Multicentric Castleman disease: Where are we now?

Stroma-Rich Hyaline Vascular Type of Castleman Disease: A Case Report and Literature Review

Castleman disease (CD) is a rare lymphoproliferative disorder characterized by abnormal lymph node enlargement. We present the first documented case of a stroma-rich variant of hyaline vascular Castleman disease in Saudi Arabia. A 24-year-old Saudi female known to have acetylcholine receptor antibody-positive myasthenia gravis (MG) presented with shortness of breath, oral thrush, and an acute myasthenia gravis exacerbation, necessitating intensive care unit (ICU) admission. During her hospitalization, she was found to have a large pelvic mass. The mass was surgically excised. The diagnosis of stroma-rich hyaline vascular Castleman disease was rendered after histopathological examination. The patient's symptoms improved after the surgery. This case underscores the importance of considering Castleman disease in complex clinical presentations, especially in the context of autoimmune and paraneoplastic diseases. Recognition and timely intervention are crucial for patient management. Additionally, the report adds to the global literature on Castleman disease, emphasizing the need for further research into its clinical manifestations and associations.

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.

Diagnostic challenges of the idiopathic plasmacytic lymphadenopathy (IPL) subtype of idiopathic multicentric Castleman disease (iMCD): Factors to differentiate from IgG4-related disease

AIMS AND METHODS

Idiopathic multicentric Castleman disease (iMCD) is currently considered to be classified into three clinical subtypes, including idiopathic plasmacytic lymphadenopathy (IPL), thrombocytopaenia, anasarca, fever, reticulin fibrosis/renal dysfunction, organomegaly (TAFRO) and not otherwise specified (NOS). Among the three, iMCD-IPL closely mimics IgG4-related disease (IgG4-RD). In diagnosing IgG4-RD, it is sometimes challenging to distinguish iMCD-IPL patients that also meet the histological diagnostic criteria for IgG4-RD. In this study, we focused on the number of IgG4-positive cells in the lymph nodes and analysed the relationship with laboratory findings to distinguish iMCD-IPL from IgG4-RD. Thirty-nine patients with iMCD-IPL and 22 patients with IgG4-RD were included.

RESULTS

Among the cases considered to be iMCD-IPL, 33.3% (13/39) cases also met the histological diagnostic criteria for IgG4-RD and serum IgG4 levels were not different between the two groups. However, the serum IgG4/IgG ratio was significantly higher in IgG4-RD, with a cut-off value of 19.0%. Additionally, a significant positive correlation between serum IgG levels and the number of IgG4-positive cells was observed in iMCD-IPL (p=0.001). The serum IgG cut-off value for distinguishing iMCD-IPL meeting histological criteria for IgG4-RD from other iMCD-IPL was 5381 mg/dL.

CONCLUSIONS

iMCD-IPL cases with high serum IgG levels (>5000 mg/dL) were likely to meet the diagnostic criteria for IgG4-RD because of the numerous IgG4-positive cells observed. A combination of clinical presentations, laboratory values including the serum IgG4/IgG ratios and histological analysis is crucial for diagnosis of IgG4-RD and iMCD-IPL.

Retroperitoneal Castlemans disease mimicking a liver cancer: a case report

Castleman disease (CD), a distinct lymphoproliferative disorder, is infrequently encountered in clinical practice and poses significant diagnostic challenges. We present the case of a 48-year-old asymptomatic female, admitted for evaluation of a hepatic mass detected in the liver's right lobe. Preoperative laboratory tests were within normal limits. Diagnostic imaging, including contrast-enhanced magnetic resonance imaging (MRI), was suggestive of hepatocellular carcinoma. Furthermore, contrast-enhanced abdominal computed tomography (CT) scans were indicative of hepatic malignancy. Subsequently, the patient underwent laparoscopic surgery targeting a retroperitoneal mass. During the surgical procedure, it was observed that the tumor was a retroperitoneal mass situated posterior to the liver, exhibiting localized adhesion to hepatic tissue. The postoperative histopathological analysis revealed the mass to be hyaline-vascular type Castleman disease (HV-CD), thereby refuting the initial diagnosis of a hepatic malignancy. This case underscores the complexity of diagnosing retroperitoneal Castleman disease, particularly when it masquerades as a hepatic tumor.

Angioimmunoblastic T-cell lymphoma and Kaposi sarcoma: A fortuitous collision?

AIMS

Follicular helper T-cell (TFH) lymphoma of the angioimmunoblastic-type (AITL), one of the most prevalent T-cell lymphomas, typically encompasses proliferation of high endothelial venules and Epstein-Barr virus-positive immunoblasts, but neither infection with HHV8 nor association with Kaposi's sarcoma (KS) have been described. The aims of this study are to characterise the association between AITL and HHV8 infection or KS.

METHODS AND RESULTS

Three male patients aged 49-76 years, HIV-negative, with concurrent nodal involvement by AITL and KS, were identified from our files and carefully studied. Two patients originated from countries where endemic KS occurs, including one with cutaneous KS. The lymphomas featured abundant vessels, expanded follicular dendritic cells and neoplastic TFH cells [PD1+ (three of three), ICOS+ (three of three), CXCL13+ (three of three), CD10+ (two of three), BCL6 (two of three)] but lacked EBV+ immunoblasts. The foci of KS consisted of subcapsular proliferations of ERG+, CD31+ and/or CD34+ , HHV8+ spindle cells. High-throughput sequencing showed AITL-associated mutations in TET2 (three of three), RHOA (G17V) (three of three) and IDH2 (R172) (two of three), which were absent in the microdissected KS component in two cases. Relapses in two patients consisted of AITL, without evidence of KS. No evidence of HHV8 infection was found in a control group of 23 AITL cases.

CONCLUSION

Concurrent nodal involvement by AITL and KS is rare and identification of both neoplastic components may pose diagnostic challenges. The question of whether the association between AITL and KS may be fortuitous or could reflect the underlying immune dysfunction in AITL remains open.

Polyclonal Hyperglobulinemia with Multiple Pulmonary Cysts and Nodules: Concerning the Mechanism Underlying Cyst Formation

We herein report a case of polyclonal hyperglobulinemia with multiple pulmonary cysts and nodules. The histopathological findings allowed us to speculate about the mechanism underlying cyst formation in these pathological conditions, which has not yet been thoroughly elucidated. The patient was a 49-year-old woman who presented with multiple pulmonary multilocular cysts and nodules. A lung biopsy revealed features of nodular lymphoid hyperplasia. Notably, lung structure fragmentation was evident, suggesting that structural destruction may have accompanied the disease during its course. The cysts were considered to have formed due to destruction of the lung structures.

Castleman Disease in an Older Patient With the Onset of Right Pleural Effusion

Castleman's disease (CD) is an uncommon lymphoproliferative disorder with various presentations in different age groups. Although CD predominantly affects younger individuals, cases in older people are rare. The presentation of CD can range from asymptomatic to severe. We present the case of a 91-year-old male who reported dyspnea and was subsequently diagnosed with right-sided pleural effusion. The patient's condition deteriorated despite an initial provisional diagnosis of tuberculous pleurisy and multiple interventions. A cervical lymph node biopsy later revealed a diagnosis consistent with the plasma cell type of CD. Considering the patient's age and atypical presentation, this case adds a unique perspective to the limited literature on CD in elderly patients. Its presentation can be highly variable, and pleural effusion is rare. Our case highlights the heterogeneity of CD presentation, particularly in older age groups. The diagnosis of CD requires high suspicion, particularly in non-traditional populations. Clinicians should be aware of the varied presentations of CD, including in older patients. Unexplained pleural effusion, even in older patients, should prompt a broad differential diagnosis, including rare conditions such as CD.

Flow Cytometry in Diagnosis, Prognostication, and Monitoring of Multiple Myeloma and Related Disorders

Flow cytometry plays a critical role in the diagnosis, prognostication, therapy response evaluation, and clinical management of plasma cell neoplasms. The review summarizes how flow cytometry is used in the initial evaluation to distinguish primary and secondary clonal plasma cell populations from each other and from reactive plasma cells. We further illustrate the kinds of prognostic information the assessment can provide at diagnosis and disease follow-up of primary plasma cell neoplasms. Technical requirements for MRD assays and their use in therapy efficacy assessment and clinical decision-making in multi-myeloma are discussed.

Clinical management of Kaposi sarcoma herpesvirus-associated diseases: an update on disease manifestations and treatment strategies

INTRODUCTION

Kaposi sarcoma herpes virus (KSHV) is associated with several diseases including Kaposi sarcoma, a form of multicentric Castleman's disease, primary effusion lymphoma, and an inflammatory cytokine syndrome. These KSHV-associated diseases (KAD) can present with heterogenous signs and symptoms that are often associated with cytokine dysregulation that may result in multiorgan dysfunction. The inability to promptly diagnose and treat these conditions can result in long-term complications and mortality.

AREAS COVERED

Existing epidemiological subtypes of existing KSHV-associated diseases, specifically Kaposi sarcoma as well as the incidence of several KSHV-associated disorders are described. We review the KSHV latent and lytic phases as they correlate with KSHV-associated diseases. Given the complicated presentations, we discuss the clinical manifestations, current diagnostic criteria, existing treatment algorithms for individual KAD, and when they occur concurrently. With emerging evidence on the virus and host interactions, we evaluate novel approaches for the treatment of KAD. An extensive literature search was conducted to support these findings.

EXPERT OPINION

KSHV leads to complex and concurrent disease processes that are often underdiagnosed both in the United States and worldwide. New therapies that exist for many of these conditions focus on chemotherapy-sparing options that seek to target the underlying viral pathogenesis or immunotherapy strategies.

A novel approach for characterization of KSHV-associated multicentric Castleman disease from effusions

A biopsy of lymphoid tissue is currently required to diagnose Kaposi sarcoma-associated herpesvirus (KSHV)-associated multicentric Castleman disease (KSHV-MCD). Patients showing clinical manifestations of KSHV-MCD but no pathological changes of KSHV-MCD are diagnosed as KSHV inflammatory cytokine syndrome. However, a lymph node biopsy is not always feasible to make the distinction. A pathognomonic feature of lymph nodes in KSHV-MCD is the expansion of KSHV-infected, lambda-restricted but polyclonal plasmablasts. To investigate whether these cells also reside in extra-nodal sites, effusion from 11 patients with KSHV-MCD and 19 with KSHV inflammatory cytokine syndrome was analysed by multiparametric flow cytometry. A distinct, lambda-restricted plasmablastic population (LRP) with highly consistent immunophenotype was detected in effusions in 8/11 patients with KSHV-MCD. The same population was also observed in 7/19 patients with KSHV inflammatory cytokine syndrome. The detection of LRP stratified KSHV inflammatory cytokine syndrome into two clinically distinct subgroups; those with detectable LRP closely resembled KSHV-MCD, showing similar KSHV viral load, comparable severity of thrombocytopenia and hypoalbuminaemia, and similar incidences of hepatosplenomegaly. Collectively, the detection of LRP by flow cytometry can serve as a valuable tool in diagnosing KSHV-MCD. KSHV inflammatory cytokine syndrome with LRP in effusions may represent a liquid-form of KSHV-MCD.

[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.

Treatment-resistant idiopathic multicentric Castleman disease with thrombocytopenia, anasarca, fever, reticulin fibrosis, renal dysfunction, and organomegaly managed with Janus kinase inhibitors: A case report

RATIONALE

Thrombocytopenia, anasarca, fever, reticulin fibrosis, renal dysfunction, and organomegaly (TAFRO) syndrome are nonmalignant but life-threatening systemic inflammatory disorders. However, many patients are refractory to treatment, resulting in significant morbidity and mortality. Additionally, established treatment options are unavailable. Therefore, we present 2 cases of adults with the iMCD-TAFRO syndrome refractory to initial treatment but responded to Janus kinase (JAK) inhibitors with ruxolitinib. The report reveals that these rare adult cases of the refractory and treatment-resistant iMCD-TAFRO syndrome can be treated using JAK inhibitors.

PATIENT CONCERNS

Case 1 is a 36-year-old previously healthy male patient who presented with fever and general fatigue for 2 weeks. Case 2 is a 42-year-old previously healthy female patient who presented with fever and general fatigue.

DIAGNOSIS

The diagnosis met the 2015 criteria for TAFRO syndrome, as determined by All Japan TAFRO Syndrome Research Group in the Research Program for Intractable Disease by the Ministry of Health, Labor and Welfare (MHLW) Japan.

INTERVENTIONS

Treatment with tocilizumab and several immunosuppressants were ineffective. So, we performed ruxolitinib.

OUTCOMES

Each patient received ruxolitinib, the general condition improved, and CRP levels decreased.

LESSONS

These cases showed that ruxolitinib was effective for treatment-resistant/ refractory TAFRO syndrome. Further prospective studies are needed on using ruxolitinib with a small number of cases.

Report of Two Cases of Pediatric IgG4-Related Lymphadenopathy (IgG4-LAD): IgG4-Related Disease (IgG4-RD) or a Distinct Clinical Pathological Entity?

IgG4-related disease (IgG4-RD) is a recently discovered immune-mediated fibroinflammatory condition, uncommon in the pediatric population, that could involve multiple organs and induce cancer-like lesions and organ damage. Its main features are multiple injuries in different sites, a dense lymphoplasmacytic infiltrate rich in IgG4 plasma cells, storiform fibrosis, and often high serological concentrations of IgG4. Autoimmune pancreatitis is the most common manifestation, mainly in adults. Two cases of IgG4-RD in children with lymph node localization of disease are reported. Localized or systemic lymph node involvement is common, but lymph node enlargement as the first and only manifestation of IgG4-RD is unusual, and therefore, hard to differentiate from other diseases. IgG4-related lymphadenopathy (IgG4-LAD) is most likely a distinct disease, described as isolated lymphadenopathy, related to the presence of elevated numbers of IgG4-positive plasma cells. Both disorders are likely to be misdiagnosed in children because they are characterized by rare and polymorphic features. IgG4-RD and IgG4-LAD should be considered in the differential diagnosis of disorders characterized by lymphadenopathy of uncertain etiology.

Assessment of type I interferon signatures in undifferentiated inflammatory diseases: A Japanese multicenter experience

Purpose

Upregulation of type I interferon (IFN) signaling has been increasingly detected in inflammatory diseases. Recently, upregulation of the IFN signature has been suggested as a potential biomarker of IFN-driven inflammatory diseases. Yet, it remains unclear to what extent type I IFN is involved in the pathogenesis of undifferentiated inflammatory diseases. This study aimed to quantify the type I IFN signature in clinically undiagnosed patients and assess clinical characteristics in those with a high IFN signature.

Methods

The type I IFN signature was measured in patients’ whole blood cells. Clinical and biological data were collected retrospectively, and an intensive genetic analysis was performed in undiagnosed patients with a high IFN signature.

Results

A total of 117 samples from 94 patients with inflammatory diseases, including 37 undiagnosed cases, were analyzed. Increased IFN signaling was observed in 19 undiagnosed patients, with 10 exhibiting clinical features commonly found in type I interferonopathies. Skin manifestations, observed in eight patients, were macroscopically and histologically similar to those found in proteasome-associated autoinflammatory syndrome. Genetic analysis identified novel mutations in the PSMB8 gene of one patient, and rare variants of unknown significance in genes linked to type I IFN signaling in four patients. A JAK inhibitor effectively treated the patient with the PSMB8 mutations. Patients with clinically quiescent idiopathic pulmonary hemosiderosis and A20 haploinsufficiency showed enhanced IFN signaling.

Conclusions

Half of the patients examined in this study, with undifferentiated inflammatory diseases, clinically quiescent A20 haploinsufficiency, or idiopathic pulmonary hemosiderosis, had an elevated type I IFN signature.

Idiopathic Plasmacytic Lymphadenopathy Forms an Independent Subtype of Idiopathic Multicentric Castleman Disease

Idiopathic multicentric Castleman disease (iMCD) is a type of Castleman disease that is not related to KSHV/HHV8 infection. Currently, iMCD is classified into iMCD-TAFRO (thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly) and iMCD-NOS (not otherwise specified). The former has been established as a relatively homogeneous disease unit that has been recently re-defined, while the latter is considered to be a heterogeneous disease that could be further divided into several subtypes. In 1980, Mori et al. proposed the concept of idiopathic plasmacytic lymphadenopathy (IPL), a disease presenting with polyclonal hypergammaglobulinemia and a sheet-like proliferation of mature plasma cells in the lymph nodes. Some researchers consider IPL to be a part of iMCD-NOS, although it has not been clearly defined to date. This is the first paper to analyze iMCD-NOS clinicopathologically, to examine whether IPL forms a uniform disease unit in iMCD. Histologically, the IPL group showed prominent plasmacytosis and the hyperplasia of germinal centers, while the non-IPL group showed prominent vascularity. Clinically, the IPL group showed significant thrombocytosis and elevated serum IgG levels compared to the non-IPL group (p = 0.007, p < 0.001, respectively). Pleural effusion and ascites were less common in the IPL group (p < 0.001). The IPL group was more likely to have an indolent clinical course and a good response to the anti-IL-6 receptor antibody, while the non-IPL counterpart frequently required more aggressive medical interventions. Thus, the IPL group is a clinicopathologically uniform entity that forms an independent subtype of iMCD.

Idiopathic Multicentric Castleman Disease with Cutaneous Manifestation: Case Report

Castleman disease constitutes a rare class of lymphoproliferative disorders, with an estimated incidence of 21 to 25 per million patient years. The idiopathic subtype exhibits a significantly diverse clinical presentation, which can imitate many autoimmune, malignant, and infectious diseases. Cutaneous manifestations are uncommon and require in-depth investigation, especially when concurrent lymphadenopathy is present. A 79-year-old female, with a chronic, complicated erysipelas-like lesion, presented with bilaterally enlarged inguinal lymph nodes; after surgical excision, their histopathological examination revealed Castleman disease. Even though it is a benign condition, patients are often predisposed to developing certain types of malignancies, which can deteriorate their prognosis. An accurate and early diagnosis, along with effective treatment and prevention of recurrence, is of utmost importance in order to increase the patients’ overall survival and quality of life.

Idiopathic plasmacytic lymphadenopathy: A conceptual history along with a translation of the original Japanese article published in 1980

The current consensus on Castleman disease is that it is a group of several distinct lymphoproliferative disorders with different underlying pathogenesis and clinical outcomes. In 1980, Mori et al. proposed the concept of idiopathic plasmacytic lymphadenopathy with polyclonal hyperimmunoglobulinemia (IPL), a disease of unknown etiology, characterized by severe polyclonal hypergammaglobulinemia and generalized superficial lymphadenopathy. After Frizzera et al.’s landmark report in 1983, the term multicentric Castleman disease (MCD) gradually became established, and for a time, IPL was regarded as identical to MCD. However, with the subsequent recognition of human herpesvirus 8 (HHV8)-related MCD in the 1990s and the contributions by Kojima et al. in the 2000s, in which non-HHV8-related MCD (now called idiopathic MCD) was at least subclassified into IPL and others (non-IPL), it is now clear that the original distinctiveness of IPL is still maintained in MCD, which is a diverse collection of diseases.

Efficacy and Safety of Regimens Used for the Treatment of Multicentric Castleman Disease: A Systematic Review

OBJECTIVES

Treatment options for multicentric Castleman disease (MCD) remain limited. The only FDA-approved drug is siltuximab for idiopathic MCD (iMCD), but the response rate with siltuximab is less than 50%. We performed a systematic review to examine the efficacy and safety of various regimens used for the treatment of MCD.

METHODS

A database search on PubMed, Embase, Cochrane, Web of Science, and Clinicaltrials.gov using the terms "Castleman disease," "treatment outcome" and "patient safety" was done.

RESULTS AND CONCLUSIONS

Results from a randomized controlled trial (RCT) and an extension study highlighted the efficacy and long-term safety of siltuximab for iMCD; other trials showed tocilizumab to be a suitable alternative. A recent trial reported high response rates with thalidomide in iMCD patients. Promising results were reported for bortezomib in relapsed/ refractory MCD. For human herpesvirus 8 (HHV-8) associated MCD, rituximab along with doxorubicin therapy followed by maintenance with zidovudine and valganciclovir is the most effective therapy. A single-arm trial has highlighted the potential role of tocilizumab in HHV-8 MCD. Data for these regimens are limited and mostly comprise non-randomized trials. Further research on emerging agents could have a major impact on the treatment of this rare disease.

International definition of iMCD-TAFRO: future perspectives

Since thrombocytopenia, anasarca, fever, reticulin fibrosis, renal insufficiency, and organomegaly (TAFRO) syndrome was first proposed in 2010, there has been considerable progress in this area, particularly regarding its association with idiopathic multicentric Castleman disease (iMCD). TAFRO syndrome is a heterogeneous category with a constellation of symptoms that can develop in the setting of infection, rheumatologic disorder, malignancy, and iMCD. Now, iMCD with TAFRO symptoms is subtyped as iMCD-TAFRO. However, confusion between TAFRO syndrome and iMCD-TAFRO remains. In this article, we discuss the current understanding and future research agenda of TAFRO syndrome and iMCD-TAFRO from the perspective of its new validated international definition.

Historical and pathological overview of Castleman disease

Castleman disease consists of several lymphoproliferative subtypes that share some histological features in the lymph nodes. On the other hand, numerous clinical findings and etiologies make the disease challenging to understand. The origin of the disease is the hyaline vascular-type unicentric Castleman disease (UCD), first reported by Benjamin Castleman et al. in 1954. Although UCD is characterized by localized lesions and lack of symptoms, multicentric Castleman disease (MCD) with multiple lesions and systemic symptoms was reported by Frizzera in 1983. MCD is further divided according to KSHV/HHV8 infection status. In KSHV/HHV8-related MCD, viral infection signals lead to excessive cytokine production, and cause clinical and pathologic abnormalities. Some cases of plasma cell-type KSHV/HHV8-negative MCD can be found in association with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-proteins, and skin changes), which is a paraneoplastic syndrome. The others are idiopathic MCD, which are currently considered a heterogeneous group of diseases with overlapping pathological and clinical features. In this article, we summarize the historical evolution of Castleman disease to help understand the disease concept. We also review the latest ideas and definitions of the subtypes within the MCD spectrum and summarize the histopathological findings.

Transcriptome and unique cytokine microenvironment of Castleman disease

Castleman disease (CD) represents a group of rare, heterogeneous and poorly understood disorders that share characteristic histopathological features. Unicentric CD (UCD) typically involves a single enlarged lymph node whereas multicentric CD (MCD) involves multiple lymph node stations. To understand the cellular basis of CD, we undertook a multi-platform analysis using targeted RNA sequencing, RNA in-situ hybridization (ISH), and adaptive immune receptor rearrangements (AIRR) profiling of archived tissue from 26 UCD, 14 MCD, and 31 non-CD reactive controls. UCD showed differential expression and upregulation of follicular dendritic cell markers (CXCL13, clusterin), angiogenesis factors (LPL, DLL4), extracellular matrix remodeling factors (TGFβ, SKIL, LOXL1, IL-1β, ADAM33, CLEC4A), complement components (C3, CR2) and germinal center activation markers (ZDHHC2 and BLK) compared to controls. MCD showed upregulation of IL-6 (IL-6ST, OSMR and LIFR), IL-2, plasma cell differentiation (XBP1), FDC marker (CXCL13, clusterin), fibroblastic reticular cell cytokine (CCL21), angiogenesis factor (VEGF), and mTORC1 pathway genes compared to UCD and controls. ISH studies demonstrated that VEGF was increased in the follicular dendritic cell-predominant atretic follicles and the interfollicular macrophages of MCD compared to UCD and controls. IL-6 expression was higher along interfollicular vasculature-associated cells of MCD. Immune repertoire analysis revealed oligoclonal expansions of T-cell populations in MCD cases (2/6) and UCD cases (1/9) that are consistent with antigen-driven T cell activation. The findings highlight the unique genes, pathways and cell types involved in UCD and MCD. We identify potential novel targets in CD that may be harnessed for therapeutics.

Idiopathic multicentric Castleman disease with positive antiphospholipid antibody: atypical and undiagnosed autoimmune disease?

Idiopathic multicentric Castleman disease (iMCD) is a systemic disorder characterized by systemic inflammation and organ dysfunction associated with an increase in pro-inflammatory cytokines. Some patients with iMCD are positive for autoantibodies, although their significance and relationship with specific associated autoimmune diseases are unclear. This study retrospectively analyzed the clinicopathological features of iMCD patients focusing on autoantibodies. Among 63 iMCD patients in our database, 19 were positive for at least one autoantibody. Among the 19, we identified five with plasma cell type (PC)-iMCD lymph node histopathology and positive anti-phospholipid antibodies. These patients were likely to have thrombocytopenia, anasarca, fever, reticulin fibrosis or renal insufficiency, organomegaly (TAFRO) symptoms, and thrombotic events. The present study suggests that patients with undiagnosed or atypical autoimmune diseases, including anti-phospholipid syndrome (APS), were treated for iMCD. APS may present with thrombocytopenia or even multi-organ failure, which overlap with clinical presentations of iMCD. Due to differences in the treatment regimen and follow-up, recognition of the undiagnosed autoimmune disease process in those suspected of iMCD is essential. Our study highlights the importance of complete exclusion of differential diagnoses in patients with iMCD in their diagnostic workup.

Castleman Disease: A Multicenter Case Series from Turkey

Objective:

Castleman disease (CD) is a rare disease also known as angiofollicular lymph node hyperplasia. The two main histological subtypes are the hyaline vascular and plasma cell variants. It is further classified as unicentric CD (UCD) or multicentric CD (MCD) according to the anatomical distribution of the disease and the number of lymph nodes involved. The aim of this multicenter study was to evaluate all cases of CD identified to date in Turkey to set up a national registry to improve the early recognition, treatment, and follow-up of CD.

Materials and Methods:

Both adult (n=130) and pediatric (n=10) patients with lymph node or involved field biopsy results reported as CD were included in the study. Patients’ demographic information, clinical and laboratory characteristics, imaging study results, treatment strategies, and clinical outcomes were evaluated retrospectively.

Results:

A total of 140 patients (69 male and 71 female) with a diagnosis of UCD (n=73) or MCD (n=67) were included. The mean age was 39 years in the UCD group and 47 years in the MCD group. Female patients were more common in the UCD group. The most common histological subtype was hyaline vascular for both UCD and MCD patients. Asymptomatic patients were more common in the UCD group. Anemia, elevations of acute phase reactants, and hypoalbuminemia were more common in the MCD group. The most commonly used treatment strategies for UCD were surgical excision, rituximab, and radiotherapy, respectively. All UCD patients were alive at a median of 19.5 months of follow-up. The most commonly used treatment strategies for MCD were methyl prednisolone, R-CHOP, R-CVP, and rituximab. Thirteen MCD patients had died at a median of 34 months of follow-up.

Conclusion:

This study is important in presenting the patient characteristics and treatment strategies for CD from Turkey, with the potential of increasing awareness about CD. Treatment data may help in making decisions, particularly in countries that do not have access to siltuximab. However, larger prospective studies are needed to make definitive conclusions.

KSHV/HHV8-mediated hematologic diseases

Kaposi sarcoma (KS) herpesvirus (KSHV), also known as human herpesvirus 8, is the causal agent of KS but is also pathogenetically related to several lymphoproliferative disorders, including primary effusion lymphoma (PEL)/extracavitary (EC) PEL, KSHV-associated multicentric Castleman disease (MCD), KSHV+ diffuse large B-cell lymphoma, and germinotropic lymphoproliferative disorder. These different KSHV-associated diseases may co-occur and may have overlapping features. KSHV, similar to Epstein-Barr virus (EBV), is a lymphotropic gammaherpesvirus that is preferentially present in abnormal lymphoid proliferations occurring in immunecompromised individuals. Notably, both KSHV and EBV can infect and transform the same B cell, which is frequently seen in KSHV+ EBV+ PEL/EC-PEL. The mechanisms by which KSHV leads to lymphoproliferative disorders is thought to be related to the expression of a few transforming viral genes that can affect cellular proliferation and survival. There are critical differences between KSHV-MCD and PEL/EC-PEL, the 2 most common KSHV-associated lymphoid proliferations, including viral associations, patterns of viral gene expression, and cellular differentiation stage reflected by the phenotype and genotype of the infected abnormal B cells. Advances in treatment have improved outcomes, but mortality rates remain high. Our deepening understanding of KSHV biology, clinical features of KSHV-associated diseases, and newer clinical interventions should lead to improved and increasingly targeted therapeutic interventions.

Castleman Disease with MDM2/CDK4 Protein Expression: a Potential Mimic of Inflammatory Variant of Liposarcoma with Significant Consequences

Castleman disease is a rare benign lymphoproliferative disorder that includes a spectrum of distinct histopathological entities. The differential diagnosis of Castleman disease is broad and includes lymphomas, HIV-related lymphadenopathy, autoimmune disorders, and inflammatory liposarcoma. When Castleman disease occurs in the retroperitoneum, the distinction from the inflammatory variant of well-differentiated liposarcoma can be very challenging in small biopsies. Herein we report a case of Castleman disease that presented as a retroperitoneal mass and expressed MDM2 and CDK4 by immunohistochemistry. To our knowledge, this is the first report of Castleman disease staining positively for MDM2/CDK4, and it underscores how immunohistochemistry can potentially serve as a pitfall when differentiating this rare entity from retroperitoneal sarcomas.

HHV-8-Associated Multicentric Castleman Disease, a Diagnostic Challenge in a Patient With Acquired Immunodeficiency Syndrome and Fever

Patients with acquired immunodeficiency syndrome (AIDS) are at an increased susceptibility to pathogens and associated malignancies which can present with a unique constellation of symptoms. In this article, we describe a case of Castleman disease in a patient with AIDS, nonadherent with antiretroviral therapy (ART), who presented with fevers, constant abdominal pain, nausea, and vomiting. After an extensive work up, a lymph node biopsy confirmed a diagnosis of human herpesvirus-8 (HHV-8)-associated multicentric Castleman disease. Patients presenting with AIDS and fever have broad differential diagnoses; therefore, reaching a diagnosis as rare as Castleman disease can be challenging. HHV-8 has a propensity to CD20 positive B cells, which allows rituximab to be an effect treatment.

Castleman’s Disease and Anticonvulsant Therapy: A Case of 52-Year-Old Female

Castleman’s disease is a disorder of the lymph nodes that encompasses heterogeneous clinical conditions and can be classified into two main types - hyaline vascular and plasma cell. The affected age group ranges widely from two to 80 years old at the time of diagnosis, with a variable clinical presentation. The etiology of Castleman’s disease is not yet well-understood; however, a number of factors have been linked to its pathogenesis including certain cytokines, viral infections, autoimmunity, immunodeficiency, chronic inflammation, and Kaposi sarcoma. In this study, we present a case of a 52-year-old Saudi female with a history of pulmonary embolism and deep venous thrombosis, who was then found to have mild splenomegaly, mediastinal, bilateral hilar, supraclavicular, paraaortic, and right axillary lymphadenopathy on CT scan, to be later diagnosed as a multicentric Castleman’s disease (MCD). Moreover, the clinical picture, pathogenesis, clinical and histological variants, as well as the treatment options of MCD are discussed.

Multicentric Castleman disease and the evolution of the concept

The term multicentric Castleman disease (MCD) encompasses a spectrum of conditions that share some overlapping clinicopathological manifestations. The fundamental pathogenetic mechanism involves dysregulated cytokine activity, causing systemic inflammatory symptoms as well as lymphadenopathy. Some of the histological changes in lymph nodes resemble the histology of unicentric Castleman disease (UCD). However, based on current knowledge, the use of this shared nomenclature is unfortunate, since these disorders differ in pathogenesis and prognosis. In Kaposi sarcoma-associated herpesvirus (KSHV)-associated MCD, cytokine overactivity is caused by viral products, which can also lead to atypical lymphoproliferations and potential progression to lymphoma. In idiopathic MCD, the hypercytokinemia can result from various mechanisms, which ultimately lead to different constellations of clinical presentations and varied pathology in lymphoid tissues. The authors review the evolving concepts and definitions of the various conditions under the eponym of multicentric Castleman disease.

Castleman disease

Castleman disease (CD), a heterogeneous group of disorders that share morphological features, is divided into unicentric CD and multicentric CD (MCD) according to the clinical presentation and disease course. Unicentric CD involves a solitary enlarged lymph node and mild symptoms and excision surgery is often curative. MCD includes a form associated with Kaposi sarcoma herpesvirus (KSHV) (also known as human herpesvirus 8) and a KSHV-negative idiopathic form (iMCD). iMCD can present in association with severe syndromes such as TAFRO (thrombocytopenia, ascites, fever, reticulin fibrosis and organomegaly) or POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder and skin changes). KSHV-MCD often occurs in the setting of HIV infection or another cause of immune deficiency. The interplay between KSHV and HIV elevates the risk for the development of KSHV-induced disorders, including KSHV-MCD, KSHV-lymphoproliferation, KSHV inflammatory cytokine syndrome, primary effusion lymphoma and Kaposi sarcoma. A CD diagnosis requires a multidimensional approach, including clinical presentation and imaging, pathological features, and molecular virology. B cell-directed monoclonal antibody therapy is the standard of care in KSHV-MCD, and anti-IL-6 therapy is the recommended first-line therapy and only treatment of iMCD approved by the US FDA and EMA.

KSHV/HHV8-Associated Lymphoproliferative Disorders: Lessons Learnt from People Living with HIV

In 1992, Kaposi sarcoma herpesvirus (KSHV/HHV8) was discovered and identified as the causative agent for Kaposi sarcoma. Subsequently, the presence of this virus has been detected in a number of lymphoproliferative disorders in people living with HIV (PLWH), including: KSHV-associated multicentric Castleman disease, primary effusion lymphoma, KSHV-positive diffuse large B-cell lymphoma, and germinotropic lymphoproliferative disorder. Each of these rare entities has subsequently been diagnosed in HIV-negative individuals. The recognition of some of these KSHV/HHV8-associated lymphoproliferative disorders has led to their inclusion in the WHO classification of lymphomas in 2008 and the revision of 2016; however, further revision is under way to update the classification. The relatively recent recognition of these lymphoproliferative disorders and their low incidence, particularly in the HIV-negative population, means that there is little published evidence and consensus on their clinical features and management. The publication of a new WHO classification of lymphomas should yield diagnostic clarity, providing an impetus for retrospective case series and prospective clinical trials in these KSHV/HHV8-associated lymphoproliferative disorders.

TAFRO Syndrome and Elusive Diagnosis of Idiopathic Multicentric Castleman Disease Treated with Empiric Anti-Interleukin-6 Therapy

TAFRO syndrome is defined by the presence of thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis/renal dysfunction (R), and organomegaly (O) and can be seen with idiopathic multicentric Castleman disease (iMCD) or as an isolated process without iMCD. Although the diagnosis of iMCD in patients with TAFRO can be challenging to make, iMCD should remain high on the differential diagnosis. Similar to iMCD, the pathophysiology of TAFRO is not well understood but is thought to be related to hypercytokinemia, with interleukin (IL)-6 playing a pivotal role. Anti-IL-6 monoclonal antibody therapy is an effective treatment modality for iMCD, but to date, there is no clear guidance on treatment of TAFRO in the absence of definitive diagnosis of iMCD, leading to suboptimal management and high morbidity. We report a case of TAFRO syndrome and demonstrate benefit with the empiric use of anti-IL-6 antibody therapy in the context of delayed diagnosis of iMCD.

Clinical and Pathological Characteristics of Hyaline-Vascular Type Unicentric Castleman Disease: A 20-Year Retrospective Analysis

The first case of hyaline vascular type of unicentric Castleman disease (HV-UCD) was reported more than six decades ago. Since patients with HV-UCD are often asymptomatic and this condition is generally discovered incidentally on imaging tests, most of the previous reports were of mediastinal origin detected by chest radiography. In recent years, improved access to imaging modalities has provided new insights in the diagnosis of this condition. In this study, we reviewed the detailed clinical and pathological findings of 38 HV-UCD cases (20 males and 18 females, mean age: 42.8 years). The most common site involved was the abdominal cavity (34.2%), followed by mediastinum (23.7%) and retroperitoneum (15.8%). In the abdominal cavity, mesenteric origin was the most common. The mean size of masses was 4.8 cm. Pathologically, thick hyalinized collagen fibers surrounding large blood vessels and calcification were observed (81.6% and 23.7%, respectively). Multinucleated giant cells resembling Warthin–Finkeldey cell were also observed in occasional cases (23.7%). This is a unique paper that summarizes detailed clinical and pathological findings of a large series of a rare disease. The clinical information presented in this paper is more plausible than previous views and is useful for accurate diagnosis and understanding of the disease.

Validated international definition of the thrombocytopenia, anasarca, fever, reticulin fibrosis, renal insufficiency, and organomegaly clinical subtype (TAFRO) of idiopathic multicentric Castleman disease

Thrombocytopenia, anasarca, fever, reticulin fibrosis, renal insufficiency, and organomegaly (TAFRO) syndrome is a heterogeneous entity manifesting with a constellation of symptoms described above that can occur in the context of idiopathic multicentric Castleman disease (iMCD) as well as infectious diseases, malignancies, and rheumatologic disorders. So, iMCD-TAFRO is an aggressive subtype of iMCD with TAFRO syndrome and often hyper-vascularized lymph nodes. Since we proposed diagnostic criteria of iMCD-TAFRO in 2016, we have accumulated new insights on the disorder and additional cases have been reported worldwide. In this systematic review and cohort analysis, we established and validated a definition for iMCD-TAFRO. First, we searched PubMed and Japan Medical Abstracts Society databases using the keyword "TAFRO" to extract cases. Patients with possible systemic autoimmune diseases and hematologic malignancies were excluded. Our search identified 54 cases from 50 articles. We classified cases into three categories: (1) iMCD-TAFRO (TAFRO syndrome with lymph node histopathology consistent with iMCD), (2) possible iMCD-TAFRO (TAFRO syndrome with no lymph node biopsy performed and no other co-morbidities), and (3) TAFRO without iMCD or other co-morbidities (TAFRO syndrome with lymph node histopathology not consistent with iMCD or other comorbidities). Based on the findings, we propose an international definition requiring four clinical criteria (thrombocytopenia, anasarca, fever/hyperinflammatory status, organomegaly), renal dysfunction or characteristic bone marrow findings, and lymph node features consistent with iMCD. The definition was validated with an external cohort (the ACCELERATE Natural History Registry). The present international definition will facilitate a more precise and comprehensive approach to the diagnosis of iMCD-TAFRO.

IL-6 expression helps distinguish Castleman's disease from IgG4-related disease in the lung

Background

It is difficult to distinguish between multicentric Castleman’s disease (MCD) and IgG4-related lung disease (IgG4-LD), an IgG4-related disease (IgG4-RD) in the lung.

Methods

We focused on IL-6, which is elevated in MCD, to distinguish between MCD and IgG4-LD by RNAscope, a highly sensitive RNA in situ method. Six cases of MCD and four cases of IgG4-LD were selected.

Results

In all cases of MCD and IgG4-LD, 10 or more IgG4-positive cells were found in one high-power field. All MCD cases were inconsistent with the pathological IgG4-related comprehensive diagnostic criteria, but 2 of 6 cases had an IgG4/IgG ratio greater than 40%. In all IgG4-LD cases, histological features were consistent with the pathological IgG4-RD comprehensive diagnostic criteria. IL-6 expression was observed in all MCD and IgG4-LD cases except for one IgG4-LD biopsy. IL-6-expressing cells were mainly identified in the stroma. Sites of IL-6 expression were not characteristic and were sparse. IL-6 expression tended to be higher in MCD compared with IgG4-LD. A positive correlation was found between the IL-6 H-score and serum IL-6 level.

Conclusion

Differences in IL-6 expression may help distinguish between MCD and IgG4-LD. In addition, the presence of high IL-6 levels may help elucidate the pathological mechanisms of IgG4-LD.

Idiopathic Multicentric Hyaline Vascular-Type Castleman Disease

Castleman disease is a rare lymphoproliferative disorder presenting with localized or disseminated lymphadenopathy and systemic symptoms. It can be categorized clinically as unicentric or multicentric, histopathologically as hyaline vascular, plasma cell, or mixed variant, and etiologically, considering the subtypes based on causative viral agents and associated syndromes. The multicentric type can mimic other haematological malignancies, ranging from asymptomatic to multiple organ involvement. Although its pathophysiology is not well known, the current approved treatments are directed towards interleukin-6, CD-20, and viral agents. The authors present an 82-year-old leucodermic man presented with a 2-week history of constitutional symptoms. Examination revealed pallor, hepatosplenomegaly, and palpable left axillary lymphadenopathy. Investigation showed anaemia, thrombocytopenia, polyclonal hypergammaglobulinemia, hypoalbuminemia, and high acute phase reactants, with image study revealing multiple axillary, mediastinal, inguinal, and pelvic lymphadenopathies. The lymph node biopsy was consistent with hyaline vascular-type Castleman disease without human herpersvirus-8 markers. He started prednisolone with initial improvement evolved poorly on a short term. Castleman disease has a broad spectrum of clinical manifestations, associations, and complications that bring a diagnostic challenge, requiring a multidisciplinary approach. Clinicians should be familiar with its features because proper diagnosis and aggressive targeted treatment are the pillars of proper management of these patients.

Castleman disease: A single-center case series

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Castleman disease is an overgrowth of lymphatic cells, usually in the chest or abdomen.

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Multicentric Castleman disease affects lymphatic cells throughout the body.

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HHV-8 and HIV have been associated with multicentric Castleman disease.

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Unicentric Castleman disease affects a single group of lymph nodes.

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Centricity is considered the most important indicator of patient outcomes.

Background

Castleman disease (CD) is a rare lymphocytic disorder. Unicentric CD (UCD) has an excellent long-term prognosis after surgical excision; however, multicentric CD (MCD) has a severe clinical course with poor outcomes.

Study design

We analyzed the clinical presentation of 28 patients treated at a single institution from 1995 to 2017. Demographics, clinical variables, anatomical site, centricity, histopathology, immunochemistry, and surgical approach were reviewed. We evaluated the 5-year recurrence and survival for patients with UCD and MCD.

Results

Of the 28 patients, 57 % (n = 16) were female, with a mean age of 41.6 ± 15.6 years. CD was asymptomatic in 57 % (n = 16) of patients, 21 % (n = 6) presented with local symptoms such as pain, and 21 % (n = 6) of patients also had systemic symptoms, including weight loss and fever. CD was unicentric in 64 % (n = 18) and multicentric in 36 % (n = 10). The hyaline vascular variant was noted in 57 % (n = 16) of the tumors, plasmacytoid variant in 36 % (n = 10), and mixed variants in 7% (n = 2) of tumors. Anatomical distributions included: head and neck (20 %), thorax and axilla (24 %), retroperitoneal (13 %), abdominopelvic (30 %) regions, and other (13 %). Complete surgical resection was performed in 95 % of patients with UCD. Surgical biopsy and medical therapy were provided to all patients with MCD. The recurrence rate for UCD and MCD was 6 % (n = 1) and 14 % (n = 1), respectively. The five-year disease-free survival rate for UCD was 95 % (n = 19) and MCD was 33 % (n = 2). We found 100 % survival in patients with UCD and histology demonstrating the HV variant.

Conclusion

CD is rare and often misdiagnosed due to the absence of specific clinical symptoms. Surgeons should include CD in their differential diagnoses when evaluating patients with lymph node hyperplasia. Surgery can be curative in nearly all patients with UCD. Patients with MCD require a combination of surgical therapy, chemotherapy, and immunotherapy; however, cytoreductive surgery benefits for patients with MCD have not been established.

Pulmonary Manifestations of Plasma Cell Type Idiopathic Multicentric Castleman Disease: A Clinicopathological Study in Comparison with IgG4-Related Disease

Plasma cell type idiopathic multicentric Castleman disease (PC-iMCD) occasionally manifests as parenchymal lung disease. This study aimed to elucidate the detailed clinicopathological features of lung lesions in PC-iMCD and compare the findings with those in immunoglobulin (Ig) G4-related disease (IgG4-RD), the most difficult differential diagnosis of PC-iMCD. We analyzed the clinicopathological findings and immunohistochemical expression patterns of interleukin-6 (IL-6) and Igs in lung specimens from 16 patients with PC-iMCD and 7 patients with IgG4-RD. Histologically, pulmonary PC-iMCD could not be differentiated from IgG4-RD based on lesion distribution patterns, the number of lymphoid follicles and obliterative vasculitis, or fibrosis types. The eosinophil count was higher in the IgG4-RD group than in the PC-iMCD group (p = 0.004). The IgG4/IgG-positive cell ratio was significantly higher in the IgG4-RD group (p < 0.001). The IgA-positive cell count and IL-6 expression intensity were higher in the PC-iMCD group than in the IgG4-RD group (p < 0.001). Based on these findings, we proposed a new diagnostic approach to differentiate lung lesions of PC-iMCD and IgG4-RD. Our approach can be utilized to stratify patients with suspected lung-dominant PC-iMCD to identify candidates for strong immunosuppressive treatment, including IL-6 blockade, at an early stage.

Insufficient evidence exists to use histopathologic subtype to guide treatment of idiopathic multicentric Castleman disease

Idiopathic multicentric Castleman disease (iMCD) is a rare immunologic disorder characterized by systemic inflammation, multicentric lymphadenopathy, and organ dysfunction. Enlarged lymph nodes demonstrate a spectrum of characteristic but variable histopathologic features historically categorized into hyaline vascular (HV) (or hypervascular [HyperV] more recently), plasmacytic, or "mixed." Though the etiology is unknown, a pro-inflammatory cytokine storm, often involving interleukin-6 (IL-6), contributes to pathogenesis. Anti-IL-6 therapy with siltuximab is the only FDA- or EMA-approved treatment based on efficacy and safety in multiple studies. Importantly, no patients considered to have HV histopathology achieved the primary endpoint in the Phase II study. NCCN currently recommends siltuximab first-line for iMCD, except for patients considered to have HV histopathology. We investigated whether histopathologic subtype should guide siltuximab treatment decisions. Secondary analyses of clinical trial and real-world data revealed similar clinical benefit across histopathologic subtypes. Notably, only 18 of 79 patients in the Phase II study were consistently classified into histopathologic subtype by three independent review panels, demonstrating limited reliability to guide treatment decisions. Real-world data further demonstrate siltuximab's effectiveness in patients considered to have HV (or HyperV). Though histopathology is a critical component for diagnosis, there is insufficient evidence to guide treatment based solely on lymph node histopathologic subtype.

Retroperitoneal castleman disease mimicking lymph node spread from clear renal cell carcinoma. A case report

Renal Cell Carcinoma (RCC) corresponds to 3% of the neoplasms in the adults. Surgery is the main mode of treatment, which can be associated toretroperitoneal lymphadenectomy in the presence of clinically tumor positive lymph nodes. Castleman Disease (CD) is a rare lymphoproliferative disorder, with little-known etiopathogenesis. It rarely affects the retroperitoneum. Thorax, neck, and abdomen are more frequently affected. Therefore, CD can simulate lymphatic spread from RCC to the retroperitoneum, also leading to a possible misdiagnosis, or diagnosis concerning a paraneoplastic syndrome due to RCC.

FDG PET/CT Findings of Castleman Disease Assessed by Histologic Subtypes and Compared with Laboratory Findings

Castleman disease (CD) is a relatively rare lymphoproliferative disorder and the pathophysiology of the subtypes are incompletely understood. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) demonstrates the metabolic activity of inflammatory and tumorous conditions. The FDG uptake intensity and sites of involved lesions on FDG PET/CT were assessed by histologic subtypes, and compared to the patient's hemoglobin, platelet, albumin, and high-sensitivity C-reactive protein (hs-CRP) levels. In total, 60 PET/CT images of 44 consecutive CD patients were included: 4 (9%) unicentric and 40 (91%) multicentric; 21 (48%) hyaline vascular subtype, 16 (36%) plasma cell, and 7 (16%) mixed or unclassified. The maximum standardized uptake value (SUVmax) and tumor-to-liver (T/L) ratio of involved lymph nodes (LNs) were 5.3 ± 2.4 (range, 1.6-11.5) and 2.8 ± 1.6 (range, 1.1-9.6), respectively, with no significant difference between the histologic subtypes. Higher number of involved LN stations and presence of extra-nodal involvement on FDG PET/CT were associated with thrombocytopenia, hypoalbuminemia, and elevated hs-CRP levels (p values < 0.05). FDG-avidity was not different by histologic subtypes and did not correlate with laboratory findings. However, the extent of nodal and extra-nodal involvement as noted on FDG PET/CT was significantly associated with abnormal laboratory findings in patients with CD.

Analysis of Clinical Characteristics, Pathological Changes and Changes of Interleukin-6 (IL-6) and C-Reactive Protein (CRP) in Children with Castleman's Disease

Background

The aim of this study was to analyze the pathological changes, clinical characteristics and changes in immunity, interleukin-6 (IL-6) and C-reactive protein (CRP) in children with Castleman’s disease (CD).

Material/Methods

A total of 15 CD child patients were enrolled as observation group, while 20 normal children receiving healthy examination were enrolled as healthy control group. The pathological changes, clinical characteristics and changes in immunity and serum IL-6 and CRP expressions were retrospectively analyzed in observation group.

Results

The clinical manifestation of unicentric CD (UCD) was mainly enlargement of cervical lymph nodes without liver-spleen enlargement and fever, and the major pathological type was the hyaline-vascular type. Multicentric CD (MCD) child patients all had anemia, fever and other systemic symptoms, and the major pathological type was the plasma-cell type. There were expressions of the immune indexes, including cluster of differentiation 3 (CD3), CD4, CD8, CD20, and CD79, in a certain degree, while CD138 and VS38C expressions displayed the polyclonal proliferation of plasma cells, rather than neoplastic proliferation. The Epstein-Barr virus and human herpes virus-8 detection results were negative, and CD21 in follicular dendritic cells in abnormal germinal center was positive. The expression levels of serum IL-6 and CRP in observation group were higher than those in control group (P<0.05).

Conclusions

There are immune dysfunction and increased expressions of serum IL-6 and CRP in child patients with CD, so it can be speculated that the immune abnormality and overexpression of serum inflammatory factors may be associated with the occurrence of CD.

A lymphoproliferative pericardial mass

Castleman disease (CD) is a rare lymphoproliferative disorder with variable presentation and prognosis. Most CD cases are unicentric and correspond to the hyaline-vascular variant, a histopathological classification associated with better outcomes, which commonly presents as an enhancing hypervascular mediastinal mass. CD is often asymptomatic and surgically resectable. Nonetheless, surgical resection can be difficult when the lymphoid mass is causing compression of vital structures. We discuss a rare case of hyaline-vascular unicentric CD presenting as an incidental pericardial mass.

[Idiopathic multicentric Castleman's disease]

Idiopathic multicentric Castlemans disease is a rare lymphoproliferative disorder that has many similar laboratory, radiological, clinical and pathological manifestations with various conditions, including IgG4-related disease. Increased activity of cytokines, especially interleukin-6, leads to systemic inflammatory symptoms with the development of lymphadenopathy and rarely extranodal lesions. Histological changes in the lymph nodesin hyaline vascular and plasma cell variants of Castlemans disease are hardly distinguishable from the pattern of reactive, tumor and IgG4-related lymphadenopathy. Idiopathic multicentric Castlemans disease can be diagnosed only when infection with human herpesvirus-8 type and human immunodeficiency virus is excluded. In the article, the authors describe two cases of idiopathic multicentric Castlemans disease, including the first world literature description of extranodal damage of the hip muscle in this disorder. In addition, the authors gave a review of the literature on the main clinical, laboratory and morphological manifestations, which allow confirming the diagnosis of Castlemans disease.

Histologic and Laboratory Characteristics of Symptomatic and Asymptomatic Castleman Disease in the Pediatric Population

OBJECTIVES

Compare the morphologic, laboratory, and clinical features of asymptomatic and symptomatic Castleman disease in the pediatric population.

METHODS

We reviewed clinical records and histopathology of patients with Castleman disease from 2 pediatric institutions.

RESULTS

Of 39 patients with pediatric Castleman disease, 37 had unicentric disease, all classified with the hyaline vascular variant of Castleman disease, 8 of which were clinically symptomatic. These 8 patients demonstrated abnormal laboratory findings, including microcytic anemia, elevated erythrocyte sedimentation rate and C-reactive protein, and hypoalbuminemia. In addition, histopathologic evaluation showed that the 8 symptomatic cases had more hyperplastic germinal centers, fewer atrophic or regressed germinal centers, fewer mantle zones containing multiple germinal centers, reduced "onion skinning" of mantle zones, and fewer "lollipop" formations compared with the asymptomatic cases.

CONCLUSIONS

This series of pediatric Castleman disease showed that lymph nodes from asymptomatic patients generally demonstrated the more classic hyaline vascular histology, whereas those with symptoms could lack or have only focal classic findings. As such, reactive lymph nodes with subtle Castleman-like features should prompt clinical correlation to ensure proper diagnosis.