Castleman Disease Pathogenesis

Immunology and targeted therapy in Castleman disease

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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

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

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.

Lymphadenopathy in the rheumatology practice: a pragmatic approach

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

Urologic Presentation of Unicentric Pediatric Castleman Disease in the Setting of Acute Renal Colic

An 11-year-old otherwise healthy female presented with renal colic and during computed tomography imaging evaluation, she was found to have a right distal ureteral stone with associated hydroureteronephrosis, medially deviated ureter, and 4-cm solid retroperitoneal mass. The mass was palpable on physical exam and was further categorized with magnetic resonance imaging, ultrasound, and laboratory testing. A multidisciplinary team approach, including pediatric surgery, radiology, oncology, and urology, led to the patient undergoing a right retrograde pyelogram, ureteroscopy with stent placement, and laparoscopic excision of retroperitoneal mass. Her pathology revealed lymphoid hyperplasia with histologic features of Castleman disease.

Castleman disease patients report mild COVID-19 symptoms and mount a humoral response to SARS-CoV-2 vaccination

The coronavirus disease of 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has resulted in increased morbidity and mortality in patients with impaired immunity, hematologic malignancies, and immunosuppressive regimens. COVID-19 can cause a cytokine storm with some patients benefiting from blockade of the pro-inflammatory cytokine, interleukin 6 (IL6). As Castleman disease (CD) is an atypical lymphoproliferative disorder that can involve a cytokine storm and often requires immunosuppressive therapies, including IL6 inhibition, we sought to evaluate outcomes following COVID-19 and SARS-CoV-2 vaccination in CD patients. We administered a survey in April 2021 to characterize experiences with COVID-19 and SARS-CoV-2 vaccination among 300 CD patients enrolled in ACCELERATE, a natural history registry of CD patients. Among 128 respondents, the prevalence of SARS-CoV-2 infection (16/95, 17%), severe disease (1/16, 6%), vaccination rates (112/128, 88%), and vaccine adverse effects after dose one (62/112, 55%) were comparable to the general U.S. population. While there were two cases of CD flares occurring shortly after SARS-CoV-2 infection (N=1) and vaccination (N=1), over 100 patients in this study that were infected and/or vaccinated did not experience CD flares. The median anti-spike titer six months after the second dose among CD patients was comparable to individuals with other immune-related diseases and healthy populations. Data from this small cohort suggest that, despite being on immunosuppressive therapies, CD patients do not appear to be at increased risk of poor COVID-19 outcomes and can mount a humoral response to SARS-CoV-2 vaccination. This study was registered on clinicaltrials.gov (#NCT02817997).

A novel cryopreservation and biobanking strategy to study lymphoid tissue stromal cells in human disease

Nonhematopoietic lymph node stromal cells (LNSCs) regulate lymphocyte trafficking, survival, and function for key roles in host defense, autoimmunity, alloimmunity, and lymphoproliferative disorders. However, the study of LNSCs in human diseases is complicated by a dependence on viable lymphoid tissues, which are most often excised prior to establishment of a specific diagnosis. Here, we demonstrate that cryopreservation can be used to bank lymphoid tissue for the study of LNSCs in human disease. Using human tonsils and lymph nodes (LN), lymphoid tissue fragments were cryopreserved for subsequent enzymatic digestion and recovery of viable nonhematopoietic cells. Flow cytometry and single-cell transcriptomics identified comparable proportions of LN stromal cell types in fresh and cryopreserved tissue. Moreover, cryopreservation had little effect on transcriptional profiles, which showed significant overlap between tonsils and LN. The presence and spatial distribution of transcriptionally defined cell types were confirmed by in situ analyses. Our broadly applicable approach promises to greatly enable research into the roles of LNSCs in human disease.

Imaging of Castleman Disease

Castleman disease (CD) is a group of rare and complex lymphoproliferative disorders that can manifest in two general forms: unicentric CD (UCD) and multicentric CD (MCD). These two forms differ in clinical manifestation, imaging appearances, treatment options, and prognosis. UCD typically manifests as a solitary enlarging mass that is discovered incidentally or after development of compression-type symptoms. MCD usually manifests acutely with systemic symptoms including fever and weight loss. As a whole, CD involves lymph nodes throughout the chest, neck, abdomen, pelvis, and axilla and can have a wide variety of imaging appearances. Most commonly, lymph nodes or masses in UCD occur in the chest, classically with well-defined borders, hyperenhancement, and possible characteristic patterns of calcification and/or feeding vessels. Lymph nodes affected by MCD, while also hyperenhancing, tend to involve multiple nodal chains and manifest alongside anasarca or hepatosplenomegaly. The polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes (POEMS) subtype of MCD may demonstrate lytic or sclerotic osseous lesions in addition to features typical of MCD. Since a diagnosis of CD based solely on imaging findings is often not possible, pathologic confirmation with core needle biopsy and/or surgical excision is necessary. Nevertheless, imaging plays a crucial role in supporting the diagnosis of CD, guiding appropriate regions for biopsy, and excluding other potential causes or mimics of disease. CT is frequently the initial imaging technique used in evaluating potential CD. MRI and PET play important roles in thoroughly evaluating the disease and determining its extent, especially the MCD form. Complete surgical excision is typically curative for UCD. MCD usually requires systemic therapy. ^©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

T-Cells Subsets in Castleman Disease: Analysis of 28 Cases Including Unicentric, Multicentric and HHV8-Related Clinical Forms

Castleman disease (CD) is a rare lymphoproliferative disorder that includes various clinico-pathological subtypes. According to clinical course, CD is divided into unicentric CD (UCD) and multicentric CD (MCD). MCD is further distinguished based on the etiological driver in herpes virus-8-related MCD (that can occur in the setting of HIV); in MCD associated with POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes); and idiopathic MCD (iMCD). The latter can also be divided in iMCD-TAFRO (thrombocytopenia, anasarca, fever, myelofibrosis, organomegaly) and iMCD not otherwise specified. To date, CD pathogenesis is still uncertain, but CD may represent the histological and clinical result of heterogeneous pathomechanisms. Transcriptome investigations in CD lymph nodes have documented the expression and up-regulation of different cytokines; furthermore, few recent studies have shown alterations of different T-cell subsets in CD patients, suggesting a possible role of the nodal microenvironment in CD development. On this basis, our study aimed to investigate the distribution of T-cell subsets in the clinico-pathological spectrum of CD. We evaluated the CD4/CD8 ratio and the number of T-regulatory (T-reg) FOXP3+ cells in 28 CD cases. In total, 32% of cases showed a decreased CD4/CD8 ratio due to increased CD8+ T-cells, including both UCD, iMCD, and HHV8+ MCD cases. The T-reg subset analysis revealed a statistically significant (p < 0.0001) lower mean number of FOXP3+ T-reg cells in CD cases when compared with non-specific reactive lymph nodes. We did not find statistically significant differences in T-reg numbers between the different CD subtypes. These findings may suggest that alterations in T-cell subpopulations that can lead to disruption of immune system control may contribute to the numerous changes in different cellular compartments that characterize CD.

Unicentric form of Castleman´s disease, pitfalls of diagnosis and surgical treatment

Background

Castleman´s disease is an extremely rare heterogenous lymphoproliferative pathology with a mostly benign behavior. It is a localized or generalized lymph node enlargement of an unknown aetiology. Unicentric form is typically a slow-growing solitary mass occurring mostly in the mediastinum, abdominal cavity, retroperitoneum, pelvis and neck. Aetiology and pathogenesis of CD is probably diverse, varying in different types of this heterogeneous disease.

Materials and Methods

Authors present a review of this issue based on their extensive experience. The aim is to summarize the crucial factors in the management of diagnostics and a surgical treatment of the unicentric form of Castleman´s disease. One of the key issues in the unicentric form is precise preoperative diagnostics and thus choosing the right surgical treatment strategy. Authors highlight pitfalls of the diagnosis and surgical treatment.

Results

All histological types such as a hyaline vascular type, plasmacytic type and a mixed type are presented as well as options of surgical and conservative treatment. Differential diagnosis and malignant potential is discussed.

Conclusion

Patients with Castleman´s disease should be treated in the high- volume centers, with a great experience in major surgical procedures as well as with preoperative imaging diagnostic techniques. Specialized pathologists and oncologists focusing on this issue are also absolutely necessary to avoid misdiagnosis. Only this complex approach can lead to excellent outcomes in patients with UCD.

A novel cryopreservation and biobanking strategy to study lymphoid tissue stromal cells in human disease

Non-hematopoietic lymph node stromal cells (LNSCs) regulate lymphocyte trafficking, survival, and function for key roles in host defense, autoimmunity, alloimmunity, and lymphoproliferative disorders. However, study of LNSCs in human diseases is complicated by a dependence on viable lymphoid tissues, which are most often excised prior to establishment of a specific diagnosis. Here, we demonstrate that cryopreservation can be used to bank lymphoid tissue for the study of LNSCs in human disease. Using human tonsils, lymphoid tissue fragments were cryopreserved for subsequent enzymatic digestion and recovery of viable non-hematopoietic cells. Flow cytometry and single-cell transcriptomics identified comparable proportions of LNSC cell types in fresh and cryopreserved tissue. Moreover, cryopreservation had little effect on transcriptional profiles, which showed significant overlap between tonsils and lymph nodes. The presence and spatial distribution of transcriptionally defined cell types was confirmed by in situ analyses. Our broadly applicable approach promises to greatly enable research into the roles of LNSC in human disease.

Novel Molecular Therapies and Genetic Landscape in Selected Rare Diseases with Hematologic Manifestations: A Review of the Literature

Rare diseases affect less than 1 in 2000 people and are characterized by a serious, chronic, and progressive course. Among the described diseases, a mutation in a single gene caused mastocytosis, thrombotic thrombocytopenic purpura, Gaucher disease, and paroxysmal nocturnal hemoglobinuria (KIT, ADAMTS13, GBA1, and PIG-A genes, respectively). In Castleman disease, improper ETS1, PTPN6, TGFBR2, DNMT3A, and PDGFRB genes cause the appearance of symptoms. In histiocytosis, several mutation variants are described: BRAF, MAP2K1, MAP3K1, ARAF, ERBB3, NRAS, KRAS, PICK1, PIK3R2, and PIK3CA. Genes like HPLH1, PRF1, UNC13D, STX11, STXBP2, SH2D1A, BIRC4, ITK, CD27, MAGT1, LYST, AP3B1, and RAB27A are possible reasons for hemophagocytic lymphohistiocytosis. Among novel molecular medicines, tyrosine kinase inhibitors, mTOR inhibitors, BRAF inhibitors, interleukin 1 or 6 receptor antagonists, monoclonal antibodies, and JAK inhibitors are examples of drugs expanding therapeutic possibilities. An explanation of the molecular basis of rare diseases might lead to a better understanding of the pathogenesis and prognosis of the disease and may allow for the development of new molecularly targeted therapies.

Case report: Multicentric Castleman disease as a manifestation of immune reconstitution inflammatory syndrome in Malawi

Introduction

Multicentric Castleman disease (MCD) is a lymphoproliferative disorder characterized by systemic inflammation, lymphadenopathy, and cytopenias. MCD caused by Kaposi sarcoma herpesvirus (MCD-KSHV) frequently arises in the context of HIV. It can be associated with immune reconstitution inflammatory syndrome (IRIS), but MCD-IRIS is rarely reported in sub-Saharan Africa (SSA) where HIV and KSHV infection are common.

Case description

A 36-year-old woman in Malawi with HIV on antiretroviral therapy (ART) for nine years presented with fatigue, weight loss, and lymphadenopathy. Lymph node biopsy was consistent with HIV lymphadenitis without evident KSHV-MCD and HIV RNA was 4,244 copies/mL. She switched to second-line ART and returned four months later with worsening lymphadenopathy, fever, night sweats, weight loss, and anemia. A repeat lymph node biopsy demonstrated unequivocal KSHV-MCD features not present on the original biopsy. Her repeat HIV viral load was undetectable and she received chemotherapy with subsequent remission on continued ART for 24 months.

Discussion

This is among the first reported cases of MCD-IRIS from SSA, which has implications for a region where HIV and KSHV are highly prevalent. MCD-IRIS may contribute to early mortality after ART initiation in SSA, and increased awareness alongside improved diagnostic and treatment capacity are needed.

Successful treatment with daratumumab, lenalidomide, and dexamethasone therapy followed by autologous stem cell transplantation for newly diagnosed polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome: a case report

Background

Transplant-eligible patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome are treated with induction therapy and autologous stem cell transplantation. Conventional induction therapies may exacerbate neuropathy and a high rate of disease progression within 5 years. Furthermore, only 50% of patients are able to walk independently after the therapies. Daratumumab, lenalidomide, and dexamethasone therapy has been reported as a less neurotoxic, highly effective therapy for patients with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome who are ineligible for transplant or whose syndrome is relapsed/refractory, but no reports have provided data from untreated transplant-eligible patients.

Case presentation

A 34-year-old Japanese woman displayed weakness, pain and edema in the lower limbs, decreased grip strength, amenorrhea, and abdominal distention. She was unable to walk independently. The patient was diagnosed with polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome and performed four courses of daratumumab, lenalidomide, and dexamethasone therapy, which enabled her to walk independently and did not exacerbate the neuropathy. Hematopoietic stem cells were collected using plerixafor and filgrastim in combination. Autologous stem cell transplantation was performed with high-dose melphalan. At 3-month post-transplantation follow-up, most of her clinical symptoms had disappeared.

Conclusions

Daratumumab, lenalidomide, and dexamethasone therapy followed by autologous stem cell transplantation may be more effective than conventional therapy for newly diagnosed polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes syndrome. Although there was concerns that daratumumab, lenalidomide, and dexamethasone therapy might lead to poor mobilization of hematopoietic stem cells, this was overcome with the combination of plerixafor and filgrastim. The benefit of daratumumab, lenalidomide, and dexamethasone as induction therapy prior to autologous stem cell transplantation should be confirmed in future clinical trials.

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.

Comprehensive analysis of 65 patients with Castleman disease in a single center in China

This study aimed to investigate the epidemiologic, clinical, pathological characteristics, and treatment of patients with Castleman disease (CD) in a single center in China. We retrospectively analyzed the data of 65 Chinese CD patients, divided into unicentric CD (UCD) and multicentric CD (MCD) groups, and also microscopic subtypes as hypervascular (HV), plasmacytic (PC) and Mixed. Based on whether HHV-8 infection existed, MCD was subdivided into HHV-8-associated MCD and idiopathic Castleman disease (iMCD). Detailed epidemiologic, clinicopathological, and treatment data were analyzed and discussed. Of total 65 patients (UCD 33, MCD 32), HV (81.8%) accounted for the most of UCD and total. More females in UCD (60.6%) and more males in MCD (65.6%) were observed. CD occurred in all age groups, most commonly in 40-49 years. The mean age of onset of total was 38.5 years with PC higher than HV (45.5 vs. 35.1 years, P = 0.0413). The median diagnosis delay of MCD was longer than that of UCD (3.00 vs. 1.25 months, P = 0.0436). Abdomen (39.4%) and neck (30.3%) were the most-seen locations of lymphadenopathy in UCD, with neck (65.6%) being predominant in MCD. Mean major diameter of specimens of UCD was greater than MCD (6.4 vs. 3.1 cm, P < 0.0001). These results provided the featured and detailed profile of Castleman disease in Henan province in China with a considerable number of cases, which presented distinct evidence with other studies.

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.

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.

Spaceflight Virology: What Do We Know about Viral Threats in the Spaceflight Environment?

Viruses constitute a significant part of the human microbiome, so wherever humans go, viruses are brought with them, even on space missions. In this mini review, we focus on the International Space Station (ISS) as the only current human habitat in space that has a diverse range of viral genera that infect microorganisms from bacteria to eukaryotes. Thus, we have reviewed the literature on the physical conditions of space habitats that have an impact on both virus transmissibility and interaction with their host, which include UV radiation, ionizing radiation, humidity, and microgravity. Also, we briefly comment on the practices used on space missions that reduce virus spread, that is, use of antimicrobial surfaces, spacecraft sterilization practices, and air filtration. Finally, we turn our attention to the health threats that viruses pose to space travel. Overall, even though efforts are taken to ensure safe conditions during human space travel, for example, preflight quarantines of astronauts, we reflect on the potential risks humans might be exposed to and how those risks might be aggravated in extraterrestrial habitats.

Human herpesvirus 8-associated multicentric Castleman disease in a patient with advanced HIV infection: A case report

RATIONAL

Multicentric Castleman disease (MCD) is a nonclonal lymphoproliferative disorder that is rarely reported from Southeast Asian countries. Here, we report a case of human herpesvirus 8 (HHV-8)-associated MCD in a patient with advanced human immunodeficiency virus (HIV) infection who presented with prolonged intermittent fever, urticarial rash, hepatosplenomegaly, and generalized lymphadenopathy.

PATIENT CONCERNS

A 34-year-old man with advanced HIV infection who was in good compliance with his antiretroviral treatment regimen presented with intermittent fever, weight loss, marked hepatosplenomegaly, and generalized lymphadenopathy. Recurrent symptoms of high-grade fever, abdominal discomfort, pancytopenia, and high C-reactive protein level occurred for 16 months.

DIAGNOSES

Histopathological findings of left inguinal lymph node revealed diffuse effacement of lymph node architecture with coexpression of HHV-8 latency-associated nuclear antigen 1 from immunohistochemical staining. The HHV-8 viral load was 335,391 copies/mL.

INTERVENTIONS

The patient was treated initially with one dose of intravenous rituximab (375 mg/m2) followed by subcutaneous rituximab (1400 mg) weekly for 5 weeks.

OUTCOMES

The patient's recurrent systemic symptoms subsided dramatically, and he has now been in remission for almost two years.

LESSONS

HHV8-associated MCD remains a diagnostic challenge in advanced HIV disease and should be suspected in those with recurrent flares of systemic inflammatory symptoms. Lymph node histopathology is essential for diagnosis and for excluding clonal malignancy. HHV-8 viral load is also useful for diagnosis and for monitoring disease activity.

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 Presenting as a Mediastinal Mass

Castleman disease is a complex benign lymphoproliferative disorder characterized by the enlargement of a single lymph node or a group of lymph nodes. Its etiology is unclear, with the mechanism of action of IL-6 and HHV-8 implicated as possibly associated with the development of the disease. Diagnosis depends on the histopathological findings of the involved lymph nodes. Surgical resection can be curative, but a small number of cases may be unresectable and need radiation and chemotherapy with subsequent resection if possible.

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.

Concurrent HIV viral blips during two episodes of multicentric Castleman disease in an adult on antiretroviral therapy: Implication for HIV persistence

Human herpesvirus-8 (HHV8)-associated multicentric Castleman disease (HHV8-MCD) is a rare nonmalignant lymphoproliferative disorder most commonly observed in PLWH. Herein, we describe an HIV-infected adult male from Cameroon with relapsing HHV8-MCD (HIV+MCD). The patient developed constitutional symptoms, diffuse lymphadenopathy, thrombocytopenia and autoimmune hemolytic anemia. Excisional lymph node biopsy findings were consistent with HHV8-MCD. He was successfully treated with corticosteroids and rituximab. One year later, he developed relapsing disease and was successfully treated again with rituximab. Interestingly, HIV viral load blips correlate with MCD flares, suggesting that low-level viremia is linked with T-cell clonal expansion and/or inflammation, rather than a lack of effective antiretroviral therapy. Rituximab either alone or in combination with chemotherapy for aggressive disease is the standard of care, with approximately 95% of treated patients achieving complete remission. Despite highly effective therapy, HIV+MCD often presents with a relapsing and remitting disease course and carries an increased risk for the development of HHV8-associated lymphoma.

A case of Castleman disease with hemophagocytic syndrome derived from HHV8 infection

Background

For a patient presenting with fever, multiple lymphadenopathy and splenomegaly, pathogen infection should be preferentially considered, followed by lymphoid malignancies. When traditional laboratory and pathological detection cannot find the pathogenic microorganism, metagenomic sequencing (MGS) which targets the person’s genome for exceptional genetic disorders may detect a rare pathogen.

Case presentation

Here, we introduced the diagnostic clue of a case of multicentric Castleman disease (MCD) with hemophagocytic syndrome which was elicited from the detection of human herpesvirus-8 in the blood of a HIV-1 infected person by MGS technology during pathogen inspection. This case highlights the need to increase the awareness of MCD among clinicians and pathologists.

Conclusions

MGS technology may play a pivotal role in providing diagnostic clues during pathogen inspection, especially when pathogens are not detectable by conventional methods.

Bilateral lung transplantation for Castleman disease with end-stage bronchiolitis obliterans

Bronchiolitis obliterans (BO) is a severe complication of Castleman disease (CD), a rare lymphoproliferative disease with unclear pathogenesis. Currently, there are no reports on the safety or outcomes of bilateral lung transplantation in patients with BO due to CD. This study aimed to characterize the clinical manifestations and features of BO and CD. We retrospectively analyzed the medical records of six consecutive patients with BO and CD who underwent bilateral lung transplantation between December 2012 and December 2020. The average age of patients at lung transplantation was 33 ± 15 years, and the age range of patients at diagnosis of CD was about 9-56 years. The body mass index was 15.2 ± 1.9 kg/m² . The average time from diagnosis to lung transplantation was 4.1 ± 2.7 years. All the patients had unicentric CD (UCD); five had concomitant paraneoplastic pemphigus, and four received extracorporeal membrane oxygenation during surgery. The average hospital stay was 51 ± 53 days. Infection was the most common postoperative complication. CD did not recur in any of the patients. Thus, bilateral lung transplantation is a viable and safe treatment for selected patients with CD and BO, which can improve the quality of life and prolong survival.

Retrohepatic Mass: A Case of Human Herpesvirus-8 Negative Multicentric Castleman's Disease

Multicentric Castleman's disease (MCD) is a rare lymphoproliferative disorder with aggressive systemic presentation and poor prognosis. Here, we present a case of MCD in a 37-year-old Asian American woman with a past medical history of the polycystic ovarian syndrome (PCOS), human papilloma virus (HPV), herpes simplex virus-1 (HSV-1), iron deficiency, and vitamin B₁₂ deficiency-related anemia. The patient underwent surgical resection with good recovery. Hemoglobin and erythrocyte sedimentation rate (ESR) normalized after surgical resection. Although the influence of risk factors such as human immunodeficiency virus (HIV) or human herpesvirus-8 (HHV-8) infections on MCD relapse are not well understood, patient education on MCD risk factors is important, as they may place the patient at greater risk for recurrence. MCD should be considered in patients with chronic inflammation and a mass on imaging.

Novel somatic alterations in unicentric and idiopathic multicentric Castleman disease

OBJECTIVES

Castleman disease (CD) is a heterogeneous group of disorders involving systemic inflammation and lymphoproliferation. Recently, clonal mutations have been identified in unicentric CD (UCD) and idiopathic multicentric CD (iMCD), suggesting a potential underlying neoplastic process.

METHODS

Patients with UCD or iMCD with next generation sequencing (NGS) data on tissue DNA and/or circulating tumor DNA (ctDNA) were included.

RESULTS

Five patients were included, 4 with iMCD and 1 with UCD. Four patients (80%) were women; median age was 40 years. Three of five patients (60%) had ≥1 clonal mutation detected on biopsy among the genes included in the panel. One patient with iMCD had a 14q32-1p35 rearrangement and a der(1)dup(1)(q42q21)del(1)(q42) (1q21 being IL-6R locus) on karyotype. This patient also had a NF1 K2459fs alteration on ctDNA (0.3%). Another patient with iMCD had a KDM5C Q836* mutation, and one patient with UCD had a TNS3-ALK fusion but no ALK expression by immunohistochemistry.

CONCLUSIONS

We report 4 novel somatic alterations found in patients with UCD or iMCD. The 1q21 locus contains IL-6R, and duplication of this locus may increase IL-6 expression. These findings suggest that a clonal process may be responsible for the inflammatory phenotype in some patients with UCD and iMCD.

Utility and Safety of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration in the Diagnosis of Isolated Mediastinal Masses

Background

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a valuable tool for diagnosing pulmonary disease due to its efficiency and safety. We retrospectively analyzed patients with mediastinal masses who underwent diagnostic EBUS-TBNA at Shanghai Chest Hospital, and evaluated the clinical accuracy of EBUS-TBNA in the diagnosis mediastinal masses.

Method

From 2009 and 2014, patients who received EBUS-TBNA to diagnose a isolated mediastinal mass were enrolled. Clinical follow-up was performed to ascertain the patient’s final diagnosis.

Results

Forty-six patients were enrolled in this study. Thirty-seven were diagnosed with an oncologic disease, 3 were diagnosed with a mediastinal infection, and 2 were found to have a mediastinal goiter. The overall sensitivity, specificity, positive predictive value, negative predictive value, diagnostic yield was 63.6%, 100%, 100%, 42.9%, and 71.4%, respectively.

Conclusion

EBUS-TBNA is a safe and effective means of diagnosing mediastinal masses.

Idiopathic multicentric Castleman disease presenting progressive reticular honeycomb infiltration of lung and immunoglobulin G and immunoglobulin G4 dominant hypergammaglobulinemia

Multicentric Castleman disease (MCD) is an uncommon systemic lymphoproliferative disorder that may cause multiple organ damage. Castleman disease-associated diffuse parenchymal lung disease (DPLD) has not been well studied. A 32-year-old man was referred to our hospital for progressive generalized weakness, light-headedness, and dyspnea on exertion for more than one year. Laboratory evaluations showed profound anemia, an elevated erythrocyte sedimentation rate, and an increased C-reactive protein level with polyclonal hypergammaglobulinemia. Chest radiography, computed tomography (CT), and positron emission tomography-CT scan demonstrated diffuse lung infiltration with multiple cystic lesions and multiple lymphadenopathy. In addition to these clinical laboratory findings, bone marrow, lung, and lymph node biopsies confirmed the diagnosis of idiopathic MCD (iMCD). Siltuximab, an interleukin-6 inhibitor, and glucocorticoid therapy were initiated. The patient has been tolerating the treatment well and had no disease progression or any complications in 4 years. Herein, we report this case of human herpesvirus-8-negative iMCD-associated DPLD accompanied by multiple cystic lesions, multiple lymphadenopathy, and polyclonal hypergammaglobulinemia with elevated immunoglobulin G (IgG) and IgG4 levels. We recommend a close evaluation of MCD in cases of DPLD with hypergammaglobulinemia.

Lung cancer combined with diffuse peritoneal and mesenteric amyloidosis detected on 18F-FDG PET/CT: A case report

RATIONALE

Amyloidosis is a heterogeneous group of diseases characterized by extracellular deposition of amyloid fibrils. Lung carcinoma is rarely reported to be associated with AA amyloidosis. With regard to the manifestation of amyloidosis infiltrating organs, most of the cases focus on the heart, liver, kidneys, and peripheral nervous system. Amyloidosis with diffuse abdominal involvement in combination with pulmonary squamous cell carcinoma carcinoma is an exceptionally rare occurrence.

PATIENT CONCERNS

A 70-year-old man was admitted to hospital for a 2-month history of repeated cough, low grade fever, hemoptysis and left back shoulder pain, which was not relieved by nonsteroid anti-inflammatory drugs. Meanwhile, he complained of intermittent diffuse abdominal discomfort and chronic persistent constipation.

DIAGNOSES

The patient was diagnosed with poorly differentiated lung squamous cell carcinoma and diffuse peritoneal and mesenteric amyloidosis based on the pathological biopsy.

INTERVENTIONS

The patient received surgery and chemotherapy for lung tumor. He did not receive any treatment against amyloidosis.

OUTCOMES

The patient died of a severe respiratory infection.

LESSONS

This case indicates that lung carcinoma is suspected to play a causative role in the development of amyloidosis. In addition, amyloidosis should be considered in the differential diagnosis in cases in which diffuse greater omentum, peritoneal, and mesenteric calcifications on 18F-2-fluoro-2-deoxy-D-glucose(18F-FDG) photon emission computed tomography (PET/CT).

A Review of Genetic Abnormalities in Unicentric and Multicentric Castleman Disease

Castleman disease (CD) is a rare lymphoproliferative disorder known to represent at least four distinct clinicopathologic subtypes. Large advancements in our clinical and histopathologic description of these diverse diseases have been made, resulting in subtyping based on number of enlarged lymph nodes (unicentric versus multicentric), according to viral infection by human herpes virus 8 (HHV-8) and human immunodeficiency virus (HIV), and with relation to clonal plasma cells (POEMS). In recent years, significant molecular and genetic abnormalities associated with CD have been described. However, we continue to lack a foundational understanding of the biological mechanisms driving this disease process. Here, we review all cases of CD with molecular abnormalities described in the literature to date, and correlate cytogenetic, molecular, and genetic abnormalities with disease subtypes and phenotypes. Our review notes complex karyotypes in subsets of cases, specific mutations in PDGFRB N666S in 10% of unicentric CD (UCD) and NCOA4 L261F in 23% of idiopathic multicentric CD (iMCD) cases. Genes affecting chromatin organization and abnormalities in methylation are seen more commonly in iMCD while abnormalities within the mitogen-activated protein kinase (MAPK) and interleukin signaling pathways are more frequent in UCD. Interestingly, there is a paucity of genetic studies evaluating HHV-8 positive multicentric CD (HHV-8+ MCD) and POEMS-associated CD. Our comprehensive review of genetic and molecular abnormalities in CD identifies subtype-specific and novel pathways which may allow for more targeted treatment options and unique biologic therapies.

An Immunocompetent HIV-Negative Elderly Patient with Low-Grade Fever, Generalized Lymphadenopathy, Splenomegaly, and Acute Phase Response: Do Not Forget Castleman Disease

Multicentric Castleman disease (MCD) is a rare lymphoproliferative disorder that mainly affects middle-aged patients with human immunodeficiency virus (HIV) infection. However, HIV-negative patients can also be affected representing a small proportion of the total MCD cases. Of note, recent studies from China in HIV-negative patients with MCD have suggested that the onset of the disease can be observed in younger age than previously thought. If undiagnosed and untreated, the MCD has a poor prognosis and may progress to lymphoma. We present an 82-year-old immunocompetent male patient who was admitted to our department because of low-grade fever, cachexia, anasarca, hepatosplenomegaly, and generalized lymphadenopathy. Laboratory findings showed anemia and increased markers of inflammation including hyperferritinemia and polyclonal hyperglobulinemia. Infectious causes including HIV were ruled out. Histological examination of a cervical lymph-node revealed lesions supportive of MCD diagnosis. Of note, the outer-zone plasmablasts' nuclei stained positive for human herpesvirus-8 (HHV8). The patient received 4 cycles of cyclophosphamide, vincristine, and dexamethasone with regression of all symptoms. This case underlines that HHV8-associated MCD should be considered as a rare cause of generalized lymphadenopathy even in HIV-negative immunocompetent patients when other causes have been appropriately excluded because a timely diagnosis can be life-saving.

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.

Clinical characteristics and immunological abnormalities of Castleman disease complicated with autoimmune diseases

Purpose

To explore the clinical features and immunological mechanisms of Castleman disease (CD) complicated with autoimmune diseases (AID).

Methods

We explored the prevalence and clinical manifestations of CD complicated with AID by reviewing clinical, pathological, and laboratory data of 40 CD patients retrospectively, and then explored abnormal immune mechanisms in the co-existence of the two entities by monitoring lymphocyte subsets in peripheral blood.

Results

Paraneoplastic pemphigus, autoimmune hemolytic anemia, Sjogren’s syndrome, myasthenia gravis, and psoriasis were found to be coexisted with CD in 9/40 (22.5%) patients with different sequence of onset. No bias in the clinical and histological type of CD was observed for the occurrence of AID. CD patients with AID were more likely to have skin and/or mucous membrane damage and pulmonary complications, and presented elevated erythrocyte sedimentation rate, hypergammaglobulinemia, and positive autoantibodies than those without AID (p < 0.05). Deregulated cellular and innate immune responses as indicated by decreased CD3⁺ T cells and increased natural killer cells were observed in peripheral blood of CD patients with AID (p < 0.05). UCD patients with AID were successfully treated with surgery and immunosuppressive therapy. MCD complicated by AID relieved with immunosuppressors, cytotoxic chemotherapy, and rituximab.

Conclusion

Systemic inflammation/immunological abnormalities and organ dysfunction were associated with the occurrence of AID in CD. Impairment of cellular and innate immunity may be a candidate etiology for the coexistence of the two entities.

ACCELERATE: A Patient-Powered Natural History Study Design Enabling Clinical and Therapeutic Discoveries in a Rare Disorder

Geographically dispersed patients, inconsistent treatment tracking, and limited infrastructure slow research for many orphan diseases. We assess the feasibility of a patient-powered study design to overcome these challenges for Castleman disease, a rare hematologic disorder. Here, we report initial results from the ACCELERATE natural history registry. ACCELERATE includes a traditional physician-reported arm and a patient-powered arm, which enables patients to directly contribute medical data and biospecimens. This study design enables successful enrollment, with the 5-year minimum enrollment goal being met in 2 years. A median of 683 clinical, laboratory, and imaging data elements are captured per patient in the patient-powered arm compared with 37 in the physician-reported arm. These data reveal subgrouping characteristics, identify off-label treatments, support treatment guidelines, and are used in 17 clinical and translational studies. This feasibility study demonstrates that the direct-to-patient design is effective for collecting natural history data and biospecimens, tracking therapies, and providing critical research infrastructure.

Overview of Castleman disease

Castleman disease (CD) describes a group of at least 4 disorders that share a spectrum of characteristic histopathological features but have a wide range of etiologies, presentations, treatments, and outcomes. CD includes unicentric CD (UCD) and multicentric CD (MCD), the latter of which is divided into idiopathic MCD (iMCD), human herpes virus-8 (HHV8)-associated MCD (HHV8-MCD), and polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes (POEMS)-associated MCD (POEMS-MCD). iMCD can be further subclassified into iMCD-thrombocytopenia, ascites, reticulin fibrosis, renal dysfunction, organomegaly (iMCD-TAFRO) or iMCD-not otherwise specified (iMCD-NOS). Advances in diagnosis, classification, pathogenesis, and therapy are substantial since the original description of UCD by Benjamin Castleman in 1954. The advent of effective retroviral therapy and use of rituximab in HHV8-MCD have improved outcomes in HHV8-MCD. Anti-interleukin-6-directed therapies are highly effective in many iMCD patients, but additional therapies are required for refractory cases. Much of the recent progress has been coordinated by the Castleman Disease Collaborative Network (CDCN), and further progress will be made by continued engagement of physicians, scientists, and patients. Progress can also be facilitated by encouraging patients to self-enroll in the CDCN's ACCELERATE natural history registry (#NCT02817997; www.CDCN.org/ACCELERATE).

Hematologic malignancies of the gastrointestinal luminal tract

Hematologic malignancies include several lymphoproliferative and myeloproliferative disorders, many of which are frequently encountered in current health care settings. These malignancies frequently affect the gastrointestinal (GI) tract, either by secondary extranodal or extramedullary extension to the GI tract, or as a primary process arising in the GI tract. In fact, the GI tract may represent the most common extranodal site of involvement in many of them, such as lymphoma. Furthermore, in the current era of improved cancer treatment and advanced transplant procedures with increased survival, it has been quite common to encounter GI involvement by these malignancies through the disease course. Post-transplant lymphoproliferative disorder following kidney transplantation, for example, very commonly involves the GI tract. Other conditions that can involve the GI tract include multiple myeloma, plasmacytoma, myeloid sarcoma, mastocytosis, and Castleman disease. Imaging diagnosis of these malignancies can be challenging, since they are much less common than primary GI cancers and both share many common imaging features as well. However, certain imaging features, particularly in combination with a matching clinical scenario, play a pivotal role in diagnosing these conditions and directing further evaluation. In this article, we review common and rare hematologic malignancies of the GI tract and discuss their pathophysiologic, clinical, and imaging features.

Updates on the diagnosis and management of multicentric Castleman disease

Multicentric Castleman disease (MCD) is an uncommon systemic lymphoproliferative disease. The diagnosis of this disease is typically challenging and requires collaboration between clinicians and pathologists. Moreover, it is important to exclude other diseases (such as malignancies, autoimmune diseases, and infectious diseases) that have similar clinical manifestations and pathological findings. Patients with untreated severe MCD have high mortality due to devastating cytokine storms. Thus, early diagnosis and prompt treatment is a key imperative. The diagnosis of MCD is based on the clinical signs of systemic inflammation, serological tests, and typical pathological features. In this review article, we provide an overview of MCD with a focus on the emerging evidence pertaining to its diagnosis and treatment.

Castleman disease. Interaction with dermatopathy: Case report

INTRODUCTION

Castleman disease (CD) is a lymphoproliferative disorder with lymph node hypertrophy. In the unicentric form (UCD), it affects one lymph node or chain of lymph nodes. In the multicentric form (DCM), there is hypertrophy of several lymph node chains with the formation of tumor masses, causing compressive symptoms. This case report showed a case of CD in a different location(inguinal region) associated to a multiple skin lesions.

PRESENTATION OF THE CASE

We reported a UCD in a 43-year-old female patient with no previous comorbidities. Since January 2016, this patient developed erysipelas lesions of the left leg (LL) from the thigh root to the foot. Concomitantly, a tumor mass appeared in the inguinal region. In 2019 we performed a biopsy that revealed changes characteristic of CD. Due to extremely poor trophic conditions, the skin area with erysipelas was resected, and the raw surface was grafted.

DISCUSSION

As an inference, the erysipelas may have been responsible for the subsequent lymphangitis, lymphedema and lymph node hypertrophy.

CONCLUSION

Resection of the diseased skin and lymph node excision constitute the treatment of UCD and result in improvement of the clinical picture. Nevertheless, further study of the inflammatory reaction and of markers such as interleukin-6 and the presence of skin disorders in DC is needed.

Unicentric Castleman's Disease: Laparoscopic Approach of a Para-Duodenal Retroperitoneal Mass

BACKGROUND Castleman's disease is a benign, lymphoproliferative disorder that is extremely uncommon. Multiple classifications have been described; however, the exact etiology remains unknown. Preoperative diagnosis is not common, as imaging cannot distinguish the disease from other processes, and biopsy is insufficient to provide the architecture of the mass, which is necessary for diagnosis. Unicentric retroperitoneal disease has been described, and management includes complete resection of the mass, which is usually curative. CASE REPORT A 34-year-old previously healthy woman presented with hematuria. Evaluation revelated a retroperitoneal mass that was abutting the duodenum and head of the pancreas. Biopsy failed to provide a diagnosis, so laparoscopic resection was performed. Postoperative diagnosis was consistent with unicentric Castleman's disease. CONCLUSIONS Castleman's disease is an uncommon process, and one that is difficult to diagnose. Unicentric Castleman's disease should always be a differential diagnosis of solitary retroperitoneal masses that are well-demarcated, as treatment can be curative with surgical resection.

Classic Hodgkin lymphoma and Castleman disease: an entity appears to be emerging

Hodgkin lymphoma is a B cell neoplasm characterized by Hodgkin and Reed-Sternberg (HRS) cells in an inflammatory background. Classic Hodgkin lymphoma (CHL) accounts for approximately 90% of all cases of HL and four types are recognized in the World Health Organization (WHO) classification: lymphocyte-rich, nodular sclerosis, mixed cellularity, and lymphocyte depleted. Castleman disease (CD) is a designation used for a heterogeneous group of diseases that involve lymph nodes. Histologically, there are hyaline vascular and plasma cell variants, the latter including human herpes virus 8 (HHV8)-positive and HHV8-negative subsets. In this study, we describe three men, 45-57 years of age, one HIV-positive, who had coexistent CHL and CD. All patients had the interfollicular variant of CHL and HHV8-negative plasma cell variant CD. Immunohistochemical analysis supported the diagnosis of CHL; the HRS cells were positive for CD15, CD30, and PAX-5 (dim). In two cases, the HRS cells and the plasma cells of CD expressed interleukin-6 (IL-6). Our review of the literature identified 34 cases of coexistent CHL and CD reported previously. In aggregate, about two-thirds of all cases of CHL have been the interfollicular variant and around 90% of CD cases were plasma cell variant, HHV8-negative in the subset of cases tested. We suggest that interfollicular variant CHL and plasma cell variant CD may be a distinct entity with a common pathogenesis, possibly related to IL-6 dysregulation. The few cases in the literature describing other forms of CHL and hyaline vascular variant CD are different from the entity reported here, with a different pathogenesis, likely similar to focal Castleman-like changes that have been described in association with various types of non-Hodgkin lymphoma.

AA amyloidosis associated with Castleman disease: A case report and review of the literature

RATIONALE

AA amyloidosis (AA) is caused by a wide variety of inflammatory states, but is infrequently associated with Castleman disease (CD). CD describes a heterogeneous group of hematologic disorders that share characteristic lymph node histopathology. CD can present with a solitary enlarged lymph node (unicentric CD, UCD) or with multicentric lymphadenopathy (MCD), constitutional symptoms, cytopenias, and multiple organ dysfunction due to an interleukin-6 driven cytokine storm.

PATIENT CONCERNS

We are reporting a case of a 26-year-old woman with no significant past medical history who presented with a 3-month history of fatigue and an unintentional 20-pound weight loss.

DIAGNOSIS

A CT-scan of the abdomen and pelvis revealed hepatosplenomegaly and a mesenteric mass. Congo Red staining from a liver biopsy showed apple-green birefringence and serum markers were suggestive of an inflammatory process. Post-excision examination of the resected mass revealed a reactive lymph node with follicular hyperplasia with kappa and lambda stains showing polyclonal plasmacytosis consistent with CD.

INTERVENTIONS

The patient underwent surgery to remove the affected lymph node.

OUTCOMES

IL-6, anemia, leukocytosis, and thrombocytosis resolved or normalized 2 weeks after resection; creatinine normalized 9 months postsurgery. Twenty two months post-surgery her IFN-γ normalized, her fatigue resolved, her proteinuria was reduced by >90% and she had returned to her baseline weight.

LESSONS

Our case and literature review suggest that patients presenting with UCD or MCD along with organ failure should prompt consideration of concurrent AA amyloidosis.

HHV-8-negative multicentric Castleman disease presenting as a crescentic immune complexes membranoproliferative glomerulonephritis

Multicentric Castleman disease is a rare polyclonal lymphoproliferative disorder mainly associated with two renal manifestations: thrombotic microangiopathy and amyloidosis. Nevertheless, we report here a case of human herpes virus-8 negative multicentric Castleman disease with membranous proliferative glomerulonephritis and extracapillary proliferation. A patient was successfully treated with corticosteroids, anti-CD20 and cyclophosphamide therapy.