Idiopathic multicentric Castleman's disease: a systematic literature review

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.

Efficacy of tocilizumab monotherapy for autoimmune hemolytic anemia associated with idiopathic multicentric Castleman disease: a case-based review

Idiopathic multicentric Castleman disease (iMCD) is a rare lymphoproliferative disorder characterized by generalized lymphadenopathy with distinctive histopathological features and systemic inflammation driven by excessive interleukin-6 (IL-6) production. Anemia due to chronic inflammation is a common manifestation of iMCD; however, this disease can also be complicated by autoimmune hemolytic anemia (AIHA). While tocilizumab (TCZ), an IL-6 receptor blockade, has demonstrated efficacy in treating iMCD, its therapeutic effect on AIHA secondary to iMCD remains unclear. Here, we report the first case of iMCD complicated by AIHA successfully treated with TCZ monotherapy, without the need for concurrent glucocorticoid therapy. Notably, AIHA improved along with the disappearance of autoantibodies under TCZ monotherapy, suggesting that IL-6 played a key role in the production of autoantibodies and causing AIHA secondary to iMCD. Furthermore, our literature review identified six other cases of iMCD with AIHA, five of which achieved favorable outcomes with a combination of TCZ and prednisolone, except for one case that developed anti-TCZ antibody. In two cases, AIHA improved without requiring an increase of prednisolone dose. These findings suggest that TCZ may represent a viable therapeutic option not only for iMCD itself but also for AIHA secondary to iMCD.

Spatial transcriptomics study of Castleman disease

BACKGROUND

Castleman Disease (CD) is a rare lymphoproliferative disorder of uncertain etiology, primarily characterized by painless lymphadenopathy. To further understand the possible pathogenesis of the disease, we utilized spatial transcriptomics to explore CD.

METHODS

Spatial transcriptomics was performed on FFPE samples from lymph nodes of three CD patients with different histologic types and one normal lymph node.

RESULTS

The sample was categorized by analysis into 14 clusters, including B cells, plasma cells, BECs, LECs, CD4 + T cells, CD8 + T cells, macrophages, monocytes, cycling cells, myofibroblasts, mDCs, NKCs, Tfh and NESCs. Our study showed that the lesion cells of CD might be B cells. In addition to this, we found that mesenchymal cells, especially myofibroblasts, play an important role in disease progression and there was a large heterogeneity of cellular communication between cell clusters in different histologic types of CD.

CONCLUSIONS

Through this study we have gained a better understanding of the pathogenesis of CD. It provides new ideas for the subsequent exploration of CD and directions for the development of new clinical drugs.

Idiopathic Multicentric Castleman's Disease Presenting with Chorioretinal Undulation: A Case Report

PURPOSE

To describe a case of idiopathic multicentric Castleman's disease (iMCD) with initial ocular involvement, presenting with chorioretinal undulation.

METHODS

Observational case report of iMCD patient with ocular manifestation on fundus photography, auto-fluorescein and swept-source optical coherence tomography (SS-OCT), initially and after treatment.

RESULTS

A 75-year-old patient with painless vision loss for 2 years right eye (RE) and 3-month left eye (LE). Fundus examination revealed several yellow-white lesions along with the inferior arcade, with extensive pigment disturbance of the right eye and exudative retinal detachment of the left eye. SS-OCT showed choroid and retinal pigment epithelium (RPE) undulations, choroid thickening and hyperreflective dots at the choroidal level. Interleukin-6 (IL-6) in the anterior chamber was very high (1595 pg/ml RE and 749.3 pg/ml LE). After cervical lymph node biopsy, the patient was finally diagnosed with iMCD. Siltuximab, an interleukin-6 inhibitor, was administered. After two cycles of therapy, the patient's ocular manifestations improved significantly, the choroid and RPE undulation and the ERD resolved without local treatment.

CONCLUSION

Chorioretinal undulation and elevated IL-6 in intraocular fluid could be ocular manifestations of MCD.

Common connective tissue disorder and anti-cytokine autoantibodies are enriched in idiopathic multicentric castleman disease patients

Introduction

Idiopathic Multicentric Castleman Disease (iMCD) is a polyclonal lymphoproliferative disorder involving cytokine storms that can lead to organ failure and death. The cause of iMCD is unknown, but some clinical evidence suggests an autoimmune etiology. For example, connective tissue disorders (CTDs) and iMCD share many clinical features, and autoantibodies have been anecdotally reported in individual iMCD patients. This study investigates whether common autoantibodies are shared across iMCD patients.

Methods

We assembled custom bead-based protein arrays consisting of 52 autoantigens traditionally associated with CTDs and 38 full-length cytokines and screened serum samples from 101 iMCD patients for IgG autoantibodies. We also screened samples with a 1,103-plex array of recombinant human protein fragments to identify additional autoantibody targets. Finally, we performed receptor blocking assays on select samples with anti-cytokine autoantibodies (ACAs) identified by array.

Results

We found that an increased proportion of iMCD patients (47%) tested positive for at least one CTD-associated autoantibody compared to healthy controls (HC) (17%). Commonly detected CTD-associated autoantibodies were associated with myositis and overlap syndromes as well as systemic lupus erythematosus (SLE) and Sjögren's Syndrome (SS). ACAs were also detected in a greater proportion of iMCD patients (38%) compared to HC (10%), while the protein fragment array identified a variety of other autoantibody targets. One iMCD sample tested positive for receptor blocking against interferon-ω (IFNω).

Discussion

IgG autoantibodies binding autoantigens associated with common CTDs and cytokines are elevated in iMCD patients compared to HC, suggesting that autoimmunity may be involved in iMCD pathogenesis.

Unicentric Castleman's Disease of Neck with Incidental Arteria Lusoria: A Rare Case Report

A 20-year-old female presented with a left large level-V lymph node enlargement, incidentally associated with aberrant vasculature arteria lusoria. She was treated with surgical excision and successful management of post-operative chyle leak. Histopathology depicted hyaline vascular variant of unicentric Castleman's disease, known to have a good prognosis.

Idiopathic multicentric Castleman disease developing after a diagnosis of sarcoidosis: A case report and literature review

A 72-year-old woman presented with an abnormal shadow on chest radiograph. She was histologically diagnosed with sarcoidosis 20 years previously, and prednisolone was initiated 8 years previously. Computed tomography revealed centrilobular micronodules and bronchovascular bundle thickening in both lungs with multicentric lymphadenopathies; multiple pulmonary nodular lesions appeared during prednisolone tapering. Laboratory findings included polyclonal hypergammaglobulinemia and elevated interleukin-6 levels. Surgical lung biopsy revealed marked lymphoplasmacytic infiltration with lymphoid aggregates. The patient tested negative for human herpesvirus-8 and clinically diagnosed with idiopathic multicentric Castleman disease. The coexistence of sarcoidosis and Castleman disease is rare; this case improved with additional tocilizumab treatment.

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.

Clinical and Radiologic Differences in Lung Involvement Between IgG4-Related Disease and Plasma Cell-Type Idiopathic Multicentric Castleman Disease

PURPOSES

Immunoglobulin G4-related disease (IgG4-RD) and plasma cell-type idiopathic multicentric Castleman disease (PC-iMCD) have many overlapping features. Their differential diagnosis is challenging and crucial for clinical management due to their different prognoses and treatments. However, reports that compare these conditions are scarce, especially for patients with lung involvement. In this study, we attempted to clarify the clinical and radiologic differences in lung involvement between IgG4-RD and PC-iMCD.

METHODS

Patients with IgG4-RD or PC-iMCD who exhibited lung involvement were enrolled. Clinical and chest CT findings at baseline were compared.

RESULTS

A total of 178 patients with IgG4-RD and 61 patients with PC-iMCD exhibited lung involvement. The IgG4-RD group consisted of older patients (P < 0.001) and had a higher male‒female ratio (P = 0.004). Patients with PC-iMCD were more inclined to present constitutional and respiratory symptoms, anemia, thrombocytosis and hypoalbuminemia (all P < 0.001). Although IgG4 levels were commonly elevated in both diseases, they were significantly greater in the IgG4-RD (median: 16,100 mg/L) than in the PC-iMCD (median: 3130 mg/L) (P < 0.001). Patients with IgG4-RD showed significantly lower levels of IgG, IgA, IgM (median: 21.59 g/L, 1.70 g/L, and 0.68 g/L, respectively) than in the PC-iMCD (median: 34.42 g/L, 4.85 g/L, and 2.11 g/L, respectively) (all P < 0.001). The levels of CRP, ESR and IL-6 were significantly greater in the PC-iMCD (median: 72.15 mg/L, 103 mm/h, and 18.30 pg/mL, respectively) than that in the IgG4-RD (median: 1.54 mg/L, 22 mm/h, and 2.85 pg/mL, respectively) (all P < 0.001). Although both nodular lesions and thickened bronchovascular bundles were common in these two diseases, PC-iMCD patients presented more extensive nodular lesions (P < 0.001), and IgG4-RD patients presented more diffuse thickened bronchovascular bundles (P < 0.001). Cysts were almost exclusively observed in PC-iMCD patients.

CONCLUSIONS

Compared with IgG4-RD, PC-iMCD is a more aggressive condition, associated with more common symptoms and more severe inflammation. Radiologically, extensive nodular lesions or cysts suggest a diagnosis of PC-iMCD, whereas diffuse thickened bronchovascular bundles indicate a diagnosis of IgG4-RD.

Interleukin-6 transcripts up-regulation in lymph nodes from unicentric and multicentric Castleman disease

Introduction

Castleman disease (CD) represents a spectrum of heterogeneous lymphoproliferative disorders sharing peculiar histopathological features, clinically subdivided into unicentric CD (UCD) and multicentric CD (MCD) and presenting with variable inflammatory symptoms. Interleukin (IL)-6 and other cytokines play a major role in mediating CD inflammatory manifestations. Although the local microenvironment seems to be among the major sources of hypercytokinemia, the precise cellular origin of IL-6 production in CD is still debated.

Methods

A series of five nodal CD of different subtypes (one UCD, two idiopathic MCDs [iMCDs], one HIV-negative human herpesvirus 8 (HHV8)-associated MCD, and one HIV-positive HHV8-associated MCD) and a non-CD reactive control were tested using RNAscope analysis and a dual in situ hybridization (ISH)/immunohistochemistry technique, in order to quantify IL-6 expression and its spatial distribution. Quantitative analyses of in situ mRNA were performed on digitalized slides using the HISTOQUANT software (3DHISTECH) and differences between cases were evaluated by the Kruskal-Wallis test.

Results

RNA-ISH documented increased IL-6 expression in all CD lymph nodes, independently from clinical and pathological subtypes, however, the highest levels were found in HHV8+ cases and statistically significant differences in IL-6 expression were found only between HHV8+ MCD and control case. Dual RNA-ISH for IL6 coupled with immunohistochemistry analysis showed that IL-6 was overexpressed in CD31-positive endothelial cells in 5/5 CD tested cases but not in the control case.

Conclusion

Our findings suggest that nodal IL-6 expression seems to be significantly upregulated in HHV8+ MCD, but a trend toward increased nodal IL-6 expression was noticed also in UCD and iMCD-not otherwise specified. CD31+ endothelial cells probably represent one of the major sources of IL-6 production in the nodal microenvironment.

The Enigma of Idiopathic Multicentric Castleman Disease: An Elusive Diagnosis

Castleman disease (CD) is a rare lymphoproliferative disorder encompassing a spectrum of conditions with distinct histopathological findings and varied clinical presentations. Diagnostic challenges are often encountered due to overlapping features with other malignancies, infections, and autoimmune disorders. Idiopathic multicentric Castleman disease (iMCD) is a subtype of CD, characterized by generalized lymphadenopathy, polyclonal lymphoproliferation, systemic inflammation, and a cytokine storm that can be life-threatening. Here, we present a case of iMCD in a 70-year-old male with constitutional symptoms, dyspnea, and pancytopenia. Imaging demonstrated multifocal lymphadenopathy. Histopathological examination of a cervical lymph node revealed Castleman-like features, meeting the major criteria for a diagnosis of iMCD. Elevated interleukin-6 (IL-6) levels further supported the diagnosis. Treatment with siltuximab was planned but was preempted by the patient's demise following acute heart failure exacerbation. Diagnosing CD necessitates a thorough evaluation to differentiate it from other diseases. Treatment strategies, particularly IL-6 blockade, play a crucial role in the management of iMCD and improve patient outcomes.

Peculiar hyper vascular manifestations in idiopathic multicentric castleman disease without tafro syndrome: a case report

BACKGROUND

Castleman disease affects lymph nodes with abnormal cell growth. It has unicentric (single node) Castleman disease (UCD) and multicentric (multiple nodes) Castleman disease (MCD) forms. MCD is systemic, with diverse symptoms, necessitating systemic treatment. Idiopathic MCD (iMCD) clinical subtypes are divided into iMCD- not otherwise specified (NOS) and iMCD-TAFRO (thrombocytopenia, anasarca, fever, reticular fibrosis, organomegaly). UCD, iMCD-NOS, and iMCD-TAFRO mainly exhibit histopathology of hyaline vascular type, plasma cell type, and hyper vascular type, respectively.

CASE PRESENTATION

A 21-year-old female with no comorbidities presented to the outpatient department (OPD) with left inguinal swelling, gradually growing over four years, accompanied by fever and weight loss. Her past medical history included pulmonary TB 5 years prior and miscarriages. Vitals are within normal limits. Examination revealed a tender, nonreducible inguinal lump and a smaller neck swelling. Serological tests for infections were negative. Imaging revealed enlarged lymph nodes. Biopsy confirmed Castleman disease of the hyper vascular type. We performed surgical removal of the enlarged lymph nodes followed by close regular follow-up along with potential chemotherapy for relapse.

CONCLUSION

Hyper vascular type of the lymph node histology in Idiopathic multicentric Castleman disease without TAFRO syndrome must be considered a differential diagnosis in lymphoproliferative disease.

Castleman disease as the great mimicker: the role of complex morpho-pathological evaluation

Castleman disease (CD) is a group of lymphoproliferative disorders characterized by abnormal enlargement of lymph nodes (LNs) and a wide range of symptoms. Only a few cases are found in the head and neck. Based on clinical presentation and evolution, the disease can be classified into two main subtypes: unicentric CD (UCD), characterized by the enlargement of a single LN or a single LN chain, and multicentric CD (MCD), characterized by the involvement of multiple LNs and regions, with more important systemic symptoms and a poor prognosis. CD is also known as "the great mimicker" and can be easily misdiagnosed, sharing similar clinical and imaging characteristics with other pathologies, mainly when it is found in the neck. A histopathological (HP) and immunohistochemical (IHC) correlation is essential in these cases to accurately diagnose and establish the proper treatment plan. In light of this, we present a rare case of a 15-year-old young female with a slowly expanding, isolated supraclavicular mass. An excisional biopsy was performed, and the results confirmed the presence of CD, hyaline-vascular type. As of this writing, there was no evidence of recurrence or new enlarged LNs. We also review CD's clinical and HP features and the diagnostic and treatment challenges it poses.

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.

The clinical picture of Castleman disease: a systematic review and meta-analysis

ABSTRACT

Castleman disease (CD) encompasses a spectrum of rare disorders, including unicentric CD (UCD), idiopathic multicentric CD (iMCD), and human herpesvirus 8-associated MCD (HHV8+ MCD). We performed a systematic review of publications reporting ≥5 cases of CD between 1995 and 2021, following preferred reporting items for systematic reviews and meta-analyses guidelines, to describe and compare subtypes. We extracted data on clinical symptoms and laboratory parameters as stated in international consensus diagnostic criteria for iMCD and estimated the frequency of each criterion using meta-analyses. We analyzed 32 studies describing 559 UCD, 1023 iMCD, and 416 HHV8+ MCD cases. Although many symptoms and laboratory abnormalities occurred at similar rates in patients with iMCD and HHV8+ MCD, patients with HHV8+ MCD had significantly higher rates of constitutional symptoms (46.6% vs 98.6%; P = .038) and splenomegaly (48.2% vs 89.2%; P = .031). Renal dysfunction was significantly more common in patients with iMCD than in patients with HHV8+ MCD before adjustment (36.9% vs 17.4%; P = .04; adjusted P = .1). Patients with UCD had lower rates of symptoms and laboratory abnormalities, although these were present in 20% of patients and were particularly pronounced in pediatric UCD. There are many similarities in the symptomatology of iMCD and HHV8+ MCD; many patients experience constitutional symptoms and organ dysfunction. Differences between these subtypes likely reflect differences in pathophysiology and/or comorbidity burdens.

scRNA-seq reveals the landscape of immune repertoire of PBMNCs in iMCD

The etiology of idiopathic multicentric Castleman disease (iMCD) is poorly understood, and the identification of targetable disease mediators remains an unmet clinical need. Thus, we firstly employed single-cell RNA sequencing (scRNA-seq) to elucidate the landscape of the immune repertoire of peripheral blood mononuclear cells (PBMNCs) in iMCD and to identify additional driver cytokines/cells/pathways to address IL-6 blockade-refractory cases. We revealed that the inflammatory cytokine storm observed in iMCD was a significant phenomenon pervasive across all immune cells. B-plasma cell subsets was the main source of IL-6. The IL-6 signaling pathway was significantly activated across a spectrum of immune cells. Systemic upregulation of CXCL13 is mainly driven by peripheral helper T (Tph) and regulatory T (Treg) cells. Notably, a significant positive interaction was observed between CXCL13-expressing T cells and IL-6 signaling-activated B cells. This study provides an immune perspective on PBMNCs in iMCD at the single-cell level, unveiling pathways or targets characterized by atypical inflammatory expression that could potentially serve as promising candidates for therapeutic intervention in iMCD.

Internal Psychometric Validation of an International Burden of Illness Survey for Idiopathic Multicentric Castleman Disease

INTRODUCTION

Idiopathic multicentric Castleman disease (iMCD) is a rare, chronic, debilitating lymphoproliferative disorder where the mainstay of treatment is symptom management. Our recent international patient survey showed that patients with iMCD have a high symptom burden that has a significant negative patient-reported impact on several aspects of daily life. As part of our ongoing work towards the development of an iMCD symptom burden scale, assessing the survey's psychometric properties is a critical step in understanding its adequacy, relevance, and usefulness. As iMCD is a rare disease, there are challenges to conducting such psychometric analyses which we describe.

METHODS

As part of the exploratory psychometric analysis, three a priori hypothesis sets (HS) were generated by interviewing an iMCD-experienced clinician, a patient, and a caregiver to explore the iMCD patient survey's internal construct validity, given no gold standard iMCD measure exists for external construct validation. HS-1 hypothesized that a convergent or discriminant relationship exists with the patients' self-assessment of symptom effect on daily life between two potentially related or unrelated symptoms, respectively. HS-2 hypothesized that having a greater number of symptoms has a positive convergent relationship with the patients' assessment of symptoms' effect on daily life. Finally, HS-3 hypothesized that patients receiving treatment versus no treatment was associated with patients reporting less effect of symptom burden on their daily life. Spearman's rank absolute correlation strength (ACS) was used for HS-1 and HS-2 (convergent relationship, ACS ≥ 0.3 and p value < 0.05; divergent relationship, ACS < 0.3), and Cohen's d to quantify standardized absolute effect sizes (AES) for HS-3 (AES ≥ 0.5 and p value < 0.05).

RESULTS

Our analyses partially supported HS-1. None of the three positive convergent relationships were supported. Of the six discriminant relationships, only dizziness with impaired cognitive function and tiredness with dizziness were supported. HS-2 analyses showed there was convergent validity between the number of symptoms and their effect on aspects of daily life. HS-3 analyses did not provide evidence to support the hypothesis.

CONCLUSION

These internal psychometric construct analyses provide initial support for the bespoke iMCD patient survey and will guide additional work towards the development of the first iMCD-specific symptom burden scale.

A hypothesis on treatment strategy of severe multicentric Castleman disease with continuous renal replacement therapy

Castleman disease (CD) is a rare lymphoproliferative disorder, with non-specific clinical manifestations, often delayed diagnosis and treatment, which pose a significant challenge in the present times. Patients diagnosed with this disease have poor prognosis due to the limited treatment options. Multicentric CD occurs at multiple lymph node stations and is associated with a proinflammatory response that leads to the development of the so-called 'B symptoms'. IL-6 seems to be a key cytokine involved in various manifestations such as lymphadenopathies, hepatosplenomegaly, and polyclonal hypergammaglobulinemia. Its levels correlate with the activity of the disease. Other consequences of MCD include increased fibrinogen levels leading to deep vein thrombosis and thromboembolic disorders, high hepcidin levels causing anaemia, elevated VEGF levels promoting angiogenesis and vascular permeability, which, along with hypoalbuminemia, induce oedema, ascites, pleural and pericardial effusions, and in severe cases, generalized anasarca. In extreme cases multiple organ failure can occur, often resulting in death. We propose the use of continuous renal replacement therapy (CRRT) in managing severe multicentric CD. Our arguments are based on the principles that CRRT is able to remove IL-6 from circulation thus attenuating the cytokine storm, can influence hepcidin levels, and reduction in oedema, and is often used in multiple organ failure to regain homeostasis control. Therefore, it could be used as a therapy or bridge therapy in severe cases. To sustain our hypothesis with evidence, we have gathered several studies from the literature confirming the successful removal of cytokines, especially IL-6 from circulation, which can be used as a starting point.

Diagnostic challenges in patients with Castleman disease, a single center experience from Hungary

Castleman disease is a rare and atypical lymphoproliferative disorder characterized by diverse clinical manifestations. It has both unicentric and multicentric forms, the latter with further subdivisions, i.e., human herpesvirus 8-associated and idiopathic forms. The diagnosis of Castleman disease is often delayed, as it is rare, and because it shares clinical features with different autoimmune, inflammatory, and malignant lymphoproliferative disorders. The first-line treatment in unicentric form is mainly surgical, while in idiopathic Castleman disease, anti-interleukin-6 treatment is the therapy of choice. In virus-associated diseases, antiretroviral therapy and rituximab are recommended. In Hungary, only a few cases of Castleman disease have been published. This report presents our two decades of experience in the challenging diagnosis and management of this rare disorder, most properly underdiagnosed in Hungary. We provide insights into seven unicentric and five idiopathic multicentric Castleman disease cases, the latter ones especially highlighting the diagnostic and therapeutic challenges due to the variable and unique clinical features both of patients and diseases, e.g., bronchiolitis obliterans, stage IV diabetic renal failure, anti-HBc positivity, siltuximab treatment period, respectively.

A rare case report of hyaline-vascular type Castleman disease in the presacral region

Castleman disease (CD), also known as giant lymph node hyperplasia or angiofollicular lymph node hyperplasia, is a rare and indeterminate group of chronic lymphoproliferative disorders. CD is highly heterogeneous, classified into unicentric Castleman disease (UCD) and multicentric Castleman disease (MCD) based on lesion distribution, and further categorized into three pathological types: hyaline vascular type (HV), plasma cell type (PC), and mixed type (Mix). This paper describes a rare case of solitary mediastinal Castleman disease with transparent vessels in the anterior sacrum, presenting as the HV type. Surgical excision of the mass was performed following coccygectomy for treatment. The patient recovered well postoperatively. During a 6-month follow-up period, there were no signs of recurrence, and the patient's quality of life significantly improved.

IgG4-related disease presenting with gastric outlet obstruction

A woman in her 20s presented with 6 weeks of fever, persistent vomiting and 28% loss of body weight. Symptoms were refractory to treatment with antiemetics and broad spectrum antibiotics.Further investigation via oesophageogastroduedenoscopy revealed a large gastric ulcer and pyloric stricture, causing gastric outlet obstruction (GOO). Biopsies of the stomach and duodenum showed plasma cell infiltration with a large proportion being IgG4 positive.Treatment with methylprednisolone, and later prednisolone, quickly improved inflammatory markers and symptoms. Balloon dilatation of the pyloric stricture also improved vomiting, allowing eventual re-establishment of oral nutrition. The patient made a full recovery with maintenance treatment on mycophenolate mofetil.IgG4-related disease (IgG4-RD) is a multisystem disorder with unpredictable presentation. The case highlights diagnostic challenges in IgG4-RD and identifies it as a rare differential in upper gastrointestinal symptoms. To our knowledge this is the first published case of IgG4-RD in the duodenum causing GOO.

Increase in Vascular Endothelial Growth Factor (VEGF) Expression and the Pathogenesis of iMCD-TAFRO

TAFRO (thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (F/R), renal failure (R), and organomegaly (O)) is a heterogeneous clinical subtype of idiopathic multicentric Castleman disease (iMCD) associated with a significantly poorer prognosis than other subtypes of iMCD. TAFRO symptomatology can also be seen in pathological contexts outside of iMCD, but it is unclear if those cases should be considered representative of a different disease entity or simply a severe presentation of other infectious, malignant, and rheumatological diseases. While interleukin-6 (IL-6) is an established driver of iMCD-TAFRO pathogenesis in a subset of patients, the etiology is unknown. Recent case reports and literature reviews on TAFRO patients suggest that vascular endothelial growth factor (VEGF), and the interplay of VEGF and IL-6 in concert, rather than IL-6 as a single cytokine, may be drivers for iMCD-TAFRO pathophysiology, especially renal injury. In this review, we discuss the possible role of VEGF in the pathophysiology and clinical manifestations of iMCD-TAFRO. In particular, VEGF may be involved in iMCD-TAFRO pathology through its ability to activate RAS/RAF/MEK/ERK and PI3K/AKT/mTOR signaling pathways. Further elucidating a role for the VEGF-IL-6 axis and additional disease drivers may shed light on therapeutic options for the treatment of TAFRO patients who do not respond to, or otherwise relapse following, treatment with IL-6 targeting drugs. This review investigates the potential role of VEGF in the pathophysiology of iMCD-TAFRO and the potential for targeting related signaling pathways in the future.

The Etiologic Landscape of Lymphoproliferation in Childhood: Proposal for a Diagnostic Approach Exploring from Infections to Inborn Errors of Immunity and Metabolic Diseases

Lymphoproliferation is defined by lymphadenopathy, splenomegaly, hepatomegaly, or lymphocytic organ and tissue infiltration. The most common etiologies of lymphoproliferation are represented by infectious diseases and lymphoid malignancies. However, it is increasingly recognized that lymphoproliferative features can be the presenting sign of rare conditions, including inborn errors of immunity (IEI) and inborn errors of metabolism (IEM). Among IEI, lymphoproliferation is frequently observed in autoimmune lymphoproliferative syndrome (ALPS) and related disorders, common variable immunodeficiency (CVID), activated phosphoinositide 3-kinase δ syndrome, and Epstein-Barr virus (EBV)-related disorders. Gaucher disease and Niemann-Pick disease are the most common IEMs that can present with isolated lymphoproliferative features. Notably, other rare conditions, such as sarcoidosis, Castleman disease, systemic autoimmune diseases, and autoinflammatory disorders, should be considered in the differential diagnosis of patients with persistent lymphoproliferation when infectious and malignant diseases have been reasonably ruled out. The clinical features of lymphoproliferative diseases, as well as the associated clinical findings and data deriving from imaging and first-level laboratory investigations, could significantly help in providing the correct diagnostic suspicion for the underlying etiology. This paper reviews the most relevant diseases associated with lymphoproliferation, including infectious diseases, hematological malignancies, IEI, and IEM. Moreover, some practical indications to orient the initial diagnostic process are provided, and two diagnostic algorithms are proposed for the first-level assessment and the approach to persistent lymphoproliferation, respectively.

Unicentric Castleman disease: A case report of an atypical presentation and successful management

INTRODUCTION

Castleman Disease (CD) is a rare benign disorder characterized by abnormal lymphoid tissue growth. It can be classified as unicentric CD (UCD) affecting a single lymph node region or multicentric CD (MCD) involving multiple regions. While UCD typically occurs in the mediastinum, MCD is associated with inflammatory symptoms and abnormal lab findings. We present a case of a young Syrian male with pelvic UCD, exhibiting unusual symptoms. Surgical excision led to complete recovery.

CASE PRESENTATION

A 27-year-old male presented with a well-defined pelvic mass discovered during routine ultrasonography. Symptoms included fever, fatigue, weight loss, and lower extremity numbness. Laboratory analysis revealed lymphocytopenia. Imaging identified a retroperitoneal pelvic mass, raising concerns of lymphoma. Surgical resection confirmed Castleman disease, specifically the hyaline vascular variant, dispelling malignancy concerns. Post-surgery, the patient demonstrated complete recovery, with normalized lymphocyte count and resolution of symptoms, affirming the effectiveness of the treatment.

DISCUSSION

Castleman Disease (CD) is characterized by abnormal lymphoid tissue growth. It presents as Unicentric (UCD) or Multicentric (MCD) forms. UCD cases are usually asymptomatic or show compressive symptoms due to mass effect, while MCD is associated with systemic symptoms. The estimated UCD incidence is 16 cases per million person-years, with median age at diagnosis around 30-34 years. Histologically, UCD is categorized into hyaline vascular (HV) and plasma cell (PC) variants. In this case, systemic symptoms and lymphocytopenia deviated from typical UCD presentation, leading to initial lymphoma suspicions. Surgical intervention facilitated recovery without adjuvant therapies.

CONCLUSION

This study emphasizes the spectrum of Castleman Disease (CD) manifestations, distinguishing Unicentric (UCD) and Multicentric (MCD) forms crucial for accurate management. It highlights atypical pelvic UCD presentation and successful surgical treatment's importance.

[Castleman's disease in the rheumatological practice]

The term Castleman's disease encompasses a group of rare lymphoproliferative diseases that show histopathological similarities in lymph node biopsy. Diagnostic criteria and a specific ICD-10 code have been available for a few years. Case studies listed at the beginning illustrate that close cooperation between clinicians and pathologists is required to enable a reliable diagnosis. For an optimal histopathological assessment, the pathologist is also dependent on the removal of a complete lymph node. Before distinguishing a potentially fatal multicentric idiopathic Castleman's disease from the resectable unicentric form, which is important in terms of prognosis and treatment, early diagnosis presupposes that Castleman's disease is considered in the differential diagnosis. Various immune phenomena and overlaps with autoimmune diseases can increase the probability of misdiagnosis or undetected cases in the clinical routine of rheumatologists. The intention of the present overview is therefore to point out the similarities with autoimmune diseases that are relevant for differential diagnoses and to point out situations that justify a review of the previous diagnosis.

Acquired Hemophilia: A Rare Complication of Pediatric Idiopathic Multicentric Castleman Disease

Acquired hemophilia is caused by acquired autoantibodies to 1 of the factors of the coagulation cascade, usually factor VIII or IX, and is an exceedingly rare phenomenon in children. The finding of an acquired factor VIII inhibitor in a pediatric patient with idiopathic multicentric Castleman disease has never been reported. Patients with acquired hemophilia can have life-threatening bleeds that are refractory to blood product support, requiring bypassing agents to manage bleeding symptoms. We present the novel finding of acquired hemophilia resulting from an autoantibody to factor VIII in a pediatric patient with idiopathic multicentric Castleman disease and discuss the optimal management of bleeding in a patient with acquired hemophilia.

Rituximab as a First-line Treatment for Autoimmune Hemolytic Anemia in Multicentric Castleman's Disease

Castleman´s disease (CD) is a rare lymphoproliferative disorder. Concurrent autoimmune disease and CD are uncommon, but even more so, comorbid CD and autoimmune hemolytic anemia (AIHA). To the best of our knowledge, this case represents the first successful AIHA and multicentric CD (MCD) treatment using rituximab as first-line treatment. We present the case of a 53-year-old woman with a 10-year history of plasma cell variant CD who arrived at the emergency department with signs and symptoms of anemia. On admission, we made a preliminary diagnosis of hemolytic anemia and initiated immunosuppressive therapy with rituximab and steroids. After seven days, the patient recovered according to clinical and laboratory parameters, and we discharged her early. We portray a rare occurrence of CD and AIHA successfully treated with rituximab and steroid therapy, which makes our case unique.

Idiopathic multicentric Castleman disease: An update in diagnosis and treatment advances

Idiopathic multicentric Castleman disease (iMCD) is a rare disease, and it is likely underdiagnosed because of the heterogeneity of clinical manifestations and laboratory findings. While the disease leads to significant morbidity and mortality, its causes are not yet fully elucidated. There have been significant advances in diagnosis and treatment of iMCD in the past decade, including the approval of the anti-IL-6 antibody siltuximab. In this review, we provide an update of the many new developments and publications surrounding iMCD.

A Case of Castleman's Disease with a Marked Infiltration of IgG4-Positive Cells in the Renal Interstitium

Multicentric Castleman's disease (MCD) is a benign lymphoproliferative disorder with heterogenous clinical symptoms, and involves systemic organs in addition to lymph nodes. Herein, we present the case of a 55-year-old man with MCD characterized by an extensive infiltration of IgG4+ plasma cells in the kidneys. The patient presented to our hospital with a high fever and diarrhea. On admission, laboratory analysis revealed anemia, renal dysfunction (eGFR 30 mL/min/1.73 m2), polyclonal gammopathy (IgG 7130 mg/dL), elevated serum IgG4 level (2130 mg/dL), and increased C-reactive protein (8.0 mg/dL). An enlargement of lymph nodes in the axillary, mediastinal, para-aortic, and inguinal regions was observed on abdominal computed tomography. Axillary lymph node biopsy revealed interfollicular expansion due to dense plasma cell infiltration. Renal biopsy demonstrated significant plasma cell infiltration into the tubulointerstitium. Immunohistochemical analysis showed a 40% IgG4-positive/IgG-positive plasma cell ratio, meeting the diagnostic criteria for an IgG4-related disease. Amyloid A deposition was observed along vessel walls, and immunofluorescence analysis indicated granular positivity of IgG and C3 along the glomerular capillary wall. Elevated levels of interleukin-6 (21 pg/mL) and vascular endothelial growth factor (VEGF; 1210 pg/mL) were noted. Based on these findings, and the histological finding of the lymph node biopsy, idiopathic MCD was diagnosed. Corticosteroid monotherapy was only partially effective. Subsequently, tocilizumab administration was initiated, leading to sustained remission, even after discontinuation of prednisolone. Due to the diverse responses to steroid therapy and the varying prognoses observed in MCD and IgG4-related disease, it is essential to carefully diagnose MCD by thoroughly assessing the organ distribution of the disease, its response to steroid therapy, and any additional pathological findings.

A Case of Idiopathic Multicentric Castleman's Disease Diagnosed From Anemia and Renal Dysfunction on an Annual Check-Up

A 34-year-old man was referred to our hospital because of mild renal dysfunction and anemia. He had no specific preexisting medical conditions; his complaint was fatigue. Physical examination revealed several mobile, pinky head-sized (no tenderness) palpable lymph nodes on the bilateral neck. Blood biochemistry tests revealed anemia, renal dysfunction, increased inflammation, and a protein-albumin discrepancy. Immunological examination revealed polyclonal elevation of immunoglobulins (no shift in κ/λ ratio). A cervical lymph node biopsy was performed, and the pathological results showed numerous clusters of mature plasma cells (plasmacytic type), leading to the definitive diagnosis of idiopathic multicentric Castleman's disease (iMCD).

Successful treatment with bortezomib in combination with dexamethasone in a middle-aged male with idiopathic multicentric Castleman's disease: A case report

Multicentric Castleman disease (MCD) is a heterogeneous, life-threatening disease. A subgroup of HIV-negative and HHV-8-negative MCD is defined as idiopathic MCD (iMCD) with a poor prognosis. Here we report an unusual case of a 47-year-old male patient with iMCD who experienced multiple treatment regimens such as chemotherapy, immunomodulatory therapy, and targeted therapy, all of which were considered ineffective. Subsequently, he was started on bortezomib in combination with dexamethasone for six cycles and he was in complete remission. The patient has survived nearly 13 years to date - the longest survival of any iMCD patient treated with bortezomib in combination with dexamethasone. Bortezomib combined with dexamethasone may be an effective salvage strategy for severe and refractory iMCD.

Spatially Resolved Multiomics: Data Analysis from Monoomics to Multiomics

Spatial monoomics has been recognized as a powerful tool for exploring life sciences. Recently, spatial multiomics has advanced considerably, which could contribute to clarifying many biological issues. Spatial monoomics techniques in epigenomics, genomics, transcriptomics, proteomics, and metabolomics can enhance our understanding of biological functions and cellular identities by simultaneously measuring tissue structures and biomolecule levels. Spatial monoomics technology has evolved from monoomics to spatial multiomics. Moreover, the spatial resolution, high-throughput detection capability, capture efficiency, and compatibility with various sample types of omics technology have considerably advanced. Despite the technological advances in this field, data analysis frameworks have stagnated. Current challenges include incomplete spatial monoomics data analysis pipeline, overly complex data analysis tasks, and few established spatial multiomics data analysis strategies. In this review, we systematically summarize recent developments of various spatial monoomics techniques and improvements in related data analysis pipeline. On the basis of the spatial multiomics technology, we propose a data integration strategy with cross-platform, cross-slice, and cross-modality. We summarize the potential applications of spatial monoomics technology, aiming to provide researchers and clinicians with a better understanding of how such applications have advanced. Spatial multiomics technology is expected to substantially impact biology and precision medicine through measurements of cellular tissue structures and the extraction of biomolecular features.

The Cytokine Storm of Multicentric Castleman Disease

As described throughout this book, different triggers can elicit a variety of different cytokine storm disorders that share overlapping clinical features (Fig. 31.1). Even within a particular cytokine storm disorder, multiple different triggers can elicit the syndrome. Like HLH, multicentric Castleman disease (MCD) serves as a great example of this as it can be caused by a viral infection, neoplastic cell population, or an unknown cause. Furthermore, the idiopathic subtype of MCD (iMCD) provides one of the first examples of a cytokine storm disorder that could be abrogated with targeted neutralization of a single cytokine when inhibition with the anti-interleukin-6 (IL-6) receptor monoclonal antibody tocilizumab was shown to effectively treat iMCD in the 1990s. Of course, this "iMCD treatment," tocilizumab, has been used in a variety of cytokine storm settings over the last 30+ years.

Clinical features and treatment outcomes of Castleman disease in children: a retrospective cohort in China

Castleman disease (CD) is a rare lymphoproliferative disorder of undetermined etiology. Unicentric CD (UCD) and multicentric CD (MCD) are two phenotypes of CD diagnosed by the histopathology of lymph nodes. We attempted to describe a pediatric CD cohort to optimize the management of this disease. We reviewed the medical records of pediatric patients diagnosed with CD between April, 2004, and October, 2022, at the Children's Hospital of Fudan University. Prognosis information was collected in January, 2023, by telephone inquiry. Twenty-two patients with UCD and 2 patients with MCD were identified, all with hyaline vascular (HV) type. The median ages at diagnosis were 10.75 years (IQR 8, 12.81) for UCD and 14.42 years (IQR 13.42, 15.42) for MCD. The most common lesion location of UCD was the neck (9/22, 40.91%) and abdomen (9/22, 40.91%). Systematic symptoms occurred on 10/22 (45.45%) patients with UCD and 1/2 (50%) patients with MCD, and abnormal laboratory indexes were detected in both. Resection and biopsy were performed on all patients. One out of two patients with MCD also received rituximab for upfront therapy. After a median of 4 years (IQR 1.5, 6) of follow-up time, the overall survival was 100% and the complete remission rate in UCD was 63%. There was no relapse or progression.

CONCLUSIONS

Our series demonstrated that HV-UCD was the most common type in children. Resection and biopsy were used for both deterministic diagnoses and treatments. Despite the high possibility to develop systematic inflammation, children with CD showed promising outcomes.

WHAT IS KNOWN

• Castleman disease is a rare lymphoproliferative disorder with limited cohort studies, especially in pediatrics. • The ubiquity of delayed confirmations and misdiagnoses points to a lack of knowledge about etiology and characteristics, which is a prerequisite for novel therapeutics.

WHAT IS NEW

• We retrospectively reviewed and analyzed the clinical and pathological symptoms, laboratory and imaging features, and treatment outcomes of a Chinese pediatric cohort with Castleman disease. • Our work may improve the recognition and optimize the management of this rare disease in children.

Symptom burden in patients with idiopathic multicentric Castleman disease and its impact on daily life: an international patient and caregiver survey

Background

Idiopathic Multicentric Castleman Disease (iMCD) is a rare inflammatory lymphoproliferative disorder with heterogenous clinical presentations. The symptomatology in iMCD patients remains poorly understood. The aim of this study was to identify the type, frequency and severity of iMCD-related symptoms and the impact of these on the daily lives of iMCD patients and informal-caregivers.

Methods

We conducted two bespoke 45-question online surveys for iMCD patients and informal-caregivers of patients recruited from the US, UK, Australia and Canada between April 14 and November 8, 2021. Descriptive data was collected, and a Likert scale was used to quantify the impact of symptoms on various aspects of daily life. Ordinal logistic regression analysis was used to determine associations between age, gender, employment status and symptom burden with aspects of daily life.

Findings

Eligible respondents included 51 iMCD patients and 11 informal-caregivers. Patients reported up to 27 unique symptoms, the mean number of symptoms experienced by a patient was 6.7 (range 0-22 symptoms). Most symptoms had a moderate to severe impact on patients' daily lives, with 'pain/discomfort', 'ability to travel', and 'sexual functioning' being the most impacted. iMCD patient characteristics such as being 40 years or older, female, and either disabled or unemployed was significantly associated with adverse impact on several aspects of daily life. Among caregivers, the aspects of daily life that were disproportionately affected was their own social life and freedom, emotional wellbeing, travel/relocation, and work.

Interpretation

iMCD patients have widely varied and unappreciated symptomatology. High symptom burden adversely impacts several aspects of patient daily lives as well as their caregivers.

Funding

Funding was provided by EUSA Pharma.

Transformation of HHV-8-negative idiopathic multicentric Castleman disease into diffuse large B-cell lymphoma: A case report from Nepal

Key Clinical Message

Idiopathic Castleman disease transforming into Diffuse Large B-cell Lymphoma has an aggressive course and can lead to mortality. Hence, early diagnosis and intervention are required.

Abstract

Idiopathic Castleman disease transforming into non-Hodgkin lymphoma has an aggressive course, poor prognosis, and high mortality rate. Hence, early diagnosis and intervention are necessary. In a developing country like Nepal, where infectious diseases, particularly TB, are high, concomitant infection worsens the disease course. It also poses a diagnostic challenge as the clinical presentation may be similar.

Cost-Effectiveness Analysis of Siltuximab for Australian Public Investment in the Rare Condition Idiopathic Multicentric Castleman Disease

OBJECTIVES

This paper presents an Australian model that formed part of the health technology assessment for public investment in siltuximab for the rare condition of idiopathic Multicentric Castleman Disease (iMCD) in Australia.

METHODS

Two literature reviews were conducted to identify the appropriate comparator and model structure. Survival gain based on available clinical trial data were modelled using an Excel-based model semi-Markov model including time-varying transition probabilities, an adjustment for trial crossover and long-term data. A 20-year horizon was taken, and an Australian healthcare system perspective was adopted, with both benefits and costs discounted at 5%. The model was informed with an inclusive stakeholder approach that included a review of the model by an independent economist, Australian clinical expert opinion and feedback from the Pharmaceutical Benefits Advisory Committee (PBAC). The price used in the economic evaluation reflects a confidential discounted price, which was agreed to with the PBAC.

RESULTS

An incremental cost-effectiveness ratio of A$84,935 per quality-adjusted life-year (QALY) gained was estimated. At a willingness-to-pay threshold of A$100,000 per QALY, siltuximab has a 72.1% probability of being cost-effective compared with placebo and best supportive care. Sensitivity analyses results were most sensitive to the length of interval between administrations (from 3- to 6-weekly) and crossover adjustments.

CONCLUSION

Within a collaborative and inclusive stakeholder framework, the model submitted to the Australian PBAC found siltuximab to be cost-effective for the treatment of iMCD.

A Multicentric Castleman Disease Associated with Mixed Warm and Cold Antibody-Mediated AHA Responsive to Siltuximab

Castleman disease is non-clonal lymphoproliferative disorders defined by hypertrophy of lymph nodes. The multicentric form (MCD), in which multiple lymph node stations are involved, is not associated with HHV8 infection, but considered idiopathic, although IL-6 appears to play a central role in its pathogenesis. Here, we report the case of a patient who presented with mixed autoimmune hemolytic anemia (AIHA) and adenopathy that was very challenging to diagnose due to very low values of hemoglobin and refractoriness of obtaining any improvement of AIHA with standard first and second lines of therapy (steroids, rituximab, immunoglobulin, erythropoietin, and cyclosporine). When we safely proceeded to lymph node biopsy, a diagnosis of MCD was established. This permitted the treatment with siltuximab, an anti-IL-6 monoclonal antibody. After only 1 week, hemoglobin raised and he was discharged. After 1 year, he was still in remission. This case underlines the challenges in diagnosis of MCD, and the first case of response to siltuximab after the failure of rituximab to relieve mixed AIHA.

Pseudohyponatremia: Mechanism, Diagnosis, Clinical Associations and Management

Pseudohyponatremia remains a problem for clinical laboratories. In this study, we analyzed the mechanisms, diagnosis, clinical consequences, and conditions associated with pseudohyponatremia, and future developments for its elimination. The two methods involved assess the serum sodium concentration ([Na]_S) using sodium ion-specific electrodes: (a) a direct ion-specific electrode (ISE), and (b) an indirect ISE. A direct ISE does not require dilution of a sample prior to its measurement, whereas an indirect ISE needs pre-measurement sample dilution. [Na]_S measurements using an indirect ISE are influenced by abnormal concentrations of serum proteins or lipids. Pseudohyponatremia occurs when the [Na]_S is measured with an indirect ISE and the serum solid content concentrations are elevated, resulting in reciprocal depressions in serum water and [Na]_S values. Pseudonormonatremia or pseudohypernatremia are encountered in hypoproteinemic patients who have a decreased plasma solids content. Three mechanisms are responsible for pseudohyponatremia: (a) a reduction in the [Na]_S due to lower serum water and sodium concentrations, the electrolyte exclusion effect; (b) an increase in the measured sample's water concentration post-dilution to a greater extent when compared to normal serum, lowering the [Na] in this sample; (c) when serum hyperviscosity reduces serum delivery to the device that apportions serum and diluent. Patients with pseudohyponatremia and a normal [Na]_S do not develop water movement across cell membranes and clinical manifestations of hypotonic hyponatremia. Pseudohyponatremia does not require treatment to address the [Na]_S, making any inadvertent correction treatment potentially detrimental.

Unmet Clinical Needs in the Management of Idiopathic Multicentric Castleman Disease: A Consensus-based Position Paper From an ad hoc Expert Panel

Castleman disease describes a group of heterogeneous clinicopathological disorders now included in the tumor-like lesions with B-cell predominance of the World Health Organization classification. Managing idiopathic multicentric Castleman disease (iMCD) is challenging, because few systematic studies or comparative randomized clinical trials have been conducted. International, consensus evidence-based guidelines for iMCD were published in 2018, but gaps in the therapeutic options for difficult-to-treat patients, who do not respond to siltuximab and other conventional therapies, still exist. This article presents the results of group discussion among an ad hoc constituted Panel of Italian experts to identify and address unmet clinical needs (UCNs) in managing iMCD. Recommendations on the appropriateness of clinical decisions and proposals for new research concerning the identified UCNs were issued through formalized multiple-step procedures after a comprehensive analysis of the scientific literature. The following key UCNs were addressed: strengthening the diagnostic certainty in iMCD patients before planning first-line therapy; management of siltuximab therapy; choice and management of immune-modulating, or chemotherapy agents in patients resistant/intolerant to siltuximab therapy. While most of the conclusions reached by the Panel are consistent with the existing guidelines, some alternative therapeutic options were stressed, and the discussion contributed to bringing forth the issues that need further investigation. Hopefully, this comprehensive overview will improve the practice of iMCD and inform the design and implementation of new studies in the field.

Rapid Clinical Improvement of Multicentric Castleman Disease (MCD) with Renal Involvement Following Treatment with Tocilizumab: AA Amyloidosis as a Possible Renal Involvement of MCD

Castleman disease (CD) is a lymphoproliferative disorder that manifests as hypergammaglobulinemia and severe inflammation with multiorgan involvement. However, renal involvement has been infrequently described in CD. We present a case of a 63-year-old Japanese male patient with multicentric CD (MCD) in whom kidney involvement, including impaired renal function and massive proteinuria, is present. He had a 2-year history of inflammatory arthritis and was referred to our clinic with newly developed proteinuria, renal dysfunction, and elevated levels of acute-phase proteins. Abdominal computed tomography scan revealed hepatosplenomegaly, including mesenteric and inguinal lymph node enlargements. The patient underwent inguinal lymph node resection. Excisional biopsy of the inguinal lymph node showed multiple lymphoid follicles and expansion of interfollicular areas by marked plasmacytosis consistent with mixed type CD. The patient was diagnosed with human herpes virus 8-negative MCD according to the international diagnostic criteria for CD. Diagnostic renal biopsy was not performed following the medical viewpoint. Tocilizumab (TCZ) treatment was highly effective in reducing proteinuria and stabilizing renal function, as well as improving other clinical symptoms. The patient responded to TCZ treatment, and the renal involvement was rapidly improved. Our preliminary immunohistochemical analysis indicated AA amyloid deposits in urinary epithelial cells suggesting a possible renal involvement of AA amyloidosis. TCZ could potentially be one of the therapeutic options in patients with MCD with renal involvement.

TAFRO syndrome was effectively treated with an inexpensive novel scheme: A case report

A man diagnosed as TAFRO syndrome was successfully responded to a novel immunosuppressive regimen containing methylprednisolone and mycophenolate mofetil. Blood cells firstly recovered, followed by the general situation and complete recover 1 month later, highlighting the danger of TAFRO syndrome and the importance of immunosuppressive agents in reversing pathological course.

Case report: Importance of early and continuous tocilizumab therapy in nephrotic syndrome associated with idiopathic multicentric Castleman disease: A case series

Idiopathic multicentric Castleman disease (iMCD) is a systemic and polyclonal lymphoproliferative disease involving multiple organs, including the kidneys, due to the overproduction of interleukin-6 (IL-6). Recently, several reports have suggested that excessive IL-6 actions in iMCD could have a causal relationship with the development of diverse histopathological renal manifestations that cause nephrotic syndrome. However, the treatment for such cases remains unclear. We report a series of three cases of nephrotic syndrome due to iMCD that helps to delineate the importance of early and continuous therapy with the anti-interleukin-6 receptor antibody tocilizumab. First, treatment was suspended for infectious control, and the patient presented with nephrotic syndrome due to diffuse mesangial and endocapillary hypercellularity without immune deposits complicating acute kidney injury. Second, iMCD was treated with prednisolone alone. The patient suddenly developed nephrotic syndrome due to immune-complex glomerulonephritis, not otherwise specified, complicated with acute kidney injury. In the third case, nephrotic syndrome secondary to membranous glomerulonephritis was diagnosed, with a skin rash and IgE antibodies to tocilizumab, and was therefore treated with prednisolone alone. In contrast to the first two cases, the third progressed to end-stage renal disease on hemodialysis. Taken together, this series suggests that clinicians should maintain clinical vigilance for iMCD as a possible underlying component of nephrotic syndrome, since iMCD presents with a variety of renal pathologies. Prompt initiation and continuous administration of tocilizumab are likely key determinants of renal outcomes in such cases. In particular, when tocilizumab is suspended due to infection or in the perioperative period, consideration of its expeditious resumption should be made, taking into account both the withdrawal period and systemic conditions.

[Castleman disease]

The term "Castleman disease" covers a variety of entities that have very different clinical, biological, pathological and physiopathological features. In this issue, we review the characteristics of the unicentric Castleman disease, of the HHV8 associated multicentric Castleman disease and the idiopathic multicentric Castleman disease associated or not with TAFRO syndrome ("thrombocytopenia, anasarca, fever, reticulin myelofibrosis and/or renal insufficiency, organomegaly"). We detail the differential diagnostics of these entities.

Analysis of albumin as a prognostic factor in HHV-8/HIV-negative Castleman disease from a multicenter study

As a rare lymphoproliferative disorder, many patients with HHV-8/HIV-negative Castleman disease (CD) have hypoalbuminemia. However, data is limited on whether hypoalbuminemia is an independent predictor of CD. We retrospectively collected data from 230 patients diagnosed at 12 medical centers in China and the U.S. Different classifications included 147 patients with unicentric CD (UCD) and 83 with idiopathic multicentric CD (iMCD). Adjusted smooth curve fitting showed that the relationship between albumin and all-cause death of patients with CD and iMCD was linear. Cox proportional hazards regression modeling showed a negative association between the risk of death and albumin level (hazard ratio [HR]: 0.84; 95% CI, 0.76, 0.93). Using the Kaplan-Meier method, we determined that hypoproteinemia was a risk factor for poorer prognosis in patients with CD, UCD, and iMCD. Albumin was independently and negatively associated with the risk of death in CD patients, especially those with iMCD.

Unicentric Castleman Disease: A Rare Diagnosis of Radiological and Histological Correlation

Castleman disease is an uncommon nonneoplastic, lymphoproliferative disorder of that is associated with lymphadenopathy and nonclonal lymph nodes hyperplasia. It is further subdivided into two types: Unicentric Castleman disease and Multicentric Castleman disease. Unicentric Castleman disease is rare to be reported in patients having AIDS, because HIV infected patients most commonly presented with Multicentric Castleman disease and they mostly coinfected with HHV-8. Herein we reported a rare presentation of Unicentric Castleman disease with hyaline vascular variety evident Histopathologically as a preoperative diagnosis. The patient was initially managed conservatively and surgical excision (excisional biopsy) of the left cervical lymph node was than performed and sent for histopathology. The Immunohistochemistry findings were also consistent with the diagnosis of Castleman disease Hyaline vascular type as evident from left cervical lymph node excisional biopsy.

Idiopathic Multicentric Castleman Disease with Strikingly Elevated IgG4 Concentration in the Serum and Abundant IgG4-Positive Cells in the Tissue: A Case Report

Idiopathic multicentric Castleman disease (iMCD) can be challenging to distinguish clinically and histopathologically from Immunoglobulin G4-related disease (IgG4RD). A 73-year-old man was referred to a rheumatologist for suspected autoimmune-related polyclonal hypergammaglobulinemia. The patient had a history of multiple lymphadenopathies in the neck for over 20 years. Laboratory data showed elevated serum immunoglobulin G4 (IgG4) levels, hypergammaglobulinemia, high C-reactive protein (CRP) levels, marked anemia, and positivity for several autoantibodies. Additionally, imaging studies revealed multiple enlarged lymph nodes and multifocal, ill-defined, small patchy opacities over the lung. Biopsies of the neck lymph node and right lung revealed typical features of multicentric Castleman disease (MCD). Immunohistochemical staining was negative for human herpesvirus-8 (HHV-8) in both lymph nodes and the right lung, sub-classified as iMCD, whereas the IgG4/IgG ratio was >40%, which raised the suspicion of IgG4RD. However, serological cytokine analysis demonstrated an increased interleukin-6 (IL-6) level, alongside systemic inflammatory and histopathological features, distinguishing MCD from IgG4RD in this patient. The patient was treated with short-term glucocorticoids and regular infusion of an anti-IL-6 receptor monoclonal antibody (tocilizumab), with satisfactory clinical and radiographic responses. Notably, differentiating MCD from IgG4RD is crucial for optimal treatment. Clinical and pathological features may assist in distinguishing between these two diseases.