Renal and thymic pathology in thymoma-associated nephropathy: report of 21 cases and review of the literature

Steroid-resistant minimal change nephrotic syndrome associated with thymoma treated effectively with rituximab following thymectomy and cyclosporine: a case report

BACKGROUND

Minimal change nephrotic syndrome (MCNS) can be complicated by thymoma; however, no standard therapy for thymoma-associated MCNS has yet been established. We herein describe a case of steroid-resistant MCNS associated with thymoma, treated effectively with rituximab.

CASE PRESENTATION

A 71-year-old Japanese man was referred to our department with severe proteinuria (20 g/gCr). Renal biopsy showed minimal change disease and computed tomography revealed an anterior mediastinal mass. Based on these findings, he was diagnosed with thymoma-associated MCNS. He was treated with oral prednisolone (50 mg/day) and cyclosporine, and underwent thymectomy and plasma exchange. However, no improvement in proteinuria was observed. He therefore received intravenous rituximab 500 mg, resulting in a marked decrease in proteinuria from 5328 to 336 mg/day after 1 week.

CONCLUSIONS

This case suggests that rituximab might be an effective therapy in patients with steroid-resistant MCNS associated with thymoma.

Case report: Complex paraneoplastic syndromes in thymoma with nephrotic syndrome, cutaneous amyloidosis, myasthenia gravis, and Morvan’s syndrome

Background

Apart from myasthenia gravis (MG), thymoma is associated with a wide spectrum of autoimmune paraneoplastic syndromes (PNSs). Here, we report on a rare case presenting with four different PNSs, namely, MG, membranous nephropathy, cutaneous amyloidosis, and Morvan’s syndrome associated with thymoma.

Case presentation

A middle-aged man was frequently hospitalized because of nephrotic syndrome (stage I membranous nephropathy), cutaneous amyloidosis, and MG with acetylcholine receptor (AChR) antibody and titin antibody positivity. Chest CT showed a thymic mass in the left anterior mediastinum, and he received intravenous immunoglobulin (IVIG), methylprednisolone pulse therapy, thoracoscopic thymoma resection, and radiotherapy. Postoperative pathological examination revealed a type B2 thymoma. During the perioperative stage, his electrocardiogram (ECG) showed myocardial infarction-like ECG changes; however, his levels of cardiac enzymes and troponin were normal, and he had no symptoms of precardiac discomfort. Six months after thymectomy, his nephrotic syndrome and MG symptoms were relieved; however, he presented with typical manifestations of Morvan’s syndrome, including neuromyotonia, severe insomnia, abnormal ECG activity, and antibodies against leucine-rich glioma-inactivated 1 (LGI1) and γ-amino-butyric acid-B receptor (GABABR). His symptoms did not improve after repeated IVIG and steroid therapies. Finally, he received low-dose rituximab, and his symptoms gradually resolved.

Conclusion

This case serves to remind us that apart from MG, thymoma is also associated with other autoimmune PNSs such as membranous nephropathy, cutaneous amyloidosis, and Morvan’s syndrome. Autoimmune PNSs can present concurrently with or after surgical or medical therapy for thymoma. For Morvan’s syndrome post-thymectomy with LGI1 antibody positivity, B-cell depletion therapy such as intravenous rituximab is an effective treatment.

Paraneoplastic Glomerular Diseases

Paraneoplastic glomerular diseases (GNs) are rare manifestations in patients with underlying hematologic and solid organ malignancies and can occur before or after the detection of cancer. In the absence of established algorithms for investigation and reliable tests, they remain difficult to diagnose. Given the heterogeneity and infrequency of cases, the pathogenesis of most paraneoplastic GNs is poorly understood. Most of our recent understanding of paraneoplastic GNs has emerged from the discovery of target antigens in membranous nephropathy such as thrombospondin type-1 domain-containing protein 7A and neural epidermal growth factor-like 1 protein that appear to be promising in differentiating a primary vs paraneoplastic cause of membranous nephropathy. Treatment of paraneoplastic GNs is usually directed at the underlying malignancy. This review will focus on the epidemiology, pathogenesis, and diagnosis of paraneoplastic glomerular processes.

Efficacy of rituximab in thymoma associated minimal change disease: case report

Background

Thymomas have been associated with a broad spectrum of autoimmune diseases. Minimal change disease (MCD) is the most frequent pathological lesion reported. Pathophysiological mechanisms involved in secondary MCD, and linking MCD to thymoma are not yet fully explained, although the hypothesis of T cell dysfunction has been suggested. The fundamental therapeutic principles are steroids and surgical treatment of thymoma, but failures and relapses often require immunosuppressant combinations.

Case presentation

A 62-year-old female was admitted in our unit for a nephrotic syndrome associated with a thymoma. The diagnosis of thymoma associated MCD was confirmed by kidney biopsy. After surgical resection of the thymoma and steroid therapy, no remission was observed. Immunosuppressive therapy was then intensified with introduction of rituximab. Here, we report a steroid-resistant nephrotic syndrome secondary to MCD associated thymoma, which achieved complete remission after rituximab therapy. To the best of our knowledge, this is the first report of the use and efficacy of rituximab therapy in this pathology.

Conclusions

Our case report suggests that primary and secondary MCD may share similar pathophysiological mechanisms. It does not allow us to draw any conclusions about the mechanism of action of rituximab, but we believe this report argues for the safety and efficacy of rituximab use in thymoma-associated MCD, and therefore constitutes a rationale for future studies.

The immune cell landscape of peripheral blood mononuclear cells from PNS patients

Existing research suggests that the human immune system and immune cells are involved in the pathogenesis of nephrotic syndrome, but there is still a lack of direct evidence. This study tried to analyze the profiling of immune cells in the peripheral blood of steroid-sensitive nephrotic syndrome (SSNS) patients and steroid-resistant nephrotic syndrome (SRNS) patients before and after standard steroid treatment to clarify the immunological mechanism of nephrotic syndrome patients. The number and proportion of CD4 + T cells in patients with nephrotic syndrome remained unchanged. However, there is an imbalance of Th1 and Th2 and an excessive increase of Th17 cells. The number of CD8 + T cells and the number of effector CD8 + T cells in them increased significantly, but only in SSNS, the number of activated CD8 + T cells increased, and the number of activated T_reg cells decreased significantly. Nephrotic syndrome patients also have B cell disorder, and it is more prominent in SSNS patients. Compared with the normal control, only the number of B cells and plasmablast in SSNS patients increased significantly (Z = − 2.20, P = 0.028). This study also observed that transitional B cells decreased in both SSNS and SRNS patients, but SSNS patients' decrease was lower than in SRNS patients. Compared with normal controls, monocytes in patients with nephrotic syndrome decreased significantly. The main reason was that Non-classical Monocyte decreased, while Classical Monocyte increased slightly. The total number of NK cells did not change, but the internal cell subgroups' composition occurred. Changes, realized as CD56hi NK cells increased, CD56low NK cells decreased; and the above trend is more evident in SSNS patients. Patients with nephrotic syndrome have immune disorders, including T cells, B cells, Monocytes, and NK cells. It can be confirmed that immune factors are involved in the pathogenesis of the nephrotic syndrome.

Renal Diseases Associated with Hematologic Malignancies and Thymoma in the Absence of Renal Monoclonal Immunoglobulin Deposits

In addition to kidney diseases characterized by the precipitation and deposition of overproduced monoclonal immunoglobulin and kidney damage due to chemotherapy agents, a broad spectrum of renal lesions may be found in patients with hematologic malignancies. Glomerular diseases, in the form of paraneoplastic glomerulopathies and acute kidney injury with various degrees of proteinuria due to specific lymphomatous interstitial and/or glomerular infiltration, are two major renal complications observed in the lymphoid disorder setting. However, other hematologic neoplasms, including chronic lymphocytic leukemia, thymoma, myeloproliferative disorders, Castleman disease and hemophagocytic syndrome, have also been associated with the development of kidney lesions. These renal disorders require prompt recognition by the clinician, due to the need to implement specific treatment, depending on the chemotherapy regimen, to decrease the risk of subsequent chronic kidney disease. In the context of renal disease related to hematologic malignancies, renal biopsy remains crucial for accurate pathological diagnosis, with the aim of optimizing medical care for these patients. In this review, we provide an update on the epidemiology, clinical presentation, pathophysiological processes and diagnostic strategy for kidney diseases associated with hematologic malignancies outside the spectrum of monoclonal gammopathy of renal significance.

The histopathological spectrum of kidney biopsies in patients with thymoma and myasthenia gravis: a report of 24 biopsies from a single institution

Background

Nephropathy in patients with thymic diseases such as thymoma and myasthenia gravis (MG) is rare and has been described mostly as isolated case reports. Here we evaluate a series of kidney biopsies from patients with thymoma and/or MG from a single institution in order to better define the spectrum and relative frequencies of thymic disease–associated nephropathies.

Methods

We conducted a retrospective case series study of 32 462 native kidney biopsies from January 2005 through December 2019 at Cedars-Sinai Medical Center, Los Angeles, CA, USA.

Results

Twenty-four biopsy specimens (0.07%) from patients with a history of thymoma and/or MG were identified. Two patients had repeat biopsies. The most common pathologic diagnosis that could be immunologically attributed to thymic disease was minimal change disease (MCD; 45%), followed by tubulointerstitial nephritis (TIN; 14%), immune complex (IC)-mediated glomerulonephritis (9%), membranous nephropathy (5%) and immunoglobulin A (IgA) nephropathy (5%). Interestingly, 50% of the MCD and 67% of TIN cases concomitantly showed mild IgG-dominant IC deposition in mesangial areas and/or in tubular basement membranes. In the two patients with repeat biopsies, mild mesangial IC deposition developed in the MCD patient but disappeared in the TIN patient with the second biopsy. Pathologic diagnoses unlikely related to the underlying thymic disease were diabetic glomerulosclerosis (9%), acute tubular necrosis (9%) and monoclonal Ig deposition disease (5%).

Conclusions

Thymic disease is associated with a wide spectrum of kidney diseases affecting the glomerular and tubulointerstitial compartments, often with low-grade IC deposition. These findings suggest a role of immunologic dysregulation in the pathogenesis of thymic disease–associated nephropathy.

Concurrent minimal change disease and retroperitoneal liposarcoma successfully treated by tumor resection and steroid therapy

A 54-year-old Japanese woman developed simultaneous abdominal distension and bilateral leg edema. Her medical history and results of periodic medical check-up were unremarkable. Blood tests revealed severe hypoproteinemia and acute kidney injury, and urinalysis revealed 4+ proteinuria and 2+ hematuria. Abdominal computed tomography revealed a large intra-abdominal mass with fat tissue density. She underwent emergency tumor excision, splenectomy, and distal pancreatectomy. However, hypoproteinemia and acute kidney injury worsened. Therefore, she was transferred to the nephrology division for confirmation of diagnosis and for treatment of acute kidney injury and nephrotic syndrome. We conducted percutaneous kidney biopsy and diagnosed minimal change disease (MCD). Intravenous prednisolone was started, and heavy proteinuria and systemic edema were gradually alleviated. She achieved complete remission 2 months later, and oral prednisolone was tapered. Histopathological diagnosis of abdominal tumor was dedifferentiated liposarcoma of retroperitoneal origin. Immunohistochemical staining revealed strong expression of vascular endothelial growth factor in the tumor cells in the dedifferentiated component. Currently, her clinical course is stable without recurrence of liposarcoma and nephrotic syndrome. MCD develops in patients with Hodgkin's lymphoma, solid organ cancers, hematological malignancies, and thymoma, whereas concurrent MCD and liposarcoma are rare. Remission of nephrotic syndrome and normalized kidney function induced by steroid therapy are important for better management of patients with malignancy.

A systematic review of paraneoplastic syndromes associated with thymoma: Treatment modalities, recurrence, and outcomes in resected cases

OBJECTIVE

Paraneoplastic syndromes associated with thymomas remain incompletely understood. The objective was to examine the association between surgically resected thymomas and paraneoplastic syndromes over the past half century.

METHODS

A primary PubMed/MEDLINE search was used to identify published articles describing paraneoplastic syndromes associated with thymomas from 1960 to 2019. A secondary search identified additional articles referenced in the articles found in the primary search. Kaplan-Meier and log-rank test were used for time-to-event data analyses.

RESULTS

From 407 articles describing 507 patients, 123 different paraneoplastic syndromes were associated with thymoma. The 5 most common paraneoplastic syndromes were myasthenia gravis, pure red cell aplasia, lichen planus, Good syndrome, and limbic encephalitis. Complete or partial resolution of paraneoplastic syndrome symptoms after surgery was noted in 76% of patients, of whom 21% had a relapse or new paraneoplastic syndrome onset after surgery. The most common adjunctive therapy associated with resolution of paraneoplastic syndrome was corticosteroids (30%). For all patients after surgery, thymoma recurrence was observed in 17% of cases, whereas recurrence of paraneoplastic syndrome was observed in 34% of cases, and both were observed in approximately 11% of cases. The 5- and 10-year overall survivals were 78% and 66%, respectively. Improved overall survival was associated with patients who had total resolution from paraneoplastic syndrome.

CONCLUSIONS

A comprehensive assessment of publications over the past half century suggests that a multimodal treatment approach that includes surgical resection of thymomas is able to achieve paraneoplastic syndrome resolution in a majority of patients. Onset of new paraneoplastic syndromes after surgery is associated with the recurrence of the first paraneoplastic syndrome, and resolution of paraneoplastic syndrome is associated with improved overall survival.

Secondary membranous nephropathy in a patient with myasthenia gravis without thymic disease, and partial remission induced by adrenocorticotropic hormone therapy

Membranous glomerulonephritis is the most common glomerular disease in adults. Its primary form has been characterized with formation of phospholipase A2 receptor antibodies. Malignancy, infections, and autoimmune disorders are the most common causes of secondary membranous glomerulonephritis. We present a case of a 55-year-old African American female who presented with nephrotic range proteinuria and diagnosed with secondary membranous glomerulonephritis based on distinct pathological features on kidney biopsy and absence of serum phospholipase A2 receptor antibodies. She initially underwent extensive workup for malignancies, infections, and common autoimmune disorders which were all negative. Her proteinuria remained resistant to steroid treatment and she was treated with subcutaneous adrenocorticotropic hormone injections. Meanwhile, she was also diagnosed with the anti-muscle specific kinase antibody variant of myasthenia gravis. In literature, there are few case reports of myasthenia gravis as a cause of secondary membranous glomerulonephritis. In our case, the lack of other inciting factors also suggested this association.

Microscopic polyangiitis associated with thymic tumor: a case report and review of the literature

Background

Thymic hyperplasia and thymic epithelial tumor (thymoma) have been associated with a variety of autoimmune diseases. Renal involvement has been reported in patients with thymoma. Minimal change disease and membranous nephropathy are frequently observed in glomerular lesions of thymoma patients, but ANCA-associated renal vasculitis is rare. We present a case of thymoma-associated microscopic polyangiitis with positivity for three ANCAs: MPO-ANCA, PR3-ANCA and azurocidin-ANCA.

Case presentation

An 89-year-old Japanese woman was admitted to our hospital following an episode of general fatigue, nausea, muscle weakness of the lower limbs, and ophthalmoplegia. On urinalysis, proteinuria, hematuria, and cellular casts were observed. Elevated levels of serum creatinine and C-reactive protein were also demonstrated, and MPO-, PR3- and azurocidin-ANCA were detected on serological examination. Renal biopsy showed pauci-immune crescentic glomerulonephritis. We therefore diagnosed rapidly progressive glomerulonephritis due to microscopic polyangiitis. Acetylcholine-receptor antibody was also detected. Chest computed tomography and MRI revealed a lobulated tumor in the anterior mediastinum. We thus also diagnosed myasthenia gravis with thymoma.

Conclusion

Considering the patient’s triple-ANCA positivity, thymic diseases may be associated with the pathogenesis of ANCA-associated vasculitis due to central T-cell tolerance. A further accumulation of cases is needed, because thymectomy does not always induce the remission of thymoma-associated autoimmune diseases.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1319-9) contains supplementary material, which is available to authorized users.

Minimal change nephrotic syndrome in patients infected with human immunodeficiency virus: a retrospective study of 8 cases

Background

Human immunodeficiency virus (HIV) is associated with diverse glomerular diseases. Characteristics of minimal change nephrotic syndrome (MCNS) in this setting have been little studied, and the specific features of this uncommon association remain to be determined.

Methods

We conduct a retrospective study. Clinical, biological and pathological characteristics of patients with MCNS and HIV infection were assessed. We evaluated HIV infection by in situ hybridization and CMIP expression by immunochemistry on kidney biopsies and compared it to HIV-associated nephropathy (HIVAN) and idiopathic MCNS.

Results

Eight patients were identifies. In all but one of these cases, MCNS occurred after HIV diagnosis (mean of 9.5 years). Acute kidney injury was detected in three cases. Mean CD4⁺ lymphocyte count was 733/mm³ and three patients had a detectable HIV viral load. In situ hybridization for HIV-1 RNA detection yielded a positive signal in a few tubular cells in the renal parenchyma in two of four patients with HIV infection associated with MCNS. Podocytes of these patients presented strong positive immunostaining for CMIP (4/4). Three patients suffered steroid-dependent nephrotic syndrome, and another two patients had at least one relapse. Rituximab treatment was initiated in four cases. After a median follow-up of 20 months, all patients were in remission (complete in 5 cases).

Conclusions

In patients with MCNS occurring in a context of HIV infection, podocyte injury seems to be associated with CMIP induction rather than renal HIV infection but further studies are needed to determine the molecular link between these two conditions.

CIDP, myasthenia gravis, and membranous glomerulonephritis - three autoimmune disorders in one patient: a case report

BACKGROUND

We present a patient fulfilling the electrophysiological criteria for definite chronic inflammatory demyelinating polyneuropathy (CIDP), antibody-positive myasthenia gravis (MG), and membranous glomerulonephritis (MGN) confirmed by biopsy. To our knowledge, this is the first case of the concomitant appearance of these three autoimmune diseases in a single patient.

CASE REPRESENTATION

A 42-year-old Caucasian male presented with rapidly progressive gait disturbance, distal weakness of the lower extremities, ascending hypoesthesia, impaired fine motor skills, and beginning cranial nerve palsy showing dysarthrophonia, facial paralysis, and eye movement abnormalities and was diagnosed as rapid onset (atypical) CIDP. After 3 months, the patient complained of increasing physical exhaustion, reduction of his walking distance, worsening of the residual dysphagia, and dysarthria with an inability to swallow. AChR antibodies (17.0 nmol/L, RF < 0.4) and titin antibodies were positive and repetitive nerve stimulation showed an abnormal decrement matching the criteria of myasthenia gravis. Over time the patient developed severe acute-on-chronic renal failure with high-grade proteinuria resulting in generalized edema followed by secondary hyperparathyroidism and dialysis-dependent renal failure. Renal biopsy confirmed beginning anti-phospholipase A2 receptor antibody membranous nephropathy.

CONCLUSION

All three diseases are of autoimmune origin with distinctive immunopathogenetic mechanisms. The present case of CIDP, MG, and MGN occurring in one patient indicates a common underlying immune mechanism in these distinct conditions, including the involvement of autoantibodies and T cells.

Molecular and Cellular Mechanisms for Proteinuria in Minimal Change Disease

Minimal Change Disease (MCD) is a clinical condition characterized by acute nephrotic syndrome, no evident renal lesions at histology and good response to steroids. However, frequent recurrence of the disease requires additional therapies associated with steroids. Such multi-drug dependence and frequent relapses may cause disease evolution to focal and segmental glomerulosclerosis (FSGS) over time. The differences between the two conditions are not well defined, since molecular mechanisms may be shared by the two diseases. In some cases, genetic analysis can make it possible to distinguish MCD from FSGS; however, there are cases of overlap. Several hypotheses on mechanisms underlying MCD and potential molecular triggers have been proposed. Most studies were conducted on animal models of proteinuria that partially mimic MCD and may be useful to study glomerulosclerosis evolution; however, they do not demonstrate a clear-cut separation between MCD and FSGS. Puromycin Aminonucleoside and Adriamycin nephrosis are models of glomerular oxidative damage, characterized by loss of glomerular basement membrane polyanions resembling MCD at the onset and, at more advanced stages, by glomerulosclerosis resembling FSGS. Also Buffalo/Mna rats present initial lesions of MCD, subsequently evolving to FSGS; this mechanism of renal damage is clearer since this rat strain inherits the unique characteristic of overexpressing Th2 cytokines. In Lipopolysaccharide nephropathy, an immunological condition of renal toxicity linked to B7-1(CD80), mice develop transient proteinuria that lasts a few days. Overall, animal models are useful and necessary considering that they reproduce the evolution from MCD to FSGS that is, in part, due to persistence of proteinuria. The role of T/Treg/Bcells on human MCD has been discussed. Many cytokines, immunomodulatory mechanisms, and several molecules have been defined as a specific cause of proteinuria. However, the hypothesis of a single cell subset or molecule as cause of MCD is not supported by research and an interactive process seems more logical. The implication or interactive role of oxidants, Th2 cytokines, Th17, Tregs, B7-1(CD80), CD40/CD40L, c-Mip, TNF, uPA/suPAR, Angiopoietin-like 4 still awaits a definitive confirmation. Whole genome sequencing studies could help to define specific genetic features that justify a definition of MCD as a “clinical-pathology-genetic entity.”

Concurrent renal amyloidosis and thymoma resulting in a fatal ventricular thrombus in a dog

Thymoma-associated nephropathies have been reported in people but not in dogs. In this report, we describe a dog with thymoma and concurrent renal amyloidosis. A 7-year-old castrated male Weimaraner was presented for progressive anorexia, lethargy, and tachypnea. The dog was diagnosed with azotemia, marked proteinuria, and a thymoma that was surgically removed. Postoperatively, the dog developed a large left ventricular thrombus and was euthanized. Necropsy confirmed the presence of a left ventricular thrombus and histopathology revealed renal amyloidosis. We speculate that the renal amyloidosis occurred secondary to the thymoma, with amyloidosis in turn leading to nephrotic syndrome, hypercoagulability, and ventricular thrombosis. This case illustrates the potential for thymoma-associated nephropathies to occur in dogs and that dogs suspected to have thymoma should have a urinalysis and urine protein creatinine ratio performed as part of the pre-surgical database.

Quantification of cancer risk in glomerulonephritis

Background

The association of increased cancer risk with glomerulonephritis (GN) is well known, but controversy exists concerning which types of GN are involved, and the size of the association. A national registry survey was performed to assess the size of this association, and the temporal relationship of cancer diagnosis to GN diagnosis.

Methods

All patients with biopsy-proven GN between 1985 and 2015 in Denmark were extracted from The Danish Renal Biopsy Registry and the National Pathology Data Bank. Incident cancer diagnoses between 10 years previous and 10 years subsequent to the GN diagnosis were extracted from the Danish Cancer Registry. Residence, birth and death data were obtained from the National Patient Register. Expected cancer incidence, classified according to cohort, age and sex were extracted from the Nordcan database.

Results

Nine hundred eleven cancers were diagnosed in 5594 patients. Thirty five percent were prevalent at renal biopsy. Prevalence at biopsy was 5.5% (expected 3.1%), but incidence was not increased < 1 year before biopsy. Increased cancer rates were seen for GN forms: minimal change, endocapillary, focal segmental glomerulosclerosis, mesangioproliferative, membranous, focal segmental, membranoproliferative, proliferative, ANCA-associated vasculitis, lupus nephritis and unclassified. Increased cancer rates were seen for lung, prostate, renal, non-Hodgkin lymphoma, myeloma, leukaemia and skin. The increased incidence was mainly limited to − 1 to 1 year after biopsy, but skin cancer showed an increased risk over time. Some diagnoses showed an increase 5–10 years after biopsy. Incidence was raised for patients with uraemia and nephrosis, but less for proteinuria or haematuria. Cancers in patients < 45 years were rare. The risk of developing cancer 0–3 years after biopsy for patients 45–64 years varied from 7.3% (minimal change) to 15.8% (unclassified GN); > 64 years from 11.8 (endocapillary GN) to 20.3% (unclassified). The diagnosis with the highest risk was membranoproliferative GN (8.6 & 19.6%).

Conclusions

Cancer rates are increased for many cancer and most GN diagnoses. Cancer screening for patients < 45 years and for patients without nephrosis or uraemia may not be necessary. The findings suggest that screening programs for specific GN diagnoses can be extended to other GN forms.

Thymoma-associated myasthenia gravis and LGI1-encephalitis, with nephrotic syndrome post-thymectomy

Thymoma is associated with a wide spectrum of autoimmune paraneoplastic syndromes, though it is uncommon for multiple paraneoplastic syndromes to be present in a single individual. We report a rare case of an elderly gentleman who was found to have thymoma-associated myasthenia gravis and LGI1-encephalitis with myokymia, who presented with nephrotic syndrome (minimal change glomerulopathy) after thymectomy. The latter two paraneoplastic syndromes had manifested when prednisolone was tapered down to low dose. This case serves to remind neurologists that apart from paraneoplastic neurological manifestations, thymoma may also be associated with renal disease. Nephropathy in myasthenia patients with thymoma should be properly evaluated, as it is treatable with immunotherapy, and it may even occur post-thymectomy.

Nephrotic Syndrome and a Retroperitoneal Mass: A Case Report of a Patient with Recurrent Invasive Thymoma

A 68-year-old man was admitted to our hospital to undergo an examination for nephrotic syndrome while concurrently complicated with recurrent thymoma in the parietal pleura and retroperitoneum. He had been diagnosed with invasive thymoma and had undergone thymo-thymectomy seven years previously. Based on the renal biopsy findings, his nephrotic syndrome was ascribed to minimal change disease. He was treated with corticosteroid monotherapy, which resulted in complete remission six months later, despite the fact that the recurrent thymoma remained. The role of thymoma in the pathogenesis of paraneoplastic glomerulopathy and the therapeutic concerns that emerged in this case are also discussed.

[Thymoma and autoimmune diseases]

The association between thymoma and autoimmunity is well known. Besides myasthenia gravis, which is found in 15 to 20% of patients with thymoma, other autoimmune diseases have been reported: erythroblastopenia, systemic lupus erythematosus, inflammatory myopathies, thyroid disorders, Isaac's syndrome or Good's syndrome. More anecdotally, Morvan's syndrome, limbic encephalitis, other autoimmune cytopenias, autoimmune hepatitis, and bullous skin diseases (pemphigus, lichen) have been reported. Autoimmune diseases occur most often before thymectomy, but they can be discovered at the time of surgery or later. Two situations require the systematic investigation of a thymoma: the occurrence of myasthenia gravis or autoimmune erythroblastopenia. Nevertheless, the late onset of systemic lupus erythematosus or the association of several autoimmune manifestations should lead to look for a thymoma. Neither the characteristics of the patients nor the pathological data can predict the occurrence of an autoimmune disease after thymectomy. Thus, thymectomy usefulness in the course of the autoimmune disease, except myasthenia gravis, has not been demonstrated. This seems to indicate the preponderant role of self-reactive T lymphocytes distributed in the peripheral immune system prior to surgery. Given the high infectious morbidity in patients with thymoma, immunoglobulin replacement therapy should be considered in patients with hypogammaglobulinemia who receive immunosuppressive therapy, even in the absence of prior infection.

Nephrotic syndrome associated with metastatic thymoma treated with chemotherapy

RATIONALE

Nephropathy with concurrent invasive thymoma is a type of paraneoplastic syndrome.

PATIENT CONCERNS AND DIAGNOSES

We report a 32-year-old female with nephrotic syndrome that was first diagnosed along with invasive thymoma and treated by means of cisplatin-based chemotherapy for the thymoma. The patient initially presented with dyspnea and generalized edema. Chest radiography and computed tomography scans revealed right pleural effusion and a mass in the right middle lung field, which were confirmed by a percutaneous lung biopsy as metastatic invasive thymoma. Severe hypoalbuminemia, heavy proteinuria, hyponatremia, and hypercholesterolemia were features of the nephrotic syndrome. A kidney needle biopsy suggested focal segmental glomerulosclerosis.

INTERVENTIONS AND OUTCOMES

All of the symptoms of nephrotic syndrome were resolved simultaneously during the first 2 cycles of chemotherapy. The patient was on regular follow-up with no specific treatment for nephrotic syndrome and underwent successful resection of the left pleura and anterior thymoma. The patient has shown no evidence of recurrence for 2 years.

LESSONS

We conclude that chemotherapy for invasive thymoma is an effective treatment for nephrotic syndrome accompanying the thymoma.

Lupus Nephritis with Thymoma Managed by Thoracoscopic Surgery and Prednisolone

A 48-year-old woman was admitted to our hospital to undergo evaluation for fatigue, severe weight loss, and nephrotic range proteinuria. Light microscopy of a renal biopsy specimen revealed class III (A) lupus nephritis, while immunofluorescence and electron microscopy only showed sparse immune deposits with findings that were not typical of lupus nephritis. Computed tomography revealed a mass in the anterior mediastinum, which was resected. The examination of the surgical specimen revealed type A noninvasive thymoma. In combination with thymomectomy, postoperative steroid therapy achieved the prompt remission of lupus nephritis. In this patient, thymoma-related autoimmunity may have contributed to the exacerbation of lupus nephritis.

Minimal change disease in a patient with myasthenia gravis: A case report

BACKGROUND

Myasthenia gravis superimposed with proteinuria is a very rare disorder with only 39 cases reported so far. Of these cases, the most commonly associated disorder is minimal change disease. Myasthenia gravis and minimal change disease are both related to the dysfunction of T lymphocytes and hence the 2 disorders may be connected.

METHODS

Here we report the first case on a patient diagnosed with myasthenia gravis concurrently with the minimal change disease, and it was presented in the absence of thymoma or thymic hyperplasia.

RESULTS

Treatment for myasthenia gravis also lowered proteinuria of minimal change disease. He ever experienced good control for myasthenia gravis and minimal change disease. However, pneumonia related septic shock occurred to him and finally he was dead. Minimal change disease is generally considered to occur subsequent to the onset of myasthenia gravis with causal association. After extensive literature review, we noted only 47.8% minimal change disease had occurred after the onset of myasthenia gravis.

CONCLUSION

Minimal change disease mostly occurs in children and if diagnosed in adults, clinicians should search for a potential cause such as myasthenia gravis and other associated thymic disorders.

Regulatory T cells and minimal change nephropathy: in the midst of a complex network

Minimal change nephrosis (MCN) is an important cause of morbidity in children. In spite of successful therapies having been developed in the last three decades, most aspects related to pathogenesis still remain poorly defined. Evolution in basic immunology and results deriving from animal models of the disease suggest a complex interaction of factors and cells starting from activation of innate immunity and continuing with antigen presentation. Oxidants, CD80 and CD40/CD40L have probably a relevant role at the start. Studies in animal models and in human beings also suggest the possibility that the same molecules (i.e. CD80, CD40) are expressed by podocytes under inflammatory stimuli, representing a direct potential mechanism for proteinuria. B and T cells could play a relevant role this contest. Implication of B cells is suggested indirectly by studies utilizing anti-CD20 monoclonal antibodies as the main therapy. The role of regulatory T cells (Tregs ) is supported mainly by results in animal models of nephrotic syndrome (i.e. adriamycin, puromycin, lipopolysaccharide), showing a protective effect of direct Treg infusion or stimulation by interleukin 2 (IL-2). Limited studies have also shown reduced amounts of circulating Tregs in patients with active MCN cells. The route from bench to bedside would be reduced if results from animal models were confirmed in human pathology. The expansion of Tregs with recombinant IL-2 and new anti-CD20 monoclonal antibodies is the beginning. Blocking antigen-presenting cells with cytotoxic T lymphocyte antigen (CTLA-4)-Ig fusion molecules inhibiting CD80 and/or with blockers of CD40-CD40 ligand interaction represent potential new approaches. The hope is that evolution in therapies of MCN could fill a gap lasting 30 years.

[Thymic disease associated with nephrotic syndrome: a new case with membranous nephropathy and literature review]

INTRODUCTION

Malignant thymoma or thymic hyperplasia is associated with various autoimmune diseases. Renal disease has rarely been reported in this condition. We report a new case with improvement of renal disease after thymectomy.

CASE REPORT

A 77-year-old-women with nephritic syndrome was found to have associated thymic mass. Renal pathology showed membranous nephropathy. The thymic mass pathology showed a B2 type thymoma. After thymectomy the nephrotic syndrome improved.

CONCLUSION

Glomerulopathy can be secondary to an acquired thymic disease. Membranous nephropathy but also other glomerular diseases can be observed often presenting with nephritic syndrome. Despite the rarity of this association this clinical observation underlines that a thymoma should be searched in the presence of a glomerulopathy. The glomerulopathy can be improved by the treatment of the thymoma.

Glomerular diseases associated with cancer, chemotherapy, and hematopoietic stem cell transplantation

Many solid and hematological malignancies have been associated with different glomerular diseases. Several case reports and case series of cancer-associated glomerular diseases have shown that treating the cancer may lead to resolution of the glomerular process. Hence, knowledge and approach to cancer-associated glomerular diseases is important for both the caring nephrologists and the cancer specialists. While membranous nephropathy has been classically associated with solid malignancies, minimal change disease has been commonly described with hematologic malignancies, especially non-Hodgkin's lymphoma. Membranoproliferative glomerulonephritis is increasingly being recognized to be associated with chronic hematologic malignancies such as chronic lymphocytic leukemia. In this article, we review various cancer-associated glomerular diseases and their pathogenesis as well as principles of treatment. In addition, we also review glomerular diseases seen after chemotherapy and hematopoietic stem cell transplantation.

[Membranous nephropathy]

Membranous nephropathy is characterized by immune complex deposits on the outer side of the glomerular basement membrane. Activation of complement and of oxidation lead to basement membrane lesions. The most frequent form is idiopathic. At 5 and 10 years, renal survival is around 90 and 65% respectively. A prognostic model based on proteinuria, level and duration, progression of renal failure in a few months can refine prognosis. The urinary excretion of C5b-9, β2 and α1 microglobuline and IgG are strong predictors of outcome. Symptomatic treatment is based on anticoagulation in case of nephrotic syndrome, angiotensin conversion enzyme inhibitors, angiotensin II receptor blockers and statins. Immunosuppressive therapy should be discussed for patients having a high risk of progression. Corticoids alone has no indication. Treatment should include a simultaneous association or more often alternating corticoids and alkylant agent for a minimum of 6 months. Adrenocorticoid stimulating hormone and steroids plus mycophenolate mofetil may be equally effective. Steroids plus alkylant decrease the risk of end stage renal failure. Cyclosporine and tacrolimus decrease proteinuria but are associated with a high risk of recurrence at time of withdrawal and are nephrotoxic. Rituximab evaluated on open studies needs further evaluations to define its use.

Membranous nephropathy, leiomyoma and autoimmune myasthenia: more than a coincidence?

Membranous nephropathy (MN) has been associated with several infectious, immunological and malignant conditions, but had only rarely been reported with malignant and other immune disorders in the same patient. We describe the case of a 56-year-old male with MN who was also diagnosed with a gastrointestinal stromal tumour (GIST), myasthenia gravis (MG) and thymic hyperplasia. Thus, we report here for the first time the coincidence of these conditions in the same patient. There was a recurrence of nephrotic syndrome without impairment of renal function 5 years after removal of the GIST (3 years after thymectomy). The possible basis for the relationship between these diseases is discussed, and some common genetic and immune physiopathological pathways are hypothesized.

Upregulation of nuclear factor-related kappa B suggests a disorder of transcriptional regulation in minimal change nephrotic syndrome

Immune mechanisms underlying the pathophysiology of idiopathic nephrotic syndrome, the most frequent glomerular disease in children, are believed to involve a systemic disorder of T cell function and cell mediated immunity. How these perturbations take place remains unclear. We report here that NFRKB, a member of the chromatin remodeling complex, is upregulated in MCNS relapse, mainly in CD4+T cells and B cells and undergo post-translational modifications including sumoylation. We showed that NFRKB was highly expressed in nuclear compartment during the relapse, while it was restricted to cytoplasm in remission. NFRKB induced the activation of AP1 signaling pathway by upregulating the expression of c-jun. We showed that NFRKB promotes hypomethylation of genomic DNA, suggesting its implication in regulation of gene expression by enhancing the binding of transcription factors through chromatin remodeling. These results suggest for the first time that NFRKB may be involved in the disorders of transcriptional regulation commonly observed in MCNS relapse.

Pathogenesis, diagnosis and management of paraneoplastic glomerulonephritis

Paraneoplastic glomerulonephritis is a rare complication of malignancy that is frequently mistaken for idiopathic glomerulonephritis. Failure to recognize paraneoplastic glomerulonephritis can subject patients to ineffective and potentially harmful therapy. The pathology of paraneoplastic glomerulonephritis varies between different types of malignancies. This Review discusses the association of glomerulonephritis with both solid tumors and hematological malignancies. The pathogenetic mechanisms of many glomerular lesions seem to relate to altered immune responses in the presence of a malignancy. Studies in the Buffalo/Mna rat model of spontaneous thymoma and nephrotic syndrome indicate that polarization of the immune response toward a T-helper-2 (T(H)2) profile has an important role in the development of thymoma-associated glomerular lesions. Furthermore, overexpression of the T(H)2 cytokine interleukin 13 in rats induces minimal change disease. Such findings from experimental studies might facilitate the identification of biomarkers that can distinguish paraneoplastic glomerulonephritis from idiopathic and other secondary glomerulonephritides. This Review describes potential pathogenetic mechanisms for paraneoplastic glomerulonephritides associated with different malignancies and highlights the need for a multidisciplinary approach to the management of patients with paraneoplastic glomerulonephritis.

[Glomerulonephritis and thymoma: a case report and review of the literature]

The authors present a case of nephrotic syndrome due to focal-segmental glomerulosclerosis, occurring three years after thymectomy and myasthenia gravis. Twenty-three other cases of nephrotic syndrome associated with thymoma and myasthenia gravis have been reported in the literature. The nephrotic syndrome may be related to T-cell dysfunction associated with thymoma.

Monoclonal antibodies for podocytopathies: rationale and clinical responses

The podocytopathies, including minimal-change nephropathy, focal segmental glomerulosclerosis, collapsing glomerulopathy, and diffuse mesangial sclerosis, involve diverse types of injury to podocytes. These injuries can have genetic causes, or can be caused by viral infection, mechanical stress, medication or-probably-immunologic injury. Several lines of evidence-including the immunosuppressive effects of standard therapies-suggest a role for immunologic injury in some cases, but the precise pathologic mechanisms are far from clear. Despite this uncertainty, newly available biologic therapies that target immune cells and cytokines have been used to treat a number of patients with different podocytopathies. Of these therapies, the greatest experience has been gained with rituximab. The data on all such therapies remain too fragmentary to provide firm conclusions, but further clinical research with such agents might help to define pathogenetic pathways and could potentially contribute to new therapies.

New insights into the pathophysiology of idiopathic nephrotic syndrome

Corticoresistant idiopathic nephrotic syndrome (INS) is a glomerulopathy of unknown etiology whose original aspect is its recurrence after kidney transplantation in 30 to 50% of patients with end-stage renal disease. This suggests the involvement of circulating factors that would alter the glomerular filtration barrier, but whose nature remains elusive. Although a T cell immune origin has been suggested, the actual role of these cells in INS recurrence is still unclear. Here we present an 8-year-old patient with corticoresistant INS who developed a recurrence of her initial disease after kidney transplantation. Rituximab therapy was proposed 11 months after transplantation; although no immediate effect was induced, a slow but persistent decrease in proteinuria began a few months after Rituximab infusions despite cessation of plasma exchanges and steroid therapy. The pathophysiology of INS and the putative mechanisms of action of Rituximab are discussed.

The concurrent presentation of minimal change nephrotic syndrome and aplastic anemia

Minimal change nephrotic syndrome (MCNS) has been associated with primary immunological disorders, such as lymphoma and thymoma. While several different explanations have been proposed, much of the literature has implicated activated T-lymphocytes in the pathogenesis. We report a patient with minimal change nephrotic syndrome presenting concurrently with thrombocytopenia and anemia, with a subsequent diagnosis of aplastic anemia. To our knowledge, this is the first such case described in the literature.

Pathophysiological lessons from rare associations of immunological disorders

Rare associations of immunological disorders can often tell more than mice and rats about the pathogenesis of immunologically mediated human kidney disease. Cases of glomerular disease with thyroiditis and Graves' disease and of minimal change disease with lymphoepithelioma-like thymic carcinoma and lymphomatoid papulosis were recently reported in Pediatric Nephrology. These rare associations can contribute to the unraveling of the pathogenesis of membranous nephropathy (MN) and minimal change disease (MCD) and lead to the testing of novel research hypotheses. In MN, the target antigen may be thyroglobulin or another thyroid-released antigen that becomes planted in the glomerulus, but other scenarios can be envisaged, including epitope spreading, polyreactivity of pathogenic antibodies, and dysregulation of T regulatory cells, leading to the production of a variety of auto-antibodies with different specificities [immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX syndrome)]. The occurrence of MCD with hemopathies supports the role of T cells in the pathogenesis of proteinuria, although the characteristics of those T cells remain to be established and the glomerular permeability factor(s) identified.