Diagnosis of Castleman Disease

Immunology and targeted therapy in Castleman disease

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Successful Renal Transplant in Castleman Disease - First Case Report from India

Castleman disease (CD) comprises a rare group of heterogenous benign lymphoproliferative disorders with pathologic similarities. However, they present with diverse clinical manifestations. Renal involvement is rare in CD and is mainly reported with plasma cell type of multicentric disease. Various glomerular pathologies, interstitial involvement, or thrombotic microangiopathies have all been reported, some of which progress to end-stage renal disease (ESRD). Progression of CD to ESRD is well documented; however, a patient on dialysis developing CD is rare. Moreover, kidney transplantations have seldom been performed on patients with CD. We report a patient with ESRD of unknown etiology who developed multicentric CD while on dialysis. He was treated with four doses of rituximab and later underwent a living kidney transplant with his wife as a donor. He has been clinically well ever since. We believe that this is possibly the first successful case of renal transplantation in CD with ESRD being reported from India.

Expert consensus on the integrated diagnosis of idiopathic multicentric Castleman disease

Idiopathic multicentric Castleman disease (iMCD) is rare. The differential diagnosis includes inflammatory, autoimmune and neoplastic disease. The identification of the histopathological features of Castleman disease in the lymph node is the main diagnostic criterion. Fifty-three experts from three medical societies (SEMI, SEHH and SEAP) have created a multi-disciplinary consensus document in order to standardise the diagnosis of Castleman disease. Using the Delphi method, specific recommendations for the initial clinical, laboratory and imaging studies have been made for an integrated diagnosis of iMCD as well as for the best way to obtain samples for histopathological confirmation, correct laboratory procedure and interpretation and reporting of results.

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.

Diagnostics différentiels de la maladie de Castleman

Clinicians are sometimes confronted with the diagnostic difficulties of the idiopathic form of Castleman's Disease (iMCD). As this review reports with demonstrative clinical cases, iMCD can mimic various serious systemic pathologies such as certain autoimmune diseases, Still's disease, POEMS syndrome, and malignant lymphoproliferations, sharing a very similar histology and identical symptoms. To make a diagnosis of iMCD, the clinician must eliminate all the pathologies mentioned above, but he must first think of it and evoke this diagnosis of rare disease before the first symptoms but also know how to evoke this diagnosis again even after several years of evolution of a disease like those mentioned above whose evolution is not favorable. © 2022 Published by Elsevier Masson SAS on behalf of Société nationale française de médecine interne (SNFMI).

Case report: Castleman's disease involving the renal sinus resembling renal cell carcinoma

Introduction

Castleman's disease (CD) is a rare benign lymphoproliferative disease that frequently involves the mediastinal thorax and the neck lymph nodes. It rarely affects extrathoracic presentations, with even fewer presentations in the renal sinus.

Patient concerns

In this report, we present a case of a 40-year-old woman with no significant past medical history who presented Castleman's disease arising in the renal sinus.

Diagnosis and interventions

The patient visited our hospital with the chief complaint of left renal sinus lesion after renal ultrasonography by regular physical examination. Subsequent abdominal computed tomography urography revealed a soft tissue mass with heterogeneous obvious enhancement in the sinus of the left kidney, which was suspected to be a renal malignant tumor. Hence, the patient underwent a left radical nephrectomy. Histological examination revealed hyperplastic lymphoid follicles in the renal sinus and was finally diagnosed as Castleman's disease of the hyaline vascular type.

Outcomes

Five days after the surgery procedure, the patient was discharged.

Conclusion

Due to the low incidence of Castleman's disease in renal sinus, there is a strong likelihood of missed diagnosis or misdiagnosis, and it is, therefore, important to be aware of the risk. Heightened awareness of this disease and its radiographic manifestations may prompt consideration of this diagnosis. Therefore, we explored the radiologic findings to find out some radiologic features suggesting this condition to help clinicians to schedule nephron-sparing surgery in the future.

Idiopathic multicentric Castleman disease and associated autoimmune and autoinflammatory conditions: practical guidance for diagnosis

Idiopathic multicentric Castleman disease (iMCD) is an infrequent and life-threatening disorder characterised by systemic inflammatory symptoms, generalised lymphadenopathy, polyclonal lymphocyte proliferation, and organ dysfunction caused by a hyperinflammatory state. It accounts for one third to one half of all multicentric Castleman disease (MCD) cases. iMCD is often associated with autoimmune manifestations that may precede the iMCD diagnosis, be identified at the same time or follow it. In addition, iMCD may also coincide with a number of autoimmune diseases (such as psoriasis or myasthenia gravis) or autoinflammatory diseases (such as familial Mediterranean fever). Moreover, diverse inflammatory disorders, such as rheumatoid arthritis, systemic lupus erythematosus, adult-onset Still disease, systemic juvenile idiopathic arthritis, immunoglobulin (IgG4) related disease, or the recently described VEXAS syndrome, can present clinical features or lymphadenopathy with histopathological "Castleman-like" findings compatible with those of iMCD. Given the iMCD clinical heterogeneity and the overlap with other autoimmune or autoinflammatory disorders, iMCD diagnosis can be challenging. In this review, we explore the overlap between iMCD and inflammatory diseases and provide practical guidance on iMCD diagnosis in order to avoid misdiagnosis and confusion with other autoimmune or autoinflammatory conditions.

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.

Human Oncoviruses and Thoracic Tumors: Understanding the Imaging Findings

Approximately 1.4 million virus-induced cancers occur annually, representing roughly 10% of the cancer burden worldwide. Seven oncogenic DNA and RNA viruses (ie, oncoviruses) are implicated in approximately 12%-25% of all human cancers owing to a variety of mechanisms as uncommon consequences of the normal viral life cycle. These seven well-recognized human oncoviruses are Epstein-Barr virus (EBV), human T-lymphotropic virus 1, hepatitis B virus, hepatitis C virus, HIV, human papilloma virus (HPV), and human herpesvirus 8 (HHV-8). Several viruses-namely, EBV, HPV, and Kaposi sarcoma herpesvirus or HHV-8-are increasingly being recognized as being related to HIV and/or AIDS, the growing number of transplant cases, and the use of immunosuppressive therapies. Infectious and inflammatory processes, and the accompanying lymphadenopathy, are great mimickers of human oncovirus-related tumors. Although it is often difficult to differentiate these entities, the associated clinical setting and radiologic findings may provide clues for an accurate diagnosis and appropriate management. Malignant lymphoid lesions are best evaluated with multidetector chest CT. The radiologic findings of these lesions are often nonspecific and are best interpreted in correlation with clinical data and histopathologic findings. ^©RSNA, 2022.

Bronchiolitis Obliterans With Anti-Epiplakin Antibodies in a Boy With Paraneoplastic Pemphigus

Paraneoplastic pemphigus is a rare and severe autoimmune blistering disease characterized by a recalcitrant and severe mucositis, and polymorphic cutaneous lesions, associated with benign and malignant neoplasms. Paraneoplastic pemphigus is caused by production of autoantibodies against various epidermal proteins involved in cell adhesion. Bronchiolitis obliterans (BO) is one of the leading causes of mortality in these patients. Recent advances have associated the presence of anti-epiplakin antibodies with the development of BO in adult patients. Here we describe the first pediatric patient in whom the association of anti-epiplakin antibodies and BO have been reported so far.

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.

Emerging role of 18F-FDG PET/CT in Castleman disease: a review

Castleman disease (CD) describes a group of rare hematologic conditions involving lymphadenopathy with characteristic histopathology and a spectrum of clinical abnormalities. CD is divided into localized or unicentric CD (UCD) and multicentric CD (MCD) by imaging. MCD is further divided based on etiological driver into human herpesvirus-8-associated MCD, POEMS-associated MCD, and idiopathic MCD. There is notable heterogeneity across MCD, but increased level of pro-inflammatory cytokines, particularly interleukin-6, is an established disease driver in a portion of patients. FDG-PET/CT can help determine UCD versus MCD, evaluate for neoplastic conditions that can mimic MCD clinico-pathologically, and monitor therapy responses. CD requires more robust characterization, earlier diagnosis, and an accurate tool for both monitoring and treatment response evaluation; FDG-PET/CT is particularly suited for this. Moving forward, future prospective studies should further characterize the use of FDG-PET/CT in CD and specifically explore the utility of global disease assessment and dual time point imaging.

Trial registration ClinicalTrials.gov, NCT02817997, Registered 29 June 2016, https://clinicaltrials.gov/ct2/show/NCT02817997

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.

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.

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.

Innate Immunity: A Common Denominator between Neurodegenerative and Neuropsychiatric Diseases

The intricate relationships between innate immunity and brain diseases raise increased interest across the wide spectrum of neurodegenerative and neuropsychiatric disorders. Barriers, such as the blood–brain barrier, and innate immunity cells such as microglia, astrocytes, macrophages, and mast cells are involved in triggering disease events in these groups, through the action of many different cytokines. Chronic inflammation can lead to dysfunctions in large-scale brain networks. Neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and frontotemporal dementia, are associated with a substrate of dysregulated immune responses that impair the central nervous system balance. Recent evidence suggests that similar phenomena are involved in psychiatric diseases, such as depression, schizophrenia, autism spectrum disorders, and post-traumatic stress disorder. The present review summarizes and discusses the main evidence linking the innate immunological response in neurodegenerative and psychiatric diseases, thus providing insights into how the responses of innate immunity represent a common denominator between diseases belonging to the neurological and psychiatric sphere. Improved knowledge of such immunological aspects could provide the framework for the future development of new diagnostic and therapeutic approaches.

Retroperitoneal Castleman Disease Invading Iliac Vein and Inferior Vena Cava Treated by Tumorectomy with Vascular Repair: A Case Report

Unicentric Castleman disease, a rare lymphoproliferative disorder, is always known as a solitary, well-defined lymph node enlargement. We reported an extraordinary case of retroperitoneal Castleman disease, which invades wall of right iliac vein and inferior vena cava, treated successfully by tumorectomy with vascular repair.

Exfoliative Erythroderma: An Unusual Presentation of Paraneoplastic Pemphigus Associated with Castleman's Disease

We report a 23-year-old woman who presented with generalized scaly erythematous rash predominately on the upper trunk and hemorrhagic stomatitis. The histopathologic and immunopathologic findings were consistent with the diagnosis of paraneoplastic pemphigus. Castleman's tumor was diagnosed with computed tomography and exploratory laparotomy. A partial clinical improvement was observed after complete tumor removal and intravenous immunoglobulin administration. However, the patient died as a result of septicemia.

Clinicopathological comparison and therapeutic approach to Castleman disease-a case-based review

Castleman disease (CD) is a rare, B-cell lymphoproliferative disorder affecting lymph nodes and extranodal anatomical locations. Four types of clinical presentations can be distinguished after exclusion of mimics. The first division is into unicentric CD (UCD) and multicentric CD (MCD). MCD is classified further as HHV-8-negative (idiopathic), MCD associated with HHV-8 infection, and POEMS associated MCD. From the histological standpoint, UCD and MCD can be classified as hyaline-vascular (HV), plasma cell (PC), or mixed cellularity (MC) type, with a spectrum of histopathological manifestations. We present clinical and histopathological features and grading of 25 cases of CD classified according to CDCN histological criteria and according to this clinical algorithm, along with outcomes. Here we provide a fine-resolution description of the histological features of CD. We review and discuss the current diagnostic algorithm, grading system, and recently recommended treatment options. In the presented group of 25 patients with CD there were 14 women and 11 men in the age range 15-79 years. UCD was identified in 15 patients and it was most often located in mediastinum. MCD most frequently occurred as generalized lymphadenopathy. The most common type of CD was HV. All patients with UCD underwent complete surgical resection with a positive outcome. Patients with MCD had diagnostic partial surgical excision of the lesions, later followed by different types of treatment (corticosteroids, chemotherapy, radiotherapy, immunomodulatory agents) or 'watch and wait'. In four cases CD was associated with other malignancies (laryngeal cancer, small lymphocytic lymphoma, gallbladder cancer with hepatic metastases, primary squamous cell lung cancer). The accuracy of histopathological examination is essential and re-evaluation has to be performed in case of relapse or unexpected course of CD. Treatment tailored to fit the disease type and severity should follow the novel recommendations, including anti-IL-6 treatment in the case of MCD.

Castleman's disease as an unusual cause for dysphagia and dyspnea in a pediatric patient

Castleman's disease is a very rare entity in pediatric population and its presentation in the neck is scarcely described in the literature. We present the case of a 10-year-old-girl with an expanding neck mass over several months causing dysphagia and dyspnea. Surgical excision of the mass was performed and the analysis revealed unicentric Castleman's Disease. This is the second largest reported case of neck pediatric CD in the literature, and it presented with a symptomatology that differs from the other cases described. This fact highlights the need to include CD in the differential diagnosis of pediatric neck masses.

Castleman disease presenting with jaundice: A case report and review of literature

BACKGROUND

Castleman disease (CD) is a rare lymphoproliferative disorder that presents with various symptoms. CD accompanied with jaundice is uncommon since there are only 11 cases reported in the literature.

CASE SUMMARY

Here we report a 62-year-old woman who was admitted to the hospital with signs and symptoms of intermittent jaundice. Biochemical tests showed higher serum levels of total and direct bilirubin, and normal serum levels of tumor markers and interleukin-6. Contrast-enhanced computed tomography detected a 6 cm × 4 cm × 2.5 cm mass between the hepatoduodenal ligament and the inferior vena cava. The mass was successfully excised and the patient had a complete resolution of symptoms. A diagnosis of idiopathic unicentric CD was made based upon histological examination, which demonstrated the pathological features of CD of mixed type, including hyperplasia of follicular lymphoids with abundant plasma cells, degenerative germinal centers, interfollicular vascularity and hyaline degeneration. The diagnosis was corroborated by immunohistochemical analysis which detected multiple biomarkers.

CONCLUSION

This is the first study that describes the clinicopathological features of CD presenting with jaundice, which may deepen and extend our understanding of this disease.

An autopsy case of TAFRO syndrome with membranoproliferative glomerulonephritis-like lesions

TAFRO syndrome (thrombocytopenia, anasarca, myelofibrosis, renal dysfunction, and organomegaly) is an atypical manifestation of multicentric Castleman's disease. Although overproduction of interleukin-6, vascular endothelial growth factor, and other cytokines may partially explain the pathophysiology of this rare syndrome, the precise mechanisms underlying the renal dysfunction associated with the condition remain unclear. Here, we describe a case of a 69-year-old male with TAFRO syndrome. He was treated with immunosuppressive agents and his renal function improved. Tapering of immunosuppressive agents resulted in a deterioration of renal function and an elevation of C-reactive protein. After 20 months of treatment, the patient died from tuberculous peritonitis and gastrointestinal bleeding. An autopsy revealed miliary tuberculosis, mediastinal lymphadenopathy, and gastric ulcers. Renal histopathology showed a membranoproliferative glomerulonephritis-like appearance. Almost all glomeruli showed lobular formations with mesangial proliferation and duplication of glomerular capillary walls on light microscopy. Immunofluorescence showed deposition of C1q and IgM along the glomerular capillary walls. Electron microscopy showed mesangial expansion and widening of the subendothelial space with a large number of electron-dense deposits. The glomerular lesions might be characteristic of TAFRO syndrome, and were regarded as the main cause of the patient's renal dysfunction.