IgM multiple myeloma presenting with spinal cord compression caused by a plasmacytoma: A case report

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.

Hematological entities with plasmacytic differentiation: a case report

INTRODUCTION

Plasmacytoma, a localized tumor of monoclonal plasma cells without any clinical, radiological or physical evidence of plasma cell neoplasm (PCN), is a rare entity that accounts for 1% of PCN. Immunoglobulin M (IgM) extramedullary plasmacytoma of mediastinal region has never been reported and is a diagnostic challenge considering other differential diagnoses.

CASE PRESENTATION

We present the case of a 51-year-old African-American female with progressively increasing cough, dyspnea, and dysphagia for 6 months with a computed tomography (CT) scan revealing a subcarinal mass. The histopathological analysis of the mass reveals a diagnosis of lymphoma with plasma cell differentiation, with a differential of lymphoplasmacytic lymphoma and plasma cell neoplasm. The lymphoma panel via next-generation sequencing (NGS) and a myeloma-targeted fluorescent in situ hybridization (FISH) panel confirmed the diagnosis of IgM extramedullary plasmacytoma, an entity of rare occurrence. Treatment with radiation led to complete regression of the plasmacytoma with normal blood work-up.

CONCLUSIONS

This report describes the challenges of diagnosing IgM extramedullary plasmactyoma. Our case report highlights the importance of cytogenetics and NGS in establishing a correct diagnosis that indeed has prognostic and therapeutic implications.

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.

Comprehensive genomic profiling of IgM multiple myeloma identifies IRF4 as a prognostic marker

Immunoglobulin M multiple myeloma (IgM MM) is an extremely rare subtype of multiple myeloma with a poor clinical outcome. In this study, bone marrow aspirates of MM patients, including two cases of IgM MM, were analyzed by whole exome sequencing and RNA sequencing. Recurrent somatic mutations in the NRAS, KRAS, CCND1, DIS3, and TP53 genes were found in IgM MM and other types of MM, in agreement with previous studies. Overall transcription profiles of IgM and other types of MM clustered together, but separate from normal blood or peripheral plasma cells. Among the differentially expressed genes in IgM MM, IRF4 was highly expressed in IgM as well as in a subset of other types of MM patients. Thus, IRF4 is an independent prognostic factor for general MM patients. Taken together, the somatic mutation and transcriptome profiles support the idea that IgM MM can be classified as an aggressive MM subtype.

Atypical imaging feature of non-secretory multiple myeloma

Non-secretory multiple myeloma (NSMM) is a rare variant of the classic form of multiple myeloma in which no monoclonal gammopathy can be demonstrated in the serum or urine. We describe a rare case of non-secretory multiple myeloma in a 23 year old female presenting with bilateral limb weakness of two years duration. Clinically she was diagnosed to have Pott's spine and was treated with category 1 anti tubercular drugs. Hematological investigations showed plasmacytosis and radiography showed osteolytic lesions. No monoclonal gammopathy was found in the serum or urine. MRI showed multiple compressions with sclerosis within vertebral bodies suggestive of osteomalacia/ diffuse infiltrative disorder. The free light chain (FLC) assay revealed increment in the free kappa light chain and an abnormal κ/λ ratio. Free Light Chain assay (FLC) when used in complement with Protein Electrophoresis (PEP) and Immunofixation Electrophoresis (IFE) were pivotal in diagnosis of non secretory multiple myeloma or light chain myelomas. FLC is a useful monitoring tool because it reflects therapy results due to short serum half life.

IgM multiple myeloma presenting with bleeding tendency: a case report with immunophenotype analysis

IgM multiple myeloma (MM) is an extremely rare lymphoproliferative disease associated with an aggressive clinical course. However, the diagnosis of IgM MM may be complicated by Waldenstrom's macroglobulinemia (WM), particularly when clinical manifestations and morphological features are not typical. It is crucial to distinguish between IgM MM and WM as their prognoses and treatment strategies are different. We report a case of IgM MM presenting with bleeding tendency and an immunophenotype analysis using flow cytometry and immunohistochemistry. Bone marrow cells exhibited a typical phenotype for plasma cells, expressing monoclonal cytoplasmatic IgL-λ, CD38 and CD138 instead of pan-B cell antigens CD19, CD20 and CD22, which are characteristic of the typical immunophenotype of WM. Therefore, the diagnosis of IgM MM was confirmed in this case, highlighting the significance of detailed immuno-phenotypic evaluation when clinical and morphological features are atypical.