Paraneoplastic diseases associated with thymoma

Taste disorders and alopecia in myasthenia gravis

BACKGROUND

Non-motor symptoms in myasthenia gravis (MG) are rarely confirmed. Although there are some small cohort studies, a large-systemic survey has not yet been performed.

METHODS

We investigated the incidence and clinical characteristics of patients with MG who had taste disorders and alopecia using data of 1710 patients with MG enrolled in the Japan MG Registry 2021.

RESULTS

Among them, 104 (6.1%) out of 1692 patients and 138 (8.2%) out of 1688 patients had histories of taste disorders and alopecia, respectively. Among the patients with MG, taste disorders were significantly more common in women, those with severe symptoms, refractory MG, or thymoma-associated MG, and were less common in those with ocular MG. The taste disorders often occurred after the onset of MG and often responded to MG treatments. Alopecia was more common in MG patients with a history of bulbar palsy and thymoma, and it often occurred before the onset of MG and sometimes responded to MG treatments. Multivariate logistic regression analysis revealed taste disturbance was associated with worst quantitative MG score and thymoma-associated MG; and alopecia was associated with thymoma-associated MG.

CONCLUSION

Clinicians should be aware of the non-motor symptoms in MG, especially in patients with severe myasthenic symptoms and thymoma-associated MG.

Autoimmunity in thymic epithelial tumors: a not yet clarified pathologic paradigm associated with several unmet clinical needs

Thymic epithelial tumors (TETs) are rare mediastinal cancers originating from the thymus, classified in two main histotypes: thymoma and thymic carcinoma (TC). TETs affect a primary lymphoid organ playing a critical role in keeping T-cell homeostasis and ensuring an adequate immunological tolerance against "self". In particular, thymomas and not TC are frequently associated with autoimmune diseases (ADs), with Myasthenia Gravis being the most common AD present in 30% of patients with thymoma. This comorbidity, in addition to negatively affecting the quality and duration of patients' life, reduces the spectrum of the available therapeutic options. Indeed, the presence of autoimmunity represents an exclusion criteria for the administration of the newest immunotherapeutic treatments with checkpoint inhibitors. The pathophysiological correlation between TETs and autoimmunity remains a mystery. Several studies have demonstrated the presence of a residual and active thymopoiesis in adult patients affected by thymomas, especially in mixed and lymphocytic-rich thymomas, currently known as type AB and B thymomas. The aim of this review is to provide the state of art in regard to the histological features of the different TET histotype, to the role of the different immune cells infiltrating tumor microenvironments and their impact in the break of central immunologic thymic tolerance in thymomas. We discuss here both cellular and molecular immunologic mechanisms inducing the onset of autoimmunity in TETs, limiting the portfolio of therapeutic strategies against TETs and greatly impacting the prognosis of associated autoimmune diseases.

Thymoma-associated autoimmune encephalitis with myasthenia gravis: Case series and literature review

OBJECTIVES

This comprehensive review aimed to compile cases of patients with thymoma diagnosed with both autoimmune encephalitis (AE) and myasthenia gravis (MG), and describe their clinical characteristics.

METHODS

Clinical records of 3 AE patients in the first affiliated hospital of Sun Yat-sen University were reviewed. All of them were diagnosed with AE between 1 November 2021 and 1 March 2022, and clinical evidence about thymoma and MG was found. All published case reports were searched for comprehensive literature from January 1990 to June 2022.

RESULTS

A total of 18 cases diagnosed with thymoma-associated autoimmune encephalitis (TAAE) and thymoma-associated myasthenia gravis (TAMG) were included in this complication, wherein 3 cases were in the first affiliated hospital of Sun Yat-sen University and the other 15 were published case reports. 5/18 patients had alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antibody (AMPAR-Ab) in their serum and cerebrospinal fluid (CSF). All of them had positive anti-acetylcholine receptor antibody (AChR-Ab). And 12/18 patients showed a positive response to thymectomy and immunotherapy. Besides, thymoma recurrences were detected because of AE onset. And the shortest interval between operation and AE onset was 2 years in patients with thymoma recurrence.

CONCLUSIONS

There was no significant difference in the clinical manifestations between these patients and others with only TAMG or TAAE. TAAE was commonly associated with AMPAR2-Ab. Significantly, AE more commonly heralded thymoma recurrences than MG onset. And the intervals of thymectomy and MG or AE onset had different meanings for thymoma recurrence and prognoses of patients.

Paraneoplastic autoimmune neurologic disorders associated with thymoma

Thymoma is often associated with paraneoplastic neurologic diseases. Neural autoantibody testing is an important tool aiding diagnosis of thymoma and its autoimmune neurologic complications. Autoantibodies specific for muscle striational antigens and ion channels of the ligand-gated nicotinic acetylcholine receptor superfamily are the most prevalent biomarkers. The autoimmune neurologic disorders associating most commonly with thymoma are myasthenia gravis (MG), peripheral nerve hyperexcitability (neuromyotonia and Morvan syndrome), dysautonomia, and encephalitis. Patients presenting with these neurologic disorders should be screened for thymoma at diagnosis. Although they can cause profound disability, they usually respond to immunotherapy and treatment of the thymoma. Worsening of the neurologic disorder following surgical removal of a thymoma may herald tumor recurrence. Prompt recognition of paraneoplastic neurologic disorders is critical for patient management. A multidisciplinary approach is required for optimal management of neurologic autoimmunity associated with thymoma.

[Thymoma-associated generalized myasthenia gravis complicated with anti-VGKC complex antibody-associated limbic encephalitis: a case report]

We present a case of a 54-year-old woman. She was attending our department for thymoma-associated generalized myasthenia gravis. While she was treated with intravenous immunoglobulins for the exacerbation of myasthenic symptoms, she suddenly lost her consciousness for the first time and continued to have mild disorientation along with anterograde and retrograde amnesia afterwards. The symptoms improved after steroid pulse therapy. After searching for autoantibodies, she was diagnosed with anti-VGKC complex antibody-associated limbic encephalitis. As one-third of cases are complicated by thymoma, anti-VGKC complex antibody-positive limbic encephalitis has the aspect of a paraneoplastic neurological syndrome. In this case, masses suspected to be a recurrence of thymoma were found. In cases of thymoma, involvement of anti-VGKC complex antibodies should be considered when central nervous system symptoms appear, and when anti-VGKC complex antibodies are positive, recurrence or exacerbation of thymoma should be considered.

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.

Thymoma-associated anti-LGI1 encephalitis and myasthenia gravis: A unique combination with autoantibodies

We report a 77-year-old woman with a thymoma, anti-LGI1antibody associated encephalitis (LGI1 encephalitis), and MG accompanied by positive anti-acetylcholine receptor antibodies (AchR Ab) and anti-titin antibodies (titin Ab). She was treated with thymomectomy followed by immunosuppressive therapy, which resulted in immediate amelioration of motor weakness and gradual improvement of cognitive impairment over the next two years. LGI1 Ab were positive at two months after thymomectomy, followed by negative conversion demonstrated on 1 year examination. The AchR Ab level had gradually decreased but titin Ab was positive on re-examination after two years, although the cognition and motor impairment symptoms had been alleviated. In patients with suspected autoimmune encephalitis, the detection of several autoantibodies including LGI1 and thymomas provides useful information for making an accurate diagnosis.

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A rare case complicated with a thymoma, anti-LGI1antibody associated encephalitis, and myasthenia gravis.

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Accompanied by positive anti-acetylcholine receptor antibodies and anti-titin antibodies.

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The symptoms of encephalitis had improved with thymomectomy and immunosuppressive therapy.

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These unique combinations of the disease and autoantibodies will help us to diagnose and treat autoimmune encephalitis.

Gastroparesis, Thymoma, and Asymptomatic Myasthenia: A Rare Clinical Scenario

Background: Paraneoplastic gastroparesis is a gastrointestinal syndrome that rarely precedes a tumor diagnosis. To increase awareness of this rare clinical entity, we present a case of severe gastroparesis, which was later proven to be associated with a thymoma. Case report: A 55-year old man had the sudden onset of severe abdominal cramps and abdominal distension, early satiety with postprandial nausea, acid regurgitation, belching, and flatulence. He lost about 20 pounds. The physical and imaging examination revealed stomach distension, gastroparesis, and the presence of a solid mass in the anterior mediastinum. Radical surgery was performed to remove the thymoma and, given the high value of Mib-1, the patient was submitted to postoperative chest radiation therapy. After thymectomy, a diagnosis of paraneoplastic myasthenia gravis with subacute autonomic failure was made. Conclusion: Autoimmune gastroparesis should be considered as a potential paraneoplastic syndrome in patients with thymoma, myasthenia gravis, and delayed gastric emptying in the absence of mechanical obstruction.

Congenital thymoma

Thymomas are a heterogeneous group of tumors arising from the epithelium of the thymus. They are categorized by the proportion of neoplastic epithelia to lymphocytes and by the degree of cytologic atypia. Thymomas constitute 0.2-1.5% of all malignancies and nearly all occur in patients over 20 years. We reviewed the available literature and found less than 50 cases of thymoma reported in children (<18 years of age), the youngest being 4 years old, and no cases in newborns. They represent less than 1% of all mediastinal tumors in children. Due to the limited number of cases in the pediatric population, the diagnosis and treatment in this population is extremely challenging. Thymomas in all age groups may be associated with paraneoplastic syndromes, being myasthenia gravis the most common, which is associated with a worse prognosis in the pediatric population. We present the first case of a newborn infant with congenital thymoma. This case demonstrates a rare tumor in an unusual age group and emphasizes the importance of multidisciplinary teamwork in the decision-making and management of this condition.

The efficacy and safety of immunotherapy in thymic epithelial tumors: more effective, more risky: a systematic review

Background

Thymic epithelial tumors (TETs) are rare malignant neoplasms originating from thymic epithelial cells. The current treatment for localized TETs is surgical removal. However, 20-30% of thymomas and 70-80% of thymic carcinomas are unresectable, recurrent, or metastatic at the time of detection. The standard therapy for these patients is chemotherapy, but the effect is limited. With a deeper understanding of tumor immunity, immunotherapy for various cancers has rapidly developed. Antibodies against cytotoxic T-lymphocyte antigen-4, programmed death-1, and programmed death-ligand 1 have been approved for the treatment of many solid tumors. Compared with traditional treatments, these immune checkpoint inhibitors (ICIs) have better efficacy and lower toxicity. Recently, ICIs have been used more enthusiastically in the treatment of TETs. However, due to the unique biological characteristics of the thymus, immunotherapy usually causes severe immune-related adverse events (irAEs). Most previous studies on immunotherapy in TETs had small sample sizes and reported diverse conclusions.

Methods

We collected relevant studies in PubMed during the last five years and analyzed the available data to discuss the efficacy and safety of ICIs in TETs.

Results

According to 14 previous studies in the past five years, all TETs showed expression of programmed death-ligand 1, while thymic carcinomas showed 100% expression. The best median progression-free survival (mPFS) among the five studies was 6.5 months, and the best median overall survival (mOS) was 24.9 months. In addition, the most common irAEs were myasthenic symptoms, liver enzyme elevation, and elevated creatine phosphokinase levels.

Conclusions

ICIs can be used in TET treatment, especially for thymic carcinomas, in the absence of standard second-line treatment. However, more attention should be paid to irAEs.

Thymoma and Autoimmune Encephalitis: Clinical Manifestations and Antibodies

OBJECTIVE

To report the clinical, neuroimaging, and antibody associations in patients with autoimmune encephalitis (AE) and thymoma.

METHODS

A retrospective cohort study of 43 patients was conducted. Antibody determination and immunoprecipitation to characterize novel antigens were performed using reported techniques.

RESULTS

Patients' median age was 52 years (range: 23-88 years). Forty (93%) had neuronal surface antibodies: gamma-aminobutyric acid receptor A (GABA_AR) (15), amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) (13), contactin-associated protein-like 2 (CASPR2) (4), leucine-rich, glioma inactivated 1 (LGI1) (3), glycine receptor (GlyR) (3), and unknown antigens (2). Concurrent antibodies against intracellular antigens occurred in 13 (30%; 9 anti-collapsin response mediator protein 5 [CRMP5]) and were more frequent in anti-AMPAR encephalitis (54% vs 20%; p = 0.037). The most common clinical presentation was encephalitis with multiple T2/fluid-attenuated inversion recovery hyperintense lesions in 23 (53%) patients (15 GABA_AR, 5 AMPAR, and 1 unknown neuropil antibody), followed by encephalitis with peripheral nerve hyperexcitability in 7 (16%; 4 CASPR2, 2 LGI1, and 1 unknown antibody), limbic encephalitis in 6 (14%; 4 AMPAR, 1 LGI1, and 1 antibody negative), progressive encephalomyelitis with rigidity and myoclonus in 4 (9%; 3 GlyR and 1 AMPAR antibodies), and encephalitis with normal MRI in 3 (7%; AMPAR antibodies). Anti-GABA_AR encephalitis was more prevalent in Japanese patients compared with Caucasians and other ethnicities (61% vs 16%; p = 0.003). In anti-AMPAR encephalitis, 3/4 patients with poor and 0/6 with good outcome had concurrent CRMP5 antibodies (p = 0.033). Immunoprecipitation studies identified metabotropic glutamate receptor 3 antibodies that were additionally found in 5 patients (3 with and 2 without encephalitis).

CONCLUSIONS

AE in patients with thymoma include several clinical-radiologic syndromes that vary according to the associated antibodies. Anti-GABA_AR encephalitis was the most frequent AE and occurred more frequently in Japanese patients.

Thymoma-associated autoimmune encephalitis with positive Titin antibodies: A case report

We report a case of thymoma-associated autoimmune encephalitis with positive Titin antibodies. The patient had cognitive dysfunction, psychiatric symptoms and symptomatic epilepsy. PET-CT indicated space-occupied lesion at the thoracic entrance. The patient was diagnosed with paraneoplastic autoimmune encephalitis. After immunotherapy, his condition improved and underwent thymectomy. Pathology revealed type A thymoma. The patient recurred 10 days after the operation. Thymoma is associated with AE. And Titin antibodies may be involved in the extensive immune response to antigens which the patient's thymoma ectopically expressed. This case reflects the complexity of the immune relationship among autoimmune encephalitis, Titin antibodises and thymoma. Titin antibody may have a certain guiding significance for the treatment and prognosis of autoimmune encephalitis.

Thymoma and thymic carcinoma in children and adolescents: The EXPeRT/PARTNER diagnostic and therapeutic recommendations

Thymic tumors are epithelial tumors arising from the anterior mediastinum and constitute 0.2-1.5% of all adult malignancies but are exceptional in pediatric population. Thymic epithelial tumors (TETs) encompass a variety of histologic subtypes associated with different clinical outcomes. Due to its rarity in children, TETs' management requires a multidisciplinary approach. However, prognosis remains still poor, especially among patients with thymic carcinoma. This study presents the internationally recognized recommendations for the diagnosis and treatment of thymic tumors in children and adolescents, established by the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) group within the EU-funded project Paediatric Rare Tumours Network - European Registry (PARTNER).

Surgical outcomes of 215 patients with thymic epithelial tumors: A single-center experience

Objectives

To evaluate the oncological prognosis and neurological outcomes for patients with thymic epithelial tumors (TETs) after thymectomy.

Methods

Consecutive patients with TETs who underwent thymectomy at Beijing Hospital from January 2011 to December 2018 were retrospectively enrolled into the study. Clinical, pathological, and perioperative data was collected. Patients were followed‐up by telephone interview and outpatient records. Statistical analyses were performed using SPSS version 19.0.

Results

A total of 215 patients (115 men and 100 women) were included in this study of which 133 patients (61.9%) had TETs associated with myasthenia gravis (MG), and 82 patients (38.1%) had thymic tumors without MG. A total of 194 (90.2%) patients were successfully followed‐up. The median follow‐up period was 42 months. The five‐year overall survival (OS) rate was 88.6%. MG was the first cause of death for patients with MG (6/10). Prognosis in MG patients was similar to those without MG. Multivariate Cox regression analysis demonstrated that TNM stage III + IV was an independent risk factor for OS. Incomplete resection and younger age were risk factors for tumor recurrence. For patients with MG, the cumulative complete stable remission (CSR) rate increased with the postoperative follow‐up period, and the five‐year CSR rate was 44.7%. Univariate Cox analysis indicated that age, preoperative MG duration and preoperative medication might correlate with CSR. Multivariate Cox analysis only indicated older age as a negative factor of achieving CSR.

Conclusions

MG had little influence on OS and tumor recurrence of thymic tumors. The new TNM staging system was an independent prognostic factor. Incomplete resection and younger age were risk factors for tumor recurrence. Older age was a negative factor of achieving CSR for thymoma patients with MG after extended thymectomy.

Key points

18F-FDG PET/CT in a Patient With Thymoma-Associated Paraneoplastic Polymyositis

A 43-year-old woman presented with progressive muscle weakness and myalgia for 1 month. Laboratory tests revealed the elevation of myogenic enzymes. MRI of the thighs demonstrated a pattern of edema for inflammatory myopathy. Electromyography showed diffuse myopathic disorder, and muscle biopsy indicated polymyositis. F-FDG PET/CT was performed to investigate the potential paraneoplastic syndrome and revealed a soft tissue lesion with F-FDG avidity in the right anterior mediastinum, as well as diffusely increased activity throughout the body muscles. The patient's symptoms and biochemical abnormalities were gradually relieved after the tumor resection, and the histopathology indicated a type AB thymoma.

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.

Thymoma-Induced Autoimmune Hepatitis: A Rare Paraneoplastic Syndrome

Thymomas are rare neoplasms of the thymus and are often associated with immune-mediated paraneoplastic syndromes, most commonly, myasthenia gravis. The same underlying mechanism can produce antibodies to other self-antigens in various organ systems. Autoimmune hepatitis is a rare complication of thymoma. We present a 35-year-old healthy male, initially thought to have drug-induced liver injury, who was subsequently diagnosed with thymoma-induced autoimmune hepatitis, a rare syndrome of which only two previous cases have been reported.

Thymoma appearing 9 years after the resection of squamous cell carcinoma of the lip: A case report of triple primary tumors and literature review

The occurrence of second primary tumor (SPT)following malignancy treatment is common. In patients with head and neck (H&N) cancer, SPTs principally occur in the H&N region, lungs or esophagus. Therefore, patient follow-up after cancer treatment is important in order to detect recurrence, metastasis and new primary tumors. However, no standard guidelines on lifelong follow-up imaging are available. Herein, we report a patient who presented with three metachronous primary tumors-squamous cell carcinoma (SCC) of the tongue, SCC of the lip and type A thymoma. The third tumor was incidentally detected during follow-up using contrast-enhanced computed tomography (CT) 9 years following resection of the second tumor. To the best of our knowledge, this specific combination of metachronous tumors has not yet been reported. Based on the literature review, we observed that thymoma occurs following H&N cancer treatment. Therefore, to ensure that the presence of subsequent thymomas is not overlooked, we suggest regular lifelong follow-up using contrast-enhanced CT in patients who had previously been diagnosed with H&N cancer. The literature review revealed that thymomas occur in patients with H&N cancer and should be detected at the earliest convenience.

Incidence and clinical variable inter-relationships of thymic epithelial tumors in northwest China

Background

Thymic epithelial tumors (TETs) are the most common primary thymus tumors, but neither the possible ethnical/regional differences in the incidence of TETs nor the inter-relationships among the clinical variables has been revealed in northwest China.

Methods

A retrospective chart review was performed among pathologically confirmed TET patients from January 2004 to December 2015 in a tertiary general hospital of northwest China and the incidence, clinical features and the inter-relationships among clinical variables were analyzed.

Results

A total of 603 pathologically confirmed TETs patients (age range, 5-78 years; 308 males) were enrolled and the most common lesion location was anterior mediastinum (98.5%), among them, 192 (31.8%) had myasthenia gravis (MG). Twenty-six (5.7%), 112 (24.6%), 83 (18.2%), 137 (30.1%), 74 (16.3%), and 23 (5.1%) patients fell into the World Health Organization (WHO) type A, AB, B1, B2, B3 and thymic carcinoma (TC), respectively. The incidence of TETs was slightly higher in the female population and the age group of 40-60 years old. In addition, MG predominantly coexisted with WHO types A-B3 TETs and the TETs with MG were smaller than those without MG. The correct diagnosis rates were 42.3% (77 out of 182), 61.1% (127 out of 208), 89.3% (250 out of 280) and 75.0% (3 out of 4) for chest X-ray, non-contrast computed tomography (CT), contrast CT scan and magnetic resonance imaging (MRI), respectively.

Conclusions

Distinct gender and age differences exist in the incidence of TETs and the A-B3 TETs are closely related with MG. Contrast CT scan plays more important role in diagnosing TETs.

Current Treatment Options for Peripheral Nerve Hyperexcitability Syndromes

PURPOSE OF REVIEW

Peripheral nerve hyperexcitability (PNH) syndromes are divided into primary and secondary groups based on the presence or absence of demonstrable peripheral nerve disease. In this review, we systematically evaluate the evidence for current therapies and supportive managements based on autoimmune, paraneoplastic, and genetic components in pathophysiology reported in the literature.

RECENT FINDINGS

Current therapy options are based on symptomatic management as well as focusing the underlying immune/genetic/paraneoplastic pathology by immunosuppressants, chemotherapy, and surgery. Further research is desired to provide treatment options geared specifically towards addressing PNH. Supportive care can also be an area for future research.

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.

Myasthenia Gravis and Lambert-Eaton Myasthenic Syndrome

PURPOSE OF REVIEW

This article discusses the pathogenesis, diagnosis, and management of autoimmune myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS).

RECENT FINDINGS

Recognition of new antigenic targets and improved diagnostic methods promise to improve the diagnosis of MG, although the clinical phenotypes associated with newer antibodies have not yet been defined. Future therapies might specifically target the aberrant immune response. The apparent increase in the prevalence of MG is not fully explained. Results of a long-awaited trial of thymectomy support the practice of performing a thymectomy under specific conditions.

SUMMARY

The current treatment options are so effective in most patients with MG or LEMS that in patients with refractory disease the diagnosis should be reconsidered. The management of MG is individualized, and familiarity with mechanisms, adverse effects, and strategies to manage these commonly used treatments improves outcome. Patient education is important. LEMS, frequently associated with an underlying small cell lung cancer, is uncommon, and the mainstay of treatment is symptomatic in most patients.

Effect of thymectomy on refractory autoimmune status epilepticus

Refractory status epilepticus (RSE) is an increasingly recognized manifestation of autoimmune encephalitis, which can occur either as a paraneoplastic or non-paraneoplastic disorder. The effect of tumor removal in paraneoplastic status epilepticus has never been explored systematically, although early tumor treatment is usually recommended. In this study, we report clinical, pathological and EEG findings of a patient who developed RSE as one of multiple paraneoplastic manifestations of thymoma and the effect of thymectomy on seizure outcome. To our knowledge, this is the first report of successful treatment of RSE with tumor removal in paraneoplastic encephalitis.

Cixutumumab for patients with recurrent or refractory advanced thymic epithelial tumours: a multicentre, open-label, phase 2 trial

BACKGROUND

No standard treatment exists for refractory or relapsed advanced thymic epithelial tumours. We investigated the efficacy of cixutumumab, a fully human IgG1 monoclonal antibody targeting the insulin-like growth factor 1 receptor in thymic epithelial tumours after failure of previous chemotherapy.

METHODS

Between Aug 25, 2009, and March 27, 2012, we did a multicentre, open-label, phase 2 trial in patients aged 18 years or older with histologically confirmed recurrent or refractory thymic epithelial tumours. We enrolled individuals who had progressed after at least one previous regimen of platinum-containing chemotherapy, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had measurable disease and adequate organ function. Eligible patients received intravenous cixutumumab (20 mg/kg) every 3 weeks until disease progression or development of intolerable toxic effects. The primary endpoint was the frequency of response, analysed on an intention-to-treat basis. We also did pharmacodynamic studies. This trial is registered with ClinicalTrials.gov, number NCT00965250.

FINDINGS

49 patients were enrolled (37 with thymomas and 12 with thymic carcinomas) who received a median of eight cycles of cixutumumab (range 1-46). At the final actuarial analysis when follow-up data were updated (Nov 30, 2012), median potential follow-up (from on-study date to most current follow-up date) was 24·0 months (IQR 17·3-36·9). In the thymoma cohort, five (14%) of 37 patients (95% CI 5-29) achieved a partial response, 28 had stable disease, and four had progressive disease. In the thymic carcinoma cohort, none of 12 patients (95% CI 0-26) had a partial response, five had stable disease, and seven had progressive disease. The most common grade 3-4 adverse events in both cohorts combined were hyperglycaemia (five [10%]), lipase elevation (three [6%]), and weight loss, tumour pain, and hyperuricaemia (two each [4%]). Nine (24%) of 37 patients with thymoma developed autoimmune conditions during treatment (five were new-onset disorders), the most common of which was pure red-cell aplasia. Two (4%) patients died; one was attributed to disease progression and the other to disease-related complications (respiratory failure, myositis, and an acute coronary event), which could have been precipitated by treatment with cixutumumab.

INTERPRETATION

Cixutumumab monotherapy is well-tolerated and active in relapsed thymoma. Development of autoimmunity during treatment needs further investigation.

FUNDING

Division of Cancer Treatment and Diagnosis at the National Cancer Institute (National Institutes of Health), ImClone Systems.

A survival case of invasive thymoma accompanied by acute fulminant myocarditis

Thymomas are associated with a wide spectrum of autoimmune paraneoplastic diseases. Here we report the case of 31-year-old male with invasive thymoma, myasthenia gravis, polymyositis, and acute fulminant myocarditis that presented with cardiogenic shock requiring intra-aortic balloon pumping and percutaneous cardiopulmonary support. Corticosteroid therapy was effective. To our knowledge, this is the first case of thymoma with acute fulminant cardiomyositis that was successfully treated by assisted circulation and corticosteroids, despite a poor prognosis.

Overlooked non-motor symptoms in myasthenia gravis

Patients with myasthenia gravis (MG) may have various non-motor symptoms in addition to fatigability and weakness of skeletal muscles. Thymomas contain abundant immature thymocytes and developing CD4 and CD8 T cells. Thymomas are found in 15-25% of patients with MG and are associated with severe symptoms. We suggest that non-motor symptoms are based on the autoimmune disorders probably owing to an abnormal T cell repertoire from thymomas. Using previously reported cases and cases from our multicentre cooperative study, we review the clinical characteristics of patients with thymoma-associated MG who have non-motor symptoms. CD8 T cell cytotoxicity against haematopoietic precursor cells in bone marrow and unidentified autoantigens in hair follicles lead to the development of pure red cell aplasia, immunodeficiency and alopecia areata. In contrast, neuromyotonia, limbic encephalitis, myocarditis and taste disorders are autoantibody-mediated disorders, as is MG. Autoantibodies to several types of voltage-gated potassium channels and the related molecules can evoke various neurological and cardiac disorders. About 25% of patients with thymoma-associated MG have at least one non-motor symptom. Non-motor symptoms affect many target organs and result in a broad spectrum of disease, ranging from the impairment of quality of life to lethal conditions. Since relatively little attention is paid to non-motor symptoms in patients with thymoma-associated MG, the symptoms may be overlooked by many physicians. Early diagnosis is important, since non-motor symptoms can be treatable. A complete understanding of non-motor symptoms is necessary for the management of patients with thymoma-associated MG.

A review of thymic tumors

Thymic tumors represent 0.2-1.5 % of all malignancies with an incidence of 0.15 per 100,000 population. Thymic tumors are most common tumors of the anterior mediastinum accounting for 20 % of all mediastinal tumors and 50 % of all anterior mediastinal tumors. Over 90 % of all thymic tumors occur in anterior mediastinum, remainder occurring in neck or other mediastinal areas especially aortopulmonary window and retro cardiac area which are common sites for ectopic thymic tissues and possible explanation for failure in some cases of simple thymectomy to improve Myasthenia Gravis(MG). The aim of this review is to discuss histologic classification, diagnostic features, evaluation, management and prognosis of thymic tumors.

Multiple paraneoplastic syndromes: myasthenia gravis, vitiligo, alopecia areata, and oral lichen planus associated with thymoma

Thymomas are associated with paraneoplastic autoimmune diseases at a high frequency. It is rare that four paraneoplastic autoimmune disorders co-occur in a single patient. We describe a thymoma patient with diagnoses of myasthenia gravis, vitiligo, alopecia areata, and oral lichen planus associated with a thymoma. After thymectomy, the weakness, vitiligo, alopecia and mucocutaneous lesions were improving progressively, possibly implicating the thymoma in initiating these autoimmune conditions. We believe that this is the first report of this particular combination of multiple paraneoplastic syndromes associated with thymoma.

Patients with thymomas have an increased risk of developing additional malignancies: lack of immunological surveillance?

AIMS

To assess the risk, for patients with thymoma, of developing an additional malignancy (AM).

METHODS AND RESULTS

We studied 68 patients with thymomas. Based on the World Health Organization classification, the tumours were categorised as A, AB or B (B1, B2, B3) thymomas. Control populations comprised 114 patients with colorectal cancer, 108 patients with lymphoma and 123 patients with thyroid carcinoma. Patients with thymomas showed a higher risk of developing an AM (22 of 68 patients versus 11 of 114, eight of 108, and eight of 123 patients, respectively; P = 0.0002). The association between thymomas and AMs was related to the thymoma histotype, with B1, B2, B3 and AB tumours showing a higher risk of developing an AM than A thymomas (P = 0.0474).

CONCLUSIONS

Patients affected by thymomas showed a significantly higher risk of developing additional malignancies than those in the control groups, and cases that exhibited a predominantly cortical component were more likely to develop other neoplasms. This may be related to the functions of cortical thymic epithelial cells in providing for T lymphocyte maturation through interaction with major histocompatibility complexes.

Paraneoplastic encephalitis associated with myasthenia gravis and malignant thymoma

We present a patient with type B2 thymoma (World Health Organization Thymoma Classification) with the complications of anti-muscle acetylcholine receptor antibody-positive myasthenia gravis and anti-voltage-gated potassium channel antibodies associated with paraneoplastic encephalitis. A timing difference between the onset of these neurological disorders and a dissociation of clinical symptoms was observed during the disease. This report alerts clinicians that long-term follow-up is needed where patients have a residual thymoma and attention should be paid to other concomitant autoimmune disorders.

Neuromuscular complications

Although direct neoplastic involvement of muscle tis-sue is surprisingly rare, considering the large amount of body mass that is represented by muscle tissue, the most important and unresolved muscle effect is muscle cachexia.Other associations, such as inflammatory, paraneo-plastic, toxic, and several extremely rare associations,have been described. Drug-induced toxicity and radiation recall syndrome need to be taken into consideration when muscle symptoms appear in patients with cancer.

Autoimmunity to endoplasmic reticulum chaperone GRP94 in myasthenia gravis

Immune responses to ER stress have been closely related to the pathogenesis of autoimmune diseases. Using an immunoprecipitation assay, 24 (7.1%) of 336 MG serum samples immunoprecipitated a 90-kDa protein from the muscle cellular extracts, but none of the disease or healthy control sera. The 90-kDa protein was affinity-purified and found to match to ER chaperon GRP94 by matrix-assisted laser desorption/ionization-time of flight mass spectroscopy analysis. The frequency of associated autoimmune diseases was much higher in the anti-GRP94-positive than the -negative patients (71% versus 11%, p<0.001). Autoimmunity to ER chaperone GRP94 is associated with a subset of MG patients who have additional autoimmune diseases.

Autoantibodies in neuromuscular transmission disorders

It is a great pleasure to be asked to honour the memory of Dr. Baldev Singh by reviewing the field of autoantibodies in myasthenia gravis and other neurotransmission disorders. The neuromuscular junction (NMJ) is the site of a number of different autoimmune and genetic disorders, and it is also the target of many neurotoxins from venomous snakes, spiders, scorpions and other species. The molecular organization of the NMJ is graphically represented in Figure 1A, where different ion channels, receptors and other proteins are shown. Four of the ion channels or receptors are directly involved in autoimmune diseases. This brief review will not only concentrate on these conditions but also illustrate how their study is helping us to understand the etiology of rare but treatable neurological syndromes of the central nervous system.

[Hodgkin disease and autoimmunity in children: 11 case reports]

The association of lymphoma and autoimmune manifestations has been predominantly studied in adults affected by non-Hodgkin lymphoma. Few publications exist in the literature concerning Hodgkin lymphoma, particularly in children and adolescents. The objectives of this study were to define the characteristics of the link between Hodgkin disease and autoimmunity in childhood. The present 25-year retrospective study was conducted in all centers affiliated with the French Society of Paediatric Oncology (SFCE). Eleven children with Hodgkin disease presented manifestations of disimmunity preceding or following their diagnosis. Four patients had thrombocytopenic purpura, the remaining 7 each had a different autoimmune pathology: lupus syndrome, antiphospholipid syndrome with transient ischemic attack, Evans syndrome, leukocytoclastic vasculitis, autoimmune hemolytic anemia, autoimmune thyroiditis, and juvenile idiopathic arthritis. Lymphoma relapse occurred in 3 patients. Two children died, death being directly attributed to the autoimmune disease in 1 case. Our data suggest that development of autoimmunity is related to significant morbidity. Possible pathophysiological mechanisms include lymphocyte proliferation secondary to chronic inflammation, cell-mediated immune deficiency in Hodgkin disease, molecular mimetics, and antineoplastic phenomena are discussed. A study with a larger patient population is needed to identify the group of children at high risk of autoimmunity for whom additional investigations and modified therapy may be indicated.

Aquaporin-4 water channel expression by thymoma of patients with and without myasthenia gravis

BACKGROUND

Neuromyelitis optica (NMO) is a serious idiopathic inflammatory demyelinating disorder characterized by acute transverse myelitis and optic neuritis. A significant proportion of NMO patients are seropositive for NMO-IgG, an autoantibody targeting aquaporin-4 (AQP4) water channel. Paraneoplastic NMO associated various tumors were recently reported.

AIM

We studied the expression of AQP4 by thymoma from patients with and without myasthenia gravis (MG).

METHODS

Thymoma obtained from thymomectomy in patients with and without MG were studied by immunohistochemistry and western blot.

RESULTS

Ten thymoma patients (9 with MG) and two control patients without thymoma or MG were studied. Immunohistochemistry revealed AQP4 immunoreactivity in cell membrane of thymoma cells from all ten thymoma specimens whereas thymic tissues from patients without thymoma or MG were negative for AQP4 immunoreactivity. Western blot revealed that lysates of nine of the ten thymoma specimens reacted with anti-human AQP4 antibody with a band of ~30 kDa compatible with the molecular weight of AQP4. Interestingly, immunofluorescence revealed that IgG isolated from 2 NMO patients seropositive for NMO-IgG bound to cell membrane of thymoma cells from all ten thymoma specimens while IgG from healthy control subject did not.

CONCLUSION

Thymoma cells of patients with and without MG express AQP4. AQP4 autoantibodies from serum of NMO patients bound to AQP4 expressed on thymoma cell membrane.