Extended thymectomy for myasthenia gravis patients: a 20-year review

Spatial transcriptomics elucidates medulla niche supporting germinal center response in myasthenia gravis-associated thymoma

Myasthenia gravis (MG) is etiologically associated with thymus abnormalities, but its pathology in the thymus remains unclear. In this study, we attempt to narrow down the features associated with MG using spatial transcriptome analysis of thymoma and thymic hyperplasia samples. We find that the majority of thymomas are constituted by the cortical region. However, the small medullary region is enlarged in seropositive thymomas and contains polygenic enrichment and MG-specific germinal center structures. Neuromuscular medullary thymic epithelial cells, previously identified as MG-specific autoantigen-producing cells, are enriched in the cortico-medullary junction. The medulla is characterized by a specific chemokine pattern and immune cell composition, including migratory dendritic cells and effector regulatory T cells. Similar germinal center structures and immune microenvironments are also observed in the thymic hyperplasia medulla. This study shows that the medulla and junction areas are linked to MG pathology and provides insights into future MG research.

Clinicopathological predictors of postoperative long-term myasthenic status in resected thymoma with myasthenia gravis

PURPOSE

Surgical patients with thymoma and myasthenia gravis (MG) must have their MG status and oncological outcomes critically monitored. We aimed to identify clinicopathological predictors of the postoperative MG status.

METHODS

We conducted a retrospective review of 40 consecutive surgical patients with MG-related thymomas between 2002 and 2020. The quantitative myasthenia gravis score (QMGS) and Myasthenia Gravis Foundation of America post-intervention status (MGFA-PIS) were used to evaluate postoperative MG status.

RESULTS

All patients underwent extended total thymectomy. The most common WHO type was type B2 (32%), while 65% of patients had type B1-B3 and 35% had type A-AB thymomas. Eleven patients (28%) achieved controlled MG status in MGFA-PIS 6 months after surgery. This controlled status was observed more frequently in type A-AB than in B1-B3 (57% vs. 12%, p = 0.007). In a multivariate analysis, WHO type (A-AB or B1-B3) was an independent predictor of worsening episodes of MG based on the QMGS (Type B1-B3, hazard ratio: 3.23, 95% confidence interval: 1.12-9.25). At the last follow-up, 23 patients (58%) achieved controlled MG status. The 5-year overall survival rate of all patients was 93.7%.

CONCLUSION

The WHO type of thymoma is an informative predictor of postoperative MG status in patients with MG-related thymoma.

Short-term outcomes of robotic subxiphoid-optical thymectomy

PURPOSE

To evaluate the usefulness of robotic subxiphoid-optical thymectomy (RST).

METHODS

Thirty-seven procedures (thymoma, n = 19; thymic carcinoma, n = 1; myasthenia gravis, n = 3; and others, n = 14) performed between October 2020 and December 2023 were included. The right and left 6th intercostal midclavicular lines and subxiphoid, with an assistant port placed in the right third intercostal anterior axillary line, were adapted. Postoperative pain was assessed using a numerical rating scale (NRS).

RESULTS

A good view of the surgical field is obtained. The median console time was 113 min and the time to roll-in was 30 min. The body mass index (BMI) was 21.6. One patient with thymic carcinoma required combined resection of the left phrenic nerve and left brachiocephalic vein without conversion to thoracotomy, and 1 patient had post-pericardiotomy syndrome with bilateral pleural effusion. There was a correlation between the prolonged time to roll-in and BMI (ρ = 0.439; p = 0.007). Pain was controlled with oral medication on postoperative day 1 and significantly decreased at discharge and at the first outpatient visit without epidural anesthesia (median NRS scores: 4, 1, and 1, respectively).

CONCLUSION

RST is a safe procedure that provides surgeons with a sufficient view of the anterior mediastinum and causes minimal postoperative pain.

Germinal centers are associated with postthymectomy myasthenia gravis in patients with thymoma

BACKGROUND AND PURPOSE

Germinal centers (GCs) can be observed in the thymic tissues of patients with thymoma-associated myasthenia gravis (MG). Although an association between thymic GCs and MG has been suggested, it is unknown whether the presence of GCs could predict the development of MG after the resection of thymoma, known as postthymectomy MG.

METHODS

We conducted a retrospective analysis of previously nonmyasthenic patients who underwent surgical removal of the thymoma. All available thymic tissue slides were rereviewed by a pathologist to assess for GCs. Patients were classified into GC-positive and GC-negative groups based on the presence of GCs. The incidence of postthymectomy MG was compared between the two groups, and the risk factors for postthymectomy MG were assessed.

RESULTS

Of the 196 previously nonmyasthenic patients who underwent thymoma resection, 21 were GC-positive, whereas 175 were GC-negative. Postthymectomy MG developed in 11 (5.6%) patients and showed a higher incidence in the GC-positive group than in the GC-negative group (33.3% vs. 2.3%, p < 0.001). No postoperative radiotherapy and the presence of GCs were risk factors for postthymectomy MG in the univariate analysis. In multivariate analysis, invasive thymoma (hazard ratio [HR] = 9.835, 95% confidence interval [CI] = 1.358-105.372), postoperative radiotherapy (HR = 0.160, 95% CI = 0.029-0.893), and presence of GCs (HR = 15.834, 95% CI = 3.742-67.000) were significantly associated with postthymectomy MG.

CONCLUSIONS

Thymic GCs may be a significant risk factor for postthymectomy MG. Even in patients with thymoma who do not show clinical symptoms of MG, postthymectomy MG should be considered, especially if thymic GCs are observed.

National Multicenter Study on the Comparison of Robotic and Open Thymectomy for Thymic Neoplasms in Myasthenic Patients: Surgical, Neurological and Oncological Outcomes

Thymectomy is the gold standard in the treatment of thymic neoplasm and plays a key role in the therapeutic path of myasthenia gravis. For years, sternotomy has been the traditional approach for removing anterior mediastinal lesions, although the robotic thymectomy is now widely performed. The literature is still lacking in papers comparing the two approaches and evaluating long-term oncological and neurological outcomes. This study aims to analyze the postoperative results of open and robotic thymectomy for thymic neoplasms in myasthenic patients. Surgical, oncological and neurological data of myasthenic patients affected by thymic neoplasms and surgically treated with extended thymectomy, both with the open and the robotic approach, in six Italian Thoracic Centers between 2011 and 2021 were evaluated. A total of 213 patients were enrolled in the study: 110 (51.6%) were treated with the open approach, and 103 (48.4%) were treated with robotic surgery. The open surgery, compared with the robotic, presented a shorter operating time (p < 0.001), a higher number of postoperative complications (p = 0.038) and longer postoperative hospitalization (p = 0.006). No other differences were observed in terms of surgical, oncological or neurological outcomes. The robotic approach can be considered safe and feasible, comparable to the open technique, in terms of surgical, oncological and neurological outcomes.

Perioperative outcomes of minimally invasive surgery for large malignant thymic epithelial tumors and for total thymectomy

PURPOSE

Minimally invasive surgery (MIS) for thymic tumors is now accepted widely, in line with improved surgical techniques; however, we occasionally encounter complicated cases of large tumors or of total thymectomy requiring prolonged operative duration or conversion to an open procedure (OP). We reviewed patients registered in a nationwide database to identify the technical feasibility of MIS for thymic epithelial tumors.

METHODS

Data on patients treated surgically between 2017 and 2019 were extracted from the National Clinical Database of Japan. Clinical factors and operative outcomes were calculated by tumor diameter using trend analyses. Perioperative outcomes of MIS for non-invasive thymoma were investigated using propensity score-matched analyses.

RESULTS

MIS was performed in 46.2% of the patients. The operative duration and conversion rate increased with the tumor diameter (p < .001). After propensity score-matching, operative duration and postoperative hospital stay were shorter (p < .001), and the transfusion rate was lower (p = .007) in patients who underwent MIS than in those who underwent OP for thymomas ≥ 5 cm. Among patients who underwent total thymectomy, blood loss was less (p < .001) and the postoperative hospital stay was shorter (p < .001) in those who underwent MIS than in those who underwent OP. There were no significant differences in postoperative complications and mortality.

CONCLUSIONS

MIS is technically feasible even for large non-invasive thymomas or for total thymectomy, although the operative duration and open conversion rate increase with the tumor diameter.

A Propensity Score-Matching Analysis: Robotic Thymectomy Through the Subxiphoid Has Advantages Over Video-Assisted Thymectomy Surgery

Objective: The purpose of this article is to evaluate the security and effectiveness of subxiphoid and subcostal robot-assisted thoracoscopic thymectomy (S-RATT) and compare it with subxiphoid and subcostal video-assisted thoracoscopic thymectomy (S-VATT) in terms of short-term perioperative results and costs. Methods: A retrospective study was carried out on 62 individuals who had undergone successful complete thymectomy for anterior mediastinal disease using subxiphoid and subcostal arch approaches. Propensity score-matching analysis was utilized between the two groups, and the perioperative outcomes were compared. Results: The S-RATT group exhibited less intraoperative blood loss (20 ± 15.35 versus 69.55 ± 69.54, P < .001), lower levels of C-reactive protein (112.38 ± 68.08 versus 72.58 ± 42.62, P = .027), and lower postoperative pain scores (2.09 ± 1.54 versus 4.27 ± 1.28, P < .001). However, the hospitalization costs of patients in the S-VATT group were found to be lower than those in the S-RATT group (33,802.41 ± 8785.05 versus 49,977.53 ± 20,221.79, P < .001). Conclusions: S-RATT appears to be a viable and secure method for managing anterior mediastinal tumors.

Analysis of Pulmonary Function in Thymoma Subjects: A 20-Year Retrospective Cohort Study

BACKGROUND

Thymoma is the most common tumor of the anterior mediastinum. However, the correlation between thymoma stage and pulmonary function was not assessed. Our objective in this study was to describe the pulmonary function in thymoma subjects stratified with different staging systems.

METHODS

A total of 143 subjects with a diagnosis of thymoma who underwent extended thymectomy for thymoma between January 2001 and December 2019 were reviewed retrospectively. All the subjects experienced pulmonary function tests (PFTs) using Master Screen PFT system and total respiratory resistance measurement.

RESULTS

We evaluated 143 subjects with a diagnosis of thymoma; the significant differences were observed in mean values of vital capacity, inspiratory volume (IC), total lung capacity (TLC), ratio of residual volume to total lung capacity (RV/TLC), forced vital capacity, forced expiratory volume in 1 second, ratio of forced expiratory volume in 1 second to forced vital capacity, peak expiratory flow, peak inspiratory flow, maximum ventilation volume, total airway resistance, and diffusing capacity for carbon monoxide (DLCO) across upper airway obstruction classification. PFTs of subjects with varying Masaoka stages are different. RV and RV/TLC of subjects in stages III and IV were higher than those of normal level, while DLCO of subjects in stage IV was lower than the normal level, and the mean level of IC showed significant difference between stage II and stage III.

DISCUSSION

The pulmonary function patterns of thymoma subjects significantly correlate with tumor location and size rather than clinical Masaoka stage.

Anti-dsDNA Is Associated with Favorable Prognosis in Myasthenia Gravis: A Retrospective Study

Objectives. To investigate the presence of serum antinuclear antibody (ANA) and anti-double-stranded DNA antibody (anti-dsDNA) in patients with myasthenia gravis (MG) and analyze the clinical characteristics and prognostic factors associated with MG. Methods. We retrospectively enrolled 363 patients with MG and analyzed the clinical characteristics and follow-up data between patients positive and negative for ANA and anti-dsDNA. We defined a Myasthenia Gravis Activities of Daily Living (MG-ADL) reduction as a main prognosis predictor and used logistic regression to determine independent factors associated with prognosis. We built a nomogram to predict prognosis and evaluate the internal validity of the model. Results. Ninety-eight (27.0%) patients were positive for ANA, and 51 (14.0%) were positive for anti-dsDNA. Patients positive for ANA and anti-dsDNA antibodies tended to be female and positive for acetylcholine receptor antibody (AChR-Ab). The rate of thymoma was higher in anti-dsDNA-positive patients with MG (p-dsDNA-MG) than in patients negative for anti-dsDNA (49.0% vs. 26.0%, $p=0.001$ ), and p-dsDNA-MG was associated with reduced MG-ADL score. Regression analysis showed that except for age of onset ( $\text{OR}=0.986$ , $95\%\text{CI}=0.973–0.999$ , $p=0.037$ ), anti-dsDNA ( $\text{OR}=2.800$ , $95\%\text{CI}=1.381–5.679$ , $p=0.004$ ), ptosis ( $\text{OR}=2.930$ , $95\%\text{CI}=1.827–4.699$ , $p<0.001$ ), and eye movement disorder ( $\text{OR}=2.815$ , $95\%\text{CI}=1.672–4.741$ , $p<0.001$ ) were independent predictive factors of a favorable prognosis of MG. These predictors were used to generate a nomogram with an excellent predictive value. Conclusions. Being female and the presence of AChR-Ab were features of ANA- or anti-dsDNA-positive MG. The presence of anti-dsDNA was associated with a favorable prognosis of MG.

Outcomes after robotic thymectomy in nonthymomatous versus thymomatous patients with acetylcholine-receptor-antibody-associated myasthenia gravis

The aim of this study was to investigate the surgical and long-term neurological outcomes of patients with acetylcholine-receptor-antibody-associated myasthenia gravis (AChR-MG) who underwent robotic thymectomy (RATS). We retrospectively analyzed the clinical-pathological data of all patients with AChR-MG who underwent RATS using the DaVinci® Robotic System at the MUMC+ between April 2004 and December 2018. Follow-up data were collected from 60 referring Dutch hospitals. In total, 230 myasthenic patients including 76 patients with a thymoma (33.0%) were enrolled in this study. Mean follow-up time, procedure time and hospitalization were, respectively 65.7 ± 43.1 months, 111±52.5 min and 3.3 ± 2.2 days. Thymomatous patients had significantly more frequently and more severe complications than nonthymomatous patients (18.4% vs. 3.9%, p<0.001). Follow up data was available in 71.7% of the included patients. The Myasthenia Gravis Foundation of America postintervention score showed any kind of improvement of MG-symptoms after RATS in 82.4% of the patients. Complete stable remission (CSR) or pharmacological remission (PR) of MG was observed in 8.4% and 39.4% of the patients, respectively. Mean time till CSR/PR remission after thymectomy was 26.2 ± 29.2 months. No statistical difference was found in remission or improvement in MGFA scale between thymomatous and nonthymomatous patients. RATS is safe and feasible in patients with MG. The majority of the patients (82.4%) improved after thymectomy. CSR and PR were observed in 8.4% and 39.4% of the patients, respectively, with a mean of 26.2 months after thymectomy. Thymomatous patients had more frequently and more severe complications compared to nonthymomatous patients.

Critical illness-associated weakness and related motor disorders

Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.

Comparison of the Perioperative Outcomes for Thoracoscopic Thymectomy Between the Subxiphoid Approach and the Lateral Intercostal Approach for Masaoka-Koga I-II Thymoma: A Propensity Score-Matching Analysis

BACKGROUND

The appropriate approach for video-assisted thoracic surgery for early-stage thymoma remains debatable. The current study compared the safety and feasibility between subxiphoid-approach thoracoscopic thymectomy (SATT) and lateral intercostal-approach thoracoscopic thymectomy (LATT) for Masaoka-Koga stages 1 and 2 thymoma.

METHODS

The study retrospectively enrolled 461 patients without myasthenia gravis who underwent SATT or LATT at the Zhongshan Hospital of Fudan University between 2016 and 2020. A 1:1 propensity score-matching (PSM) analysis was performed to control for selection bias. A series of perioperative outcomes, including surgical outcomes, inflammatory factors, morbidity and mortality, pain assessment, and quality of life, were compared.

RESULTS

Each group consisted of 144 patients after PSM. The results showed that the SATT group had a significantly higher rate of exposure to the bilateral phrenic nerves (SATT [98.6 %] vs. LATT [77.1 %]; p < 0.001) as well as a larger maximum length (9.20 ± 3.08 vs. 7.52 ± 3.44 cm; p < 0.001) and width (6.13 ± 1.81 vs. 5.04 ± 1.77 cm; p < 0.001) of resected tissue than the LATT group. In addition, the SATT group had lower postoperative high-sensitivity C-reactive protein (hs-CRP) levels (9.37 ± 2.17 vs. 12.69 ± 2.13 mg/L; p < 0.001), better postoperative days 1, 3, and 7 visual analog pain scale (VAS) scores (p < 0.001), and better postoperative days 30 and 90 quality of life (p < 0.05). However, the two groups showed no significant increase in surgical time, estimated blood loss, total drainage time, postoperative total drainage volume, complications, or postoperative hospital stays.

CONCLUSIONS

The study results suggest that the SATT is feasible and safe for Masaoka-Koga stages 1 and 2 thymoma.

On the path to evidence-based therapy in neuromuscular disorders

Neuromuscular disorders encompass a diverse group of acquired and genetic diseases characterized by loss of motor functionality. Although cure is the goal, many therapeutic strategies have been envisioned and are being studied in randomized clinical trials and entered clinical practice. As in all scientific endeavors, the successful clinical translation depends on the quality and translatability of preclinical findings and on the predictive value and feasibility of the clinical models. This chapter focuses on five exemplary diseases: childhood spinal muscular atrophy (SMA), Charcot-Marie-Tooth (CMT) disorders, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), acquired autoimmune myasthenia gravis (MG), and Duchenne muscular dystrophy (DMD), to illustrate the progress made on the path to evidenced-based therapy.

[The Myasthenia Gravis Activities of Daily Living score and associated factors to distinguish the refractory phase in generalized myasthenia gravis patients with 5 years or more disease duration]

Associated factors of the Myasthenia Gravis Activities of Daily Living (MG-ADL) score were investigated in 55 patients who had had generalized MG for more than 5 years. In multivariate analysis, correlates of the MG-ADL score at the last follow-up were the total number of fast-acting treatments (FTs) (standardized regression coefficient 0.617，P < 0.001) and Myasthenia Gravis Foundation of America (MGFA) classification (standardized regression coefficient 0.227，P = 0.032) (F = 32.7，P < 0.001). In patients with a score of 5 or more on MG-ADL at the last follow-up, tendency as follows were seen: 1) early-onset (P = 0.002), 2) longer duration (P = 0.014), 3) high frequency of MGFA classification V (P = 0.017), 4) high frequency of the total number of FTs (P < 0.001), and 5) higher dose of prednisolone at the last follow-up (P = 0.003). MGFA V, early-onset without depending on E-L-T classification, or difficulty of reduction for high doses of prednisolone can be the target of novel treatment for MG, and future prospective study will be expected.

Safety of sugammadex for myasthaenia gravis patients undergoing general anaesthesia: a retrospective database study

Background

Using neuromuscular blocking drugs (NMBDs) for patients with myasthaenia gravis remains a challenge in perioperative management. Sugammadex has enabled the safe use of NMBDs. We investigated whether the adverse outcomes, and the treatment used for myasthaenic crises and tracheotomy, are affected by NMBD use in patients with myasthaenia gravis under general anaesthesia.

Methods

Patients with myasthaenia gravis who underwent general anaesthesia were retrieved from the Diagnostic Procedure Combination/Per-Diem Payment systems in Japan between 1 January 2010 and 30 November 2020. This database did not contain information on the severity of myasthaenia gravis (Osserman classification). Patients who received rocuronium and sugammadex were compared with those who did not receive NMBDs after propensity-score matching. We excluded patients who underwent emergency or cardiac surgery or tracheal intubation before anaesthesia. The primary outcome was receipt of postoperative treatment used for myasthaenic crises.

Results

Among 2304 surgical patients with comorbid myasthaenia gravis, propensity-score matching identified 788 patients administered rocuronium and sugammadex and 449 not administered NMBDs. On comparing the treatment used for myasthaenic crises, we found no significant difference between the two groups (6.2% vs 5.3%; hazard ratio, 1.14; 95% confidence interval, 0.70-1.85).

Conclusions

Use of rocuronium and sugammadex in patients with myasthaenia gravis did not significantly affect the receipt of postoperative treatment used for myasthaenic crises compared with no use of NMBDs. As well as the severity of myasthaenia gravis was not fully adjusted, it is unclear whether intraoperative administration of rocuronium with the use of sugammadex postoperatively is acceptable and further investigations are needed.

Tracking Eye Movements for Diagnosis in Myasthenia Gravis: A Comprehensive Review

BACKGROUND

Around 60%--75% of myasthenia gravis (MG) patients initially present with nonspecific ocular symptoms. Failed recognition of these symptoms may delay the diagnosis of MG up to 5 years or more, leading to a reduced likelihood of remission and increased morbidity. Current diagnostic tests are either poorly sensitive for patients presenting with ocular symptoms alone or are time consuming, invasive, require a high level of technical expertise, and generally are universally difficult to obtain. This review will explore quantitative eye and pupil tracking as a potential noninvasive, time-effective, and less technically demanding alternative to current diagnostic tests of MG.

EVIDENCE ACQUISITION

Comprehensive literature review.

RESULTS

Thirty-two publications using oculography for the diagnosis of MG and 6 studies using pupillometry were evaluated. In MG patients, extra ocular muscle fatigue was evident in reports of intersaccadic, intrasaccadic and postsaccadic abnormalities, changes in optokinetic nystagmus, slow eye movements, disconjugate saccades, and pupillary constrictor muscle weakness.

CONCLUSIONS

Our review identified several potentially useful variables that derive from oculography and pupillometry studies that could assist with a timely diagnosis of MG. Limitations of this review include heterogeneity in design, sample size, and quality of the studies evaluated. There is a need for larger, well-designed studies evaluating eye-tracking measures in the diagnosis of MG, especially for patients presenting with purely ocular symptoms.

Transareolar uniportal thoracoscopic extended thymectomy for patients with myasthenia gravis

Background

Transareolar uniportal thoracoscopic extended thymectomy (TUTET) has not been previously reported. We attempted to assess the feasibility and safety of TUTET for male myasthenia gravis (MG) patients.

Patients and methods

From February 2013 to February 2020, 46 men with MG underwent TUTET. All patients were followed up for 12–84 months postoperatively by clinic visits or telephone/e-mail interviews.

Results

All surgeries were completed successfully, with an average operation time of 72.6 min. The mean length of transareolar uniportal incision was 3.0 ± 0.4 cm, and the mean postoperative cosmetic score was 3.1 ± 0.5 at discharge. Three months postoperatively, no patients had an apparent surgical scar on the chest wall or complained of postoperative pain. Substantial amelioration of the disease was achieved in a short period, and several benefits were clear. At the 1-year follow-up, all patients showed a good cosmetic effect and high satisfaction.

Conclusions

TUTET is an effective and safe way for men with MG. The uniportal incision is hidden in the areola with sound cosmetic effects. We believe that TUTET is an acceptable procedure for extended thymectomy.

Efficiency of ectopic thymectomy by three surgical approaches in non-thymomatous myasthenia gravis

Background

To explore the efficiency of ectopic thymectomy by the three surgical approaches of trans-sternum, right unilateral thoracoscopy and thoracoscopic subxiphoid in patients with non-thymomatous myasthenia gravis.

Methods

155 consecutive non-thymomatous myasthenia gravis patients who underwent extended thymectomy by 3 approaches including trans-sternum, right unilateral thoracoscopy and thoracoscopic subxiphoid in 1st affiliated hospital of Sun Yat-Sen University from January 2017 to October 2019 were reviewed. Differences of perioperative clinical characteristics in three surgical approaches were analyzed.

Results

Time to onset of myasthenia gravis (early or late) (p = 0.018), blood loss (p < 0.001), duration of operation (p = 0.031), duration and volume of thoracic drainage (p = 0.039 and p = 0.026), length of hospitalization (p = 0.039), the efficiency of ectopic thymectomy (p = 0.037), and the detection rate of ectopic thymus in the second quadrant (p = 0.018) were different among the three surgical approaches. In univariate logistic regression analysis, higher efficiency of ectopic thymectomy were associated with transsternal (OR 2.36, 95% CI 1.32–4.22, p = 0.011) and thoracoscopic subxiphoid approaches (OR 2.07, 95% CI 1.12–3.82, p = 0.033). In the multiple logistic regression analysis, the transsternal approach (OR 2.02, 95% CI 1.10–3.71, p = 0.024) was an independent protective factor for the efficiency of ectopic thymectomy.

Conclusions

Both the right unilateral thoracoscopic and thoracoscopic subxiphoid approaches have advantages over the transsternal approach in short-term postoperative recovery. Transsternal approach is still the best choice for ectopic thymectomy while thoracoscopic subxiphoid approach show the potential as an alternative way.

Thymic Lesions in Myasthenia Gravis: A Clinicopathological Study from India

Background and Objectives: Thymic pathology is common in Myasthenia Gravis(MG) and plays a crucial role in its pathogenesis and clinical outcome. This study aims to discuss the clinicohistopathological spectrum of thymic lesions in MG. Methods: In this retrospective study, MG patients who underwent thymectomy from 2011 to 2020 were included. Clinical, radiological, serological, and histopathological details are described. Results: Of 83 patients(F = 45; M = 38), 7(8%) had ocular myasthenia, and the remaining 76(92%) had the generalized form. At onset, the median age was 36 years(M = 44; F = 31). AChR antibody was positive in 71/79 patients. RNST showed decrement response in 68/78 patients. The histopathological study demonstrated thymoma in 44(53%), thymic hyperplasias [32(38%)], involuted thymus [5(6%)], thymic cyst (1) and thymic lipoma (1). WHO grading of thymoma: B2- 48%, AB-18%, B-18%, B3-14%, A-2.3% . In these, capsular infiltration was noted in 11/44, 9 had focal and 2 had diffuse infiltration. Active germinal centers were present in 20/32 patients with thymic hyperplasia and 4/44 with thymoma. Thymomas were predominant in males and thymic hyperplasia in females. The age of onset and antibody positivity rate was higher in thymoma patients. Conclusion: In our cohort, there is a female preponderance. Thymoma was the commonest pathology followed by hyperplasia. We observed earlier onset of myasthenia in females. AChR antibody positivity rate was more frequent in thymomas. This study indicates that clinico-radiological evaluation adequately supported by serology and histopathology can effectively recognize the type of thymic pathology that can guide these patients’ treatment planning, management, prognosis and follow-up.

Maximal Thymectomy via Mini Sternotomy with Pleural Preservation

Gaurav PatelBackground  There are different surgical techniques used for maximal thymectomy. Each technique has its own advantages and disadvantages. We propose a mini sternotomy with pleural preservation approach for complete maximal thymectomy. Methods  Over time range of 5 years, 32 patients with diagnosis of thymoma with or without myasthenia gravis (MG) underwent maximal thymectomy by mini sternotomy in our institute. Patient records were examined for the following parameters: age, sex, preoperative medication, symptoms of MG as per Myasthenia Gravis Foundation of America grading system, operating time, duration of postoperative ventilation, length of stay in the intensive care unit, overall length of hospitalization, and postoperative complications. Results  The mean age of patients in our study was 43.66. Sex ratio in this study was almost equal. Sixty-nine percent of patients were stage I thymoma according to Masaoka staging. Size of the tumor ranged from 3 to 8 cm with mean size being 4.54 cm. Complete resection with negative tumor margins was possible in all the cases. Four patients had intraoperative pleural injury out of which two patients required intercostal tube insertion. We did not have any serious postoperative complications with no perioperative mortality. Conclusions  Mini sternotomy allows maximal removal of thymus through a less invasive approach and is associated with a significantly smoother postoperative course, less overall complications, and good clinical outcome. It is a simple technique that can be performed by any thoracic and surgical oncologists especially in Indian subcontinent where facilities of video-assisted thoracoscopic surgery and robotic video-assisted thoracoscopic surgery are not available in all areas and are expensive.

Myasthenia Gravis and Thymectomy

Myasthenia gravis (MG) is a rare autoimmune neuromuscular disorder. Though MG was diagnosed four centuries ago, its rational management started in 1930s. In the present era, MG is managed by multimodality care including pharmacological agents, plasmapheresis, intravenous immunoglobulins, and surgical thymectomy. Thymectomy has evolved from open trans-sternal to video-assisted thoracoscopic and robotic thymectomy. In this article, the concise history of MG, its clinical features, diagnosis, and management are described.

Robotic thymectomy for myasthenia gravis surgical techniques and outcomes

Myasthenia gravis (MG) is an autoimmune disorder in which antibodies are produced against post-synaptic acetylcholine receptors, thereby causing impairment of neuromuscular transmission. Diagnosis of MG is confirmed with the AChR antibody test and via an Electromyography. Although medical treatment with acetylcholinesterase inhibitors remains the main treatment of MG, in recent years thymectomy has become an integral part of the treatment algorithm. Numerous factors such as the Patient’s age, presence of AChR antibodies, or MuSK antibody, the severity of disease affect the decision of preforming the thymectomy. Historically thymectomy was preformed via sternotomy associated with significant morbidity. Advancement in the minimally invasive approaches to thymic resection has led to more acceptance of thymectomy in the management of MG. Among these approaches, robotic thymectomy is gaining popularity across the globe due to the unique advantages of the robotic platform like 3D visibility, enhanced dexterity, and wrist like articulating movements of instruments. This has led to less post-operative pain and morbidity; faster recovery and shorter hospital stay. Successful treatment of MG requires a multi-modality approach, which has led to the formation of MG teams in most academic centers, comprising of a specialist neurologist, intensivist, and thoracic surgeon. In this article, we describe the techniques and outcomes of the robotic thymectomy for MG.

Thymectomy and Risk of Generalization in Patients with Ocular Myasthenia Gravis: A Multicenter Retrospective Cohort Study

This study aims to investigate the association between thymectomy and the risk of generalization in patients with ocular myasthenia gravis (MG). Data on patients with ocular MG from seven neurological centers in China were retrospectively reviewed. Ocular MG naïve to immunotherapy was categorized according to whether thymectomy was performed (thymectomized group vs. nonsurgical group). Patients in the thymectomized group all underwent surgery within 2 years since ocular symptom onset. The main outcome measure was the generalization. The follow-up period was defined from the date of ocular symptom onset to the date of generalization confirmation, immunotherapy initiation, or last follow-up (defined as 60 months). Of 519 eligible patients (mean [SD] age, 48.7 [15.2] years, 46.6% women), 31 (23.7%) of 131 generalized in the thymectomized group and 122 (31.4%) of 388 did in the nonsurgical group during a median follow-up of 19 months (IQR 8.0-50.0). Thymectomy was independently associated with reduced generalization risk (adjusted HR 0.41, 95% CI 0.25-0.66, P < 0.001). Multivariable stratified analysis also verified this association across the subgroups. Kaplan-Meier curves showed that the 5-year cumulative rate was significantly lower in the thymectomized group than in the nonsurgical group. To conclude, thymectomy may be considered effective in modifying the progression from ocular to generalized MG irrespective of thymoma.

Thymectomy in Myasthenic Patients With Thymoma: Killing Two Birds With One Stone

BACKGROUND

Thymoma and myasthenia gravis share several pathogenetic aspects including the role of surgery as a therapeutic option. Extended thymectomy is associated with excellent survival and good local control, especially in early stages, and its role for the neurologic disease has been recently validated. The aim of this study is evaluating oncologic and neurologic outcomes of myasthenic patients with thymoma who underwent extended thymectomy.

METHODS

We retrospectively collected surgical, oncologic, and neurologic data of all myasthenic patients with thymoma who underwent extended thymectomy at our department from January 1994 to December 2016. Clinical and pathologic data, neurologic remission rate, and overall survival and disease-free interval were analyzed.

RESULTS

In all, 219 patients underwent extended thymectomy. The B2 histotype was the most represented thymoma (24.2%), and the most prevalent pathologic Masaoka stage was IIB (37.9%). The overall survival and disease-free survival were statistically different between early stage and advanced stage. During the surveillance, 33 patients (15.1%) had recurrences, treated in 21 cases with iterative surgery. Regarding neurologic outcomes, 75 patients (34.2%) reached a complete stable remission, 84 (38.4%) a pharmacologic remission, 51 (23.3%) had an improvement of their symptoms, and in 9 patients (4.1%) myasthenia was unchanged or worsened.

CONCLUSIONS

Surgery is a cornerstone in the treatment of patients with both thymoma and myasthenia gravis. Extended thymectomy, as proposed by Masaoka, offers considerable oncologic outcomes with an excellent survival and low recurrence rate of thymoma; moreover, surgery leads to remarkable neurologic results.

Evaluation of extended thymectomy approaches based on residual fat tissue

OBJECTIVES

This study analysed the patterns of extraction ranges, characteristics, advantages and disadvantages of median sternotomy (MS) and subxiphoid (SX) approaches for extended thymectomy.

METHODS

This study included patients with anterior mediastinum tumour and myasthenia gravis who underwent extended thymectomy at our institution between 2015 and 2018. There were 5 MS and 6 SX extended thymectomy surgeries with the VINCENT software. On preoperative computed tomography, the thymus area and fat tissue surrounding the thymus, which were planned for extraction, were traced using VINCENT (Ver. 4.0). We then constructed three-dimensional images and calculated the volumes. Evaluation of the extended thymectomy approach based on the residual fat tissue was required to determine the area of extended thymectomy.

RESULTS

No significant differences in operation time (min) [SX: 197.3 ± 34.0, MS: 206.6 ± 91.4, drainage duration (days), SX: 2.2 ± 1.0, MS: 2.2 ± 0.4, hospital stay (days), SX: 11.8 ± 1.2, MS: 13.4 ± 2.1, residual rate (%), SX: 29.9 ± 17.5, MS: 58.7 ± 18.0 (P = 0.0519)] were observed between the 2 groups. Bleeding was significantly lower for SX than for MS. The residual rate was lower for SX than for MS.

CONCLUSIONS

Considering the amount of the residual fat tissue, the SX approach allows an adequate dissection area for extended thymectomy compared with the MS approach.

Determinants of Suboptimal Outcome Following Thymectomy in Myasthenia Gravis

Background

Response to thymectomy in myasthenia gravis (MG) is influenced by various patient-, disease-, and therapy-related factors.

Methods

Retrospective analysis of 128 patients with MG who underwent maximal thymectomy over 15 years was done to identify the determinants of suboptimal clinical outcome.

Results

Among the 128 patients, 62 (48.4%) were females with a mean age of 38.97 (12.29) years. Thymomatous MG occurred in 66 (51.6%). Overall improvement from preoperative status was noted in 88 (68.8%) patients after mean follow-up of 51.68 (33.21) months. The presence of thymoma was the major predictor of suboptimal clinical outcome (P = 0.001), whereas age, gender, preoperative disease severity, and seropositive status did not attain significance. Patients with better outcome had received higher steroid dose preoperatively (P = 0.035).

Conclusions

Suboptimal response after thymectomy occurred in one-third of MG patients, more commonly with thymomatous MG. Relationship of preoperative steroid therapy to remission merits evaluation.

Subxiphoid versus Unilateral VATS Thymectomy for Thymomas: A Propensity Score-matching Analysis

BACKGROUND

The appropriate surgical approach of VATS for early-stage thymoma remains unclear. The present study aimed to explore the safety and feasibility of subxiphoid and subcostal arch thoracoscopic thymectomy in comparison with unilateral thoracoscopic thymectomy for treatment of early-stage thymoma.

METHODS

The outcomes of 237 patients without myasthenia gravis who had undergone thoracoscopic thymectomy for Masaoka stage I and II thymoma from January 2015 to May 2019 at our center were retrospectively evaluated (subxiphoid and subcostal arch approach: 39; unilateral VATS approach: 198). A propensity score-matching analysis was generated to control for selection bias due to nonrandom group assignment in a 1:1 manner.

RESULTS

There was no surgery-related mortality in included patients. Matching of patients according to propensity score resulted in a cohort that consisted of 39 patients in both groups. Patients had similar clinical characteristics in both groups. Compared with those in the unilateral group, patients in the subxiphoid group yielded lower pain scores at 24- and 72-hours post-operation, respectively (P<0.01). In addition, the operation time was longer in the subxiphoid group (147.5±43.6min vs. 93.2±33.8min, p<0.01). There were no significant differences in blood loss, total volume and time of drainage, complications or postoperative hospital stays between the two groups.

CONCLUSIONS

Subxiphoid and subcostal arch thoracoscopic thymectomy for early-stage thymoma appears to be a safe and feasible procedure. It is considered to be less invasive as it may cause minimal postoperative pain compared to the unilateral VATS approach.

Prevalence and risk factors of myasthenia gravis recurrence post-thymectomy

Objectives:

To evaluate the prevalence and the factors associated with recurrence of myasthenia gravis following thymectomy.

Methods:

Six electronic databases which reported on recurrence of myasthenia gravis following thymectomy and/or its risk factors from 1985 to 2018 were searched. Summary prevalence and risk values obtained based on the random effect models were reported.

Results:

Seventy (70) papers containing 7,287 individuals with myasthenia gravis who received thymectomy as part of their management were retrieved. The patients had a mean follow-up of 4.65 years post-thymectomy. The prevalence of myasthenia gravis recurrence post-thymectomy was 18.0% (95% CI 14.7–22.0%; 1865/7287). Evident heterogeneity was observed (I²=93.6%; p<0.001). Recurrence rate was insignificantly higher in male compared with female patients (31.3 vs. 23.8%; p=0.104). Pooled recurrence rates for thymomatous (33.3%) was higher than the rate among non-thymomatous (20.8%) myasthenia gravis patients (Q=4.19, p=0.041). Risk factors for recurrence include older age, male sex, disease severity, having thymomatous myasthenia gravis, longer duration of the myasthenia gravis before surgery, and having an ectopic thymic tissue.

Conclusion:

A fifth of individuals with myasthenia gravis experience recurrence after thymectomy. Closer monitoring should be given to at-risk patients and further studies are needed to understand interventions to address these risks.

Clinical features and prognostic impact of coexisting autoimmune disease other than myasthenia gravis in resected thymomas: analysis of a Japanese multi-institutional retrospective database

OBJECTIVES

The purpose of this study was to clarify the prevalence, clinical features and survival of patients with thymoma and non-myasthenia gravis autoimmune disease (NMAD) using a nationwide cohort.

METHODS

The Japanese Association for Research on the Thymus nationwide database, which includes data from 32 institutions, was examined to clarify the prevalence and characteristics of NMAD associated with thymomas and elucidate the prognostic impact of NMAD for thymoma patients.

RESULTS

Among the 2423 patients with thymomas who were surgically treated between 1991 and 2010, 114 (4.7%) were identified with NMAD. The most frequently observed NMAD was pure red cell aplasia (PRCA) in 44 (1.8%), followed by hypogammaglobulinaemia (0.5%) and rheumatic arthritis (0.5%). Twenty-eight percent of patients with NMAD had concomitant myasthenia gravis. The presence of NMAD was not an independent prognostic factor for overall survival (OS) irrespective of the type of NMAD [PRCA+: hazard ratio (HR) 1.99, 95% confidence interval 0.74-4.47; PRCA- NMAD: HR 1.28, 0.30-3.56]; however, there were more cases with advanced age and disease of the thymoma amongst PRCA+ patients and these showed a worse OS than patients with PRCA- NMAD (P < 0.001), who had an OS similar to those without NMAD (P = 0.489). The 10-year OS rates in PRCA+, PRCA- NMAD and NMAD- groups were 45.5%, 97.4% and 89.5%, respectively. The main causes of death in PRCA+ patients were the progression of thymoma and other diseases including pneumonia.

CONCLUSIONS

Although the presence of NMAD itself did not significantly affect survival after surgery for thymoma, the type of NMAD was associated with different clinical features and prognosis. The NMAD+ thymomas should be separately categorized according to the presence or absence of PRCA.

SS-A52 antigen expression in thymic carcinoma accompanied with Sjögren syndrome: A case report

RATIONALE

The relationship between thymic tumors and Sjögren syndrome (SjS) is unknown, and surgical resection has not been optimized. Especially, thymic carcinoma with autoimmune disease is rare. Analysis of SS-A52, germinal centers, plasma cells, and Foxp3+ Treg in thymic carcinoma has never been reported, and their pathological roles in causing SjS have not been studied.

PATIENT CONCERNS

A 78-year-old man presented with sputum production and xerostomia while asleep. Chest computed tomography showed a homogeneous and hypodense mass in the anterosuperior mediastinum. Serum levels of the antinuclear antibody, antibody to SS-A, and antibody to SS-B were positive.

DIAGNOSES

Thymic carcinoma (squamous cell carcinoma) and SjS.

INTERVENTIONS

Video-assisted thoracoscopic resection of the mediastinal tumor and postoperative radiation therapy was performed.

OUTCOMES

The histological diagnosis was thymic squamous cell carcinoma. Histologically, the squamous carcinomatous cells were arranged in nests and cords in the fibrohyaline stroma with capsular invasion. In the stroma, dense lymphoid tissues containing large reactive germinal centers and many plasma cells were also noted. In the involuted thymus, CD20-positive mature lymphocytes infiltrated, and germinal centers were noted. Double immunohistochemical staining revealed that SS-A52 antigen was positive in both the carcinoma component and CD20-positive mature B cells. Postoperatively, the xerostomia persisted, and serum SS-A and SS-B remained positive. No evidence of carcinoma recurrence with chest computed tomography scan was observed at 18-months follow-up.

LESSONS

In the surgical treatment of thymic tumors with SjS, extended thymectomy might be worth considering to stop the progressive destruction of the targets of SjS-specific autoantibodies. However, the postoperative symptoms may not dramatically improve because the target organs might have changed irreversibly, and memory B cells might persist. This is the first report that demonstrated the SS-A52 antigen presentation in a thymic tumor to the best of our knowledge.

Thymomatous myasthenia gravis: 10-year experience of a single center

OBJECTIVES

To summarize the clinical features of thymomatous myasthenia gravis (T-MG), examine the association between MG and thymoma, and identify the related factors or predictors for long-term prognosis of T-MG.

METHODS

A retrospective, observational study was conducted on 100 patients with T-MG and 96 patients with non-T-MG (NT-MG) between January 1, 2009 and December 31, 2019. The baseline characteristics were recorded for each patient. Logistic regression was used to measure the association between all clinical variables and T-MG prognosis.

RESULTS

Between the T-MG and NT-MG groups, age at onset (45.66 ± 11.53 years vs 39.06 ± 14.39 years); age >40 years (72.0% vs. 40.6%); AChR-Ab positive rate (100.0% vs. 83.3%); Myasthenia Gravis Foundation of America (MGFA) classification at the worst condition (≥grade III, 61.0% vs. 33.0%); thyroid dysfunction (7.0% vs. 20.8%); and outcome (complete stable remission + pharmacologic remission + improvement, 74.0% vs. 93.7%) were statistically significant (P < .05). Presence of thymoma (OR = 0.196, 95%CI = 0.076-0.511, P = .001) was a risk factor for MG. Male sex, post-operative complications, higher grade of MGFA classification, and thymoma Masaoka-Koga pathological stage were risk predictors for long-term prognosis of T-MG (P < .1). Use of preoperative anticholinesterase drugs (OR = 5.504, 95%CI = 1.424-21.284, P = .013) was identified as an independent predictor for T-MG.

CONCLUSION

T-MG is clinically different from NT-MG, and thymoma is considered a risk factor for MG. Preoperative anticholinesterase drug use is a protective factor for long-term prognosis of T-MG. A comprehensive understanding of the characteristics of T-MG will likely help improve its prognosis.

Ectopic cervical thymoma with myasthenia gravis: a rare association

Thymic masses are one of the most common tumors in the anterior mediastinum. Nevertheless, because the thymus originates in the third and fourth pharyngeal pouches and descends into the anterior mediastinum, ectopic thymic tissue may be found anywhere from the angle of the mandible to the superior mediastinum. Ectopic cervical thymoma (ECT) is an extremely rare tumor that originates from ectopic thymic tissue trapped during the migration of the embryonic thymus and is often misdiagnosed as a thyroid tumor or other neck masses. Herein, we report an unusual case of ectopic cervical thymoma associated to myasthenia gravis (MG).

Prediction of improvement after extended thymectomy in non-thymomatous myasthenia gravis patients

BACKGROUND

It is popularly believed that myasthenia gravis (MG) patients show acetylcholine receptor antibody (AChRAb) production associated with the thymus (germinal centers, approximately 80%). It has been suggested that thymectomy can remove the area of autoantibody production. This study aimed to determine whether the solid volume of the thymus calculated using three-dimensional (3D) imaging could be used to predict the efficacy of thymectomy. Additionally, the study assessed the relationships of the solid volume with germinal centers, change in the serum AChRAb level, postoperative MG improvement, and prednisolone (PSL) dose reduction extent.

METHODS

This retrospective study included 12 consecutive non-thymomatous MG patients (9 female and 3 male patients), who underwent extended thymectomy at our institution over the last 10 years. The mean patient age was 43.3 ± 14.2 years (range, 12-59 years). The study assessed the number of germinal centers per unit area, change in the serum AChRAb level, postoperative MG improvement, PSL dose reduction extent, and solid volume of the thymus.

RESULTS

The number of germinal centers per unit area was significantly correlated with the solid volume of the thymus. The PSL dose reduction extent tended to be correlated with the solid volume.

CONCLUSIONS

Our findings suggest that the solid volume of the thymus can possibly predict steroid dose reduction. Additionally, the solid volume of the thymus in 3D images is the most important indicator for predicting the efficacy of extended thymectomy.

Extended thymectomy with blood vessel resection and reconstruction improves therapeutic outcome for clinical stage III thymic carcinoma patients: a real-world research

OBJECTIVES

We examine the therapeutic efficacy of extended thymectomy with blood vessel resection and reconstruction in thymic carcinoma patients with great vessel invasion.

METHODS

In total 26 patients diagnosed as clinical stage III thymic carcinoma with severe great vessel invasion were enrolled in this retrospective study. Among these patients, 14 cases received adjuvant chemo- and radiotherapy (non-operation subgroup, NOG), the other 12 patients received extended thymectomy with vessel resection and reconstruction followed by the adjuvant treatment (operation subgroup, OG).

RESULTS

All surgical procedures went smoothly with no perioperative death. R0 resection was obtained in all surgical cases, and we also observed a lymph node metastasis rate of 38.8%. The overall survival (OS) was 34 months for the whole cohort, 48 and 26 months for the OG and NOG respectively (p = 0.013). The median disease metastasis free survival (DMFS) was 47 months for the OG and 18 months for the NOG (p = 0.019).

CONCLUSION

Extended thymectomy with vessel resection is feasible for patients with clinical stage III thymic carcinoma. Surgery significantly improves the overall survival and the prognosis of clinical stage III thymic carcinoma.

Subxiphoid completion thymectomy for refractory non-thymomatous myasthenia gravis

Background

Completion thymectomy may be performed in patients with non-thymomatous refractory myasthenia gravis (MG) to allow a complete and definitive clearance from residual thymic tissue located in the mediastinum or in lower neck. Hereby we present our short- and long-term results of completion thymectomy using subxiphoid video-assisted thoracoscopy.

Methods

Between July 2010 and December 2017, 15 consecutive patients with refractory non-thymomatous myasthenia, 8 women and 7 men with a median age of 44 [interquartile range (IQR) 38.5–53.5] years, underwent video-thoracoscopic completion thymectomy through a subxiphoid approach.

Results

Positron emission tomography (PET) showed mildly avid areas [standardized uptake value (SUV) more than or equal to 1.8] in 11 instances. Median operative time was 106 (IQR, 77–141) minutes. No operative deaths nor major morbidity occurred. Mean 1-day postoperative Visual Analogue Scale value was 2.53±0.63. Median hospital stay was 2 (IQR, 1–3.5) days. A significant decrease of the anti-acetylcholine receptor antibodies was observed after 1 month [median percentage changes −67% (IQR, −39% to −83%)]. Median follow-up was 45 (IQR, 21–58) months. At the most recent follow-up complete stable remission was achieved in 5 patients. Another 9 patients had significant improvement in bulbar and limb function, requiring lower doses of corticosteroids and anticholinesterase drugs. Only one patient remained clinically stable albeit drug doses were reduced. One-month postoperative drop of anti-acetylcholine receptor antibodies was significantly correlated with complete stable remission (P=0.002).

Conclusions

This initial experience confirms that removal of ectopic and residual thymus through a subxiphoid approach can reduce anti-acetylcholine receptor antibody titer correlating to good outcome of refractory MG.

Invasive thymoma with intravascular growth into the great veins and right atrium: A case report

Here, we present a case of invasive thymoma with intraluminal growth into the left and right brachiocephalic veins, superior vena cava and the right atrium. Resection of the mass, double partial upper lobe lobectomy and superior vena cava, and left and right brachiocephalic vein replacement were performed. Pathological diagnosis indicated a mixed histological pattern indicative of type B1 and type B2 thymoma, predominantly type B2 thymoma. The patient was well and without local recurrence or distal metastasis after 50 months of follow‐up.

[Ectopic thymic tissue and ectopic thymic tumors]

Ectopic thymic tissue outside its core position in the antero-superior mediastinum is quite common owing to the complexity of embryonal thymus development, whereby reported prevalence values (1 to 90%) are heavily dependent on the method of investigation and the intensity of the workup. The debated prevalence and relevance of ectopic thymic tissue and its accessibility underlie the ongoing discussion whether modern, minimally invasive thymectomy strategies can match the proven benefit of the radical transsternal thymectomy procedure for the treatment of Myasthenia gravis. In this context, the following article covers the etiology, prevalence, and location of normal-looking, reactive, and neoplastic ectopic thymic tissue. Furthermore, ectopic tissues and tumors inside or adjacent to the thymus are mentioned.

Surgical Techniques for Myasthenia Gravis: Video-Assisted Thoracic Surgery

We describe the various video-assisted thoracic surgery approaches to the thymus currently adopted in nonthymomatous and thymomatous myasthenic patients. Despite several controversies, video-assisted thoracic surgery thymectomy gained worldwide popularity. Classic 3-port approaches proved safe and effective. Uniportal video-assisted thoracic surgery requires consolidated experience, whereas the bilateral approach is considered more extensive. Subxiphoid represents the ultimate and exciting challenge. As an effect of video-assisted thoracic surgery approach, thymectomy is performed earlier; both patients and neurologists are more prone to accept the procedure given the quicker recovery, lesser pain, and better cosmesis. Outcomes are equivalent to those achieved by sternotomy.

Surgical Approaches to Myasthenia Gravis: Perspective of Anatomy and Radicality in Surgery

The effectiveness of thymectomy for nonthymomatous myasthenia gravis is analyzed with regard to extensiveness of removal of the adipose tissue of the mediastinum and the lower neck region with various techniques of thymectomy. The approach necessary to achieve maximal radicality must include access to both pleural cavity and the lower neck area up to the thyroid gland. Surgical techniques include extended transsternal approach, which might be combined with separate transcervical incision, bilateral videothoracoscopic (VATS) approach combined with transcervical incision, and extended subxiphoid approach, either uniportal or combined with bilateral VATS. Anatomic aspects of maximally extensive thymectomy are described in detail.

A Neurologist's Perspective on Thymectomy for Myasthenia Gravis: Current Perspective and Future Trials

The first randomized blinded study of thymectomy in nonthymomatous myasthenia gravis was designed to answer 3 questions: does the combination of prednisone and removal of the thymus gland via extended transsternal thymectomy after 3 years compared with an identical dosing protocol of prednisone alone (1) lead to better disease status for generalized MG patients with antiacetylcholine receptor antibodies, (2) reduce their prednisone requirements, and/or (3) reduce the side-effect burden from medications used to treat the disease? The study demonstrated that thymectomy confers these benefits for patients and sets the stage for inquiries into the benefits of less-invasive approaches to thymic resection.

Optimal timing of thymectomy in nonthymomatous myasthenia gravis patients in China: A prospective study

INTRODUCTION

While thymectomy is a recommended therapy for patients with Myasthenia Gravis (MG), there is insufficient evidence of its benefits over other therapies in patients in China, specifically, or of the most optimal timing for the procedure. Thus, there remains a clinical need for the investigation of these questions. Therefore, it is important to compare the clinical efficacy of thymectomy plus oral prednisone, an immunosuppressant protocol with prednisone, or immunosuppressants alone.

CONCLUSION

We propose here to prospectively assess 822 cases of MG and 1886 medical records from individuals hospitalized at the First Affiliated Hospital of Guangzhou University of Chinese Medicine and follow them for 3 years. Inclusion criteria will include the following: a Myasthenia Gravis Foundation of America (MGFA) clinical classification between I and IV while on optimal anticholinesterase therapy with or without oral prednisone or immunosuppressive therapy, an MG history of longer than 3 years, being 18 to 60 years of age, and positive testing for serum acetylcholine receptor antibodies (AchR-Ab). Both thymomatous-naïve and non-naïve participants will be included. The primary outcomes will be: mortality, frequency of myasthenic crises, MGFA classification, and changes to the required dose of prednisone and immunosuppressants. Based on these outcomes, we will evaluate the efficacy of thymectomy as well as oral drugs in managing patients with nonthymomatous MG. As of September 2017, this study has been approved by the ethics committee of the First Affiliated Hospital of Guangzhou University of Chinese Medicine and the Registration number is ChiCTR1800017564(Version1.0, September 8,2017).

Predictive value of the thymofatty specimen weight index in outcomes of extended thymectomy due to non-thymomatous myasthenia gravis

OBJECTIVES

To evaluate the predictive value of the intraoperative thymofatty specimen weight (TFSW) index on predicting the prognosis of extended thymectomy (ET) for non-thymomatous myasthenia gravis.

METHODS

This is a prospective non-interventional study in which patients who underwent ET between January 2012 and June 2015 were enrolled. Resected thymus and surrounding adipose tissues were weighed using an electronic scale intraoperatively and adjusted to the body surface area (BSA) to calculate the TFSW index. The primary end point was defined as complete stable remission (CSR) according to the Myasthenia Gravis Foundation of America (MGFA) guidelines.

RESULTS

One hundred and eighteen patients who completed postoperative follow-up were included in this study. After a mean follow-up period of 44 months, 68 (57.6%) patients reached clinical CSR. The MGFA class, histopathology and TFSW index were associated with a postoperative CSR in univariate analysis. When the Cox hazard multiple regression model was used, the TFSW index was found to be an independent predictor for CSR (hazard ratio 2.056; 95% confidence interval 1.182-3.576). Based on ROC analysis, an optimal TFSW index cut-off value (35.9 g/m2) with the highest sensitivity and specificity was determined.

CONCLUSIONS

The TFSW index is an important independent predictor for mid-term CSR after ET in non-thymomatous myasthenia gravis patients. During the ET surgery, every effort should be made to take a tissue specimen with a TFSW index more than 35.9 g/m2.

G, Cataneo DC. Thymectomy in nonthymomatous myasthenia gravis - systematic review and meta-analysis

BACKGROUND

The objective of this study is to evaluate by means of a systematic review, the efficacy of thymectomy as compared to medical treatment for non-thymomatous myasthenia gravis (MG).

METHODS

Medline, Embase, and Lilacs were searched for experimental and observational studies that compared non-surgical (drug therapy) and surgical treatment of non-thymomatous MG (thymectomy performed by the transsternal approach). Inclusion criteria were: studies that compared the two types of treatment and had at least 10 adult patients in each group. Exclusion criteria were articles published before 1970, as well as those that included patients treated before 1950. The outcomes evaluated were: remission, and improvement rates. RevMan 5.3 software provided by the Cochrane Collaboration was used. When the heterogeneity between the studies was greater than 75%, a meta-analysis was not performed according to RevMan guidelines.

RESULTS

The total number of patients evaluated in 19 articles selected was 5841 (2911 surgical and 2930 non-surgical). Two included randomized clinical trials showed superiority of the surgical treatment over the non-surgical. Four retrospective studies with 379 patients paired by gender, age, and other confounders, also showed superiority of surgical treatment (OR 4.10, 95% CI 2.25 to 7.44; I2 = 20%). In meta-analyses, remission assessed in 17 studies (5686 patients) was greater in patients who underwent surgical treatment (OR 2.34, 95% CI 1.79 to 3.05; I2 = 56%). For improvement assessed in 13 studies (3063 patients) were not appropriate to carry out the meta-analysis due to the high heterogeneity among the studies in the outcome (87%).

CONCLUSION

Thymectomy may be considered effective in the treatment for non-thymomatous MG, with remission rate higher than for non-surgical treatment.

Independent long-term result of robotic thymectomy for myasthenia gravis, a single center experience

Background

Robotic thymectomy has been suggested a feasible and safe approach for myasthenia gravis (MG). Few investigations have revealed the independent effect of robotic thymectomy without the confounding impact of immunosuppressive (IM) therapy.

Methods

Between May 2009 and December 2012, robotic extended thymectomy was carried out for patients with diagnosis of MG. The clinical data, subsequent neurological therapy and postintervention status were collected.

Results

Data of 37 cases was available for analysis. The mean follow-up was 70.0±13.3 months. The median age was 40 years. Twelve (32.4%) patients kept free of IM therapy, and 25 (67.6%) patients accepted postoperatively. The overall 5-year complete stable remission (CSR) rate was 40.6% and improvement rate was 81.6%. The young (age ≤40) displayed a significant better CSR rate (P=0.015) and a trend of better improvement rate (P=0.050) compared to the old (age >40). Patients without usage of IM therapy showed significant higher CSR rate (P=0.014) and improvement rate (P=0.024) compared to those with usage of IM therapy. Patients with Myasthenia Gravis Foundation of America (MGFA) classes I showed a trend of higher remission rate by multivariate analysis. No significant differences were found for the remission rate according to gender, pathology, and the duration of symptoms.

Conclusions

The mono-therapy of robotic thymectomy may bring with a satisfactory long-term result for part of MG patients. Precision selection and individualized therapy are of the most importance.