POEMS Syndrome: 2019 Update on diagnosis, risk-stratification, and management

IgG4-related disease and other fibro-inflammatory conditions

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder usually characterized by multi-organ involvement. Its pathogenesis is complex and involves genetic and environmental factors, while immune responses usually mediate organ damage and promote fibrosis, which is a key feature of the disease. IgG4 responses, however, are not exclusive to IgG4-RD and can be encountered in other diseases with phenotypes that partially overlap that of IgG4-RD. Although IgG4-RD has clinical and histological hallmarks, the lack of validated diagnostic criteria often makes the diagnosis challenging, requiring a multi-dimensional approach that integrates clinical, radiological and serological data. The present Review covers recent advances in the understanding of disease drivers and its clinical phenotypes, mainly focusing on the differential diagnosis with potential IgG4-RD mimickers, namely histiocytoses, lymphoproliferative disorders, systemic vasculitides and other immune-mediated conditions. The Review also provides a schematic approach to IgG4-RD treatment, including a brief overview of glucocorticoid-sparing agents and emerging therapies, from B cell-depleting monoclonal antibodies to cytokine-targeting drugs, the majority of which are currently under investigation in randomized clinical trials.

Kidney thrombotic microangiopathy with concurrent monoclonal gammopathy

BACKGROUND

The concurrence of monoclonal gammopathy and thrombotic microangiopathy (TMA) has been suggested in a few studies. However, the complement activation was not fully studied in previous cases. In this study, we aimed to determine the complement activation in these group of patients and the association with clinical, laboratory and pathological features.

METHODS

Between 2007 and 2020, 20 patients with biopsy-proven renal TMA and monoclonal gammopathy in Peking University First Hospital were included in the study. Complement activation was tested by enzyme-linked immunosorbent assay. Associations with clinical features, pathological data and laboratory findings were further investigated.

RESULTS

Among renal TMA patients beyond 50 years of age, the prevalence of monoclonal gammopathy was 16.51% (18/109) which is almost 4-fold greater than the expected rate in population (4.2%). Eleven patients had acute kidney injury, and two patients required dialysis. Hematological diagnosis was consistent with monoclonal gammopathy of undetermined significance (MGUS) (n = 10), unconfirmed MGUS (n = 3), POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes) syndromes (n = 4), Castleman's disease (n = 2) and chronic lymphocytic leukemia (n = 1). A majority of patients (84.2%) showed the activation of complement classical pathway. Fifteen percent (3/20) of patients received conservative therapy, 5% (1/20) received steroid only, 30% (6/20) with immunosuppression and 50% (10/20) received clone-targeted chemotherapy. During a median 56 months of follow-up, end-stage renal disease developed in two patients, and five patients died mainly because of hematological progression.

CONCLUSION

This study found the dysregulation of complement activation, especially the classical pathway, involved in the pathogenesis of biopsy-proven renal TMA and monoclonal gammopathy.

Unmasking POEMS (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Gammopathy, and Skin Changes) Syndrome in a Heart Failure Patient: A Diagnostic Challenge

POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome remains poorly understood. It is a paraneoplastic syndrome caused by underlying plasma cell dyscrasia, and there is uncertainty about the features required to establish the diagnosis, treatment efficacy, and prognosis. Almost all patients have polyneuropathy or plasma cell disorder, and approximately one-third have Castleman's disease. Peripheral neuropathy often serves as the primary presenting complaint. While extensive discussions exist regarding POEMS syndrome diagnosis and treatment advancements, literature reports of heart failure symptoms associated with POEMS syndrome are scarce. In this article, we present a case of newly diagnosed POEMS syndrome in a 47-year-old man who initially presented with bilateral lower extremities edema and weakness. Although the initial workup was suggestive of heart failure, subsequent evaluation revealed monoclonal gammopathy, sclerotic bone lesions, and Castleman's disease, ultimately leading to the diagnosis of POEMS syndrome.

Clinical and biochemical characteristics for patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes syndrome: a pilot observational study

Background

Polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome is rare life-threatening condition associated with a clonal plasma cell neoplasm.

Objective

The aim of this study is to investigate the clinical and biochemical features in patients with POEMS syndrome before and post-therapy.

Methods

Characteristics of demographic information, underlying diseases, clinical manifestations, laboratory indicators, and imaging examination were retrospectively collected when diagnosed and post-therapy in the patients POEMS syndrome between 2018 and 2024.

Results

Nineteen newly-diagnosed, treatment-naïve patients with POEMS syndrome were enrolled. The diagnosis of POEMS syndrome was re-analyzed and matched the diagnostic criteria updated in 2023. All patients presented the symptoms of polyneuropathy and positive for M-protein. Most patients suffered with hyperpigmentation (n = 18), organomegaly (n = 18), elevated vascular endothelial growth factor (VEGF) (n = 17), extravascular volume overload (n = 15), sclerotic bone lesions (n = 11), and hypothyroidism (n = 10). Serum alanine aminotransferase, aspartate aminotransferase, total bilirubin, total protein, and albumin levels were down-regulated, while uric acid level was up-regulated in patients with POEMS syndrome. Reduced triiodothyronine, thyroxine, free triiodothyronine levels were negatively correlated with urea nitrogen, creatinine, and uric acid levels in patients with POEMS syndrome. VEGF level, which was negatively correlated with Ca2+ level (r = -0.56), was reduced in most patients with POEMS syndrome receiving bortezomib/ixazomib and lenalidomide/thalidomide therapy. Aspartate aminotransferase, total protein, and estimated glomerular filtration rate levels were increased, while creatinine and uric acid levels were reduced post-therapy in patients with POEMS syndrome.

Conclusion

Patients with POEMS syndrome had impaired liver and renal function, and effective therapy might partly repair the liver and renal dysfunction.

Castleman disease-type histopathological patterns of lymph nodes in patients with plasma cell neoplasia and POEMS syndrome

Plasma cell neoplasia and POEMS syndrome patients may present Castleman disease (CD)-type features in lymph nodes. Our aim was to better characterize the histopathological patterns found in plasma cell neoplasia associated CD and to improve the detection of clonal plasma cell populations in the lymph node biopsies of these patients. Lymph node and bone marrow samples from six cases with plasma cell neoplasia associated CD, including POEMS syndrome and multiple myeloma were analyzed. A complete analysis including morphology, IHC and PCR-based clonality detection in the lymph node biopsies and morphology; IHC and FCM in the bone marrow biopsies was done. Correlation with clinical and laboratory features was performed. Both plasma cell rich and hyper vascular Castleman disease like histopathological features were found. In two out of six cases, sheets of plasma cells with light chain and isotype restriction were identified in the lymph nodes. B cell clonality analysis provided evidence of clonal populations in 5 out of 6 cases, increasing the sensitivity for the detection in cases without morphologically identifiable monotypic plasma cells. None of the twelve control cases with iMCD and HHV-8 positive CD showed clonal populations. In conclusion, the combination of morphology, complete immunophenotyping and B cell clonality analysis in the lymph node biopsy may provide evidence of clonal populations in up to 83 % of cases with plasma cell neoplasia/POEMS syndrome associated Castleman disease. Clinical work-up for the confirmation of plasma cell dyscrasia is advisable in such cases.

Top 10 Clinical Pearls in Paraproteinemic Neuropathies

Paraproteinemic neuropathies represent an important subset of peripheral neuropathies. Once identified, further evaluation into the paraproteinemic subtype, clinical exam pattern, and electrodiagnostic phenotype helps clarify if the paraproteinemia is coincidental or causal of the neuropathy, as not all paraproteinemias cause neuropathy. Of all paraproteinemias, immunoglobulin M (IgM)-associated peripheral neuropathy, or IgM neuropathy, is of particular importance as half of IgM neuropathies also harbor anti-myelin-associated glycoprotein antibodies, which produce a characteristic demyelinating pattern on nerve conduction testing. Immunoglobulin G and immunoglobulin A paraproteinemias are less strongly associated with peripheral neuropathy, except in the setting of multiple myeloma or osteosclerotic myeloma (POEMS syndrome), which have characteristic systemic features. In multiple myeloma, chemotherapy is more likely to result in neuropathy than the myeloma itself. Finally, the presence of systemic features (e.g., cardiomyopathy, nephropathy, recurrent carpal tunnel syndrome, and autonomic insufficiency) should raise concern for hereditary or acquired light (AL) chain amyloidosis. AL amyloidosis can occur in the setting of any light or heavy chain paraproteinemia. Central to the proper evaluation of paraproteinemic neuropathy is electrodiagnostic testing, which helps delineate axonal versus demyelinating paraproteinemic neuropathy, the latter often misdiagnosed as chronic inflammatory demyelinating polyradiculoneuropathy.

Idiopathic multicentric Castleman disease in children: a single-center retrospective analysis

OBJECTIVE

To investigate the clinical features, pathological phenotype, treatment and prognosis of idiopathic multicenter Castleman disease (iMCD)in children.

METHODS

From January 2017 to September 2023, basic information, laboratory tests, treatment and prognosis of children diagnosed with iMCD who attended Beijing Children's Hospital of Capital Medical University were collected.

RESULTS

A total of 9 children were enrolled, with a median age of onset of median 11 (2-15) years, 6 males and 3 female. 3 cases were pathologically typed as plasma cell type, 1 case was mixed type, and the remaining 5 cases were hyaline vascular type. 9 children received different regimens of chemotherapy. The median follow-up time was 26 (13, 58) months, with no deaths, 7/9 cases showing improvement, 1/9 cases showing stable condition, and 1/9 cases showing active condition.

CONCLUSION

Children with multicentric CD often have systemic symptoms, lymph node enlargement and related compression symptoms are the most common manifestations, followed by fever, malaise and other systemic symptoms. Anti-IL-6-based therapy combined with hormones lenalidomide and other medications have a specific therapeutic effect on multicentric CD.

Canonical effects of cytokines on glomerulonephritis: A new outlook in nephrology

Glomerulonephritis (GN) is an important cause of renal inflammation resulting from kidney-targeted adaptive and innate immune responses and consequent glomerular damage. Given the lack of autoantibodies, immune complexes, or the infiltrating immune cells in some forms of GN, for example, focal segmental glomerulosclerosis and minimal change disease, along with paraneoplastic syndrome and a special form of renal involvement in some viral infections, the likeliest causative scenario would be secreted factors, mainly cytokine(s). Since cytokines can modulate the inflammatory mechanisms, severity, and clinical outcomes of GN, it is rational to consider the umbrella term of cytokine GN as a new outlook to reclassify a group of previously known GN. We focus here, particularly, on cytokines that have the central "canonical effect" in the development of GN.

Clinical Impact of Osteolytic Bone Lesions in POEMS Syndrome: A Single-Center Experience of 114 Patients

POEMS syndrome is a multisystemic disease associated with monoclonal plasma cell disorders. Although the presence of bone lesions is included in the diagnostic criteria, their precise manifestations remain unknown. Here, we retrospectively analyzed the bone lesions in patients with POEMS syndrome and evaluated their clinical features. Clinical data and bone lesion information by computed tomography (CT) imaging were obtained from the 114 patients with POEMS syndrome. Regardless of the presence of sclerotic bone lesions, patients were divided into two groups according to the presence (lytic group: n = 17, 14.9%) or absence (non-lytic group: n = 97, 85.1%) of osteolytic lesions. In the lytic group, several patients were histologically diagnosed with plasmacytoma. In the evaluation by CT imaging, osteolytic lesions had a higher response rate than sclerotic lesions (75.0% vs. 42.2%, p = 0.079). Nevertheless, patients in lytic group showed earlier clinical progression than patients in non-lytic group (2-year progression-free survival, 66.7% vs. 90.2%, p = 0.069). The presence of innumerable bone lesions was an independent poor prognostic factor in multivariate analysis, regardless of the presence of osteolytic lesions (hazard ratio, 3.4; 95% confidence interval 1.1-10.9; p = 0.040). Osteolytic and innumerable bone lesions are potential prognostic factors. Further studies involving histopathological evaluations of bone lesions are warranted.

A case report of an M protein-negative patient with POEMS syndrome associated with renal involvement

BACKGROUND

POEMS syndrome with polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes is an uncommon plasma cell paraneoplastic syndrome involving multiple system. It is relatively rare in clinical practice, and renal involvement is a usual yet easily overlooked symptom.

CASE PRESENTATION

We successfully treated a patient with M protein-negative POEMS syndrome with membranoproliferative glomerulonephritis (MPGN) findings and thrombotic microangiopathic changes by comparing the level of Vascular endothelial growth factor (VEGF) in the serum and the changes in polyserositis before and after the patient's treatment.

CONCLUSION

POEMS syndrome clinically involves multiple systems and has complex symptoms. Because of the diversity of the disease manifestations, identification of atypical POEMS syndrome and timely intervention are important for patient survival and prognosis.

MGCS: where do we stand today?

Monoclonal gammopathies of clinical significance (MGCS) are a heterogeneous group of disorders characterized by the presence of an indolent B-cell or plasma-cell clone producing a toxic monoclonal immunoglobulin resulting in end-organ dysfunction. MGCS is a clinicopathologic diagnosis that requires the demonstration of a monoclonal immunoglobulin in the correct clinical setting. The most common MGCS syndromes are renal, neurologic, and cutaneous, although hematologic and multi-organ MGCS syndromes are also increasingly recognized. Therapy most commonly targets the underlying clonal population; immunoglobulin-targeting therapies as well as complement and cytokine antagonists have emerged for selected MGCS syndromes and may be temporizing in a subset of patients. Other chapters review renal and neurologic MGCS; this chapter focuses on hematologic and multi-organ MGCS syndromes.

Overview of Research Status in Castleman Disease

Castleman disease (CD) is characterized by the proliferation of lymphoid tissue and encompasses a range of disorders that vary in clinical presentation, histopathological features, and therapeutic approaches. This article presents a comprehensive review of the current state of CD research, emphasizing the etiology, pathogenesis, clinical manifestations, diagnostic criteria, treatment options, and prognostic factors. CD is a relatively rare condition infrequently encountered in clinical practice. Certain subtypes of CD progress rapidly and pose a significant threat to patient health. Consequently, a timely and accurate diagnosis is crucial. This article aimed to equip clinicians and researchers with an updated and detailed understanding of CD, thereby enhancing the management of this complex condition.

Dermatologic manifestations of hematologic disorders

Distinguishing key morphologic features and understanding the pathophysiology of common cutaneous manifestations of hematologic disorders is essential to ensure prompt and appropriate treatment. In fact, classic cutaneous signs may provide the first clue to the diagnosis of an underlying hematologic disease. Disorders of coagulation, vascular abnormalities, or cutaneous infiltration and deposition are responsible for the underlying pathophysiology of cutaneous manifestations in the majority of cases. Hematologists often feel ill-equipped in identifying morphologic changes in the skin. Thus, the purpose of this review is to provide a comprehensive overview of classic cutaneous manifestations and diagnostic considerations of the associated hematologic conditions. Though there is a specific focus on non-malignant disorders, those straddling the spectrum of malignancy are also discussed. In many disease states, the skin may serve as an important marker of an emerging hematologic disorder, so close collaboration and multidisciplinary input remain essential to provide optimal and timely care for these patients.

Castleman Disease: A Rare Lymphoproliferative Disorder With Diverse Clinical Presentation, Diagnosis, and Treatment Approach

Castleman disease (CD) includes rare and intricate lymphoproliferative disorders characterized by the abnormal growth of lymph nodes and immune system disturbances. It primarily presents in two forms: unicentric Castleman disease (UCD), which affects a single lymph node area, and multicentric Castleman disease (MCD), which involves multiple lymph nodes and systemic manifestations. The disease's underlying mechanisms are often linked to immune system irregularities, especially involving interleukin-6 (IL-6). The condition was first documented by Dr. Benjamin Castleman in 1954, laying the groundwork for understanding this complex disorder. MCD can be further divided into idiopathic MCD (iMCD), which includes thrombocytopenia, ascites, fibrosis, renal impairment, and organ enlargement (TAFRO) syndrome, and human herpesvirus-8 (HHV-8)-associated MCD, which can occur in individuals with or without HIV. The prevalence of CD shows a higher occurrence of UCD, with the disease typically presenting in individuals in their fifth to seventh decades of life and being more common in areas with high HIV prevalence. The clinical presentation of CD can include symptoms such as swollen lymph nodes, fever, anemia, and systemic inflammation. Diagnostic challenges arise due to the disease's rarity, and its symptoms overlap with other conditions. Treatment approaches differ based on the subtype. UCD generally responds favorably to the surgical removal of the affected lymph nodes, while MCD often requires antiviral treatments, interleukin-6 (IL-6) inhibitors, and new biologic therapies. Recent advances in treatment, including innovative biologic agents and combination therapies, offer promising prospects for improving patient outcomes. Accurate diagnosis and customized treatment strategies are essential for the effective management of this complex disease.

Immunology and targeted therapy in Castleman disease

INTRODUCTION

Castleman disease (CD) is a benign lymphoproliferative disease causing severe systemic inflammation. Interleukin-6 (IL-6) is a major pathogenesis of multicentric CD (MCD), but only 30-60% of patients respond to IL-6 inhibitors. Novel agents for IL-6 inhibitor-refractory cases are needed. Clinical data and samples are being collected on a large scale and the clinical, pathological, and pathogenetic aspects are being elucidated.

AREAS COVERED

The pathological and clinical classification of CD is outlined. Focusing on idiopathic MCD (iMCD), this review identifies therapeutic targets and summarizes currently recommended drugs and promising therapeutic candidates.

EXPERT OPINION

The pathogenesis of MCD has been implicated in the activation of the Janus kinase (JAK)-transcriptional signaling activator (STAT) 3 pathway and the phosphatidylinositol 3-kinase (PI3K)/Akt/mechanical target of rapamycin (mTOR) signaling pathway. iMCD-TAFRO (thrombocytopenia, anasarca, fever/elevated CRP, reticulin myelofibrosis/renal dysfunction, organ enlargement) is resistant to IL-6 inhibitors, and cyclosporine and mTOR inhibitors are sometimes effective. JAK inhibitors and mTOR inhibitors may be therapeutic agents for iMCD. Recently, we have shown that peripheral helper T (Tph) cell abnormalities are at the core of iMCD pathogenesis. Therapies targeting chemokine (C-X-C motif) ligand 13 (CXCL13) produced by Tph cells and blocking the Tph-CXCL13-B cell pathway may satisfy unmet need in refractory cases.

[Eosinophilic fasciitis: From pathophysiology to therapeutics]

Eosinophilic fasciitis (EF) is a rare connective tissue disorder characterized by painful edema and induration of the limbs and trunk, likely associated with hypereosinophilia and hypergammaglobulinemia. EF causes arthralgia and range of motion limitation, leading to significant functional impairment and poor quality of life. Since its description by Shulman in 1974, over 300 cases have been reported. We present here a review of the latest diagnostic, pathophysiological and therapeutic developments in this disease. Magnetic resonance imaging appears useful to guide diagnosis and biopsy. Diagnosis is based on a deep skin biopsy involving the fascia, which will reveal edema, sclerofibrosis of the muscular fascia and subcutaneous tissue, and an inflammatory infiltrate sometimes composed of eosinophilic polynuclear cells. EF may occur in patients treated with immune checkpoint inhibitors and the diagnosis should be raised in case of cutaneous sclerosis in these patients. The pathophysiology of the disease remains poorly understood, and its management lacks randomized, controlled, blinded trials. First-line treatment consists in oral corticosteroid therapy, sometimes combined with an immunosuppressant, mainly methotrexate. A better understanding of the pathophysiology has opened new therapeutic perspectives and clarified the role of targeted therapies in the management of EF, such as interleukin-6 inhibitors, whose efficacy has been reported in several cases.

Paraproteinemic neuropathies

The diagnostic evaluation of a peripheral neuropathy includes testing for the presence of monoclonal gammopathy, which can be found in about 10% of patients with peripheral neuropathy. Our role, as physicians, is to determine whether the neuropathy is directly related to the gammopathy or whether the co-occurrence of these two disorders is purely coincidental. The evaluating physician needs to be familiar with the different types of neuropathies associated with monoclonal gammopathies, their clinical and electrodiagnostic characteristics, and their appropriate diagnostic evaluation and management. Testing for monoclonal protein disorders includes serum protein electrophoresis (SPEP) and immunofixation of blood, and in some cases of urine, as well as measurement of free light chains and quantitative immunoglobulins. Specific antibody testing is directed by paraprotein type and neuropathy phenotype. Patients with abnormal free light chains in association with sensory and autonomic neuropathy should be evaluated for AL amyloidosis. When a lambda monoclonal protein is identified together with a clinical phenotype of chronic inflammatory demyelinating neuropathy (CIDP), a diagnosis of polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes (POEMS) syndrome should be considered. Patients with IgM paraprotein associated neuropathy should be assessed for distal acquired demyelinating sensorimotor (DADS) neuropathy, with or without anti myelin associated glycoprotein (MAG) antibody or CANOMAD syndrome. In many cases, a monoclonal gammopathy of uncertain significance (MGUS) is incidental and unrelated to the neuropathy. Collaboration with oncology is critical in evaluating patients with monoclonal proteins to assess for underlying plasma cell neoplasms or B cell lymphomas.

Intersecting Pathologies: A Case Report on the Co-presentation of Quasi-Moyamoya Disease and Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Plasma Cell Disorder, and Skin Changes (POEMS) Syndrome

Moyamoya disease (MMD) is a rare chronic vasculopathy characterized by progressive stenosis of the internal carotid arteries and the formation of fragile collateral vessels in the brain. Polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) syndrome is a rare paraneoplastic syndrome with a complex presentation that includes polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes. Here, we report a unique case of a 54-year-old male with MMD presenting with recurrent speech loss and mumbling, later diagnosed with POEMS syndrome. Initial imaging revealed Moyamoya vasculopathy, confirmed by computed tomographic angiography (CTA) and magnetic resonance imaging (MRI). Further examination revealed polyneuropathy, organomegaly, and elevated vascular endothelial growth factor (VEGF), meeting the diagnostic criteria for POEMS syndrome. The patient was treated with a cyclophosphamide-bortezomib-dexamethasone regimen, followed by the addition of daratumumab, resulting in clinical improvement. This case highlights the importance of thorough diagnostics and a multidisciplinary treatment approach for patients with complex comorbidities, emphasizing the need for early detection and targeted therapy in managing dual pathologies of MMD and POEMS syndrome.

Case report: POEMS syndrome with portal hypertension

This patient was an elderly patient with abdominal distension and shortness of breath. According to relevant examinations, his condition was initially considered to be related to cirrhosis, but pathological biopsy confirmed the diagnosis of noncirrhotic portal hypertension of unknown etiology. The portal vein pressure was significantly reduced after transjugular intrahepatic portosystemic shunt (TIPS). Nevertheless, the relief of the hydrothorax and ascites was not significant, and the numbness in both lower limbs gradually worsened. POEMS syndrome was ultimately diagnosed following a comprehensive examination. After two courses of bortezomib combined with dexamethasone, the patient died due to a systemic infection. The clinical symptoms of the patient were atypical, as was the presence of portal hypertension, which hindered the diagnosis of POEMS. Due to the patient's advanced age, the diagnosis was delayed, and the prognosis was poor. This case reminds clinicians that POEMS patients can also have portal hypertension as the main manifestation.

[Clinical characteristics of POEMS syndrome initially diagnosed as increased extravascular volume load: a single-center retrospective study]

POEMS syndrome is a rare plasma cell dysplasia. Its clinical manifestations include polyneuropathy, monoclonal protein, increased extravascular volume load, endocrinopathy, organomegaly and skin changes. The complex and atypical symptoms at presentation make early diagnosis challenging due to multiple system involvement. Peripheral neuropathy, limb numbness, is the most common initial symptom of this disease. However, case reports of increased extravascular volume load are rare. This article collected and analyzed the clinical data of two groups of patients with different initial symptoms (increased extravascular volume load and limb numbness). The clinical characteristics and treatment responses were summarized.

An Unusual Presentation of Multiple Sclerotic Bone Lesions in Unicentric Castleman's Disease

Castleman's disease is a rare lymphoproliferative disease that usually presents as a solitary mass in the mediastinal or cervical region. Castleman's disease can be usually of two types: unicentric type (which involves only one site of lymph nodes) and multicentric type (which involves multiple sites of lymph nodes). We report the case of a 26-year-old female with multiple sclerotic bone lesions in unicentric Castleman's disease. The definitive diagnosis was made by excisional biopsy with immunohistochemistry, 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) study, and MRI scan. This case report emphasizes the need for proper workup for systemic manifestations in unicentric Castleman's disease.

Monoclonal gammopathy-associated peripheral neuropathies: Uncovering pearls and challenges

Monoclonal gammopathy-related peripheral neuropathies encompass a spectrum of clinical presentations in which the monoclonal protein directly damages the tissues, including the peripheral nervous system. Given the prevalence of both peripheral neuropathy and monoclonal gammopathy in the general population, these conditions may overlap in clinical practice, posing a challenge for clinicians in determining causality. Therefore, a comprehensive understanding of primary clinical syndromes and their neurophysiological patterns is of great importance for accurate differential diagnoses and effective treatment strategies. In this article, we examine the main forms of monoclonal gammopathies that affect the peripheral nerve. We explore the clinical and electrophysiological aspects and their correlation with each syndrome's corresponding monoclonal protein type. This knowledge is essential for healthcare professionals to diagnose better and manage patients presenting with monoclonal gammopathy-related peripheral nervous system involvement.

Unusual Types of Plasma Cell Dyscrasias Associated With HIV: Polyneuropathy, Organomegaly, Endocrinopathy, M-protein, and Skin Changes (POEMS) Syndrome

Polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome is a multisystem paraneoplastic disorder due to an underlying plasma cell neoplasm, and its occurrence among HIV patients is extremely rare. The diagnosis of POEMS syndrome can be challenging in this context, particularly if its disabling polyneuropathy is misdiagnosed as neuropathy related to HIV. Herein, we report the case of a female patient with treated HIV who later developed POEMS syndrome. After a misdiagnosis of chronic inflammatory demyelinating polyneuropathy related to HIV and unsuccessful corticosteroids and cyclophosphamide therapies, the correct diagnosis of POEMS syndrome was made. The patient achieved significant hematological and neurological improvement after six cycles of lenalidomide. Autologous stem cell transplantation was then scheduled to prevent eventual relapses.

Detection of clonal plasma cells in POEMS syndrome using multiparameter flow cytometry

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein [M-protein], and skin changes) is a rare systemic disorder characterized by various symptoms caused by underlying plasma cell (PC) dyscrasia. Detection of monoclonal PCs is mandatory for the diagnosis of POEMS syndrome; however, the usefulness of EuroFlow-based next-generation flow cytometry (EuroFlow-NGF) in POEMS syndrome for detecting monoclonal PCs in bone marrow (BM) and the gating strategy suitable for flow cytometry study of POEMS syndrome remain unknown. We employed EuroFlow-NGF-based single-tube eight-color multiparameter flow cytometry (MM-flow) and established a new gating strategy (POEMS-flow) to detect the monoclonal PCs in POEMS syndrome, gating CD38 broadly from dim to bright and CD45 narrowly from negative to dim compared to MM-flow. MM-flow detected monoclonal PCs in 9/25 (36.0%) cases, including 2/2 immunofixation electrophoresis (IFE)-negative cases (100%). However, POEMS-flow detected monoclonal PCs in 18/25 cases (72.0%), including 2/2 IFE-negative cases (100%). POEMS-flow detected monoclonal PCs with immunophenotypes of CD19- in 17/18 (94.4%). In six cases where post-treatment samples were available, the size of the clones was significantly reduced after the treatment (P = 0.031). POEMS-flow can enhance the identification rate of monoclonal PCs in POEMS syndrome and become a valuable tool for the diagnosis of POEMS syndrome.

Lymphadenopathy in the rheumatology practice: a pragmatic approach

Lymphadenopathy is a common clinical finding and diagnostic challenge within general medicine and rheumatology practice. It may represent a primary manifestation of an underlying immune-mediated disease or indicate an infectious or neoplastic complication requiring differing management. Evaluating lymphadenopathy is of particular relevance in rheumatology, given that lymph node enlargement is a common finding within the clinical spectrum of several well-known rheumatologic disorders including RA, SLE and SS. In addition, lymphadenopathy represents a hallmark manifestation of rare immunological diseases such as Castleman disease and IgG4-related disease that must be considered in the differential diagnosis because effective targeted treatments can now impact the prognosis of these conditions. In this review we present an overview of the clinical significance of lymphadenopathy in common and rare rheumatologic diseases and propose a practical approach to lymphadenopathy in the rheumatology practice. Differential diagnosis of Castleman disease and therapeutic options for this condition of increasing rheumatologic interest will be discussed in detail.

From Castleman disease histopathological features to idiopathic multicentric Castleman disease: a multiparametric approach to exclude potential iMCD histopathological mimickers

AIMS

International consensus diagnostic criteria for idiopathic multicentric Castleman disease (iMCD) includes lymph node Castleman disease (CD) histopathological features as major criteria. Our aim was to apply those criteria in a series of 42 cases with CD to find differences among unicentric CD, iMCD, HHV-8+multicentric CD (HHV-8+MCD) and POEMS/plasma cell neoplasia (PCN)-associated CD.

METHODS

Available clinical and laboratory criteria were collected. Histopathological features (germinal centre hyperplasia/regression, plasmacytosis, hypervascularity and follicular dendritic cell (FDC) prominence) were graded and immunohistochemistry with antibodies against CD20, CD3, CD138, HHV-8, Ig isotype (IgG, IgG4, IgA, IgM, IgD), kappa, lambda was performed in all cases.

RESULTS

Fourteen cases had hyaline-vascular type unicentric CD, 15 were HHV-8+MCD, 7 cases PCN/POEMS-associated CD and 5 cases were iMCD. One case was consistent with systemic lupus erythematosus (SLE) lymphadenopathy. Differences in grading of the CD-associated histopathological features showed that FDC proliferation was prominent in unicentric CD, hypervascularity was increased in HHV-8 positive MCD and germinal centre hyperplasia was restricted to iMCD cases and SLE. Monotypic plasma cells were readily identifiable in the lymph node biopsies in 43% of PCN/POEMS-associated CD. All three cases had lambda light chain restriction with IgA (two cases) and IgG (one case) isotypes.

CONCLUSIONS

HHV-8+ MCD and PCN/POEMS-related CD are the major mimickers of iMCD in lymph node biopsies. Grading of the five histopathological features for CD might be useful to, in conjunction with complete ancillary testing, suggest for specific disease entities.

Non-POEMS osteosclerotic multiple myeloma: Clinical characteristics and differential diagnosis

Osteosclerosis in multiple myeloma (MM) is typically associated with rare POEMS syndrome, characterized by polyneuropathy (P), organomegaly (O), endocrinopathy (E), M-protein (M), and skin changes (S). However, osteosclerosis in multiple myeloma (MM) without POEMS syndrome, defined as non-POEMS Osteosclerotic MM, is exceedingly rare. We report a 70-year-old man with rib pain, remarkably high bone mineral density and diffuse osteosclerosis. The diagnosis of non-POEMS osteosclerotic MM was confirmed by biopsy and aspiration of bone marrow through surgery. A literature review spanning from 1990 identified 12 cases of similar non-POEMS osteosclerotic MM, including 5 males and 7 females with a mean age of 59.7 ± 10.6 years. The non-POEMS osteosclerotic MM can be divided into two subtypes, the osteosclerotic lesion subtype and the diffuse osteosclerosis subtype. Absence of polyneuropathy and organomegaly are the main factors that differentiate non-POEMS osteosclerotic MM from POEMS. A hyperactive osteoblastic process might be the etiology of diffuse osteosclerosis. Further research is needed to understand its etiology and pathophysiology.

Human Herpesvirus 8-Positive Multicentric Castleman Disease in an Immunocompetent Patient: A Diagnostic Challenge

We present a clinical case of a 79-year-old male admitted to inpatient care for longstanding asthenia and respiratory symptoms. Associated features were polyserositis, multiple enlarged lymphatic nodules, acute kidney injury, and heart failure. The patient's recent medical history revealed SARS-CoV-2 vaccination a week prior and an upper respiratory tract infection. The laboratory results from thoracentesis were compatible with a transudate, with no immunological stain. Epstein-Barr virus polymerase chain reaction (PCR) was positive. The thoracic, abdominal, and pelvic CT scans revealed multiple enlarged lymphatic nodules, worsening the pre-existent polyserositis and hepatosplenomegaly. The patient began to show signs of neurologic symptoms and deterioration of the global health status. An enlarged lymphatic nodule was excised and the pathology showed human herpesvirus 8 multicentric Castleman disease. The disease evolved rapidly into hematological dysfunction and blood transfusions were necessary. Even though the patient was started on high-dose rituximab therapy combined with etoposide, the disease evolved into multiorgan dysfunction with a fatal outcome.

Paraneoplastic Dermatoses and Cutaneous Metastases

Paraneoplastic syndromes include a variety of cutaneous presentations that have an associated internal malignancy. Some syndromes have a strong correlation to specific internal malignancies, whereas others are associated with a multitude of tumors. There are many cutaneous manifestations that suggest hematologic disorders, which will be reviewed in detail. Cutaneous metastases are commonly from breast and lung cancers and can present as nodules, vascular lesions, eczematous dermatitis, or inflammatory lesions. The most common histologic presentation of cutaneous metastasis is that of a dermal-based or subcutaneous-based nodule with sparing of the epidermis. Determination of origin of tumor requires immunohistochemistry and clinical correlation.

Polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome with dilated cardiomyopathy: A case report

BACKGROUND

Polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes (POEMS) syndrome is a rare paraneoplastic syndrome that encompass multiple systems. The most common clinical symptoms of POEMS syndrome are progressive sensorimotor polyneuropathy, organ enlargement, endocrine disorders, darkening skin, a monoclonal plasma cell proliferative disorder, and lymph node hyperplasia. The organomegaly consists of hepatosplenomegaly and/or lymphadenopathy; cases of cardiomyopathy are rare. Diagnoses are often delayed because of the atypical nature of the syndrome, exposing patients to possibly severe disability. Therefore, identifying atypical symptoms can improve the prognosis and quality of life among POEMS syndrome patients.

CASE SUMMARY

Herein, we report the case of a 59-year-old woman with POEMS syndrome that involved dilated cardiomyopathy. The patient presented to the hospital with complaints of shortness of breath and discomfort in the chest. The patient reported previous experiences of limb numbness. During hospitalization, the brain natriuretic peptide levels were 3504.0 pg/mL. Color doppler echocardiography showed an enlarged left side of the heart, along with ventricular wall hypokinesis and compromised functioning of the same side of the heart. Abdominal color ultrasonography revealed that the patient's spleen was enlarged. Observations from cardiac magnetic resonance imaging showed that the left side of the heart was enlarged. Slight myocardical fibrosis was also observed. Electromyography was described as a symmetric sensorimotor demyelinating polyneuropathy. Further immunoelectrophoresis of the serum showed the presence of a monoclonal IGA λ M protein. The vascular endothelial growth factor levels were 622.56 pg/mL. Flow cytometric and immunohistochemical staining of the bone marrow detected no monoclonal plasma cells. Finally, the patient was diagnosed with POEMS syndrome associated with dilated cardiomyopathy. The chest-related discomfort and the shortness of breath resolved after the administration of lenalidomide and dexamethasone.

CONCLUSION

When patients with cardiomyopathy have systemic manifestations such as numb limbs and darkening skin, the POEMS syndrome is the most possible diagnosis.

Paraneoplastic neuropathies and peripheral nerve hyperexcitability disorders

Peripheral neuropathy is a common referral for patients to the neurologic clinics. Paraneoplastic neuropathies account for a small but high morbidity and mortality subgroup. Symptoms include weakness, sensory loss, sweating irregularity, blood pressure instability, severe constipation, and neuropathic pain. Neuropathy is the first presenting symptom of malignancy among many patients. The molecular and cellular oncogenic immune targets reside within cell bodies, axons, cytoplasms, or surface membranes of neural tissues. A more favorable immune treatment outcome occurs in those where the targets reside on the cell surface. Patients with antibodies binding cell surface antigens commonly have neural hyperexcitability with pain, cramps, fasciculations, and hyperhidrotic attacks (CASPR2, LGI1, and others). The antigenic targets are also commonly expressed in the central nervous system, with presenting symptoms being myelopathy, encephalopathy, and seizures with neuropathy, often masked. Pain and autonomic components typically relate to small nerve fiber involvement (nociceptive, adrenergic, enteric, and sudomotor), sometimes without nerve fiber loss but rather hyperexcitability. The specific antibodies discovered help direct cancer investigations. Among the primary axonal paraneoplastic neuropathies, pathognomonic clinical features do not exist, and testing for multiple antibodies simultaneously provides the best sensitivity in testing (AGNA1-SOX1; amphiphysin; ANNA-1-HU; ANNA-3-DACH1; CASPR2; CRMP5; LGI1; PCA2-MAP1B, and others). Performing confirmatory antibody testing using adjunct methods improves specificity. Antibody-mediated demyelinating paraneoplastic neuropathies are limited to MAG-IgM (IgM-MGUS, Waldenström's, and myeloma), with the others associated with cytokine elevations (VEGF, IL6) caused by osteosclerotic myeloma, plasmacytoma (POEMS), and rarely angiofollicular lymphoma (Castleman's). Paraneoplastic disorders have clinical overlap with other idiopathic antibody disorders, including IgG4 demyelinating nodopathies (NF155 and Contactin-1). This review summarizes the paraneoplastic neuropathies, including those with peripheral nerve hyperexcitability.

Nerve transcriptomes in autoimmune and genetic demyelinating neuropathies: Pathogenic pathway assessment of nerve demyelination

The pathogenesis of autoimmune demyelinating neuropathies is poorly understood compared to inherited demyelinating forms. We performed whole transcriptome (RNA-Seq) using nerve biopsy tissues of patients with different autoimmune and inherited demyelinating neuropathies (CIDP n = 10, POEMS n = 18, DADS n = 3, CMT1 n = 3) versus healthy controls (n = 6). A limited number of differentially expressed genes compared to healthy controls were identified (POEMS = 125, DADS = 15, CMT = 14, CIDP = 5). Divergent pathogenic pathways including inflammatory, demyelinating and neurite regeneration such as with the triggering receptor expressed on myeloid cells (TREM1) part of the immunoglobulin superfamily and RhoGD1 are found. Shared and discordant pathogenic injury are discovered between autoimmune and inherited forms.

Small vessel platelet thrombosis in the peripheral nerves in POEMS syndrome

INTRODUCTION/AIMS

Vascular thrombosis is prevalent among patients with polyneuropathy, organomegaly, endocrinopathy M-protein, and skin changes (POEMS) syndrome. The endothelial cells in the endoneurium are often hypertrophied and the lumen is frequently occluded. Consequent local hypoxia may increase vascular endothelial growth factor (VEGF), which induces hypercoagulation and vascular permeability.

METHODS

This study presents two patients in the fifth decade of life, who had rare nerve biopsy findings of vascular occlusion mainly by platelets. Before the cases presented here, we encountered nine confirmed POEMS patients whose nerve biopsies did not show similar findings.

RESULTS

A small artery and a vein were occluded, but no atherosclerotic changes were observed. The endothelial cells that adhered to the packed platelets lost their junctions.

DISCUSSION

Platelet aggregation, degranulation, and ischemia may cause a loose endothelial barrier and leak proinflammatory cytokines, such as interleukin-12. This may increase production of VEGF and may cause nerve demyelination. Small vessel platelet thrombosis may contribute to the pathogenesis of this disorder.

POEMS (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal Plasma Cell Disorder, and Skin Changes) Syndrome as a Sequela of Castleman Disease: A Case Report

Polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) syndrome is a rare multisystemic paraneoplastic disorder caused by an underlying plasma cell dyscrasia. Its diagnosis is based on the presence of two mandatory criteria and at least one major and one minor criterion. We report a case of a 52-year-old female patient who presented with complaints of acrocyanosis, night sweats, scaly skin, and swelling on the left side of the neck. She was a known case of hypothyroidism, antiphospholipid syndrome, and cerebral venous thrombosis, and had other comorbidities as well. She also exhibited weakness and paresthesia of the limbs and muscle wasting in the hands. All necessary examinations and investigations were performed and the patient was eventually diagnosed with POEMS syndrome. She underwent chemotherapy along with immunotherapy initially, but as the disease relapsed, she was referred for high-dose therapy (HDT) and autologous stem cell transplantation.

Case Report: A case of TAFRO syndrome with severe and prolonged thrombocytopenia: diagnostic pitfalls

Thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and organomegaly (TAFRO) syndrome is a rare condition with diverse clinical and pathological characteristics related to multi-organ damage. We report a case of TAFRO syndrome complicated by immune thrombocytopenia with prolonged fever and thrombocytopenia for several weeks. A 61-year-old man was transferred with sepsis caused by Enterococcus faecalis, and developed disseminated intravascular coagulation. Antibiotics treatment was initiated: however, low-grade fever and thrombocytopenia persisted despite the adequate antimicrobial treatment. Systemic edema, pleural effusion, and ascites had developed before hospitalization, and renal and liver function had deteriorated, resulting in progressive multi-organ damage. Prednisolone 40 mg/day was initiated based on the assumption of a condition in which excessive production of inflammatory cytokines would lead to systemic deterioration and fatal organ damage. Subsequently, the fever resolved, and renal function began to normalize. However, thrombocytopenia did not show much recovery trend after Helicobacter pylori eradication therapy and initiation of thrombopoietin receptor agonists. Bone marrow biopsy results showed normal bone marrow with no malignant findings. Alternatively, significant clinical signs met the diagnostic criteria for TAFRO syndrome, and a renal biopsy revealed thrombotic microangiopathy, which is also reasonable for renal involvement in TAFRO syndrome. The use of cyclosporine remarkably corrected the thrombocytopenia. We considered this a case of TAFRO syndrome that developed after sepsis with disseminated intravascular coagulation and performed the differential diagnosis of prolonged thrombocytopenia and excluded it. Although TAFRO syndrome is a unique disease concept, diagnostic criteria may consist of nonspecific elements such as generalized edema, thrombocytopenia, persistent fever, and elevated inflammatory response, and there are many differential conditions to exclude, requiring caution in diagnosing TAFRO syndrome.

POEMS syndrome in the 21st century: A bibliometric analysis

BACKGROUND

POEMS syndrome is a rare and complex plasma cell disorder characterized by polyneuropathy, organomegaly, endocrinopathy, high M protein levels, and skin changes. Understanding of POEMS syndrome has advanced rapidly since the 21st century. This study aims to summarize and evaluate the research status of POEMS syndrome in the past 23 years through a bibliometric and visualization analysis, and identify research focuses and emerging hotspots for the future.

METHODS

POEMS syndrome-related articles published between January 1, 2000, and March 8, 2023, were systematically retrieved from the Web of Science Core Collection. Data processing and visualization analysis were carried out using a combination of R software, HistCite, VOSviewer, and CiteSpace.

RESULTS

Since entering the 21st century, 3677 authors from 1125 institutions in 68 countries/regions have published 830 original and review articles on POEMS syndrome in 408 journals so far, among which the USA, Japan, and China published the most articles, and Mayo Clinic, Udice French Research Universities, and Peking Union Medical College listed the top three most prolific institutions. However, collaborative research across countries and groups in the study of POEMS syndrome remain significantly limited. Angela Dispenzieri ranked first in POEMS syndrome research from every aspect of authors, producing the most papers and contributing the most-cited article, followed by Satoshi Kuwabara and Sonoko Misawa. Internal medicine was the most productive journal on POEMS syndrome. "endothelial growth factor" was the keyword with the highest occurrence except for "POEMS syndrome", and "bevacizumab", "lenalidomide", "dexamethasone", and "management" were recognized as emerging topics.

CONCLUSION

This study utilized bibliometric and visualization analysis to systematically summarize the research of POEMS syndrome in the first two decades of the 21st century, offering a data-based and objective perspective on the field of POEMS syndrome and guiding researchers in the identification of novel research directions.

Paraproteinemic Neuropathies

OBJECTIVE

Coexistence of polyneuropathy and gammopathy is a common but potentially challenging situation in clinical practice. This article reviews the clinical, electrophysiologic, and hematologic phenotypes of the paraproteinemic neuropathies and the diagnostic and treatment strategies for each.

LATEST DEVELOPMENTS

Advances in our understanding of the underlying pathophysiology of various paraproteinemic neuropathies and their corresponding phenotypes have identified potential new therapeutic targets. Therapeutic strategies to diminish anti-myelin-associated glycoprotein (MAG) IgM antibodies have shown partial and inconsistent efficacy; however, antigen-specific immune therapy is being investigated as a novel treatment to remove the presumably pathogenic anti-MAG antibody. Advances in genetic and cell signaling studies have resulted in the approval of Bruton tyrosine kinase inhibitors for Waldenström macroglobulinemia. Monoclonal antibodies are being investigated for the treatment of light chain amyloidosis.

ESSENTIAL POINTS

Early recognition and treatment of underlying plasma cell disorders improves clinical outcomes in patients with paraproteinemic neuropathy. Despite significant progress, our knowledge regarding underlying mechanisms for paraproteinemic neuropathy is still limited. Clinicians' awareness of clinical phenotypes, electrophysiologic hallmarks, and hematologic findings of the different paraproteinemic neuropathies is crucial to promptly identify and treat patients and to avert misdiagnosis. Multidisciplinary collaboration among specialists, including neurologists and hematologists, is paramount for the optimal treatment of these patients with overlapping conditions.

Chronic Immune-Mediated Demyelinating Neuropathies

OBJECTIVE

This article is an overview of chronic demyelinating neuropathies and highlights the phenotypic categorization, diagnosis, and treatment of chronic immune-mediated neuropathies. The clinical and diagnostic characteristics of other chronic demyelinating neuropathies that are common mimics of immune-mediated neuropathies are also discussed.

LATEST DEVELOPMENTS

The underlying pathophysiology of chronic demyelinating neuropathies is heterogeneous, and components of both humoral and cellular immune responses are thought to play a role in the immune-mediated types of chronic demyelinating neuropathy. The role of the humoral response is highlighted with a specific focus on the relatively recent discovery of antibody-mediated antinodal and paranodal demyelinating neuropathies. Additionally, new diagnostic criteria for some of the chronic demyelinating neuropathies, as well as ways to differentiate chronic inflammatory demyelinating polyradiculoneuropathy from other chronic demyelinating polyneuropathies, are discussed.

ESSENTIAL POINTS

Chronic demyelinating neuropathies can present with overlapping clinical characteristics with seemingly subtle variations. It is clinically important to differentiate these types of neuropathies because the treatment and management can vary and affect prognosis.

POEMS syndrome: an unusual cause of exuberant callus formation

Several growth factors are expressed in distinct temporal and spatial patterns during fracture repair. Together, they lead to angiogenesis-osteogenesis coupling and hence bone healing by callus formation. Of these growth factors, vascular endothelial growth factor is of particular interest because of its ability to induce neovascularisation (angiogenesis) and osteoclast invasion in soft callus. Hyperplastic callus can be seen in metabolic bone disease, endocrine disease and in patients with traumatic brain injury, but has not been described so far in polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes (POEMS) syndrome. This report is a case of POEMS syndrome with unusual presentation in the form of exuberant callus formation at fracture sites.

JAK2 unmutated erythrocytosis: 2023 Update on diagnosis and management

DISEASE OVERVIEW

JAK2 unmutated or non-polycythemia vera (PV) erythrocytosis encompasses a heterogenous spectrum of hereditary and acquired entities.

DIAGNOSIS

Foremost in the evaluation of erythrocytosis is the exclusion of PV through JAK2 (inclusive of exons 12-15) mutation screening. Initial assessment should also include gathering of previous records on hematocrit (Hct) and hemoglobin (Hgb) levels, in order to streamline the diagnostic process by first distinguishing longstanding from acquired erythrocytosis; subsequent subcategorization is facilitated by serum erythropoietin (Epo) measurement, germline mutation screening, and review of historical data, including comorbid conditions and medication list. Hereditary erythrocytosis constitutes the main culprit in the context of longstanding erythrocytosis, especially when associated with a positive family history. In this regard, a subnormal serum Epo level suggests EPO receptor mutation. Otherwise, considerations include those associated with decreased (high oxygen affinity Hgb variants, 2,3-bisphosphoglycerate deficiency, PIEZO1 mutations, methemoglobinemia) or normal oxygen tension at 50% Hgb saturation (P50). The latter include germline oxygen sensing pathway (HIF2A-PHD2-VHL) and other rare mutations. Acquired erythrocytosis commonly results from central (e.g., cardiopulmonary disease, high-altitude habitat) or peripheral (e.g., renal artery stenosis) hypoxia. Other noteworthy conditions associated with acquired erythrocytosis include Epo-producing tumors (e.g., renal cell carcinoma, cerebral hemangioblastoma) and drugs (e.g., testosterone, erythropoiesis stimulating agents, sodium-glucose cotransporter-2 inhibitors). Idiopathic erythrocytosis is an ill-defined terminology that presumes the existence of an increased Hgb/Hct level without an identifiable etiology. Such classification often lacks accounting for normal outliers and is marred by truncated diagnostic evaluation.

MANAGEMENT

Current consensus treatment guidelines are not supported by hard evidence and their value is further undermined by limited phenotypic characterization and unfounded concerns for thrombosis. We are of the opinion that cytoreductive therapy and indiscriminate use of phlebotomy should be avoided in the treatment of non-clonal erythrocytosis. However, it is reasonable to consider therapeutic phlebotomy if one were to demonstrate value in symptom control, with frequency determined by symptoms rather than Hct level. In addition, cardiovascular risk optimization and low dose aspirin is often advised.

FUTURE DIRECTIONS

Advances in molecular hematology might result in better characterization of "idiopathic erythrocytosis" and expansion of the repertoire for germline mutations in hereditary erythrocytosis. Prospective controlled studies are needed to clarify potential pathology from JAK2 unmutated erythrocytosis, as well as to document the therapeutic value of phlebotomy.

Daratumumab plus lenalidomide and dexamethasone for relapsed POEMS syndrome with bone plasmacytoma harboring 17p deletion

The standard therapies for polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes (POEMS) syndrome are radiation therapy, high-dose chemotherapy followed by autologous stem cell transplantation, and lenalidomide combined with dexamethasone. Daratumumab was reported to be effective for treatment-naive and relapsed POEMS syndrome, but treatment options for relapsed POEMS syndrome with poor prognostic factors or cytogenetic abnormalities have not been established due to a lack of studies in these patients. Here, we describe a case of relapsed POEMS syndrome with bone plasmacytoma harboring a newly detected 17p deletion after high-dose chemotherapy followed by autologous stem cell transplantation and radiation therapy in a male patient. He was successfully treated with daratumumab plus lenalidomide and dexamethasone (Dara-Rd). Dara-Rd could be effective in relapsed POEMS syndrome with 17p deletion, which is known as a poor cytogenetic abnormality in multiple myeloma. This report may broaden the application of Dara-Rd for POEMS syndrome.