Thymoma in myasthenia gravis: from diagnosis to treatment

Treating myasthenia gravis beyond the eye clinic

Myasthenia gravis (MG) is one of the most well characterised autoimmune disorders affecting the neuromuscular junction with autoantibodies targeting the acetylcholine receptor (AChR) complex. The vast majority of patients present with ocular symptoms including double vision and ptosis, but may progress on to develop generalised fatiguable muscle weakness. Severe involvement of the bulbar muscles can lead to dysphagia, dysarthria and breathing difficulties which can progress to myasthenic crisis needing ventilatory support. Given the predominant ocular onset of the disease, it is important that ophthalmologists are aware of the differential diagnosis, investigations and management including evolving therapies. When the disease remains localised to the extraocular muscles (ocular MG) IgG1 and IgG3 antibodies against the AChR (including clustered AChR) are present in nearly 50% of patients. In generalised MG this is seen in nearly 90% patients. Other antibodies include those against muscle specific tyrosine kinase (MuSK) and lipoprotein receptor related protein 4 (LRP4). Even though decremental response on repetitive nerve stimulation is the most well recognised neurophysiological abnormality, single fibre electromyogram (SFEMG) in experienced hands is the most sensitive test which helps in the diagnosis. Initial treatment should be using cholinesterase inhibitors and then proceeding to immunosuppression using corticosteroids and steroid sparing drugs. Patients requiring bulbar muscle support may need rescue therapies including plasma exchange and intravenous immunoglobulin (IVIg). Newer therapeutic targets include those against the B lymphocytes, complement system, neonatal Fc receptors (FcRn) and various other elements of the immune system.

Analysis of events from sudden isolated dysarthria to diagnosis of myasthenic crisis: myasthenia gravis mimicking acute lacunar stroke-a case report

BACKGROUND

Myasthenic crisis (MC) is a life-threatening complication of myasthenia gravis (MG), necessitating ventilation. Achieving a safe and timely diagnosis of myasthenic crisis with atypical, isolated presentation is a considerable challenge particularly in elderly patients, where myasthenia gravis can present with isolated dysarthria in rare instances, giving a clinical impression of lacunar stroke.

CASE PRESENTATION

We present a compelling case of a 73-year-old Caucasian female presenting with abrupt onset of isolated dysarthria. Despite initial treatment for a presumed lacunar stroke, subsequent evaluations led to her diagnosis of a myasthenic crisis. Within 72 h of admission, the patient developed dysphagia and shortness of breath, requiring supplemental oxygen. The case highlights the sequential progression of events from the atypical presentation of isolated dysarthria and its course to the management of a myasthenic crisis.

CONCLUSION

Our reported case focuses on the discussion of myasthenia that mimicked a lacunar stroke and was finally diagnosed at a critical time of medical crisis. This case highlights the imperative notion that isolated dysarthria in elderly individuals warrants vigilant monitoring for possible myasthenia gravis, given the low incidence of lacunar stroke presenting with only dysarthria.

Long-term prognosis in patients with thymoma combined with myasthenia gravis: a propensity score-matching analysis

Introduction

We aimed to assess the impact of myasthenia gravis (MG) on the long-term prognosis in patients with thymoma after surgery and identify related prognostic factors or predictors.

Methods

This retrospective observational study included 509 patients with thymoma (thymoma combined with MG [MG group] and thymoma alone [non-MG group]). Propensity score matching was performed to obtain comparable subsets of 96 patients in each group. A comparative analysis was conducted on various parameters.

Results

Before matching, the 10-year survival and recurrence-free survival rates in both groups were 93.8 and 98.4%, and 85.9 and 93.4%, respectively, with no statistically significant difference observed in the survival curves between the groups (p > 0.05). After propensity score matching, 96 matched pairs of patients from both groups were created. The 10-year survival and recurrence-free survival rates in these matched pairs were 96.9 and 97.7%, and 86.9 and 91.1%, respectively, with no statistical significance in the survival curves between the groups (p > 0.05). Univariate analysis of patients with thymoma postoperatively revealed that the World Health Organization histopathological classification, Masaoka-Koga stage, Tumor Node Metastasis stage, resection status, and postoperative adjuvant therapy were potentially associated with tumor recurrence after thymoma surgery. Multivariate analysis demonstrated that the Masaoka-Koga stage and postoperative adjuvant therapy independently predicted the risk of recurrence in patients with thymoma after surgery.

Conclusion

There was no difference in prognosis in patients with thymoma with or without MG. The Masaoka-Koga stage has emerged as an independent prognostic factor affecting recurrence-free survival in patients with thymoma, while postoperative adjuvant therapy represents a poor prognostic factor.

Epidemiology, Patient Characteristics, and Treatment Patterns of Myasthenia Gravis in Taiwan: A Population-Based Study

INTRODUCTION

Myasthenia gravis (MG) is a chronic neuromuscular disease leading to significant disease burden. This study aimed to investigate the epidemiology of MG in Taiwan.

METHODS

A retrospective study was conducted using the Taiwan National Health Insurance Research Database. Prevalent patients with MG diagnosis (either ocular or generalized MG) from 2013 to 2019 were identified, and 2813 patients with initial MG diagnosis from 2014 to 2019 were further defined as the incident cohort. Patient characteristics, treatment patterns, and the occurrence of MG-related events were analyzed.

RESULTS

The number of prevalent patients with MG increased from 4476 in 2013 to 5752 in 2019, with the prevalence rate increasing from 19 to 24 per 100,000 population. The incidence rate also slightly increased from 1.9 to 2.3 per 100,000 population during the study period. Almost all incident patients (99%, n = 2791) received MG-related treatment during the follow-up period. Among 1876 patients who received monotherapy as their initial treatment in the outpatient setting, the mean time from the index date to initial treatment was 48.8 (standard deviation 164.3) days, and most patients received acetylcholinesterase inhibitors (88.5%, n = 1661) as their initial treatment. During the first year after the index date, 133 (4.7%) incident patients experienced their first myasthenic crisis, and 96.2% of these events occurred within 3 months.

CONCLUSION

The prevalence of MG increased steadily in Taiwan, and the treatment of patients with MG was consistent with guidelines. Despite a high treatment rate, patients still experienced MG-related events, highlighting the limitation of current treatments and emphasizing the need for early intervention and novel treatment approaches.

Coexistence of myasthenia gravis and lichen planus: A case report and systematic review of related case reports from 1971 to 2024

Key Clinical Message

The co-occurrence of myasthenia gravis (MG) and lichen planus (LP) is a rare phenomenon, with only 13 cases reported in the English literature between 1971 and 2024. Patients with MG or LP, regardless of the thymoma status, require close monitoring for other autoimmune diseases.

Abstract

Myasthenia gravis (MG) is an uncommon autoimmune disease, resulting in fatigable muscle weakness in the ocular, bulbar, and respiratory muscles, as well as muscles of the extremities. Lichen planus (LP) is an autoimmune mucocutaneous disease, presenting with pruritic and violaceous plaques on the skin and mucosal surfaces. So far, MG and LP co-occurrence is only reported in anecdotal individuals. This study reports a patient with MG and LP and systematically reviews the English literature on this rare co-occurrence from 1971 to 2024, indicating only 13 cases with similar conditions. A 67-year-old man presented with ocular and progressive bulbar symptoms, a year after being diagnosed with generalized LP. Laboratory evaluations were normal except for the high anti-AchR-Ab titer and a positive ANA titer. Neurologic examinations revealed asymmetric bilateral ptosis, weakness and fatigability in proximal muscles, and a severe reduction in the gag reflex. He was diagnosed with late-onset, seropositive MG. The treatment included pyridostigmine (60 mg, three times daily), intravenous immunoglobulin (25 g daily for 5 days), and oral prednisolone. There was no evidence of thymoma in the chest x-ray and CT scan without contrast. However, a CT scan with contrast was not performed due to the patient's unstable condition. A common autoimmune mechanism may underlie the unclear pathophysiology of MG and LP co-occurrence, with or without thymoma. Patients with MG, LP, or thymoma require close monitoring and assessment for other possible autoimmune diseases.

International recommendations for screening and preventative practices for long-term survivors of transplantation and cellular therapy: a 2023 update

As hematopoietic cell transplantation (HCT) and cellular therapy expand to new indications and international access improves, the volume of HCT performed annually continues to rise. Parallel improvements in HCT techniques and supportive care entails more patients surviving long-term, creating further emphasis on survivorship needs. Survivors are at risk for developing late complications secondary to pre-, peri- and post-transplant exposures and other underlying risk-factors. Guidelines for screening and preventive practices for HCT survivors were originally published in 2006 and updated in 2012. To review contemporary literature and update the recommendations while considering the changing practice of HCT and cellular therapy, an international group of experts was again convened. This review provides updated pediatric and adult survivorship guidelines for HCT and cellular therapy. The contributory role of chronic graft-versus-host disease (cGVHD) to the development of late effects is discussed but cGVHD management is not covered in detail. These guidelines emphasize special needs of patients with distinct underlying HCT indications or comorbidities (e.g., hemoglobinopathies, older adults) but do not replace more detailed group, disease, or condition specific guidelines. Although these recommendations should be applicable to the vast majority of HCT recipients, resource constraints may limit their implementation in some settings.

Epidemiology of myasthenia gravis in France: Incidence, prevalence, and comorbidities based on national healthcare insurance claims data

BACKGROUND

The European literature has reported high variability in the incidence and prevalence rates of myasthenia gravis (MG), but no specific epidemiological data for France have been published. This study aimed to assess the incidence and prevalence rates of myasthenia gravis in France based on data extracted from the French National Health Insurance Claims Database (the SNIIRAM database).

METHODS

We conducted a retrospective repeated cross-sectional population study from 2008 to 2018 using a representative sample of the French population (Échantillon généraliste des bénéficiaires) covered by health insurance. We calculated the incidence, prevalence, and sex ratio of MG and screened for comorbidities associated with MG (standardized to the general population).

RESULTS

In total, 331 MG patients were identified between 2008 and 2018. The average incidence of MG in France was 50 per million person-years, while the mean prevalence was 465 per million people. The female-to-male ratio was 1.33. The Incidence of MG gradually increased from 40years of age for women and 60 for men. Thymoma was present for 5.1% of MG patients and a thymectomy was performed for 4.7%. Thyroid disease was the most prevalent autoimmune comorbidity, affecting approximately 8.5% of cases. MG patients had an increased cancer risk, with a standardized rate ratio of 2.38 (95% CI: 1.64-3.46).

CONCLUSION

The incidence and prevalence rates of MG are significantly higher than those previously reported in the literature and the incidence increases with age. The excess risk of cancer raises concerns for MG patients, in particular, concerning the management of immunosuppressive drugs.

Are the minimally invasive techniques the new gold standard in thymus surgery for myasthenia gravis? Experience of a reference single-site in VATS thymectomy

The thymus is the primary lymphoid organ responsible for the maturation and proliferation of T lymphocytes. During the first years of our lives, the activation and inactivation of T lymphocytes occur within the thymus, facilitating the correct maturation of central immunity. Alterations in the positive and negative selection of T lymphocytes have been studied as the possible origins of autoimmune diseases, with Myasthenia Gravis (MG) being the most representative example. Structural alterations in the thymus appear to be involved in the initial autoimmune response observed in MG, leading to the consideration of thymectomy as part of the treatment for the disease. However, the role of thymectomy in MG has been a subject of controversy for many years. Several publications raised doubts about the lack of evidence justifying thymectomy's role in MG until 2016 when a randomized study comparing thymectomy via sternotomy plus prednisone versus prednisone alone was published in the New England Journal of Medicine (NEJM). The results clearly favored the group of patients who underwent surgery, showing improvements in symptoms, reduced corticosteroid requirements, and fewer recurrences over 3 years of follow-up. In recent years, the emergence of less invasive surgical techniques has made video-assisted or robotic-assisted thoracoscopic (VATS/RATS) thymectomy more common, replacing the traditional sternotomy approach. Despite the increasing use of VATS, it has not been validated as a technique with lower morbidity compared to sternotomy in the treatment of MG. The results of the 2016 trial highlighted the benefits of thymectomy, but all the patients underwent surgery via sternotomy. Our hypothesis is that VATS thymectomy is a technique with lower morbidity, reduced postoperative pain, and shorter postoperative hospital stays than sternotomy. Additionally, VATS offers better clinical improvement in patients with MG. The primary objective of this study is to validate the VATS technique as the preferred approach for thymectomy. Furthermore, we aim to analyze the impact of VATS thymectomy on symptoms and corticosteroid dosage in patients with MG, identifying factors that may predict a better response to surgery.

Prolapsing Intrigue: A Case of Superior Vena Cava Mass Visualized by Echocardiography From the Subcostal Window Unveiling an Anterior Mediastinal Type B2 Thymoma

Imaging the superior vena cava (SVC) during two-dimensional (2D) transthoracic echocardiographic examination is challenging and should be performed routinely. Here, we present a case where a lower (juxta-atrial) SVC mass was seen prolapsing into the right atrium by 2D transthoracic echocardiography; in this case, the imaging of the lower (juxta-atrial) SVC was done from the subcostal window. It was not possible to image the SVC from the suprasternal, right supraclavicular, left parasternal, or apical windows. CT scan of the chest with intravenous contrast was done in this case and showed an anterior mediastinal mass invading the SVC and prolapsing into the right atrium. CT-guided biopsy proved the mass to be a type B2 thymoma.

Therapeutic and prognostic features in myasthenia gravis patients followed in a tertiary neuromuscular diseases center in Turkey

Introduction

In this study, we aim to evaluate the treatment responses and prognostic characteristics of Myasthenia Gravis (MG) patients followed in a tertiary neuromuscular diseases center in Turkey.

Methods

One hundred seventy four MG patients (between years 2011 and 2022) in Antalya, Turkey were diagnosed, and evaluated on a classification of MG was based on Myasthenia. Gravis Foundation of America (MGFA) clinical classification. Exclusion of other possible diseases in the differential diagnosis and support by beneficial response to treatment with acetylcholinesterase inhibitors were also taken into consideration.

Results

Mean age of participants was 54.86 (SD = 14.856; min-max = 22-84). Ninety (51.7%) were female. MG was more common in women under the age of 65 (58%) and in men over the age of 65 (64%). Generalized MG was seen in 75.3% of the patients. Anti-AChR positivities were detected in 52.3%, Anti-MuSK positivity in 4.6%, and seronegativity in 22.4%. Thymoma was detected in nearly 9.8% and thymectomy was performed in 28.7 percent. Most of the patients (57.5%) were using corticosteroids. Azathioprine was used by 39% and mycophenolate mofetil by 10.3% of patients. Mortality was higher and disease was more severe in late-onset (>50 years) MG patients (especially in the COVID-19 pandemic). Eight patients (four women, four men, mean age 75.5 years) died during follow-up. None of them died due to myasthenic worsening, two died due to malignancy and two due to infection. During the COVID pandemic, 16 patients (9.2%) had COVID infection. Four patients died due to COVID-19 infection, these four patients had serious comorbidities, and three of them were elderly (>75 years).

Conclusion

In conclusion, MG is more common in women between the ages of 20-40 and in men over the age of 65. The use of corticosteroids was more common under the age of 50, and the use of non-steroidal immunosuppressant agents was more common over the age of 50. Thymectomy is still an important supportive treatment approach in anti-AChR positive and seronegative generalized patients under 50 years of age. IVIG and plasmapheresis are effective treatments during acute exacerbations and bridging periods of treatments. Specific treatments are needed especially for resistant group of patients.

COVID-19 vaccination-related autoimmune hepatitis-a perspective

Autoimmune hepatitis (AIH) is the inflammation of the liver with clear-cut interface hepatitis and piecemeal necrosis located at the boundary between portal areas and periportal hepatocytes, and characterized by autoimmunity to hepatocytes with an increase in the antinuclear antibody. After the disastrous SARS-CoV-2 pandemic flagellated several countries, several vaccines have been commercialized and have become a ground for social responsibility. The mRNA vaccines, issued by Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273), do not use prebuilt viruses to supply the antigen in the subject's body and are not perfect but have been useful in tackling the pandemic. Nevertheless, both myocarditis and AIH have been reported as side effects of the vaccination programs in addition to thromboembolic events. Here, we explore this topic and give a data-based perspective, gathering a comparison between the titin protein of the sarcomere and myocarditis. The isolation of a Drosophila gene using the serum from a patient with autoimmune scleroderma recognized an epitope on chromosomes (condensed mitotic form) in both human cultured cells and early Drosophila embryos. It revealed that this gene encodes a Drosophila homolog of the vertebrate titin (D-Titin). Moreover, anti-titin antibodies have been found in a subset of patients with myasthenia gravis, a neuromuscular junction disease that is mostly associated with autoimmune antibodies, such as the anti-acetylcholine receptor antibody. The co-existence of myasthenia gravis and autoimmune hepatitis is rare, and a cohort of patients with myasthenia gravis anti-titin antibodies seems to be highly relevant. In consideration of these data and the number of patients who may not be symptomatic, we postulated that autoimmune phenomena may not be exceedingly rare, following the administration of mRNA technology-based vaccines, and a balance between pros and cons in administrating boosters is critical.

Novel Immunotherapies for Myasthenia Gravis

Myasthenia gravis (MG), a prototype autoimmune neurological disease, had its therapy centred on corticosteroids, non-steroidal broad-spectrum immunotherapy and cholinesterase inhibitors for several decades. Treatment-refractory MG and long-term toxicities of the medications have been major concerns with the conventional therapies. Advances in the immunology and pathogenesis of MG have ushered in an era of newer therapies which are more specific and efficacious. Complement inhibitors and neonatal Fc receptor blockers target disease-specific pathogenic mechanisms linked to myasthenia and have proven their efficacy in pivotal clinical studies. B cell-depleting agents, specifically rituximab, have also emerged as useful for the treatment of severe MG. Many more biologicals are in the pipeline and in diverse stages of development. This review discusses the evidence for the novel therapies and the specific issues related to their clinical use.

Atypical Seropositive Striated Muscle Antibody Myasthenia Gravis Presentation With Metastatic B1 Thymoma: A Rare Case

The association between myasthenia gravis (MG) and thymomas is well-documented. Thymomas are rare epithelial cell tumors that arise from the thymus gland and occur in the mediastinum. Myasthenia gravis is a neuromuscular disorder that causes skeletal muscle weakness due to the presence of anti-acetylcholinesterase antibodies. Roughly 60% of thymomas are associated with MG, while only 10% of MG patients have thymomas. We present an atypical presentation of myasthenia gravis with an associated unusual metastatic thymoma. This case is of a young, previously healthy 26-year-old male with no previous medical history who presented with non-specific symptoms of fatigue, diarrhea, abdominal pain, back pain, blurry vision, and unintended weight loss. He underwent treatment with intravenous immunoglobulins (IVIG), had two surgical resections of the thymoma, and ultimately received radiotherapy. Based on our experience with this case, diagnosing myasthenia gravis by testing for specific muscle antibodies for patients with ptosis in the setting of non-specific complaints, including fatigue, vomiting, diarrhea, and abdominal or back pain, should be considered. Routine imaging should follow with a chest computed tomography to screen for thymomas if the specific anti-titin and anti-ryanodine receptor (anti-RyR) muscle antibodies are positive and myasthenia gravis is suspected. If a thymoma is confirmed, it is best to confirm; and mass characterizes with chest magnetic resonance imaging. A treatment approach of IVIG followed by surgical resection and possible debulking if the lesion is deemed metastatic could also be considered thereafter, especially in young patients with few comorbidities. Treatment with Pyridostigmine 30 mg twice daily for 25 days post-surgically and radiation for treatment of any remaining unresectable tumor should also be considered.

Aberrant Dendritic Cell Subsets in Patients with Myasthenia Gravis and Related Clinical Features

INTRODUCTION

Dendritic cells (DCs) play critical roles in the pathogenesis of myasthenia gravis (MG), and a series of DC-based experimental strategies for MG have recently been developed. However, the definite roles of different DC subsets in the mechanism of MG have scarcely been covered by previous studies. The present study aimed to investigate the levels of three main DC subsets, plasmacytoid DCs (pDCs) (CD303 positive) and two distinct subsets of conventional DCs (cDCs), namely CD1c+ cDCs and CD141+ cDCs, in MG patients and analyze related clinical features.

METHODS

From January 2016 to December 2020, 160 newly diagnosed MG patients and matched healthy controls (n = 160) were included in the study, and their clinical data were collected. The blood samples from MG patients before treatment and controls were collected for flow cytometry analysis. A total of 14 MG thymoma, 24 control thymoma, and 3 thymic cysts were used to immunostain the DC subsets.

RESULTS

The flow cytometry analysis showed a significantly higher frequency of circulating pDCs, CD1c+ cDCs, and CD141+ cDCs in MG patients than in healthy controls (p < 0.001 for all). Patients with early-onset MG (<50 years old) had a lower frequency of circulating pDCs but a higher frequency of circulating CD1c+ cDCs than those with late-onset MG (≥50 years old) (p = 0.014 and p = 0.025, respectively). The frequency of circulating pDCs was positively associated with the clinical severity of late-onset MG patients (r = 0.613, p < 0.001). 64.3% (9/14) of MG thymoma is of type B2 under the World Health Organization classification, which is higher than that in control thymoma (33.3%, 8/24) (p = 0.019). For type B2 thymoma, there were significantly more pDCs but fewer CD1c+ cDCs in MG thymoma than in the controls.

CONCLUSION

The distribution of aberrant pDCs, CD1c+ cDCs, and CD141+ cDCs in MG patients displayed age- and thymoma-related differences, which may contribute to the impaired immune tolerance and lead to the onset of MG.

B3 thymoma mimicking poorly differentiated thyroid carcinoma: Diagnostic pitfalls of anterior mediastinal mass fine needle aspiration

B3 thymoma is a rare malignant type of thymic epithelial neoplasm found in the anterior mediastinum. Diagnosis of thymoma from fine needle aspiration (FNA) can be challenging due to the infrequency of sampling and its morphologic overlap with other entities such as squamous cell carcinoma, lymphoma or thyroid carcinoma. We report a case of B3 thymoma mimicking poorly differentiated thyroid carcinoma. We present its diagnostic pitfalls on cytology specimens, especially where it concerns identifying the correct location of the lesion, discuss the differential diagnosis, and correlation with the corresponding surgical resection specimen. A neck computed tomography angiogram (CTA) revealed a partially calcified 2.1 cm mass inferior to the left thyroid lobe in a 51 yr old woman being evaluated for stroke/TIA symptoms. She was referred for evaluation of the lesion. On the initial FNA and core needle biopsy, the lesion showed high-grade epithelioid cells with abundant lymphocytic infiltration and occasional necrosis, and was diagnosed as a high-grade carcinoma, favored to represent a poorly differentiated thyroid carcinoma considering the location on imaging. The patient subsequently underwent total thyroidectomy, central neck dissection, and thymectomy. Final surgical pathologic diagnosis indicated a type B3 thymoma. Due to the infrequency of sampling, thymoma poses a diagnostic challenge on preoperative FNA or core needle biopsy. Herein, we present a case of B3 thymoma with a preoperative cytologic specimen that consisted of hyperchromatic sheets of epithelioid tumor cells with a background of lymphocytes without definitive follicular cells or colloid. The core needle biopsy and cell block material showed abundant necrosis, intermixed lymphocytes and neoplastic epithelial cells with strong positive staining for pan-keratin and p40. The cytology and core needle biopsy material were interpreted as representing a probable thyroid neoplasm and raised a broad differential including anaplastic thyroid carcinoma, poorly differentiated thyroid carcinoma with squamous features, metastatic squamous carcinoma, and metastatic carcinoma to a lymph node. The final surgical resection specimen showed a B3 type-thymoma.

A Rare Phenomenon of Isaacs Syndrome: A Case Report

We illustrate the case of a 71-year-old male who initially presented with sudden onset muscle weakness and ambulation difficulty. Following medication discontinuation and additional clinical studies, he failed to improve and was admitted to the hospital 11 weeks later. He had an associated 20-pound weight loss, sudorrhea, and muscle stiffness only when weight-bearing. A complete connective tissue cascade and a paraneoplastic panel were obtained. Clinical diagnosis of acquired neuromyotonia, or Isaacs syndrome (IS), was made, and he began experiencing significant improvement after intravenous steroid infusion. IS is a rare disease that has been poorly documented in the literature. There have only been a limited number of cases which are globally documented. One of the difficulties is a lack of definite autoantibody with which to correlate the disease; however, there has been some correlation linking the disease to voltage-gated potassium channels. Ultimately, the diagnosis should be driven by history and clinical presentation. The aim of this case report is to highlight a rare disease process and increase awareness among clinicians. We also describe the associated evaluation and recommended treatment for an optimal patient outcome.

Myasthenia gravis-specific aberrant neuromuscular gene expression by medullary thymic epithelial cells in thymoma

Myasthenia gravis (MG) is a neurological disease caused by autoantibodies against neuromuscular-associated proteins. While MG frequently develops in thymoma patients, the etiologic factors for MG are not well understood. Here, by constructing a comprehensive atlas of thymoma using bulk and single-cell RNA-sequencing, we identify ectopic expression of neuromuscular molecules in MG-type thymoma. These molecules are found within a distinct subpopulation of medullary thymic epithelial cells (mTECs), which we name neuromuscular mTECs (nmTECs). MG-thymoma also exhibits microenvironments dedicated to autoantibody production, including ectopic germinal center formation, T follicular helper cell accumulation, and type 2 conventional dendritic cell migration. Cell–cell interaction analysis also predicts the interaction between nmTECs and T/B cells via CXCL12-CXCR4. The enrichment of nmTECs presenting neuromuscular molecules within MG-thymoma is further confirmed immunohistochemically and by cellular composition estimation from the MG-thymoma transcriptome. Altogether, this study suggests that nmTECs have a significant function in MG pathogenesis via ectopic expression of neuromuscular molecules.

Invasive type B2 thymoma associated with myasthenia gravis, resection with superior vena cava reconstruction

After being diagnosed with myasthenia gravis, a 55-year-old male was referred for treatment of an invasive thymoma. Preoperative imaging revealed a thymoma adjacent to the superior vena cava (SVC) with possible invasion of the left innominate vein. After multidisciplinary discussion, he underwent upfront en bloc resection of the tumor with SVC resection and reconstruction. He was discharged after an uncomplicated postoperative course with improvement of his symptoms.

Myasthenia Gravis: An Acquired Interferonopathy?

Myasthenia gravis (MG) is a rare autoimmune disease mediated by antibodies against components of the neuromuscular junction, particularly the acetylcholine receptor (AChR). The thymus plays a primary role in AChR-MG patients. In early-onset AChR-MG and thymoma-associated MG, an interferon type I (IFN-I) signature is clearly detected in the thymus. The origin of this chronic IFN-I expression in the thymus is not yet defined. IFN-I subtypes are normally produced in response to viral infection. However, genetic diseases called interferonopathies are associated with an aberrant chronic production of IFN-I defined as sterile inflammation. Some systemic autoimmune diseases also share common features with interferonopathies. This review aims to analyze the pathogenic role of IFN-I in these diseases as compared to AChR-MG in order to determine if AChR-MG could be an acquired interferonopathy.

A Pan-Cancer Analysis of Tumor-Infiltrating B Cell Repertoires

Tumor-infiltrating B cells can play an important role in anti-tumor responses but their presence is not well understood. In this study, we extracted the B cell receptor repertoires from 9522 tumor and adjacent non-tumor samples across 28 tumor types in the Cancer Genome Atlas project and performed diversity and network analysis. We identified differences in diversity and network statistics across tumor types and subtypes and observed a trend towards increased clonality in primary tumors compared to adjacent non-tumor tissues. We also found significant associations between the repertoire features and mutation load, tumor stage, and age. Our V-gene usage analysis identified similar V-gene usage patterns in colorectal and endometrial cancers. Lastly, we evaluated the prognostic value of the repertoire features and identified significant associations with survival in seven tumor types. This study warrants further research into better understanding the role of tumor-infiltrating B cells across a wide range of tumor types.

Sphingomonas and Phenylobacterium as Major Microbiota in Thymic Epithelial Tumors

The microbiota has been reported to be closely associated with carcinogenesis and cancer progression. However, its involvement in the pathology of thymoma remains unknown. In this study, we aimed to identify thymoma-specific microbiota using resected thymoma samples. Nineteen thymoma tissue samples were analyzed through polymerase chain reaction amplification and 16S rRNA gene sequencing. The subjects were grouped according to histology, driver mutation status in the GTF2I gene, PD-L1 status, and smoking habits. To identify the taxa composition of each sample, the operational taxonomic units (OTUs) were classified on the effective tags with 97% identity. The Shannon Index of the 97% identity OTUs was calculated to evaluate the alpha diversity. The linear discriminant analysis effect size (LEfSe) method was used to compare the relative abundances of all the bacterial taxa. We identified 107 OTUs in the tumor tissues, which were classified into 26 genera. Sphingomonas and Phenylobacterium were identified as abundant genera in almost all the samples. No significant difference was determined in the alpha diversity within these groups; however, type A thymoma tended to exhibit a higher bacterial diversity than type B thymoma. Through the LEfSe analysis, we identified the following differentially abundant taxa: Bacilli, Firmicutes, and Lactobacillales in type A thymoma; Proteobacteria in type B thymoma; Gammaproteobacteria in tumors harboring the GTF2I mutation; and Alphaproteobacteria in tumors without the GTF2I mutation. In conclusion, Sphingomonas and Phenylobacterium were identified as dominant genera in thymic epithelial tumors. These genera appear to comprise the thymoma-specific microbiota.

Ophthalmologic manifestations in myasthenia gravis: presentation and prognosis

We investigated the ophthalmologic manifestations and factors that influence outcomes in patients with myasthenia gravis (MG). We retrospectively analyzed the prevalence of neuro-ophthalmologic findings and clinical and outcome measures of 100 consecutive patients (53 males, 47 females), aged 55.7 ± 17.5 (range 15-85) years with an established diagnosis of MG. Forty-eight patients had purely ocular symptoms at the onset of disease (OMG) and 52 patients presented with generalized symptoms (GMG). Overall, 21 patients presented with extraocular muscle (EOM) weakness. Bilateral EOM weakness was seen in 12 patients, and unilateral EOM weakness was seen in nine patients. Diplopia responded partially to immunosuppressive treatments in 60% of patients with ophthalmoparesis. Twenty-five (52.1%) patients with ocular-onset MG converted to secondary GMG at a mean time of 14.5 months. Patients who developed secondary GMG were younger and had an earlier age of disease onset when compared with patients with pure OMG (p < 0.05). Patients with secondary GMG presented more frequently with ptosis and diplopia (72% vs. 28%) compared with patients with pure ocular MG who presented more frequently with isolated ptosis (66.7% vs. 33.3%) (p = 0.02). Remission and minimal manifestation status were achieved in 50 (79.3%) of all patients with a clinical follow-up ≥ 3 years. Poor outcome was associated with the presence of thymoma (p < 0.05). Myasthenic ophthalmoparesis is bilateral and heterogeneous and partly responds to treatment with immunotherapy. Younger patients with ptosis and diplopia at disease onset had an increased risk of secondary GMG. The presence of thymoma increases the risk for poor prognosis.

Pan-Cancer Analysis of Immune Complement Signature C3/C5/C3AR1/C5AR1 in Association with Tumor Immune Evasion and Therapy Resistance

Despite the advances in our understanding of the genetic and immunological basis of cancer, cancer remains a major public health burden with an ever-increasing incidence rate globally. Nevertheless, increasing evidence suggests that the components of the complement system could regulate the tumor microenvironment (TME) to promote cancer progression, recurrence, and metastasis. In the present study, we used an integrative multi-omics analysis of clinical data to explore the relationships between the expression levels of and genetic and epigenetic alterations in C3, C5, C3AR1, and C5AR1 and tumor immune evasion, therapy response, and patient prognosis in various cancer types. We found that the complements C3, C5, C3AR1, and C5AR1 have deregulated expression in human malignancies and are associated with activation of immune-related oncogenic processes and poor prognosis of cancer patients. Furthermore, we found that the increased expression levels of C3, C5, C3AR1, and C5AR1 were primarily predicted by copy number variation and gene methylation and were associated with dysfunctional T-cell phenotypes. Single nucleotide variation in the gene signature co-occurred with multiple oncogenic mutations and is associated with the progression of onco-immune-related diseases. Further correlation analysis revealed that C3, C5, C3AR1, and C5AR1 were associated with tumor immune evasion via dysfunctional T-cell phenotypes with a lesser contribution of T-cell exclusion. Lastly, we also demonstrated that the expression levels of C3, C5, C3AR1, and C5AR1 were associated with context-dependent chemotherapy, lymphocyte-mediated tumor killing, and immunotherapy outcomes in different cancer types. In conclusion, the complement components C3, C5, C3AR1, and C5AR1 serve as attractive targets for strategizing cancer immunotherapy and response follow-up.

GOECP/SEOR radiotherapy guidelines for thymic epithelial tumours

Thymic epithelial tumours (TET) are rare, heterogeneous neoplasms that range from resectable indolent tumours to aggressive thymic carcinomas with a strong tendency to metastasize. The pathological diagnosis is complex, in part due to the existence of several different classification systems. The evidence base for the management of TETs is scant and mainly based on non-randomised studies and retrospective series. Consequently, the clinical management of TETs tends to be highly heterogenous, which makes it difficult to improve the evidence level. The role of technological advances in the field of radiotherapy and new systemic therapies in the treatment of TETs has received little attention to date. In the present clinical guidelines, developed by the GOECP/SEOR, we review recent developments in the diagnosis and classification of TETs. We also present a consensus-based therapeutic strategy for each disease stage that takes into consideration the best available evidence. These guidelines focus primarily on the role of radiotherapy, including recent advances, in the management of TETs. The main aim of this document is to promote the standardisation of clinical practice and lay the foundations for future studies to clarify the main unresolved questions related to the optimal management of TET.

Thymoma pathology and myasthenia gravis outcomes

INTRODUCTION

There is limited evidence regarding the impact of World Health Organization (WHO) subtype of thymoma on post-thymectomy outcome of thymoma-associated myasthenia gravis (TAMG). The objective was to determine if the pathological subtypes of thymoma were associated with post-thymectomy outcomes of myasthenia gravis (MG), in patients with TAMG.

METHODS

We performed a retrospective study of consecutive patients with TAMG who attended the neuromuscular clinic between January 2018 and December 2019 with a minimum follow-up of 1 y after thymectomy. Outcome measures were MG Impairment Index (MGII), single-simple question (SSQ), Myasthenia Gravis Foundation of America post-intervention status (MGFA PIS) and non-responder MG status at last assessment.

RESULTS

Ninety-five patients were included; mean age at onset was 48.1 ± 12.1 y; 54(56.8%) were females. Thirteen patients developed MG post-thymectomy. The most common thymoma was WHO type B2 in 39 (41.1%). Most patients (40, 42.1%) had Masaoka stage II thymoma. There was no association of thymoma subtypes or Masaoka stage of disease with age, gender, MG phenotype, serology, post-thymectomy onset, interval from onset to thymectomy, MGII, SSQ, MGFA PIS, or non-responder status. Associations were found between positive serology and lower MGII (11.1 ± 14.2 vs 23 ± 12.9, P = .050), thymic follicular hyperplasia (TFH) and higher SSQ (89.3 ± 11.7 vs 80.1 ± 20.2, P-.043), and lack of recurrence and higher SSQ (84.1 ± 18 vs 72.5 ± 20, P = .037).

DISCUSSION

The WHO pathological subtype of thymoma did not correlate with MG outcomes. However, positive acetylcholine antibody serology, presence of TFH, and non-recurrence of thymoma predict a favorable outcome.

The contribution of thymic tolerance to central nervous system autoimmunity

Autoimmune diseases of the central nervous system (CNS) are associated with high levels of morbidity and economic cost. Research efforts have previously focused on the contribution of the peripheral adaptive and innate immune systems to CNS autoimmunity. However, a failure of thymic negative selection is a necessary step in CNS-reactive T cells escaping into the periphery. Even with defective thymic or peripheral tolerance, the development of CNS inflammation is rare. The reasons underlying this are currently poorly understood. In this review, we examine evidence implicating thymic selection in the pathogenesis of CNS autoimmunity. Animal models suggest that thymic negative selection is an important factor in determining susceptibility to and severity of CNS inflammation. There are indirect clinical data that suggest thymic function is also important in human CNS autoimmune diseases. Specifically, the association between thymoma and paraneoplastic encephalitis and changes in T cell receptor excision circles in multiple sclerosis implicate thymic tolerance in these diseases. We identify potential associations between CNS autoimmunity susceptibility factors and thymic tolerance. The therapeutic manipulation of thymopoiesis has the potential to open up new treatment modalities, but a better understanding of thymic tolerance in CNS autoimmunity is required before this can be realised.

Orthostatic hypotension secondary to a suspected thymoma in a dog: a case report

BACKGROUND

This is the first case report description, to our knowledge, of a cranial mediastinal mass (suspected thymoma) causing orthostatic hypotension in a dog.

CASE PRESENTATION

A Labrador Retriever presented for urethral stent placement during cystoscopy secondary to transitional cell carcinoma diagnosis. During anesthesia, the patient had unexpected severe and poorly-responsive hypotension following a shift in position. Several days later, an intrathoracic mass was discovered, raising concerns that the position of the mass in relation to the great vessels and heart may have been the cause of the hypotension. The patient returned for a second stent placement, and computed tomography of the chest confirmed a cranial mediastinal mass, most suspected to be thymoma based on the results of cytology. The patient was kept in sternal recumbency, but when re-positioning to left lateral recumbency, there was a dramatic blood pressure drop that corrected with a return to sternal positioning.

CONCLUSIONS

To our knowledge, orthostatic hypotension has not been described in relation to thymoma in dogs. Thymomas are rare; however, they may be associated with disease of autonomic dysfunction, such as myasthenia gravis, that may lead to orthostatic hypotension. This has been described within the human literature, and we hypothesize it was present in the currently described case. Concurrently, thymomas may grow to a substantial size and cause direct compression of the intrathoracic vasculature. As such, it should be on the differential list for poorly-responsive hypotension following a shift in body positioning under anesthesia.

Case Series: A case of familial thymomatous myasthenia gravis in a family of three male brothers

Myasthenia gravis (MG) is an autoimmune disease that occurs as a consequence of anti-acetylcholine (Ach) antibodies specifically targeting postsynaptic Ach receptors (AchR). This leads to the evolution of the classic symptoms of the disease, which range from mild symptoms of diplopia, muscle fatigue with repetitive movement up to severe affection of the respiratory muscle. The disease can occur as an isolated finding or co-exist with a concomitant thymic tumor or hyperplasia. Careful diagnosis is crucial for the development of the management plan. Nearly 10-15% of MG cases coexist with a thymic pathology and in these cases, surgical resection leads to the resolution of symptoms. Although thymomatous MG occurrence is non-heritable, its polygenic nature accounts for its rare familial variant. In this case, we report a family of three brothers with familial thymomatous MG who underwent thymectomy and improved after thymic surgical resection. Myasthenia gravis can occur as an isolated finding or as an association of thymic pathology. Careful discrimination between the two should be made for the elaboration of a management plan. Familial variant thymomatous myasthenia gravis is exceedingly rare. A familial survey is crucial for its management.

Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability

Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca²⁺ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.

Noninfectious neurologic complications of hematopoietic cell transplantation: A systematic review

OBJECTIVE/BACKGROUND

Neurological complications occur at a high frequency after hematopoietic cell transplantation (HCT). However, an absence is noted in the published literature as regards the quantification of the exact burden and the outcomes thereof. In this systematic review, we endeavored to detail if the recipients of HCT developed any noninfectious neurological events/complications.

METHODS

According to the PICO criteria, medical literature was searched. Complications that were evaluated included: stroke, peripheral neuropathy, myasthenia gravis, seizures, and posterior reversible encephalopathy syndrome. After strictly defining relevant variables and parameters, data from 173 eligible articles were then extracted accordingly, from the full text for each, for quantitative analysis; additionally, two American Society of Hematology conference abstracts were also subject to data extraction.

RESULTS

As is evident from the results of the data analysis, an increased frequency of these complications was seen in the HCT recipient population in comparison to the general population. The relative risk ranged from 1.33× to 142× depending on the complication studied.

CONCLUSION

These findings demonstrate that the recipients of HCT had a significantly higher risk of neurological complications and that their early recognition can enhance the monitoring of HCT survivors for the early developmental signs of neurological toxicity. This would facilitate timely interventions, thus ensuring a better quality of life.

Thymic B Cells Promote Germinal Center-Like Structures and the Expansion of Follicular Helper T Cells in Lupus-Prone Mice

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the activation of autoreactive T and B cells, autoantibody production, and immune complex deposition in various organs. Previous evidence showed abnormal accumulation of B cells in the thymus of lupus-prone mice, but the role of this population in the progression of the disease remains mostly undefined. Here we analyzed the spatial distribution, function, and properties of this thymic B cell population in the BWF1 murine model of SLE. We found that in diseased animals, thymic B cells proliferate, and cluster in structures that resemble ectopic germinal centers. Moreover, we detected antibody-secreting cells in the thymus of diseased-BWF1 mice that produce anti-dsDNA IgG autoantibodies. We also found that thymic B cells from diseased-BWF1 mice induced the differentiation of thymocytes to follicular helper T cells (T_FH). These data suggest that the accumulation of B cells in the thymus of BWF1 mice results in the formation of germinal center-like structures and the expansion of a T_FH population, which may, in turn, activate and differentiate B cells into autoreactive plasma cells. Therefore, the thymus emerges as an important niche that supports the maintenance of the pathogenic humoral response in the development of murine SLE.

Autoimmune polyglandular syndrome type 2 and autoimmune hepatitis with thymoma-associated myasthenia gravis: case report

BACKGROUND

Autoimmune polyglandular syndrome type 2 (APS-2) is a rare and complex clinical entity, and little is known about its etiology and progression.

CASE PRESENTATION

A 52-year-old woman with autoimmune hepatitis (AIH) and bronchial asthma was diagnosed with APS-2; autoimmune Addison's disease (AD), and Hashimoto's thyroiditis (HT), and she underwent prednisolone (PSL) treatment. Five months later, she presented ptosis and was diagnosed with thymoma-associated myasthenia gravis (MG). Thymectomy and PSL treatment with immuno-suppressants appeared to ameliorate MG, AD, AIH, HT, and bronchial asthma. HLA typing analysis revealed that the patient had susceptible HLA alleles to MG, AIH, and HT in a Japanese population.

CONCLUSIONS

This case suggests common endocrinological and autoimmune aspects of APS-2 and AIH with thymoma-associated MG, which are considered to be extremely rare complications.

Presence of Multiple Autoimmune Antibodies Involved in Concurrent Myositis and Myocarditis and Myasthenia Gravis Without Thymoma: A Case Report

Inflammatory myositis (IM) and myasthenia gravis (MG) are both immune disorders involving muscle. The concurrent presence of both conditions in the same patient is extremely rare and the diagnosis is important and challenging. Here, we report a case of concurrent myositis and myocarditis and MG without thymoma in a 69-year-old man with progressive proximal muscle weakness and dysphagia. As an atypical finding, the laboratory immunity assay showed the presence of multiple antibodies (acetylcholine receptor-Ab, titin-Ab, M7-Ab, smooth muscle alpha (SMA)-Ab, and citrate acid extract (CAE)-Ab). We predicted that thymoma-associated antibodies (titin-Ab, SMA-Ab, and CAE-Ab) and anti-M7 antibodies play an important role in the concurrent presence of MG and myositis and myocarditis. In this overlap case, immunotherapy was determined to be effective.

Comparison between CT and MRI in the Diagnostic Accuracy of Thymic Masses

Purpose: The aim of this study was to compare diagnostic accuracy between CT and MRI for thymic masses.

Methods: We searched literature and collected information on first author, publication year, cases of different types of thymic lesions, correct diagnostic cases of CT and MRI and results of quantitative analysis of CT and MRI. The ROC curve was applied to compare the diagnostic performance of different imaging modalities.

Results: Eight literatures were finally included and analyzed in this study. There were 253 cases examined by CT and 340 cases by MRI in total. We showed outcomes of quantitative analysis of each study in this article. The sensitivity of CT and MRI was both 100%, while the specificity was 75% and 80%, respectively. AUC of CT was 0.875 [95%CI: 0.473, 0.997] and that of MRI was 0.880 [95%CI: 0.531, 0.995].

Conclusion: The diagnostic accuracy of MRI is superior to CT in detecting thymomas, thymic cysts or thymic hyperplasia but that of CT and MRI is still unclear in differentiating thymic carcinomas and lymphomas/germ cell tumors.

Thymoma Recurrence and its Predisposing Factors in Iranian Population: a Single Center Study

BACKGROUND

Thymoma is relatively rare tumor. Prognosis and patients' outcome vary across different studies. We aimed to study the predisposing factors causing tumor recurrence in thymoma patients.

MATERIALS AND METHODS

A total of 43 thymoma or thymic carcinoma patients treated at the National Institute of Tuberculosis and Lung Disease (NRITLD), Masih Daneshvari Hospital from September 2005 to January 2017 were evaluated. The primary endpoint was the progression free survival (PFS). The relation of predisposing factors to PFS was studied.

RESULTS

Median age was 55 years old. The mean of follow-up duration was 22.9 months. The most prevalent pathology was thymoma unspecified. Pure red cell aplasia (n=3, 6.9%) was the most prevalent Para neoplastic syndrome. Most of the patients (n=23, 54%) were in stage III and IV Masaoka-Koga staging system. Disease progression was observed in 17 patients (39. 5%). Most recurrences occurred locally. None of demographic characteristics differed between patients who experienced disease recurrence and those who did not. After univariate and multivariate analysis, predisposing factor for disease progression was only Masaoka-Koga stage (P-value=0.015 and 0.031 respectively).

CONCLUSION

In this study, among different probable predisposing factors, only Masaoka-Koga stage had significant effect on disease recurrence. Large case-control studies may be required for better evaluation of risk factors.

Unintended consequences of Mayo paraneoplastic evaluations

OBJECTIVE

To determine the proportion of true and false positives from paraneoplastic panels and effects on downstream testing/treatment.

METHODS

Using a retrospective cohort study design, we identified 500 consecutive patients with Mayo paraneoplastic autoantibody testing and performed chart abstraction. Paraneoplastic presentation types were categorized into probable, possible, and other by consensus. True positives were defined as a positive antibody titer with no other explanation found in addition to one of the following: syndrome known to be associated with the antibody, clinical improvement with treatment, and new malignancy. Comparisons of diagnostic testing and treatments between false and true positives were performed. Multivariable logistic regression was used to evaluate associations between patient-level factors and true positives.

RESULTS

The mean (SD) age of the population was 55.4 (17.1) years, and 55.4% were female, with 1.3 (1.2) years of follow-up. Of the 500 tests, 87 (17.4%, 95% confidence interval [CI] 14.1%-20.7%) were positive and 62 (71.3%, 95% CI 61.8%-80.8%) of these were false positives. Of those with a possible/other presentation (n = 369), 2 (0.5%, 95% CI 0.0%-1.0%) were true positives. CT of the chest (30.7% vs 11.8%, p ≤ 0.01) was performed more often in false positives than true negatives. Probable presentation type (odds ratio [OR] 57.9, 95% CI 12.5-268.0) and outpatient setting (OR 8.7, 95% CI 2.4-31.8) were associated with true-positive results.

CONCLUSION

Paraneoplastic tests result in a large proportion of false positives, particularly in those with clinical presentations that are not well established as paraneoplastic diseases. Future work should construct panels targeted to specific clinical presentations and ensure that tests are ordered in the appropriate clinical context.

IL-4Rα Polymorphism Is Associated With Myasthenia Gravis in Chinese Han Population

Interleukin-4 (IL-4) is a potent growth and differentiation factor for B cells which play a vital role in the pathogenesis of myasthenia gravis (MG). IL-4 exerts its function by binding to three types of IL-4 receptor (IL-4R) complexes. IL-4Rα is the key component of the IL-4R complex. We hypothesize that polymorphism of IL-4Rα gene may be associated with the susceptibility and severity of MG. A Chinese cohort of 480 MG patients and 487 healthy controls were recruited. Polymorphisms of IL-4Rα gene were determined with SNPscan™ methods and compared between MG and control groups, as well as among MG subgroups. Rs2107356 and rs1805010 were found to be associated with adult thymoma associated MG, and rs1801275 was found to be associated with adult non-thymoma AChR-Ab positive MG. We did not found association between IL-4Rα polymorphism and the severity of MG. Genetic variations of IL-4Rα were found associated with the susceptibility of MG in Chinese Han population.

Acquired Amegakaryocytic Thrombocytopenia and Pure Red Cell Aplasia in Thymoma

Association of thymoma with myasthenia gravis, pure red cell aplasia, and aplastic anemia is well documented. However, thymoma complicated by acquired amegakaryocytic thrombocytopenia (AAMT) is rarely reported. Here, we present a case of a 60-year-old male with past medical history of recurrent invasive thymoma who presented with cough and blood in sputum. He was found to have severe normocytic normochromic anemia and thrombocytopenia that did not improve with intravenous steroids or multiple transfusions of red cells and platelets. Subsequent bone marrow biopsy showed severely depleted megakaryocytes and erythroid precursor cells with relative myeloid hyperplasia suggestive of amegakaryocytic thrombocytopenia and red cell aplasia. He was started on oral cyclosporine but subsequently developed leukopenia and refused any further treatment or diagnostic procedures and left the hospital against medical advice. AAMT, thus, may be a very early presentation of impending aplastic anemia, and treating physicians need to be aware of this entity.

Myasthenic Crisis In Pregnancy

This case reviews the management of a 27-year-old pregnant female in myasthenic crisis. She presented to the emergency department in respiratory distress refractory to standard therapy, necessitating airway and ventilatory support and treatment with plasmapheresis. Myasthenic crisis in the setting of pregnancy is rare and presents unique management challenges for emergency physicians.

Mechanisms of Autoantibody-Induced Pathology

Autoantibodies are frequently observed in healthy individuals. In a minority of these individuals, they lead to manifestation of autoimmune diseases, such as rheumatoid arthritis or Graves' disease. Overall, more than 2.5% of the population is affected by autoantibody-driven autoimmune disease. Pathways leading to autoantibody-induced pathology greatly differ among different diseases, and autoantibodies directed against the same antigen, depending on the targeted epitope, can have diverse effects. To foster knowledge in autoantibody-induced pathology and to encourage development of urgently needed novel therapeutic strategies, we here categorized autoantibodies according to their effects. According to our algorithm, autoantibodies can be classified into the following categories: (1) mimic receptor stimulation, (2) blocking of neural transmission, (3) induction of altered signaling, triggering uncontrolled (4) microthrombosis, (5) cell lysis, (6) neutrophil activation, and (7) induction of inflammation. These mechanisms in relation to disease, as well as principles of autoantibody generation and detection, are reviewed herein.

Therapeutic Potential of Docetaxel plus Cisplatin Chemotherapy for Myasthenia Gravis Patients with Metastatic Thymoma

The prognosis of myasthenia gravis (MG) in association with invasive or metastatic thymoma is usually worse, and therapeutic options are quite limited. Here, we retrospectively reported the therapeutic effect of docetaxel plus cisplatin (docetaxel/cisplatin) chemotherapy in 7 MG patients with metastatic thymoma. Previously, all patients underwent thymectomy at the first onset of thymoma. After the metastasis of thymoma, none of the patients received thymectomy due to unresectable conditions after surgeon's evaluation for great risk of myasthenic crisis (n = 5) or patients' refusal (n = 2). All patients received docetaxel (75 mg/m²) and cisplatin (70 mg/m²) on day 1 (d1) every 21 days, with the cycle ranging from 1 to 4. After docetaxel/cisplatin chemotherapy, one patient achieved partial response, and 6 with stable disease of the tumors. The clinical symptoms of MG were alleviated in all patients, 2 with complete remission and the other 5 with marked improvement. Myelosuppression was the major adverse event, occurring in 2 patients (grade II and IV). MG relapse occurred in one patient during the follow-up. Our study presented a series of MG patients with metastatic thymoma who underwent docetaxel/cisplatin chemotherapy. Besides the improved/stabilized thymoma, markedly improvement of MG with the tolerable adverse events was achieved. Docetaxel/cisplatin chemotherapy appears to be an effective treatment for selected patients with MG in association with unresectable metastatic thymoma. Further follow-up of these patients and additional subjects will be needed to determine whether the therapeutic benefits are durable.

Metastatic Thymoma-Associated Myasthenia Gravis: Favorable Response to Steroid Pulse Therapy Plus Immunosuppressive Agent

BACKGROUND Our study retrospectively reviewed the therapeutic effect of steroid pulse therapy in combination with an immunosuppressive agent in myasthenia gravis (MG) patients with metastatic thymoma. MATERIAL AND METHODS MG patients with metastatic thymoma that underwent methylprednisolone pulse therapy plus cyclophosphamide were retrospectively analyzed. Patients initially received methylprednisolone pulse therapy followed by oral methylprednisolone. Cyclophosphamide was prescribed simultaneously at the beginning of treatment. Clinical outcomes, including therapeutic efficacy and adverse effects of MG and thymoma, were assessed. RESULTS Twelve patients were recruited. According to histological classification, 4 cases were type B2 thymoma, 3 were type B3, 2 were type B1, and 1 was type AB. After combined treatment for 15 days, both the thymoma and MG responded dramatically to high-dose methylprednisolone plus cyclophosphamide. The symptoms of MG were improved in all patients, with marked improvement in 6 patients and basic remission in 4. Interestingly, complete remission of thymoma was achieved in 5 patients and partial remission in 7 patients. Myasthenic crisis was observed in 1 patient and was relieved after intubation and ventilation. Adverse reactions were observed in 7 patients (58.3%), most commonly infections, and all were resolved without discontinuation of therapy. During the follow-up, all patients were stabilized except for 1 with pleural metastasis who received further treatment and another 1 who died from myasthenic crisis. CONCLUSIONS The present study in a series of MG patients with metastatic thymoma indicated that steroid pulse therapy in combination with immunosuppressive agents was an effective and well-tolerated for treatment of both metastatic thymoma and MG. Glucocorticoid pulse therapy plus immunosuppressive agents should therefore be considered in MG patients with metastatic thymoma.

Clinical Profile and Outcome of Postthymectomy versus Non-Thymectomy Myasthenia Gravis Patients in the Philippine General Hospital: A 6-Year Retrospective Study

Background

Myasthenia gravis is an autoimmune neuromuscular disorder characterized by the production of abnormal autoantibodies directed against the receptors present in the neuromuscular junction. It has been the standard practice to offer thymectomy in all generalized myasthenia gravis patients despite the lack of robust evidence.

Objectives

The objectives of this study are to describe the clinical profile and differentiate the clinical outcomes of thymectomy versus non-thymectomy and thymomatous versus non-thymomatous myasthenia gravis patients in the Philippine General Hospital.

Methodology

Between 2009 and 2014, a total of 69 postthymectomy and 16 non-thymectomy patient records were successfully retrieved. The demographic characteristics, surgical approach, and histopathologic results were obtained. The clinical outcome after 6 months or 1 year-follow-up was also determined and grouped according to the following: (1) complete remission, (2) pharmacological remission, (3) no clinical change, (4) worsening symptoms, and (5) mortality.

Results

Majority of the patients were females (68.0%) with a mean age of 39.8 years and a mean duration of myasthenic symptoms of 21 months. Using the Myasthenia Gravis Foundation of America classification, 54.1% of patients fell under Class II and 48.2% of them presented with generalized weakness. In this study, 60.8% of postthymectomy myasthenia gravis patients had either complete remission or pharmacologic remission compared with 12.5% among non-thymectomy patients (p-value <0.001). No significant difference in the clinical outcome was found between thymomatous and non-thymomatous myasthenia gravis after thymectomy (p-value = 0.29).

Conclusion

This study showed that both thymomatous and non-thymomatous myasthenia gravis patients who underwent thymectomy had a higher incidence of complete stable remission and pharmacologic remission as compared with myasthenia gravis patients who did not undergo thymectomy.

Myasthenia Crisis Induced by Pegylated-Interferon in Patient With Chronic Hepatitis C: A Case Report

Myasthenia gravis is occasionally associated with thymoma that needs surgical resection and may progress to severe respiratory failure. We experienced a rare case of myasthenia crisis during antiviral therapy for chronic hepatitis C, in whom mediastinal thymoma was discovered and successfully managed with surgical thymectomy and meticulous medical care.A 47-year-old-male patient complained of sudden diplopia 1 week after stopping 11-week administration of pegylated-interferon and ribavirin for chronic hepatitis C. Ophthalmologic examinations revealed ptosis on the right eyelid and restricted right eye movement. Myasthenia gravis was confirmed by positive repetitive nerve stimulation test and positive serum antiacetylcholine receptor antibody test, and mediastinal thymoma was found on chest CT scan. The ocular myasthenia gravis progressed to respiratory failure even after discontinuing antiviral treatment but eventually recovered with thymectomy, anticholinesterase administration, steroid pulse therapy, and prolonged ventilator care. We describe the clinical features of this life-threatening complication of interferon treatment along with previous myasthenia crisis cases by interferon for chronic hepatitis C.In patients with chronic hepatitis C who is going to receive interferon-based antiviral treatment, physicians need to keep in mind the potential life-threatening manifestations of myasthenia gravis before and during antiviral treatment especially when patients complain of muscular weakness and easy fatigability.

Thymoma exhibiting spontaneous regression in size, pleural effusion and serum cytokeratin fragment level: A case report

A 30-year-old man was admitted to Toho University Omori Medical Center for assessment of right chest pain and fever. Chest computed tomography (CT) revealed an anterior mediastinal tumor sized 11.0×6.0×5.0 cm, with right pleural effusion. The laboratory analysis revealed elevated white blood cell count (11,000/µl), C-reactive protein (4.1 mg/dl) and cytokeratin fragment (CYFRA; 12.7 ng/ml; normal, <2 ng/ml). The level of CYFRA in the pleural effusion was also markedly elevated (143 ng/ml). On the first day after admission (6 days after the initial CT), there was a mild regression on CT (10.0×5.5×4.4 cm; reduction rate, 26.7%), with decrease of the pleural effusion volume. A CT-guided needle biopsy was performed, but the findings were not conclusive, as most of the tissue was necrotic. Seven days later (13 days after the initial CT), a CT revealed further regression (9.5×5.4×4.2 cm; reduction rate, 34.7%) with disappearance of the pleural effusion. The patient was followed up on an outpatient basis. At 35 days after the initial CT, the tumor continued to shrink without treatment (8.0×3.6×3.0 cm; reduction rate, 73.8%) and the serum CYFRA level had decreased to 0.8 ng/ml, although it had not returned to normal levels. At 62 days after the initial CT, the patient underwent surgical resection. The resected specimen was diagnosed as thymoma (World Health Organization type B2; Masaoka classification, stage II), with prominent degeneration and necrosis. One possible cause of the spontaneous regression may be increased internal pressure, probably associated with rapid tumor growth, leading to massive necrosis with resulting chest pain, inflammatory reaction with pleural effusion and subsequent tumor regression. The serum CYFRA level may be a useful marker for the evaluation of the clinical course of thymoma with extensive necrosis.