plasma cell proliferation called monoclonal gammopathy of undetermined significance (MGUS). Diagnosis of these disorders requires integration of clinical, laboratory, and morphological features. While their classification mostly remains unchanged compared to the revised 2016 WHO classification and the 2014 International Myeloma Working Group consensus, some changes in criteria and terminology were proposed in the 2022 International Consensus Classification (ICC) of mature lymphoid neoplasms. MGUS of IgM type is now divided into IgM MGUS of plasma cell type, precursor to the rare IgM MM and characterized by MM-type cytogenetics, lack of clonal B-cells and absence of MYD88 mutation, and IgM MGUS, NOS including the remaining cases. Primary cold agglutinin disease is recognized as a new entity. MM is now formally subdivided into cytogenetic groups, recognizing the importance of genetics for clinical features and prognosis. MM with recurrent genetic abnormalities includes MM with CCND family translocations, MM with MAF family translocations, MM with NSD2 translocation, and MM with hyperdiploidy, with the remaining cases classified as MM, NOS. For diagnosis of localized plasma cell tumors, solitary plasmacytoma of bone, and primary extraosseous plasmacytoma, the importance of excluding minimal bone marrow infiltration by flow cytometry is emphasized. Primary systemic amyloidosis is renamed immunoglobulin light chain amyloidosis (AL), and a localized AL amyloidosis is recognized as a distinct entity. This review summarizes the updates on plasma cell neoplasms and related entities proposed in the 2022 ICC. KEY POINTS: • Lymphoplasmacytic lymphoma can be diagnosed with lymphoplasmacytic aggregates in trephine biopsies < 10% of cellularity and evidence of clonal B-cells and plasma cells. • IgM MGUS is subdivided into a plasma cell type and a not otherwise specified (NOS) type. • Primary cold agglutinin disease is recognized as a new entity. • The term "multiple myeloma" replaces the term "plasma cell myeloma" used in the 2016 WHO classification. • Multiple myeloma is subdivided into 4 mutually exclusive cytogenetic groups and MM NOS. • Minimal bone marrow infiltration detected by flow cytometry is of major prognostic importance for solitary plasmacytoma of bone and to a lesser extent for primary extraosseous plasmacytoma. • Localized IG light chain amyloidosis is recognized as a separate entity, distinct from systemic immunoglobulin light chain (AL) amyloidosis. [ABSTRACT FROM AUTHOR]

Lymphoplasmacytic lymphoma (LPL) is a rare indolent mature B-cell lymphoma. LPL secreting immunoglobulins other than IgM are rare. There are very few case series on non-IgM LPL, and little is known about the clinical features and outcomes of patients with this disease. We report the case of a 65-year-old-male who was referred to our hospital for further investigations of persistent chronic anaemia and was diagnosed with IgG-LPL based on the presence of M protein from serum electrophoresis. Bone marrow morphology exhibit a spectrum of B-cell differentiation ranging from small mature lymphocytes to plasma cells. The patient underwent treatment with a combination of bortezomib, dexamethasone and rituximab and showed positive response. LPL with paraprotein IgG is a rare indolent disease and has a heterogeneous clinicopathological presentation with limited literature reviews. Our case report and literature review provide insights and knowledge in the description of the clinicopathological features of IgG LPL. [ABSTRACT FROM AUTHOR]

Considerable healthcare resource utilization and financial burden have been associated with the treatment of WM; however, the impact of health insurance status on outcomes has not been previously reported. We conducted a National Cancer Database analysis of newly diagnosed cases of active WM between 2004 and 2017 to evaluate the impact of insurance status on outcomes. For patients <65 years old (n = 1249, male sex: 62.4%, median age: 58 years), significant insurance-based survival differences were observed on multivariable analysis; patients who were uninsured [n = 63; HR 3.11 (95%CI, 1.77–5.45), p < 0.001], on Medicaid [n = 87; HR 1.88 (95% CI, 1.01–3.48), p = 0.045], or on Medicare [n = 122; HR 2.78 (95%CI, 1.76–4.38), p < 0.001], had inferior survival compared to patients with private insurance (n = 977; reference). In patients ≥65 years, no insurance-based survival differences were found (p = 0.10). Overall, significant insurance-based outcome disparities exist in WM. Further work is desperately needed to systematically uncover and address these disparities. [ABSTRACT FROM AUTHOR]

Bing–Neel syndrome (BNS) is a rare neurological complication of Waldenström macroglobulinaemia. We highlight key issues in clinical presentation, diagnosis, and treatment while focusing on new and emerging therapies available for patients diagnosed with BNS. It is anticipated that further development of Bruton Tyrosine Kinase (BTK) inhibitors and less toxic chemoimmunotherapies will improve treatment delivery and response. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM) is a rare lymphoplasmacytic disorder characterized by an IgM paraprotein. The clinical presentation of WM varies and can include common manifestations such as anemia and hyperviscosity, in addition to less common features such as cryoglobulinemia, IgM-related neuropathy, and immunoglobulin light chain (AL) amyloidosis. Amyloidosis is a protein-folding disorder in which vital organ damage occurs due to the accumulation of misfolded protein aggregates. The most common type of amyloidosis in patients with an IgM paraprotein is AL amyloidosis, although other types of amyloidosis may occur. IgM-related amyloidosis has distinct clinical features when compared with other subtypes of AL amyloidosis. This review highlights the diagnostic criteria of IgM-related AL amyloidosis, as well as the clinical characteristics and treatment options for this disorder. [ABSTRACT FROM AUTHOR]

Lymphoplasmacytic lymphoma (LPL) is a low-grade B-cell neoplasm, composed of small B-lymphocytes, plasmacytoid lymphocytes, and plasma cells involving bone marrow and sometimes lymph nodes or spleen and forms 1% of all non-Hodgkin lymphomas. LPL with bone marrow involvement and an Immunoglobulin M (IgM) monoclonal gammopathy of any concentration is designated as Waldenström macroglobulinemia (WM). Due to their frequent co-occurrence, the terms LPL and WM are often used interchangeably in clinical practice. However, although the clinical diagnosis of WM is restricted to cases with an IgM monoclonal protein, the World Health Organization recognizes that LPL can rarely present with paraproteins of immunoglobulin G (IgG) or immunoglobulin A (IgA). LPL associated with non IgM gammopathies are extremely rare and form >5% of all LPLs. We hereby present the case of a 65-year-old female with no previous co morbidities who presented with nonspecific complaints of weight loss, easy fatigability, and night sweats. Examination was within the normal limits except for the presence of subcentimetric axillary lymphadenopathy. She was found to have anemia with an altered A/G ratio M spike of 2.10 g/which was IgG kappa on immunofixation electrophoresis. The bone marrow revealed a mixture of lymphocytes, lymphoplasmacytoid cells, and plasma cells along with the presence of amyloid deposits. MYD88 L265P mutation done on peripheral blood was positive, and based on these, she was diagnosed with a case of IgG Kappa LPL with associated amyloidosis.

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.

Lymphoplasmacytic lymphoma (LPL) is a relatively rare form of indolent B-cell non-Hodgkin's lymphoma, termed Waldenström's macroglobulinaemia (WM) in the presence of an IgM paraprotein. Although traditionally treated with combination chemoimmunotherapy, the management is evolving in the era of targeted molecular therapies including Bruton's tyrosine kinase inhibitors (BTKi). However, intolerance and refractoriness to BTKi mean newer agents are required, and the prognosis of so-called quadruple-refractory patients is poor. BCL2 is an anti-apoptotic, pro-survival protein that promotes lymphoma cell survival. Inhibition of BCL2 using first-in-class agent venetoclax has already altered the treatment paradigm in other conditions, including chronic lymphocytic leukaemia (CLL). In-vivo inhibition of BCL2 has been shown to lead to apoptosis of LPL/WM cells. Five studies have published results on the use of BCL2 inhibitors in WM to date, including oblimersen sodium, venetoclax, and sonrotoclax. Fixed-duration venetoclax resulted in high response rates, but many patients relapsed following the completion of therapy. The combination of venetoclax with ibrutinib resulted in higher and relatively deep response rates, but unexpected deaths due to ventricular events mean this combination cannot be explored. Two pivotal trials are currently evaluating the use of fixed-duration venetoclax, either in combination with rituximab or pirtobrutinib, whereas another multi-arm study is studying the use of continuous sonrotoclax monotherapy for R/R WM or in fixed-duration combination with Zanubrutinib for treatment-naïve patients. The potential role of BCL2 inhibitors in WM/LPL remains under study, with many hopeful that they may provide an additional chemotherapy-free oral alternative for patients requiring treatment. In an indolent condition with existing effective treatment regimens, including CIT and cBTKi, cost-effectiveness and toxicity profile will be key, although an additional treatment modality for quadruple-refractory patients with limited treatment options is urgently required., Competing Interests: SD’S has received research support from Janssen and BeiGene, and advisory board honoraria from Janssen, BeiGene, HillStarBio, Kite and Sanofi. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Tomkins and D’Sa.)

Tarinee Rungjirajittranon, Yingyong Chinthammitr, Chattree Hantaweepant Division of Hematology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, ThailandCorrespondence: Chattree HantaweepantClinical Lecturer of Hematology, Division of Hematology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Wanglang Road, Bangkoknoi, Bangkok, 10700, ThailandTel +66 2-419-4448Email chattree.hantaweepant@gmail.comBackground: Acquired factor X deficiency is an uncommon condition, and affected individuals have severe and spontaneous bleeding. The associated conditions include malignancy, infection, burn, and inflammatory bowel disease. Many previous studies reported association between lymphoproliferative disease and factor X disappearance. Amyloid deposition causing factor X absorption was the most common mechanism. Here, we report a case of stage IV lymphoplasmacytic lymphoma (LPL) with factor X deficiency who was successfully treated with bendamustine plus rituximab (BR) regimen.Case Presentation: A 52-year-old Thai woman presented with heavy menorrhea, hoarseness, and widespread ecchymosis at her extremities. On physical examination, the patient had bilateral periorbital purpura and vocal cord hematoma. Coagulation testing showed prolonged prothrombin time (PT) and prolonged activated thromboplastin time (aPTT); however, after mixing with 1:1 normal pooled plasma, PT and aPTT were both corrected to normal levels. Factor assays demonstrated markedly decreased factor X levels, but no presence of factor X inhibitor. Bone marrow examination revealed numerous abnormal lymphoplasmacytoid lymphocytes with kappa light chain expression. Serum free light chain assay also showed kappa light chain restriction [kappa 716.16 mg/L, lambda 16.96 mg/L, ratio 42.23 (0.26– 1.65)]. The patient was diagnosed as lymphoplasmacytic lymphoma with factor X deficiency. She received chemotherapy with 6 cycles of bendamustine plus rituximab (BR) regimen. The patient responded favorably to treatment, she remains in lymphoma remission at one year after diagnosis, and her factor X level was more than 20%.Conclusion: We performed a literature review to identify previous case reports about lymphoma-associated factor X deficiency or inhibitor to determine a possible explanation in our patient. It is important to emphasize that when patients present with acquired factor deficiency, including factor X, lymphoproliferative disease is commonly one of the underlying conditions. Furthermore, the recovery of coagulation factor deficiency is possible if successful remission of lymphoma can be achieved.Keywords: factor X, lymphoproliferative disorder, lymphoplasmacytic lymphoma, amyloidosis

Abstract Background Primary malignant tumours of the retropharyngeal space are rare with only a few case reports in the literature. Lymphoplasmacytic lymphoma is a rare subtype of non-Hodgkin lymphoma and is very rarely found as a primary tumour of the retropharyngeal space. Case presentation We report the case of progressive upper airway obstruction in a 49-year-old male caused by a primary malignant tumour of the retropharyngeal space lymph nodes. He had an emergency tracheostomy to relieve the upper airway obstruction followed a week later by an elective surgical excision of the tumour via the trans-cervical route. A mixed population of lymphocytes, with a marked presence of Dutcher bodies, was noted on histopathology and positive CD20 on immunohistochemistry, confirming the lymphoplasmacytic lymphoma of the retropharyngeal space. The watchful waiting treatment method for the lymphoma was employed for him since he had no symptoms relating to lymphoma and no serum Waldenström’s macroglobulinemia. He has remained symptom-free 3 years post-surgery. Conclusion Primary malignant tumours involving the retropharyngeal space lymph nodes are very rare. They can rarely grow to a size huge enough to cause obstructive upper aerodigestive symptoms. Primary lymphoma of the retropharyngeal space should be considered in the diagnosis of the tumours involving the retropharyngeal space lymph nodes. Excisional biopsy is important to obtain tissue for histopathological diagnosis and the relief of upper aerodigestive tract obstruction when present.

Background: Anti-myelin-associated-glycoprotein (MAG) neuropathy is a distal, predominantly demyelinating, sensory or sensory-motor polyneuropathy most often developing in the context of an IgM-type monoclonal gammopathy due to monoclonal gammopathy of undetermined significance or lymphoplasmacytic lymphoma. Rituximab is considered standard therapy for treatment naïve patients, but optimal treatment methods for relapsed/refractory patients have not been established. Case presentation: We demonstrate that tirabrutinib, a second-generation Burton kinase inhibitor, led to drastic improvements of polyneuropathy that were affirmed by nerve conduction studies in a rituximab-refractory anti-MAG neuropathy patient. Tirabrutinib continues to give excellent disease control with no apparent adverse events at 11 months since initiation, and the patient remains free of plasmapheresis sessions which were originally mandatory. Conclusion: Tirabrutinib is an extremely promising treatment option for anti-MAG neuropathy.

Bing-Neel syndrome (BNS) is a rare presentation of Waldenström macroglobulinemia (WM). BNS is a consequence of the central nervous system (CNS) involvement by lymphoplasmacytic lymphoma (LPL) and, rarely, the peripheral nervous system. The data on BNS are extremely scarce. Therefore, we performed a multicenter retrospective analysis of BNS patients diagnosed and treated in centers aligned with the Polish Lymphoma Research Group. The analysis covers the years 2014–2021. Eleven patients were included, 55% females and the median age at BNS diagnosis was 61 years. The median time from WM to BNS was 3.5 years; 27% of patients did have a diagnosis of WM and BNS made simultaneously or within 30 days from each other. Isolated parenchymal involvement was the least frequent (20%). Patients were treated with different regimens, mostly able to cross the blood-brain barrier, including 18% treated with ibrutinib first line. The cumulative objective response to treatment was 73%. With the median follow-up of 20 months (95% CI, 2–32), the 36-month estimates were: overall survival (OS) 47%, progression-free survival (PFS) 33%, and cumulative incidence of BNS-associated death 41%. The performance status according to ECOG was significant for PFS (HR = 7.79) and the hemoglobin concentration below 11 g/dL was correlated with PFS. To conclude, BNS is a very rare manifestation of WM. It is associated with a poor outcome with most patients succumbing to BNS. [ABSTRACT FROM AUTHOR]

A 7‐year‐old male castrated Maine Coon cat presented with edema of the right hindlimb and a markedly enlarged right popliteal lymph node. A CBC showed a neutropenia of 1.5 × 103/μL. Radiographs and ultrasonographic examination were unremarkable. Cytology of the right popliteal lymph node revealed a mixed population of cells, consisting predominantly of medium to large plasmacytoid lymphocytes, low to moderate numbers of well‐differentiated plasma cells and low numbers of small lymphocytes. Plasmacytoid lymphocytes had round nuclei with finely stippled chromatin and one prominent round nucleolus. Low numbers of binucleated cells and bizarre mitotic figures, and rare multinucleated cells were observed. Histopathologic examination of the lymph node showed effacement of the normal lymph node architecture by dense sheets of neoplastic cells. Round to polygonal tumor cells of intermediate size had a low to moderate amount of cytoplasm. Round to indented hyperchromatic nuclei were often eccentrically located and contained one distinct nucleolus. Anisocytosis and anisokaryosis were moderate and 21 mitoses/10 high power field (HPF) were present. Congo red staining was negative. High numbers of tumor cells were positive for lambda light chain immunoglobulin; moderate numbers stained positive for MUM‐1. A clonal BCR gene rearrangement was detected with an immunoglobulin heavy chain target (IGH), immunoglobulin lambda light chain (IgL), and kappa deleting element (Kde). Differential diagnoses for the lymphoproliferative disease in this cat included lymphoplasmacytic lymphoma and myeloma‐related disorder. [ABSTRACT FROM AUTHOR]

Dang Nguyen Van,1,2 Nghia Duong Van,1 Quang Le Van,1 Tung Ngo Thanh,2 To Ta Van3 1Department of Oncology, Hanoi Medical University, Hanoi, Vietnam; 2Department of Head and Neck Radiation Oncology, Vietnam National Cancer Hospital, Hanoi, Vietnam; 3Center of Pathology and Molecular Biology, Vietnam National Cancer Hospital, Hanoi, VietnamCorrespondence: Dang Nguyen VanDepartment of Oncology, Hanoi Medical University, 01 Ton That Tung Street, Dong Da District, Hanoi, 10000, VietnamTel +84 94 2727 899Email nguyenvandang@hmu.edu.vn; drdangnguyen@gmail.comBackground: Primary central nervous system (CNS) lymphoma is an uncommon non-Hodgkin disease limited to the CNS, and most cases are diffuse large B-cell lymphomas. Other pathologies, including lymphoplasmacytic lymphoma (LPL), are exceedingly rare and poorly understood. The clinical presentation of primary CNS LPL is diverse. It depends on the original site and the tumor’s extension. There is currently no consensus on a treatment strategy for this uncommon manifestation. To our knowledge, no previously published case was successfully treated with radiation therapy alone.Case Presentation: We present here a case of primary CNS LPL. A 46-year-old, previously healthy woman was presented with a worsening headache and lower extremity numbness. Multifocal enhanced masses were detected in an MRI with biopsy results consistent with LPL. A complete staging workup was performed with no evidence of systemic disease. The patient received external-beam radiotherapy alone and had a complete remission. After 2 years of follow-up, she remains disease-free.Conclusion: Radiation alone is a promising treatment option for primary CNS lymphoplasmacytic lymphoma.Keywords: lymphoplasmacytic lymphoma, primary CNS lymphoma, radiation therapy

Siriorn Sukanjanapong,1 Kumutnart Chanprapaph,1 Suthinee Rutnin,1 Paisan Boonsakan,2 Sulada Pukiat3 1Division of Dermatology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 3Division of Hematology, Department of Internal Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandCorrespondence: Kumutnart ChanprapaphDivision of Dermatology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Ratchathewi, Bangkok, 10400, ThailandTel +66-2-2011141Fax +66-2-2011211Email kumutnartp@hotmail.comAbstract: Cutaneous macroglobulinosis is a rare manifestation of Waldenstrom macroglobulinemia when there is deposition of IgM in the dermis. The clinical presentation varies from skin colored to pink papules and ulcerative nodules on trunk, extensor surfaces of upper and lower limbs to hyperkeratotic lesions on the soles. We herein report a 78-year-old-male with Waldenstrom macroglobulinemia who presented with serpiginous purpura. The differential diagnoses included occlusion of vessel lumen by the lymphoplasmacytoid cells, high level of IgM or cryoglobulin, as well as small to medium vasculitis secondary to Waldenstrom macroglobulinemia. The histopathology revealed vasculopathy and vasculitis, while further immunohistochemistry highlighted deposition in the vessel lumen and vessel wall with IgM, suggesting the diagnosis of cutaneous macroglobulinosis. In this case report, we discuss this rare presentation and reviewed previous cases of cutaneous macroglobulinosis.Keywords: Waldenstrom macroglobulinemia, lymphoplasmacytic lymphoma, monoclonal gammopathy, vasculitis, vasculopathy

Composite lymphoma, defined as two or more distinct well-defined entities involving the same anatomic site, is rare. Here we report a 79-year-old woman with composite mantle cell lymphoma (MCL) and lymphoplasmacytic lymphoma (LPL) involving bone marrow at the time of initial diagnosis. The patient presented with splenomegaly and lymphadenopathy and laboratory studies showed an elevated serum IgM level and IgM kappa paraprotein. Bone marrow evaluation showed concurrent involvement by MCL and LPL, supported by immunophenotypic studies that revealed two distinct aberrant B-cell populations. Next-generation sequencing analysis identified concurrent MYD88 and CXCR4 mutations and fluorescence in-situ hybridization showed CCND1 translocation, supporting the diagnosis of concomitant MCL and LPL. In conclusion, composite lymphoma can present in the bone marrow. The use of ancillary studies was essential in reaching the diagnosis in this case, as the results excluded the possibility of MCL lymphoma with plasmacytic differentiation, as well as other CD5- and CD10-negative small B-cell lymphomas. • Composite lymphomas defined as two distinct entities involving the same anatomic site are rare. • We present the first case of composite mantle cell and lymphoplasmacytic lymphoma in the bone marrow. • Ancillary studies are critical for identifying components of composite lymphomas. • Investigating clonal relationship is important in understanding their pathogenesis. [ABSTRACT FROM AUTHOR]

Lymphoplasmacytic lymphoma (LPL)/Waldenström macroglobulinemia (WM) is an uncommon mature B cell lymphoma usually involving the bone marrow and, less commonly, the spleen and/or lymph nodes. This case presents a pathology-confirmed isolated extramedullary relapse of LPL, located in subcutaneous adipose tissue, 5 years after successful treatment of WM. [ABSTRACT FROM AUTHOR]

A 2-year-old neutered female Small Munsterlander dog was presented for an insect bite. Physical examination revealed a poor body condition, a peripheral lymphadenomegaly, and suspected splenomegaly. A complete blood count (Sysmex XN-V) revealed marked leukocytosis with lymphocytosis and abnormal dot plots. An abnormal monomorphic lymphoid population and marked rouleaux formation were noted on the blood smear. Lymph node aspirates contained an atypical bimorphic population of lymphocytes, either with a plasmacytoid or a blastic appearance. This double population was also found in the spleen, liver, bone marrow, tonsils, and other tissues. Peripheral blood and lymph node clonality assays revealed clonal BCR gene rearrangement. Flow cytometry revealed a mixed population of small-sized B-cells (CD79a+ CD21+ MHCII+) and medium-sized B-cells (CD79a+ CD21− MHCII−) in lymph nodes and a dominant population of small-sized mature B-cells (CD21+ MHCII+) in peripheral blood. Though normoproteinemic, serum protein electrophoresis revealed an increased α2-globulin fraction with an atypical restricted peak, identified as monoclonal IgM by immunofixation. Urine protein immunofixation revealed a Bence-Jones proteinuria. A diagnosis of Waldenström’s macroglobulinemia was made. Chemotherapy was initiated, but the dog was euthanized 12 months after the initial presentation due to marked clinical degradation.

Immune-related neurological syndromes (affecting both the central and peripheral nervous system, as well as the neuromuscular junction) can associate with low-grade B-cell lymphomas. Methods: We conducted a retrospective study on the records of patients with miscellaneous immune-related neuropathies followed by the "Referral Centre for Neuromuscular Diseases and ALS" in collaboration with the Services of Internal Medicine and Hematology (La Timone Hospital, and the Paoli Calmettes-Insitute, Marseille, France; Geneva University Hospitals, Geneva, Switzerland). Clinical, biological, immunological and histological work-up was carried out and data collected. Results: We identified 12 patients with neurological syndromes and atypical presentation/course. In all these patients multiple autoantibodies were found. This prompted us to perform thorough hematologic investigations, that led to the diagnosis of different type of Low-Grade B-Cell lymphomas [i.e. marginal zone lymphomas with lymphoplasmacytic differentiation (n=3), splenic marginal area lymphoma with secondary lymph node invasion (n=1), unclassified marginal area lymphomas (n=8)]. Treatment of the underling lymphoma resulted in an improvement (n=8) or stabilization (n=4) of neurological disease. Conclusion: Atypical presentation of immune-related neurological syndromes, as well as the presence of antibodies with different antigenic targets should be regarded as "warning signs" and raise the suspicion of a paraneoplastic origin sustained by an underlying low-grade B-cell lymphoma that should be actively sought and treated. Close collaboration between internists, neurologists and hematologists allows for the appropriate management of each case. [ABSTRACT FROM AUTHOR]

A 53-year-old woman was diagnosed with lymphoplasmacytic lymphoma (LPL)/Waldenström's macroglobulinemia (WM) in 2008. Six courses of R-COP (rituximab, cyclophosphamide, vincristine, and prednisolone) resulted in complete remission, but LPL/WM relapsed in 2015. After six courses of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone), the M-peak disappeared, but the patient presented with muscle weakness and sensory disturbance in the lower extremities. No lesions were apparent in the brain parenchyma, but T2-weighted magnetic resonance imaging (MRI) showed a signal-hyperintense area with contrast enhancement in the spinal cord at the C2–4 and Th2–3 levels, and cerebrospinal fluid (CSF) examination showed only a few mononuclear cells. In 2020, the patient started to require walking assistance, and MRI findings worsened. Neurologically, lower limb muscle strength was reduced (manual muscle test score 3), and sensations of touch and pain were about 30% of normal. Vibratory sensation was absent at the knees and medial malleoli, accompanied by dysuria due to neurogenic bladder. CSF cell count was 15/μl (all mononuclear cells). Bing–Neel syndrome (BNS) was diagnosed and tirabrutinib was started. Within 2 months of treatment, lower extremity muscle strength had normalized and MRI findings had improved. Tirabrutinib may offer a promising therapeutic option for BNS. [ABSTRACT FROM AUTHOR]

Summary: Lymphoplasmacytic lymphoma (LPL) not fulfilling the WHO diagnostic criteria (2017) for Waldenstrom's macroglobulinemia (WM) (named non‐WM LPL) is a rare disease and only a few systematic studies have been published. Here, we present a population‐based study of non‐WM LPL focusing on diagnostic difficulties, patient characteristics, and outcome. From 1511 patients included in the Swedish Lymphoma Registry 1 Jan 2000 – 31 Dec 2014 with a diagnosis of WM/LPL, we could confirm the diagnosis of non‐WM LP in only 33 patients. The median age at diagnosis was 69 years. A paraprotein was found in most (IgG in 54%, IgA in 15%) and 12% of the cases were non‐secretory. Compared with the WM patients, the non‐WM LPL patients were younger, had more adverse prognostic factors such as elevated LDH, anaemia, and lymphocytosis at diagnosis. In addition, the non‐WM LPL patients more often were symptomatic and received treatment at diagnosis. The overall survival (OS) did not significantly differ between the non‐WM LPL and WM groups (P = 0.247), with a median survival time of 71 and 96 months, respectively. To conclude, we found differences in clinical features between WM and non‐WM LPL, but no difference in survival. [ABSTRACT FROM AUTHOR]