IgM multiple myeloma: disease definition, prognosis, and differentiation from Waldenstrom's macroglobulinemia

Osteonecrosis of the Jaw Associated with Bisphosphonates Infusion for Treatment of Plasma Cell Myeloma-A Retrospective Observational Study of Northern Portuguese Population

Objectives: To verify medication-related osteonecrosis of the jaw (MRONJ) frequency among patients with plasma cell myeloma (PCM) that had been treated with bisphosphonates, to identify predisposing factors that could influence the development of osteonecrosis. Methods: This observational retrospective study was performed at the Department of Hematology of Hospital Center of Porto (CHUP), Portugal. Results: The study population (n = 112) had a 15.2% (n = 17) prevalence of osteonecrosis. Clinically, bone exposure was the most frequently observed sign, present in 100% (n = 17) of the patients, followed by inflammation in 82.4% (n = 14), orofacial pain in 70.6% (n = 12), suppuration in 47.1% (n = 8), and intra or extra-oral fistula in 17.6% (n = 3) of the cases. The most frequent triggering local factor was dental extraction (82.4%). There was a dependence between the presence of extractions and the development of MRONJ (p < 0.001) but not with the time elapsed from the initiation of infusions with BPs and dental extractions (p = 0.499). In the sample of patients with multiple myeloma (MM), 13.8% were found to be more likely to develop MRONJ after an extraction. Conclusions: The most common local predisposing factor was dental extraction. No dependence was observed between the development of osteonecrosis and the time elapsed from the beginning of treatment with bisphosphonates infusions to surgical procedures.

An overview of multiple myeloma: A monoclonal plasma cell malignancy's diagnosis, management, and treatment modalities

Multiple Myeloma (MM) is a plasma cell cancer with high mortality and morbidity rates. Its incidence rate has increased by 143% since 1975. Adipokines, cytokines, chemokines, and genetic variations influence the development and progression of MM. Chromosomal translocations cause mutations associated with MM. The pathogenesis of MM is complicated by novel issues like miRNAs, RANKL, Wnt/DKK1, Wnt, and OPG. Conventional diagnosis methods include bone marrow biopsy, sPEP or uPEP, sIFE and uIFE, and sFLC assay, along with advanced techniques such as FISH, SNPA, and gene expression technologies. A novel therapeutic strategy has been developed recently. Chemotherapy, hematopoietic stem cell transplantation, and a variety of drug classes in combination are used to treat patients with high-risk diseases. Alkylating agents, PIs, and IMiDs have all been developed as effective treatment options for MM in recent years. This review overviews the current recommendations for managing MGUS, SMM, MM, SP and NSMM and discusses practices in diagnosing and treating MM.

Challenging diagnosis of IgM multiple myeloma

IgM monoclonal gammopathies such as IgM myeloma and Waldenström macroglobulinaemia are distinct haematological conditions; however, differentiating between these entities can often present as a challenge.In this review, we explore the challenging diagnosis and treatment of IgM myeloma in a patient presenting with unexplained macrocytic anaemia, elevated serum protein and IgM levels in the absence of t(11;14) and lytic bone lesions that are classically associated with the diagnosis of IgM myeloma. The diagnosis was established based on 40% monoclonal plasma cell population on a bone marrow biopsy, gain of 1q21 on fluorescence in situ hybridisation, cyclin D1 positivity and absence of MYD88 mutation.

Mouse models of human multiple myeloma subgroups

Multiple myeloma (MM), a tumor of germinal center (GC)-experienced plasma cells, comprises distinct genetic subgroups, such as the t(11;14)/CCND1 and the t(4;14)/MMSET subtype. We have generated genetically defined, subgroup-specific MM models by the GC B cell-specific coactivation of mouse Ccnd1 or MMSET with a constitutively active Ikk2 mutant, mimicking the secondary NF-κB activation frequently seen in human MM. Ccnd1/Ikk2ca and MMSET/Ikk2ca mice developed a pronounced, clonally restricted plasma cell outgrowth with age, accompanied by serum M spikes, bone marrow insufficiency, and bone lesions. The transgenic plasma cells could be propagated in vivo and showed distinct transcriptional profiles, resembling their human MM counterparts. Thus, we show that targeting the expression of genes involved in MM subgroup-specific chromosomal translocations into mouse GC B cells translates into distinct MM-like diseases that recapitulate key features of the human tumors, opening the way to a better understanding of the pathogenesis and therapeutic vulnerabilities of different MM subgroups.

Monoclonal Gammopathy of Undetermined Significance

Monoclonal gammopathy of undetermined significance (MGUS) is of considerable clinical importance to primary care physicians given its high prevalence in the general population. MGUS has a variable but lifelong risk for progression to hematologic cancer, such as multiple myeloma, Waldenström macroglobulinemia, or light-chain amyloidosis. In addition, MGUS has been associated with several nonmalignant yet symptomatic disorders that require therapy directed toward eliminating the monoclonal gammopathy. Thus, it is important not only to understand the essentials of diagnosing and monitoring patients with MGUS but also to recognize when to refer patients with MGUS to a specialist.

Immunoglobulin M Monoclonal Gammopathies of Clinical Significance

Immunoglobulin M monoclonal gammopathy of undetermined significance (MGUS) comprises 15-20% of all cases of MGUS. IgM MGUS is distinct from other forms of MGUS in that the typical primary progression events include Waldenstrom macroglobulinaemia and light chain amyloidosis. Owing to its large pentameric structure, IgM molecules have high intrinsic viscosity and precipitate more readily than other immunoglobulin subtypes. They are also more commonly associated with autoimmune phenomena, resulting in unique clinical manifestations. Organ damage attributable to the paraprotein, not fulfilling criteria for a lymphoid or plasma cell malignancy has recently been termed monoclonal gammopathy of clinical significance (MGCS) and encompasses an important family of disorders for which diagnostic and treatment algorithms are evolving. IgM related MGCS include unique entities such as cold haemagglutinin disease, IgM related neuropathies, renal manifestations and Schnitzler's syndrome. The diagnostic approach to, and management of these disorders differs significantly from other categories of MGCS. We describe a practical approach to the evaluation of these patients and our approach to their treatment. We will also elaborate on the key unmet needs in IgM MGCS and highlight potential areas for future research.

Does Waldenstrom's macroglobulinemia also cause bone destruction? A rare case report

Waldenstrom's macroglobulinemia (WM) is a rare type of malignant B-cell lymphoma. The main feature of WM is elevated serum monoclonal immunoglobulin M, similar to multiple myeloma (MM). Unlike in MM, the rarity of destructive bone lesions in WM has been repeatedly emphasized. We report a unique case of WM with a vertebral compression fracture as the first symptom. This case highlights that the presence or absence of bone destruction may not clearly distinguish between WM and MM. The possibility of WM should be considered in patients with vertebral fracture and destruction as the first presentation. Performing vertebral bone marrow aspiration biopsy during percutaneous vertebroplasty is a convenient and effective method to assist in the diagnosis of WM.

IgM Plasma Cell Myeloma

OBJECTIVES

Immunoglobulin M plasma cell myeloma (IgMPCM) is a rare entity that is difficult to distinguish from other IgM-related neoplasms. The study aims to characterize the clinicopathologic features of IgMPCM, including MYD88 L265P and CXCR4 mutations.

METHODS

From our institutional archives, bone marrow biopsy specimens from January 1, 2008, to December 1, 2018, with monotypic plasma cells (PCs) expressing IgM that met current International Myeloma Working Group/World Health Organization criteria for PCM were included. Sanger sequencing was used to test for MYD88 L265P and WHIM-like CXCR4 mutations.

RESULTS

Nine cases of IgMPCM were identified. Serum IgM paraproteins were detected in eight cases. CD138-positive PC burden averaged 41.9% (5%-80%). In four cases, PCs had lymphoplasmacytic morphology with cyclin D1 expression by immunohistochemistry. Three of four tested cases were positive for t(11;14) by fluorescence in situ hybridization, one with monosomy 13. The remaining case was positive for del13q14. All were negative for MYD88 L265P and WHIM-like CXCR4 mutations. Eight patients received immunochemotherapy, with four receiving autologous hematopoietic stem cell transplant. Median follow-up was 61 months (range, 11-120). All patients were alive except one.

CONCLUSIONS

Distinguishing IgMPCM from other IgM-related disorders requires correlation with clinical, laboratory, and radiologic findings. Exclusion of MYD88 L265P and WHIM-like CXCR4 mutations may be useful to diagnose IgMPCM.

Management of lytic bone disease in lymphoplasmacytic lymphoma: A case report and review of the literature

Waldenström macroglobulinemia (WM)/lymphoplasmacytic lymphoma (LPL) is often differentiated from myeloma based on the presence of lytic bone lesions (LBL). However, WM/LPL can present with LBL, and management is poorly understood. We describe a case of an 81-year-old woman with LPL who presented with LBL and was successfully treated with chemoimmunotherapy.

[Immunoglobulin M multiple myeloma: a six-case report and literature review]

Objective: To investigate the clinical characteristics, responses, and prognosis of immunoglobulin M multiple myeloma (IgM MM) . Methods: The clinical characteristics, laboratory results, bone marrow biopsy results, response, and prognosis of six cases of IgM MM in the Blood Diseases Hospital, Chinese Academy of Medical Sciences, from December 18, 2009 to October 29, 2020 were collected and analyzed. Results: All six cases met the diagnosis criteria of IgM MM. There were four males and two females. The median age at first diagnosis was 70 (59-81) years. According to Durie-Salmon (DS) staging, 2 cases were in ⅠA, and 4 cases were in ⅢA. According to the International Staging System (ISS) , 4 cases were in Ⅱ, and 2 cases were in Ⅲ. The initial symptoms were as follows: 4 cases of bone pain, 3 cases of hyperviscosity, and 2 cases of lymphadenopathy or hepatosplenomegaly. Laboratory results showed the following: median blood M protein: 39.11 (3.61-75.56) g/L; median serum IgM: 69.35 (4.35-137.00) g/L; median hemoglobin: 87.0 (70-131) g/L; median blood creatinine: 83.6 (53.0-129.6) μmol/L; median blood calcium: 2.12 (2.11-2.50) mmol/L. The median ratio of bone marrow plasma cells was 0.390 (0.255-0.590) , and in four cases, plasma cells were observed in blood smears. Karyotype analysis and fluorescence in situ hybridization (FISH) examination showed the following: 1 case of hypodiploidy, 2 cases of P53 gene deletion, 1 case of 1q21 amplification positive, and 4 cases of RB-1 gene deletion positive. The immunoglobulin heavy chain (IgH) rearrangement was positive in all cases, of which 3 cases were CCND1/IgH fusion gene-positive identified with t (11;14) rearrangement. Immunophenotyping revealed that all cases were positive for CD38, CD138, and monoclonal light chain and four cases were weakly positive for CD20. All cases accepted proteasome inhibitor-based regimens and attained the response of partial remission to strict complete remission. Conclusion: In addition to the typical clinical manifestations of myeloma, IgM MM is also characterized by hyperviscosity, lymphadenopathy, or hepatosplenomegaly, and t (11;14) is the most frequent cytogenetics aberration. Furthermore, the response and prognosis of IgM MM are similar to other common myeloma subtypes.

IgM-MM is predominantly a pre-germinal center disorder and has a distinct genomic and transcriptomic signature from WM

Immunoglobulin M (IgM) multiple myeloma (MM) is a rare disease subgroup. Its differentiation from other IgM-producing gammopathies such as Waldenström macroglobulinemia (WM) has not been well characterized but is essential for proper risk assessment and treatment. In this study, we investigated genomic and transcriptomic characteristics of IgM-MM samples using whole-genome and transcriptome sequencing to identify differentiating characteristics from non-IgM-MM and WM. Our results suggest that IgM-MM shares most of its defining structural variants and gene-expression profiling with MM, but has some key characteristics, including t(11;14) translocation, chromosome 6 and 13 deletion as well as distinct molecular and transcription-factor signatures. Furthermore, IgM-MM translocations were predominantly characterized by VHDHJH recombination-induced breakpoints, as opposed to the usual class-switching region breakpoints; coupled with its lack of class switching, these data favor a pre-germinal center origin. Finally, we found elevated expression of clinically relevant targets, including CD20 and Bruton tyrosine kinase, as well as high BCL2/BCL2L1 ratio in IgM-MM, providing potential for targeted therapeutics.

Waldenström macroglobulinemia: 2021 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, lymphadenopathy, and rarely hyperviscosity.

DIAGNOSIS

Presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis. The L265P mutation in MYD88 is detectable in more than 90% of patients and is found in the majority of IgM MGUS patients.

RISK STRATIFICATION

Age, hemoglobin level, platelet count, β₂ microglobulin, LDH and monoclonal IgM concentrations are characteristics that are predictive of outcomes.

RISK-ADAPTED THERAPY

Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab-monotherapy is inferior to regimens that combine it with bendamustine, an alkylating agent, a proteosome inhibitor, or ibrutinib. Purine nucleoside analogues are active but usage is declining in favor of less toxic alternatives. The preferred Mayo Clinic induction is rituximab and bendamustine.

MANAGEMENT OF REFRACTORY DISEASE

Bortezomib, fludarabine, thalidomide, everolimus, Bruton Tyrosine Kinase inhibitors, carfilzomib, lenalidomide, and bendamustine have all been shown to have activity in relapsed WM. Given WM's natural history, reduction of therapy toxicity is an important part of treatment selection.

Efficacy of Venetoclax and Dexamethasone in Refractory IgM Primary Plasma Cell Leukemia with t(11;14) and TP53 Mutation: A Case Report and Literature Review

Primary plasma cell leukemia (pPCL) is an uncommon disease. IgM multiple myeloma (MM) is an infrequent subtype that accounts for less than 1 percent of MM cases. IgM pPCL is quite rare with only a few cases published to date. We describe a case of a patient with IgM pPCL who initially presented with hyperviscosity syndrome requiring urgent plasma exchange. His bone marrow biopsy demonstrated t(11;14). He progressed on proteasome inhibitors, immunomodulating agents, and other chemotherapy medications but later achieved very good partial response (VGPR) to venetoclax and dexamethasone. Given the poor prognosis of pPCL, further studies using venetoclax alone or in combination with other novel agents as first-line treatment options are warranted particularly in patients with t(11;14).

B-Cell-Specific Myd88 L252P Expression Causes a Premalignant Gammopathy Resembling IgM MGUS

A highly recurrent somatic L265P mutation in the TIR domain of the signaling adapter MYD88 constitutively activates NF-κB. It occurs in nearly all human patients with Waldenström’s macroglobulinemia (WM), a B cell malignancy caused by IgM-expressing cells. Here, we introduced an inducible leucine to proline point mutation into the mouse Myd88 locus, at the orthologous position L252P. When the mutation was introduced early during B cell development, B cells developed normally. However, IgM-expressing plasma cells accumulated with age in spleen and bone, leading to more than 20-fold elevated serum IgM titers. When introduced into germinal center B cells in the context of an immunization, the Myd88^L252P mutation caused prolonged persistence of antigen-specific serum IgM and elevated numbers of antigen-specific IgM plasma cells. Myd88^L252P-expressing B cells switched normally, but plasma cells expressing other immunoglobulin isotypes did not increase in numbers, implying that IgM expression may be required for the observed cellular expansion. In order to test whether the Myd88^L252P mutation can cause clonal expansions, we introduced it into a small fraction of CD19-positive B cells. In this scenario, five out of five mice developed monoclonal IgM serum paraproteins accompanied by an expansion of clonally related plasma cells that expressed mostly hypermutated VDJ regions. Taken together, our data suggest that the Myd88^L252P mutation is sufficient to promote aberrant survival and expansion of IgM-expressing plasma cells which in turn can cause IgM monoclonal gammopathy of undetermined significance (MGUS), the premalignant condition that precedes WM.

Immunoglobulin M Paraproteinaemias

Monoclonal paraproteinaemia is an increasingly common reason for referral to haematology services. Paraproteinaemias may be associated with life-threatening haematologic malignancies but can also be an incidental finding requiring only observation. Immunoglobulin M (IgM) paraproteinaemias comprise 15–20% of monoclonal proteins but pose unique clinical challenges. IgM paraproteins are more commonly associated with lymphoplasmacytic lymphoma than multiple myeloma and can occur in a variety of other mature B-cell neoplasms. The large molecular weight of the IgM multimer leads to a spectrum of clinical manifestations more commonly seen with IgM paraproteins than others. The differential diagnosis of B-cell and plasma cell dyscrasias associated with IgM gammopathies can be challenging. Although the discovery of MYD88 L265P and other mutations has shed light on the molecular biology of IgM paraproteinaemias, clinical and histopathologic findings still play a vital role in the diagnostic process. IgM secreting clones are also associated with a number of “monoclonal gammopathy of clinical significance” entities. These disorders pose a novel challenge from both a diagnostic and therapeutic perspective. In this review we provide a clinical overview of IgM paraproteinaemias while discussing the key advances which may affect how we manage these patients in the future.

Immunoglobulin M (IgM) multiple myeloma versus Waldenström macroglobulinemia: diagnostic challenges and therapeutic options: two case reports

Background

Immunoglobulin M multiple myeloma and Waldenström macroglobulinemia are two different hematological diseases with the common finding of an immunoglobulin M monoclonal gammopathy of unknown significance. However, clinical characteristics of the two entities can overlap.

Case presentation

In this report, we describe two cases of immunoglobulin M neoplasm with the same histological bone marrow presentation but with different clinical behavior, cytogenetics, and biological assessment. On the basis of comprehensive diagnostic workup, these patients were considered to have different diseases and treated accordingly with different approaches. Patient 1 (Caucasian man) presented with increased serum protein and immunoglobulin M (7665 mg/L) with an M-spike electrophoresis of 4600 mg/L. His bone marrow biopsy revealed a small-cell immunoglobulin M multiple myeloma. The result of testing for the MYD88 L265P mutation was negative, while fluorescence in situ hybridization analysis showed translocation t(11,14). A diagnosis of immunoglobulin M-κ multiple myeloma was made. Patient 1 was a candidate for bortezomib plus thalidomide and dexamethasone, followed by autologous stem cell transplant consolidation. Patient 2 (Caucasian man) showed an M-spike by protein electrophoresis (300 mg/L, 4.9%), with serum immunoglobulin M level of 327 mg/L. His bone marrow biopsy revealed immunoglobulin M-κ multiple myeloma. Computed tomography showed many enlarged lymph nodes and splenomegaly. Patient 2’s clinical features were suggestive of Waldenström macroglobulinemia, in contrast to the bone marrow biopsy results. The result of testing for the MYD88 L265P mutation was positive. Patient 2 was diagnosed with Waldenström macroglobulinemia and received rituximab, cyclophosphamide, and dexamethasone.

Conclusions

A correct differential diagnosis between immunoglobulin M multiple myeloma and Waldenström macroglobulinemia is a critical point in the setting of a new immunoglobulin M monoclonal gammopathy onset. These patients should undergo a complete diagnostic workup with pathological, radiological, and serological examinations to establish the diagnosis and plan the most appropriate treatment in order to improve the prognosis.

Diagnosis of a difficult to differentiate case of early-onset hyperviscosity syndrome caused by IgM type multiple myeloma: a case report

Hyperviscosity syndrome (HVS) can cause multiple organ damage if not treated immediately. IgM multiple myeloma (IgM MM) is a very rare form of myeloma with clinical features such as elevated serum IgM, and anemia, that resemble Waldenström macroglobulinemia (WM). Distinguishing between these two diseases is important, but can be a challenging problem. It is well known that MyD88 mutations and t(11;14) translocations are useful for differential diagnosis. We diagnosed HVS in a 29-year-old male with IgM MM. He was treated with triplet therapy, autologous hematopoietic stem cell transplantation, and carfilzomib consolidation therapy. His clinical course was monitored by serum IgM levels, and bone marrow myeloma cell counts by multiparameter flow cytometry analysis. After this series of treatments, his HSV disappeared and he reached stringent complete response. In cases of early onset of HVS, IgM MM should be considered in addition to WM.

A Rare Case of Non-Secretory Multiple Myeloma: A Case Report and Literature Review

Non-secretory myeloma (NSM) is a rare form of myeloma. It is defined as monoclonal plasmocytic proliferation of the bone marrow with the same clinical and radiological manifestations of myeloma. However, plasma cells are unable to secrete immunoglobulin (serum and urinary electrophoresis are negative and free light chain measurement is unquantifiable). This variant of multiple myeloma (MM) usually poses a diagnostic challenge to the biologist and clinician. We report a rare case of non-secretory myeloma in a 76-year-old patient who was diagnosed at the Mohammed V University Hospital Center in Oujda, Morocco.

Waldenström macroglobulinemia: 2019 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, lymphadenopathy, and rarely hyperviscosity.

DIAGNOSIS

Presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis. The L265P mutation in MYD88 is detectable in >90% of patients and is found in the majority of IgM monoclonal gammopathy of undetermined significance patients.

RISK STRATIFICATION

Age, hemoglobin level, platelet count, β2 microglobulin, and monoclonal IgM concentrations are characteristics that are predictive of outcomes.

RISK-ADAPTED THERAPY

Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab-monotherapy is inferior to regimens that combine it with bendamustine, an alkylating agent, a proteosome inhibitor, or ibrutinib. Purine nucleoside analogs are active but usage is declining for less toxic alternatives. The preferred Mayo Clinic induction is rituximab and bendamustine. Potential for stem cell transplantation should be considered in selected younger patients.

MANAGEMENT OF REFRACTORY DISEASE

Bortezomib, fludarabine, thalidomide, everolimus, ibrutinib, carfilzomib, lenalidomide, and bendamustine have all been shown to have activity in relapsed WM. Given WM's natural history, reduction of therapy toxicity is an important part of treatment selection.

Monoclonal IgM Gammopathy and Waldenström's Macroglobulinemia

BACKGROUND

3.2-3.5% of persons over age 50 have a monoclonal gammopathy. Monoclonal gammopathies have many causes, including cancer. 10-20% of monoclonal gammopathies are of isotype IgM. A systematic approach to the differential diagnosis of IgM gammopathies is essential because of the different therapeutic implications of the various underlying conditions.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and current guidelines from Germany and abroad.

RESULTS

The diagnosis of a monoclonal IgM gammopathy is established by serum electrophoresis in combination with immune fixation. Further evaluation enables the identification of the underlying condition: the differential diagnosis includes IgM-MGUS (monoclonal gammopathy of unclear significance), Waldenström's disease, and IgM myeloma. The therapeutic implications of the under - lying condition vary from watchful waiting in IgM-MGUS to combined rituximab and antineoplastic chemotherapy (off-label first-line use of rituximab) in symptomatic Waldenström's macroglobulinemia. Ibrutinib has been approved for the treatment of patients with recurrences, or of those for whom first-line treatment with rituximab and chemotherapy is not suitable. The current treatment options do not result in cure. In symptomatic Waldenström's disease, the goal of treatment is to keep the disease under control for as long as possible without impairing the patient's quality of life.

CONCLUSION

Evidence-based treatment decisions in Waldenström's macroglobulinemia now rely mainly on small-scale, single-armed trials. Patients with this disease should be treated in the setting of a clinical trial if possible. Trials aimed at improving the quality of treatment for other IgM-associated diseases, such as IgM neuropathies and cold agglutinin disease, would also be desirable.

Clinical Presentation and Gene Expression Profiling of Immunoglobulin M Multiple Myeloma Compared With Other Myeloma Subtypes and Waldenström Macroglobulinemia

PURPOSE

Multiple myeloma (MM) is a clonal bone marrow disease characterized by the neoplastic transformation of differentiated postgerminal B cells. It is a heterogeneous disease both at the genetic level and in terms of clinical outcome. Immunoglobulin M (IgM) MM is a rare subtype of myeloma. Similar to Waldenström macroglobulinemia (WM), patients with MM experience IgM monoclonal gammopathy; however, both diseases are distinct in terms of treatment and clinical behavior.

MATERIALS AND METHODS

To shed light on the presentation of IgM MM, its prognosis, and its gene expression profiling, we identified and characterized 21 patients with IgM MM from our database.

RESULTS

One of these patients presented with a rare IgM monoclonal gammopathy of undetermined significance that progressed to smoldering myeloma. The median survival of the 21 patients was 4.9 years, which was comparable to a matched group of patients with non-IgM MM with similar myeloma prognostic factors (age, gender, albumin, creatinine, anemia, lactate dehydrogenase, β₂-microglobulin, cytogenetics abnormalities), but much less than the median survival reported for patients with WM (9 years). We identified a cluster of genes that differ in their expression profile between MM and WM and found that the patients with IgM MM displayed a gene expression profile most similar to patients with non-IgM MM, confirming that IgM MM is a subtype of MM that should be differentiated from WM.

CONCLUSION

Because the prognosis of IgM MM and WM differ significantly, an accurate diagnosis is essential. Our gene expression model can assist with the differential diagnosis in controversial cases.

Case Report of IgM Multiple Myeloma: Diagnosing a Rare Hematologic Entity

IgM multiple myeloma is an exceedingly rare hematologic entity comprising only less than 0.5% of multiple myeloma cases. Given the rarity of this disorder, it makes it a challenge to differentiate from other more prevalent hematologic disorders like Waldenstrom macroglobulinemia. These 2 diseases have the common finding of an IgM monoclonal gammopathy and distinguishing between these 2 diagnoses is of great importance given that therapy and prognosis differ significantly. This report illustrates the case of a 64-year-old man who presented with IgM lambda monoclonal gammopathy in whom signs, symptoms, laboratories, and imaging were initially thought to be consistent with Waldenstrom macroglobulinemia. Upon further analysis, which included bone marrow biopsy, flow cytometry, immunohistochemistry, fluorescence in situ hybridization, and MYD88 (L265P) gene mutation analysis, the rare diagnosis of IgM multiple myeloma was confirmed. As highlighted by this patient's case, reaching the diagnosis of IgM multiple myeloma can be a difficult task which requires a high index of suspicion and accurate diagnostic methods. By using the approach detailed in this report, more cases of IgM multiple myeloma can be diagnosed early, which in turn may lead to earlier treatment and better outcomes.

Kidney Involvement of Patients with Waldenström Macroglobulinemia and Other IgM-Producing B Cell Lymphoproliferative Disorders

BACKGROUND AND OBJECTIVES

Kidney involvement in Waldenström macroglobulinemia is less well described compared with kidney manifestations in multiple myeloma.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Of the 1363 patients seen with Waldenström macroglobulinemia and other IgM-secreting B cell lymphoproliferative disorders seen at the Mayo Clinic between 1996 and 2015, 57 kidney biopsies were retrospectively studied. The biopsy findings were correlated with clinical, kidney, and hematologic characteristics. Criteria for inclusion were evidence of a monoclonal IgM protein and availability of a kidney and a bone marrow biopsy for review. Glomerular and tubulointerstitial pathologies were categorized according to whether they were related to the monoclonal IgM.

RESULTS

Of the 57 patients identified, monoclonal gammopathy-related kidney lesions were identified in 82% (47 of 57 biopsies), whereas nonmonoclonal gammopathy-related kidney lesions were seen in 18% (ten of 57). Monoclonal gammopathy-related kidney lesions included monoclonal Ig-related amyloidosis (n=19; 33%), nonamyloid glomerulopathy (n=20, 35%), and tubulointerstitial nephropathies (n=8; 14%). The most common monoclonal gammopathy-related kidney lesion was monoclonal Ig-related amyloidosis (n=19; 33%) followed by cryoglobulinemic GN (n=13; 28%). Lymphoma infiltration was the most common tubulointerstitial lesion (n=4; 9%). The hematologic diagnosis was Waldenström macroglobulinemia in 74% (n=42), monoclonal gammopathy of renal significance in 16% (n=9), and marginal zone lymphoma (n=2), chronic lymphocytic leukemia (n=2), and low-grade B cell lymphoma (n=2) in 4% each.

CONCLUSIONS

Our study confirms a diverse variety of kidney lesions in patients with monoclonal IgM gammopathy.

IgM myeloma: A multicenter retrospective study of 134 patients

IgM myeloma is a rare hematologic malignancy for which the clinicopathological features and patient outcomes have not been extensively studied. We carried out a multicenter retrospective study in patients with diagnosis of IgM myeloma defined by >10% marrow involvement by monoclonal plasma cells, presence of an IgM monoclonal paraproteinemia of any size, and anemia, renal dysfunction, hypercalcemia, lytic lesions and/or t(11;14) identified by FISH. A total of 134 patients from 20 centers were included in this analysis. The median age at diagnosis was 65.5 years with a male predominance (68%). Anemia, renal dysfunction, elevated calcium and skeletal lytic lesions were found in 37, 43, 19, and 70%, respectively. The median serum IgM level was 2,895 mg dL^-1 with 19% of patients presenting with levels >6,000 mg dL^-1 . International Staging System (ISS) stages 1, 2, and 3 were seen in 40 (33%), 54 (44%), and 29 (24%) of patients, respectively. The malignant cells expressed CD20 (58%) and cyclin D1 (67%), and t(11;14) was the most common cytogenetic finding (39%). The median overall survival (OS) was 61 months. Higher ISS score was associated with worse survival (P = 0.02). Patients with IgM myeloma present with similar characteristics and outcomes as patients with more common myeloma subtypes.

Waldenström macroglobulinemia: 2017 update on diagnosis, risk stratification, and management

Disease Overview: Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, lymphadenopathy, and rarely hyperviscosity.

DIAGNOSIS

Presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis. The L265P mutation in MYD88 is detectable in more than 90% of patients. Risk Stratification: Age, hemoglobin level, platelet count, β₂ microglobulin, and monoclonal IgM concentrations are characteristics required for prognosis. Risk-Adapted Therapy: Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab-based therapy is used in virtually all U.S. patients with WM and can be combined with bendamustine, an alkylating agent, or a proteosome inhibitor. Purine nucleoside analogues are widely used in Europe. The preferred Mayo Clinic nonstudy therapeutic induction is rituximab and bendamustine. Potential for stem cell transplantation should be considered in induction therapy selection. Management of Refractory Disease: Bortezomib, fludarabine, thalidomide, everolimus, ibrutinib, carfilzomib, lenalidomide, and bendamustine have all been shown to have activity in WM. Given WM's natural history, reduction of complications will be a priority for future treatment trials. Am. J. Hematol. 92:209-217, 2017. © 2016 Wiley Periodicals, Inc.

B-cell Non-Hodgkin Lymphomas with Plasmacytic Differentiation

B-cell non-Hodgkin lymphomas with plasmacytic differentiation are a diverse group of entities with extremely variable morphologic features. Diagnostic challenges can arise in differentiating lymphoplasmacytic lymphoma from marginal zone lymphoma and other low-grade B-cell lymphomas. In addition, plasmablastic lymphomas can be difficult to distinguish from diffuse large B-cell lymphoma or other high-grade lymphomas. Judicious use of immunohistochemical studies and molecular testing can assist in appropriate classification.

Clone-specific MYD88 L265P and CXCR4 mutation status can provide clinical utility in suspected Waldenström macroglobulinemia/lymphoplasmacytic lymphoma

MYD88 L265P, a diagnostic marker for lymphoplasmacytic lymphoma (LPL)/Waldenström macroglobulinemia (WM) can also be detected in other hematopoietic malignancies. We demonstrate a novel approach to increase the specificity of this marker for WM/LPL diagnosis by combining flow cytometric cell sorting with molecular analysis. Clonal B-lymphocyte and co-occurring clonal plasma cell populations of low-grade B-cell lymphomas were sorted by flow cytometry and analyzed for immunoglobulin gene rearrangements (PCR), and for MYD88 and CXCR4 mutations. Identical clonal origin was confirmed by PCR for 21 LPL/WM cases and MYD88 L265P was detected in both B-cell and plasma cell fractions. 9/20 other B-cell lymphomas with identical light chain restriction on B-cells and plasma cells were genotypically identical by PCR and MYD88 L265P was detected in both cell fractions in 7/9 whereas in 11/20 specimens with different clonal origin, MYD88 L265P was absent (5/11), or only found in B-lymphocytes (4/11), or plasma cells (2/11). CXCR4 mutations were detected in 17/39 cases, but missed in 63% of these without cell sorting. Confirming MYD88L265P in both B-cells and plasma cell fractions can provide a novel and powerful discriminator to distinguish LPL/WM from phenotypically similar disorders. Furthermore, this approach significantly increases CXCR4 detection sensitivity.

IgM multiple myeloma with an extremely rare non-aggressive presentation: A case report

In the present study, the case of a 41-year-old man with immunoglobulin (Ig)M multiple myeloma (MM) that presented with an unusually non-aggressive clinical course who has survived for >9 years to date, is presented. Initial diagnosis of symptomatic MM was established according to the International Myeloma Working Group consensus statement and guidelines. Due to the mild symptoms, no therapy was administered and the patient was closely followed up. Eight years after initial diagnosis, clinical, morphological and genetic progression occurred with the development of hypercalcemia, progressively deteriorating polyneuropathy, clonal expansion of plasma cells up to 50% of hematopoietic cells and demonstration of the typical t(11;14) translocation (Ig heavy chain locus rearrangement). Subsequently, 4 cycles of induction chemotherapy with velcade, cyclophosphamide and dexamethasone, were administered. At the time of writing, the patient remained alive in generally good health. To the best of our knowledge, with a survival time of >9 years, this case reports the longest survival time of an IgM MM patient to date, which contradicts previous evidence that suggests IgM MM exhibits an aggressive clinical course.

Atypical IgM multiple myeloma with deletion of c-MAF

IgM multiple myeloma (MM) is a rare subtype of myeloma that shares clinical and pathological features with Waldenström's macroglobulinaemia. These are two separate entities that differ both in therapy and prognosis. We report a 57-year-old male, who presented with anaemia, hypercalcaemia, acute renal failure and several vertebral fractures that clinically suggested a multiple myeloma. Further investigations revealed a serum monoclonal component of IgM lambda type and a bone marrow infiltrated by small, lymphoplasmocytic cells. IgM MM was finally diagnosed by means of both inmunophenotypic and immunohistochemistry techniques, stressing the importance of inmunophenotypic evaluation when clinical and morphological features are discordant. Fluorescence in situ hybridization (FISH) studies disclosed a particular combination of deletion 13q14, t(11;14) and monoallelic deletion C-MAF without t(14;16). The clinical evolution after a Bortezomib-containing polychemotherapy and autologous stem cell transplantation (ASCT) conditioned with busulphan and melphalan is also presented. This very uncommon case highlights the impact of immunophenotyping on the differential diagnosis between IgM MM and WM, to choose the best treatment and establish an appropriate outcome.

Waldenström macroglobulinemia: 2015 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, lymphadenopathy, and rarely hyperviscosity.

DIAGNOSIS

Presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis. The L265P mutation in MYD88 is detectable in more than 90% of patients.

RISK STRATIFICATION

Age, hemoglobin level, platelet count, β2 microglobulin, and monoclonal IgM concentrations are characteristics required for prognosis.

RISK-ADAPTED THERAPY

Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab-based therapy is used in virtually all US patients with WM and can be combined with alkylating agent or purine nucleoside analog (or both). The preferred Mayo Clinic nonstudy therapeutic induction is rituximab, cyclophosphamide, and dexamethasone. Future stem cell transplantation should be considered in induction therapy selection. Management of Refractory Disease: Bortezomib, thalidomide, everolimus, ibrutinib, carfilzomib, lenalidomide, and bendamustine have all been shown to have activity in WM. Given WM's natural history, reduction of complications will be a priority for future treatment trials.

International Myeloma Working Group updated criteria for the diagnosis of multiple myeloma

This International Myeloma Working Group consensus updates the disease definition of multiple myeloma to include validated biomarkers in addition to existing requirements of attributable CRAB features (hypercalcaemia, renal failure, anaemia, and bone lesions). These changes are based on the identification of biomarkers associated with near inevitable development of CRAB features in patients who would otherwise be regarded as having smouldering multiple myeloma. A delay in application of the label of multiple myeloma and postponement of therapy could be detrimental to these patients. In addition to this change, we clarify and update the underlying laboratory and radiographic variables that fulfil the criteria for the presence of myeloma-defining CRAB features, and the histological and monoclonal protein requirements for the disease diagnosis. Finally, we provide specific metrics that new biomarkers should meet for inclusion in the disease definition. The International Myeloma Working Group recommends the implementation of these criteria in routine practice and in future clinical trials, and recommends that future studies analyse any differences in outcome that might occur as a result of the new disease definition.

Serum Free Light Chain Only Myeloma with Cytoplasmic IgM

In the past decade, the serum free light chain (FLC) immunoassays have become widely available enabling greater sensitivity in the diagnosis and management of monoclonal light chain diseases. Here, we describe a rare case of serum free light chain only myeloma with cytoplasmic IgM. A 75-year-old woman presented with a progressively worsening lumbosacral pain. FDG PET/CT images showed increased FDG uptake in the sacral mass, vertebral bodies, and ribs. Laboratory data found hypogammaglobulinemia and the bone marrow aspirate revealed only 2.2% of plasma cells. The serum and urine protein electrophoresis did not detect a monoclonal band. However, the serum FLC immunoassays reported an abnormal kappa/lambda ratio (0.001) indicating the presence of monoclonal lambda FLC. The sacral tumor biopsy revealed proliferation of plasma cells and immunohistochemical staining showed that the plasma cells were positive for CD138, IgM, and lambda light chain but negative for CD20. This case may have previously been described as a nonsecretory IgM myeloma but recently would be identified as free light chain only myeloma. The immunohistochemical and genetic features of the clonal plasma cells in free light chain only myeloma need to be further investigated to better understand the relevance and incidence of this myeloma type.

IgM Myeloma or Waldenstrom's Macroglobulinemia Is the Big Question?

Although critical from therapeutic and prognostic perspectives, differentiating IgM Myeloma (MM) from Waldenstrom's macroglobulinemia (WM) is fraught with failure. WM can usually be distinguished from IgM MM by the lymphoplasmacytic versus pure plasmacytic morphology, absent versus present lytic bone lesions, and immunophenotypic findings. However, all these features have their own limitations; hence, it requires constant vigilance and periodic re-evaluation. Here we describe a case of a 70-year-old woman initially diagnosed as smoldering IgM MM, who eventually turned out to have WM.

Monoclonal gammopathy of undetermined significance and risk of lymphoid and myeloid malignancies: 728 cases followed up to 30 years in Sweden

In 728 Swedish cases of monoclonal gammopathy of undetermined significance (MGUS), followed up to 30 years (median, 10 years), we estimated the cumulative risk of hematologic disorders originating from lymphoid and myeloid lineages. Using Cox regression models, we examined associations of demographic and laboratory factors with progression and determined the discriminatory power of 3 prediction models for progression. Eighty-four MGUS cases developed a lymphoid disorder, representing a cumulative risk of 15.4%. Multiple myeloma (MM) occurred in 53 patients, and the 30-year cumulative risk was 10.6%; an ∼0.5% annual risk. Three factors were significantly associated with progression: abnormal free light-chain (FLC) ratio (<0.26 or >1.65), M-protein concentration (≥1.5 g/dL), and reduction of 1 or 2 noninvolved immunoglobulin isotype levels (immunoparesis). A prediction model with separate effects for these 3 factors and the M-protein isotype had higher discriminatory power than other models, although the differences were not statistically significant. The 30-year cumulative risk for myeloid malignancies was <2%. Our study confirms that abnormal FLC ratio and M-protein concentration >1.5 g/dL, factors previously considered by Mayo Clinic researchers, are predictors for MM progression and suggests that separate consideration of immunoparesis and the Mayo Clinic risk factors could improve identification of MGUS patients at high risk for progression.

IgM multiple myeloma: pathologic evaluation of a rare entity

OBJECTIVES

To delineate the pathology of immunoglobulin M-producing multiple myeloma (IgM MM).

METHODS

Clinicopathologic data were reviewed for 15 cases meeting World Health Organization criteria for MM and having a serum IgM paraprotein. Immunohistochemistry was performed on diagnostic bone marrow specimens for common B-cell and plasma cell markers.

RESULTS

Of the 15 IgM MM bone marrows reviewed, 6 (40%) had lymphoplasmacytoid cytology, and 12 (80%) expressed CD19, CD20, and/or CD45. Cyclin D1 expression was common (11 cases, 73%) and usually associated with t(11;14). No cases expressed CD5 or had an associated CD5-positive B-cell population. CD117 was positive in 20% of cases.

CONCLUSIONS

The frequent B-cell-associated antigen expression by IgM MM distinguishes it from other MM types, causing significant pathologic overlap with lymphoplasmacytic lymphoma (LPL). However, IgM MM is usually distinguished from LPL by aberrant cyclin D1 expression or t(11;14). Therefore, assessing for these abnormalities is recommended when evaluating bone marrow involvement by IgM-associated lymphoplasmacytoid disorders.

Waldenström macroglobulinemia: 2013 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, and lymphadenopathy.

DIAGNOSIS

The presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis.

RISK STRATIFICATION

Age, hemoglobin level, platelet count, β2 microglobulin, and monoclonal IgM concentrations are characteristics required for prognosis.

RISK-ADAPTED THERAPY

Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab-based therapy is used in virtually all US patients with WM and can be combined with alkylating agent or purine nucleoside analog (or both). The preferred Mayo Clinic nonstudy therapeutic induction is rituximab, cyclophosphamide, and dexamethasone. Future stem cell transplantation should be considered in induction therapy selection.

MANAGEMENT OF REFRACTORY DISEASE

Bortezomib, thalidomide, everolimus, lenalidomide, and bendamustine have all been shown to have activity in WM. Given WM's natural history, reduction of complications will be a priority for future treatment trials.

How to manage Waldenstrom's macroglobulinemia

Waldenstrom's macroglobulinemia (WM) is very distinct from other indolent lymphoma subtypes: by definition it is accompanied by a monoclonal IgM gammopathy; it presents always with bone marrow infiltration and often with clinical symptoms such as neuropathy or hyperviscosity. These disease characteristics and the frequently advanced age of the WM patient pose a major challenge to the treating clinician even today. Recently, there has been not only substantial progress in our understanding of the biology of WM, but we have also significantly improved our tools to prognostify and to treat patients with this disease. This review summarizes our current knowledge about WM and aims at offering a guideline for the clinical management of patients with this lymphoma subtype, covering questions on how to manage diagnosis, prognostification and treatment based on the most recent data.

Are you sure this is Waldenström macroglobulinemia?

Waldenström macroglobulinemia (WM) is a rare lymphoproliferative disorder characterized by the presence of lymphoplasmacytic cells in the BM and IgM monoclonal protein in the serum. The origin of the malignant clone is thought to be a B cell arrested after somatic hypermutation in the germinal center and before terminal differentiation to plasma cells. In this review, recent advances in the genetic and epigenetic regulators of tumor progression are discussed. Risk factors include IgM-monoclonal gammopathy of undermined significance, familial disease, and immunological factors. The clinical manifestations of the disease include those related to clonal infiltration of the BM, lymph nodes, and, rarely, other sites such as pulmonary or CNS infiltration (Bing-Neel syndrome). Other manifestations are related to the IgM monoclonal protein, including hyperviscosity, cryoglobulinemia, protein-protein interactions, Ab-mediated disorders such as neuropathy, hemolytic anemia, and Schnitzler syndrome. IgM deposition in organs can lead to amyloidogenic manifestations in WM. The diagnostic workup for a patient with WM and rare presentations of WM are described herein. Prognosis of WM depends on 5 major factors in the International Staging System, including age, anemia, thrombocytopenia, β-2 microglobulin, and IgM level. The differential diagnosis of WM includes IgM-multiple myeloma, marginal zone lymphoma, mantle cell lymphoma, and follicular lymphoma.

Case vignettes and other brain teasers of monoclonal gammopathies

There are a number of rare monoclonal gammopathies that do not have a characteristic laboratory, imaging, or pathologic study. Recognition requires keeping the specific syndrome in mind. This article reviews 6 rare syndromes associated with monoclonal proteins and gives specific “pearls” so a clinician can be certain not to overlook these important disorders that easily can be misdiagnosed as MGUS, Waldenstrom, and multiple myeloma.

Waldenström macroglobulinemia: 2012 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Waldenström macroglobulinemia (WM) is a lymphoplasmacytic lymphoma with immunoglobulin M (IgM) monoclonal protein. Clinical features include anemia, thrombocytopenia, hepatosplenomegaly, and lymphadenopathy.

DIAGNOSIS

Presence of IgM monoclonal protein associated with ≥10% clonal lymphoplasmacytic cells in bone marrow confirms the diagnosis.

RISK STRATIFICATION

Age, hemoglobin level, platelet count, β(2) microglobulin, and monoclonal IgM concentrations are characteristics required for prognosis.

RISK-ADAPTED THERAPY

Not all patients who fulfill WM criteria require therapy; these patients can be observed until symptoms develop. Rituximab-based therapy is used in virtually all US patients with WM and can be combined with alkylating agent or purine nucleoside analog (or both). The preferred Mayo Clinic nonstudy therapeutic induction is rituximab, cyclophosphamide, and dexamethasone. Future stem-cell transplantation should be considered in induction therapy selection.

MANAGEMENT OF REFRACTORY DISEASE

Bortezomib, thalidomide, lenalidomide, and bendamustine have all been shown to have activity in WM. Given WM's natural history, reduction of complications will be a priority for future treatment trials.

Waldenström macroglobulinemia: a review of the entity and its differential diagnosis

The definition of Waldenström macroglobulinemia (WM), originally described in 1944, has been refined substantially over time. The current fourth edition of the World Health Organization of lymphoid neoplasms, in large part, adopted criteria proposed for WM at a consensus conference in 2002. WM is defined as lymphoplasmacytic lymphoma involving the bone marrow associated with a serum immunoglobulin (Ig) M paraprotein of any concentration. Morphologically, WM is composed of a variable mixture of lymphocytes, plasmacytoid lymphocytes, and plasma cells. Immunophenotypically, the neoplastic cells express monotypic IgM and light chain: B lymphocytes express pan-B-cell antigens and surface Ig are usually negative for CD5 and CD10; and plasma cells are typically positive for CD138, CD38, CD45, cytoplasmic Ig, and CD19 (in a substantial subset of cases). The putative cell of origin of WM is a postantigen selected memory B-cell that has undergone somatic hypermutation. The most common cytogenetic abnormality in WM is del(6q), usually in the region 6q23-24.3, present in 40% to 50% of cases. IGH gene translocations are rare and recurrent chromosomal translocations or gene aberrations have not been identified in WM. Here, we provide a historical perspective of WM, review clinical and pathologic aspects of the disease as it is currently defined, and discuss some practical issues in the differential diagnosis of WM that pathologists encounter in the signout of cases.