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Aim: This nationwide study evaluated the clinical impact that an early thymectomy, during congenital heart defect (CHD) surgery, had on the health of children and adolescents. Methods: The subjects were patients aged 1–15 years who had undergone CHD surgery at the University Children's Hospital, Helsinki, where all CHD surgery in Finland is carried out, from 2006 to 2018. The parents or the cases and population‐based controls, matched for sex, age and hospital district, completed electronic questionnaires. We excluded those with low birth weights or a known immunodeficiency. Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were calculated for prespecified outcomes. Results: We received responses relating to 260/450 (58%) cases and 1403/4500 (31%) controls and excluded 73 cases with persistent cardiac or respiratory complaints after surgery. The CHD group reported more recurrent hospitalisations due to infections (aOR 6.3, 95% CI 3.0–13) than the controls and more pneumonia episodes (aOR 3.5, 95% CI 2.1–5.6), asthma (aOR 2.5, 95% CI 1.5–4.1) and wheezing (aOR 2.1, 95% CI 1.5–2.9). Conclusion: Hospitalisation due to infections, pneumonia, wheezing and asthma was more common in children after a thymectomy due to open‐heart surgery than population‐based controls, underlining the importance of immunological follow‐ups. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is an autoimmune disease characterized by muscle fatigability due to acetylcholine receptor (AChR) autoantibodies. To better characterize juvenile MG (JMG), we analyzed 85 pre- and 132 post-pubescent JMG (with a cutoff age of 13) compared to 721 adult MG patients under 40 years old using a French database. Clinical data, anti-AChR antibody titers, thymectomy, and thymic histology were analyzed. The proportion of females was higher in each subgroup. No significant difference in the anti-AChR titers was observed. Interestingly, the proportion of AChR+ MG patients was notably lower among adult MG patients aged between 30 and 40 years, at 69.7%, compared to over 82.4% in the other subgroups. Thymic histological data were examined in patients who underwent thymectomy during the year of MG onset. Notably, in pre-JMG, the percentage of thymectomized patients was significantly lower (32.9% compared to more than 42.5% in other subgroups), and the delay to thymectomy was twice as long. We found a positive correlation between anti-AChR antibodies and germinal center grade across patient categories. Additionally, only females, particularly post-JMG patients, exhibited the highest rates of lymphofollicular hyperplasia (95% of cases) and germinal center grade. These findings reveal distinct patterns in JMG patients, particularly regarding thymic follicular hyperplasia, which appears to be exacerbated in females after puberty. [ABSTRACT FROM AUTHOR]

The thymus gland aids in the maturation of the immune system. An overactive or malfunctioning thymus gland, as seen in thymomas, can lead to disrupted immune systems. Thymectomy, the usual treatment, can paradoxically lead to further derangements in the immune system, leading to new autoimmune disorders. Most of these reported disorders are rheumatological. Except preclinical studies, there are no reported cases of autoimmune diabetes post-thymectomy. A 25-year-old woman who had malignant thymoma underwent chemotherapy, followed by thymectomy and radiotherapy. She developed autoimmune diabetes mellitus (AID) approximately 1 year post-thymectomy, evident from raised glycated hemoglobin, anti-glutamic acid decarboxylase (GAD) antibodies, ineffectiveness of oral glucose-lowering agents, and positive response to insulin. AID can occur after thymectomy, as evidenced by animal studies and this case report. Whether these patients would have long-term outcomes and control of diabetes differently than classic type 1 diabetes mellitus (T1D) is uncertain. Further research is needed to prove causality between thymectomy and diabetes. [ABSTRACT FROM AUTHOR]

The thymus is a lymphoid organ involved in the differentiation of T cells, and has a central role in the physiopathogenesis of Myasthenia Gravis (MG). This connection is proved by a series of changes in the level of neuromuscular junctions, which leads to a decrease in the amplitude of the action potential in the post-synaptic membrane. Because of this, the presence of anti-cholinergic receptor antibodies (AChR), characteristic of MG, is found, which causes the progressive regression of the effect of acetylcholine at the level of neuromuscular junctions, with the appearance of muscle weakness. The thymectomy is a surgical variant of drug therapy administered to patients with MG. In the case of patients with nonthymomatous MG, thymectomy has become a therapeutic standard, despite the fact that there is no solid scientific evidence to explain its positive effect. Videothoracoscopic surgery or robotic surgery led to a decrease in the length of hospital stay for these patients. This paper aims to synthesize the information presented in the literature in order to create a background for the perspectives of thymectomy. [ABSTRACT FROM AUTHOR]

We report a unique case of a 66-year-old man who was incidentally identified to have a mass in the thymus region by computerized tomography scan. CT revealed a well-defined 1.6 × 1 × 0.9 cm thymus mass with moderate uniform enhancement. Thoracoscopic thymectomy was performed, and the pathological diagnosis was primary glomus tumor of the thymus. There were no atypia or malignant histological features, and no primary tumors in other sites. To our knowledge, this is the first case of primary thymic glomus tumor reported in the literature. [ABSTRACT FROM AUTHOR]

Extended thymectomy is performed to excise the ectopic thymic tissue around the thymus; however, the distribution of the ectopic thymic tissue in the adipose tissue remains unclear. This study investigated the distribution of ectopic thymic tissue in extended thymectomy. This study included 31 patients who underwent extended thymectomy. Pathological specimens were reviewed to examine the distribution of ectopic thymic tissues in six locations: the right and left outer sides of the thymus tissue and the upper and lower ends of the resected tissue in extended thymectomy. The frequency of ectopic thymic tissue and the ratio to the surrounding adipose tissue were estimated. In our study, all patients, including patients >60 years, had thymic tissue in the surrounding adipose tissue removed during extended thymectomy. The probability of an ectopic thymus existing near the diaphragm, i.e., at the caudal end of the resection, was 13–19%, and the ratio of the area of the ectopic thymus to that of adipose tissue was <1% in almost all cases. In three patients with myasthenia gravis, an ectopic thymus was found in the adipose tissue around the diaphragm at a rate of >1%; there were no cases exceeding 10%. This value is extremely low compared with those of the other excision areas of extended thymectomy. Ectopic thymic tissues are far less likely to be present in adipose tissue on the diaphragm compared with that of other areas. This finding may help surgeons during the excision of adipose tissue around the thymus. [ABSTRACT FROM AUTHOR]

Objective: To describe the post-surgical clinical evolution of a case series of patients with juvenile myasthenia gravis (JMG) treated with right video-assisted thoracoscopic (TVA) thymectomy. Materials and Methods: Retrospective study that included 13 pediatric patients with JMG who underwent right TVA thymectomy at the Siglo XXI National Medical Center of Mexico between March 2016 and April 2022. Patients were clinically characterized, and the disease was classified according to Osserman’s criteria. Post-surgical evolution was evaluated using the DeFilippi classification to determine the proportion of patients with improvement and complete remission. Results: The included patients were mostly women (84.6%) with a mean age at diagnosis of 11.1 ± 3.1 years. The four MG classifications were included, with the highest proportion of mild generalized MG (38.5%), followed by ocular (23.1%) and moderatesevere generalized (23.1%). The evaluation of post-surgical progression showed that after three months of follow-up, 92.3% presented improvements, including a decrease in the use of medications. Complete remission was only recorded in one of the patients. Patients who underwent surgery before 12 months of evolution of JMG had better results after TVA thymectomy. Conclusion: The usefulness of TVA thymectomy in Mexican pediatric patients with JMG was demonstrated. Our experience adds evidence that pediatric patients benefit from thymectomy by improving their clinical status and decreasing the use of medications and complications of the disease. [ABSTRACT FROM AUTHOR]

The case report of a 54 years patient is described, who was admitted to Hermanos Ameijeiras Clinical-Surgical Teaching Hospital in Havana city due to fever, hypotension and diarrhea, to which complicated respiratory difficulty was added during his hospitalization and he required mechanical ventilator support in the Intensive Care Unit. As a radiographic finding, a shade in the left lung was observed that turned out to be a thymoma; while the blood test revealed hipogammaglobulinemia. It was decided to carry out conventional thymectomy by means of midline sternotomy, after which the patient had a favorable clinical course and was discharged from the hospital 10 days later. [ABSTRACT FROM AUTHOR]

BACKGROUND The function of the thymus in human adults is unclear, and routine removal of the thymus is performed in a variety of surgical procedures. We hypothesized that the adult thymus is needed to sustain immune competence and overall health. METHODS We evaluated the risk of death, cancer, and autoimmune disease among adult patients who had undergone thymectomy as compared with demographically matched controls who had undergone similar cardiothoracic surgery without thymectomy. T-cell production and plasma cytokine levels were also compared in a subgroup of patients. RESULTS After exclusions, 1420 patients who had undergone thymectomy and 6021 controls were included in the study; 1146 of the patients who had undergone thymectomy had a matched control and were included in the primary cohort. At 5 years after surgery, all-cause mortality was higher in the thymectomy group than in the control group (8.1°/o vs. 2.8%; relative risk, 2.9; 95% confidence interval [CI], 1.7 to 4.8), as was the risk of cancer (7.4% vs. 3.7%; relative risk, 2.0; 95% CI, 1.3 to 3.2). Although the risk of autoimmune disease did not differ substantially between the groups in the overall primary cohort (relative risk, 1.1; 95% CI, 0.8 to 1.4), a difference was found when patients with preoperative infection, cancer, or autoimmune disease were excluded from the analysis (12.3% vs. 7.9%; relative risk, 1.5; 95% CI, 1.02 to 2.2). In an analysis involving all patients with more than 5 years of follow-up (with or without a matched control), all-cause mortality was higher in the thymectomy group than in the general U.S. population (9.0% vs. 5.2%), as was mortality due to cancer (2.3% vs. 1.5%). In the subgroup of patients in whom T-cell production and plasma cytokine levels were measured (22 in the thymectomy group and 19 in the control group; mean follow-up, 14.2 postoperative years), those who had undergone thymectomy had less new production of CD4+ and CD8+ lymphocytes than controls (mean CD4+ signal joint T-cell receptor excision circle [sjTREC] count, 1451 vs. 526 per microgram of DNA [P=0.009]; mean CD8+ sjTREC count, 1466 vs. 447 per microgram of DNA [PcO.001]) and higher levels of proinflammatory cytokines in the blood. CONCLUSIONS In this study, all-cause mortality and the risk of cancer were higher among patients who had undergone thymectomy than among controls. Thymectomy also appeared be associated with an increased risk of autoimmune disease when patients with preoperative infection, cancer, or autoimmune disease were excluded from the analysis. (Funded by the Tracey and Craig A. Huff Harvard Stem Cell Institute Research Support Fund and others). [ABSTRACT FROM AUTHOR]

Background: Primary thymic adenocarcinoma represents an exceptionally rare malignancy, for which the cornerstone of therapy is margin-negative resection, with radiation and systemic therapy reserved for invasive and advanced disease. Thymic adenocarcinoma has not been previously reported in the setting of a concomitant malignancy, as reported herein.Case Presentation: We present a case of a 55-year-old previously healthy male diagnosed with acute myeloid leukemia, also found to have a mediastinal mass. Evaluation of the mediastinal mass with tumor markers, biopsies, and next-generation sequencing proved non-diagnostic, while he was simultaneously treated with induction chemotherapy to prevent leukemia-related blast crisis. After completing and recovering from induction chemotherapy, he underwent successful thymectomy during a chemotherapy holiday, with a margin-negative resection of thymic adenocarcinoma. He has subsequently recovered and undergone successful allogeneic hematopoietic stem cell transplant.Conclusions: We present a case of synchronous adult acute myeloid leukemia and primary thymic adenocarcinoma requiring a tailored approach for management of simultaneous malignancies. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES Our goal was to compare the oncological outcomes and efficacy between minimally invasive thymectomy (MIT) and open thymectomy (OT) in patients with early or locally advanced thymoma using a multicentre study database. METHODS We retrospectively collected data from 1,239 patients who underwent thymectomy between January 2000 and December 2013, as recorded in the database of the Korean Association for Research on Thymus. We compared the postoperative outcomes of the MIT and OT groups using unmatched and propensity score (PS) matched data. RESULTS We excised the thymoma using MIT and OT in 455 and 784 patients, respectively. We matched 378 patients with Masaoka-Koga stage I or II thymoma by their PS. The operative time, duration of hospital stay and complications were significantly shorter in the MIT group than in the OT group (all P  <   0.005). In the PS matched data, the groups did not show significant differences in the 10-year survival rate (87.7% in OT vs 85.5% in MIT, stage II, mean follow-up duration: 12.9 years in OT vs 11.1 years in MIT), recurrence-free survival (94.0% in OT vs 86.4% in MIT) and R0 resection (97.35% in OT and MIT, P  =   0.59). CONCLUSIONS Compared with OT, MIT was associated with shorter operative times, shorter durations of hospital stay and fewer complications. Long-term survival, recurrence-free survival and complete resection were not significantly different between the OT and MIT groups. Our findings may help physicians track the progress of patients with early or locally advanced thymomas and design treatment plans for them. [ABSTRACT FROM AUTHOR]

Hypothalamic-pituitary-gonadal axis function is necessary for maintaining proper female reproductive cycle. This study aimed to evaluate the ovarian histomorphometric and histoarchitectural changes in neonatal, prepubertal and pubertal thymectomized female guinea pigs. A total of 30 female guinea pigs, sham-operated (n-5) and thymectomized (n-5) were studied in each group. The diameter and number of ovarian follicles among the thymectomized and sham operated female guinea pigs during estrus phase of estrous cycle was compared. Gonadal and accessory reproductive organs weights and microscopic features were studied in the sham operated guinea pigs and thymectomized. There were statistically significant changes in the number and diameter of follicles in the ovary in neonatal thymectomized female guinea pigs, but no significant changes were observed in prepubertal and pubertal female guinea pigs. Neonatal thymectomized female guinea pigs showed significant changes in their weight as well as changes in the microscopic features including reduced thickness of myometrium of uterus and less mucosal folding in the fallopian tube compared to the sham-operated group. But prepubertal and pubertal thymectomy did not affect the weight and microscopic features of gonads and accessory reproductive organs. Depending on the time of thymectomy, these results indicate morphological changes in the ovaries after thymectomy in females. [ABSTRACT FROM AUTHOR]

The article discusses the historical and contemporary understanding of the thymus, previously considered the "seat of the soul" by Galen, and its role in immune function. Topics include the historical perception of the thymus, its role in immune function, adverse effects of thymectomy in adults, and the need to reconsider thymus preservation during surgery.

Background: Castleman disease is a lymphoproliferative disorder of uncertain origin that is most commonly found in the mediastinum. It is classified based on pathological features into hyaline-vascular, plasma cell, and mixed variants. An association between Castleman disease and myasthenia gravis very rarely has been reported, except of the hyaline variant type, because it is associated with various clinical abnormalities. Castleman disease typically is diagnosed based on an incidental radiology finding of enlarged local lymph nodes, which result in compression symptoms. Case Report: Here, we report the case of a 31-year-old Saudi woman who presented with a 2-year history of exertional dyspnea associated with mouth and eye ulcers. She had no other associated symptoms, such as muscular weakness, rapid fatigue, or drooping eyelids. She was referred to our institution for further investigation and management and was diagnosed with myasthenia gravis after testing positive for acetylcholinesterase antibodies. A computed tomography (CT) scan then was performed, which showed an enlarged thymus gland. The patient eventually underwent a bilateral thoracoscopic thymectomy. Conclusions: The aim of the present report was to add to the literature by presenting a rare case of asymptomatic subclinical myasthenia gravis associated with Castleman disease. The findings underscore the importance of considering Castleman disease in an asymptomatic patient who has a mediastinal mass and avoiding an unusual intraoperative occurrence such as massive bleeding by performing a preoperative biopsy and angiography. [ABSTRACT FROM AUTHOR]

Background: Thymic tumors are unusual neoplasms, representing 0.2 to 1.5% of tumors in humans, but correspond to 20% of mediastinal tumors and 50% of those that occur in the anterior mediastinum. They tend to appear around the fourth and fifth decades of life without gender predilection. Up to 30% of patients are asymptomatic, therefore many are incidentally diagnosed. Radical thymectomy is the treatment of choice with high survival rates when detected in the early stages.Methods: This was a retrospective descriptive study, including 18 adult patients' diagnosis of thymic neoplasm, who were managed with surgical resection from 2011 to 2019. Information about demographics, clinical characteristics, imaging findings, surgical and medical management, plus histological findings was obtained and reported.Results: 18 patients with thymic tumors were included, of which specific histologic studies reveled thymomas, carcinomas, neuroendocrine tumors, thymolipoma and thymic cyst. Mean age was 52.7 years, with a predominance of male population. The main symptom was dyspnea, followed by cough and chest pain. Paraneoplastic syndromes such as myasthenia gravis, aplastic anemia and Cushing syndrome were reported. 89% of cases were treated by radical thymectomy alone, while only 2 cases required chemotherapy and radiotherapy. There were no surgical complications. Mean hospital stay length was 11. 9 days, with only 1 mortality during hospital admission. 5-year survival rate was 81%.Conclusions: The treatment of choice is radical thymectomy, which has been shown to positively impact patient mortality. Early detection is key to improve patient outcomes. [ABSTRACT FROM AUTHOR]

Myasthenia gravis is an autoimmune disease in which antibodies which are generated to the acetylcholine nicotinic receptors at the motor end plate cause skeletal muscle weakness.1 There appears to be an association with the thymus gland, where T cells generate antibodies after being sensitised to a protein similar to the acetylcholine receptor.1 Historically, myasthenia gravis was classified into five classes by Osserman, ranging from eye involvement alone, to mild, moderate or severe weakness, and the need for intubation and ventilation.1 Patients with myasthenia gravis are commonly treated with the acetylcholinesterase inhibitor, pyrodistigmine, glucocorticosteroids, other immune suppressants, as well as plasma exchange and intravenous immunoglobulins. Patients with generalised disease may present for surgery to remove the thymus gland, after which approximately 75% of patients enter remission.¹ In the perioperative period, the nuances of the disease process must be appreciated in order to provide the most beneficent care. Neuromuscular blockade should be avoided unless absolutely necessary, and when non-depolarising agents are used, they must always be accompanied by monitoring of the neuromuscular junction and appropriately reduced doses, due to the increased sensitivity to these agents. Sugammadex should also be available. These patients are relatively resistant to succinylcholine, and an increased dose should be used with the knowledge that prolonged blockade may ensue.¹ [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is a disease of neuromuscular junction and mainly autoimmune in aetiology. The state of thymus is a critical determinant for the prognosis. In this retrospective review study, we aimed at clarifying the relationship between the mode of clinical presentation of MG and the radiopathological classification of the thymus. We identified patients with MG from the database of our medical center from 1988 -- 2017. The patients were classified into two groups according to their clinical presentation: those with a typical presentation with diurnal variation, and those with an atypical presentation of persistent weakness or respiratory failure from the beginning. The underlying thymic state was categorized into six groups: normal, abnormal by imaging (if no operation was performed), hyperplasia, benign thymoma, cortical type thymoma, and malignant thymoma. In total, 227 patients (133 females and 94 males) were included in the analysis, of whom 68% were classified into the typical presentation group. The atypical presentation correlated significantly with thymic categories (p = 0.014) and sex (p = 0.026) but not age at onset (p = 0.232). The atypical presentation was more common in the male patients and in those with thymic carcinoma. [ABSTRACT FROM AUTHOR]

We report on a 35‐year‐old woman who complained of myasthenia in ocular, bulbar, and limb muscles, but who was negative for antibodies against acetylcholine receptor, muscle‐specific kinase, or low‐density lipoprotein receptor‐related protein 4, accompanied by the suppression of thyroid‐stimulating hormone with elevated free T3 and free T4. Administration of edrophonium significantly ameliorated blepharoptosis, and electromyography revealed 13.9% waning after 3 Hz repetitive stimulation in the left accessory nerve. Thus, she was suspected of having triple seronegative myasthenia gravis or thyrotoxic myasthenia. She was remitted after the resection of her enlarged thymus with an elevated uptake in fluorine‐18 fluorodeoxyglucose positron emission tomography, suggesting an unknown autoimmune target that escaped detection by current autoantibody screens. Consequently, thymectomy may still be effective in patients with seronegative MG plus hyperthyroidism. [ABSTRACT FROM AUTHOR]

The relationship between thymic epithelial tumour and demyelinating disease (DD) is unknown and surgical resection has not been optimized. A 39‐year‐old woman was administrated methylprednisolone for newly diagnosed multiple sclerosis. A thymic tumour was found in the antero‐superior mediastinum via computed tomography of the chest. Video‐assisted thoracoscopic thymectomy was performed. Histologically, the tumour was diagnosed as Type AB thymoma. Immunohistochemical staining showed positive myelin basic protein (MBP) in the cytosol of spindle cells in the tumour specimen. Germinal centres or lymphocytes infiltration were not noted. Ectopic MBP presentation in thymoma might be correlated with DD. [ABSTRACT FROM AUTHOR]

The thymus plays an integral role in immune system regulation, modulating the development, diversity, and selection of T lymphocytes, a critical feature for the prevention of T cell-mediated autoimmunity. Thymoma is a rare tumor of the thymus. Autoimmune diseases and paraneoplastic syndromes such as myasthenia gravis, pure red blood cell aplasia, and systemic lupus erythematosus, although relatively uncommon, have been described in association with thymomas. Rare cases of post-thymectomy autoimmune related diseases, including systemic lupus erythematosus and pure red cell aplasia, have been reported in the literature. Here, we present the case of a 65-year-old male who developed systemic lupus erythematosus 2 years after thymectomy in the setting of thymoma-associated pure red cell aplasia. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide Open in new tab Download slide OBJECTIVES Thymectomy is the treatment of choice for thymomatous myasthenia gravis (MG) for both oncological and neurological aspects. However, only a few studies comprising small numbers of patients have investigated post-thymectomy neurological outcomes. We examined post-thymectomy long-term neurological outcomes and predictors of thymomatous MG using a multi-institutional database. METHODS In total, 193 patients (47.3 ± 12.0 years; male:female = 90:103) with surgically resected thymomatous MG between 2000 and 2013 were included. Complete stable remission (CSR) and composite neurological remission (CNR), defined as the achievement of CSR and pharmacological remission after thymectomy, were evaluated. Predictors for CSR and CNR were examined by Cox regression analysis. RESULTS The median duration between MG and thymectomy was 3.1 months. In addition, 161 patients (83.4%) had symptoms less than Myasthenia Gravis Foundation of America clinical classification III. All patients underwent an extended thymectomy; there were no perioperative deaths. The 10-year cumulative probability of CSR and CNR was 36.9% and 69.1%, respectively. Mild preoperative symptoms were a significant predictor for CSR (P  = 0.040), and a large tumour was a predictor for CNR (P  < 0.001). Patients with a large tumour were associated with early MG onset and no steroid treatment. Surgical methods, thymoma stage and histological subtypes were not associated with long-term neurological remission. CONCLUSIONS Large tumour size and preoperative mild symptoms were predictors for long-term neurological outcome in thymomatous MG. Considering that patients with early onset of MG and no immunosuppressive treatment tend to have large tumours, early surgical intervention for patients with thymomatous MG having mild symptoms might be beneficial for controlling neurological outcomes. [ABSTRACT FROM AUTHOR]

Barely 60 years ago, the thymus was considered to be a vestigial organ with no known function or just a graveyard for dying lymphocytes. Now, the thymus and its cells cover a vast area of immunology, genetics and epigenetics relating to medicine, including inflammation, infection, vaccination, dysbiosis, immunodeficiency, allergy, autoimmunity, transplantation, tissue repair, pregnancy and cancer. New technology and approaches, now becoming available, will lead to a much deeper understanding of many of these conditions. Hence, the thymus and its cells will be occupying researchers and clinicians for decades to come. Work performed in the last 60 years has shown that T cells, or lymphocytes derived from the thymus, previously believed to be redundant, do have a crucial immune function and are implicated in many medical conditions. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the thymuses of non-thymomatous myasthenia gravis (MG) patients by computed tomography (CT) for differentiating lymphoid follicular hyperplasia (LFH) thymus from normal/involuted thymus in order to assist surgeons in determining whether a non-thymomatous MG patient requires an operation. In the present retrospective review over 10 years, 80 patients who received CT scan and thymectomy at the Affiliated General Hospital of Tianjin Medial University (Tianjin, China) were included. According to the pathological records, 54 of the cases initially detected on CT were confirmed as LFH thymus. Thymic measurements, including anteroposterior and transverse dimensions, width (the longest axis of the lobe on a transverse scan) and thickness (the largest dimension perpendicular to the long axis of the lobe) and CT attenuation of the thymus region, adipose tissue and chest wall musculature in each CT slice were included to assess differences between the LFH group and the normal/involuted thymus group. Although a negative association between patient age and the CT attenuation of the thymus region was identified (r=−0.779, P<0.05, Pearson's correlation test), the LFH thymus group featured nodular changes on CT, while no such changes were observed in the normal/involuted thymus group. The mean age of disease onset in the LFH thymus group was significantly lower than that in the normal thymus group (40.2±17.3 vs. 59.2±9.3 years). Furthermore, significant differences in CT attenuation were identified between the LFH group and the normal/involuted thymus group [-41.21±54.42 vs. −108.23±8.72 Hounsfield units (HU) on unenhanced CT; −25.57±58.65 vs.-117.40±6.22 HU on contrast-enhanced CT]. In the LFH group, the difference in mean CT attenuation between the thymus region and adipose tissue was significant, while no significant difference was observed in the normal/involuted thymus group. In conclusion, CT may be used to distinguish LFH thymus from normal/involuted thymus in MG patients. [ABSTRACT FROM AUTHOR]

Abstract Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction. Most patients have pathogenic autoantibodies against the acetylcholine receptor (AChR). In the last years a novel subpopulation of MG patients has been described that harbors antibodies against low-density lipoprotein receptor-related protein 4 (Lrp4), another postsynaptic neuromuscular antigen. In early-onset AChR MG (EOMG), the thymus plays an important role in immunopathogenesis, and early thymectomy is beneficial. It is still unknown if the thymus plays any role in Lrp4-MG. In this pilot study, we compared thymus samples from four patients with Lrp4-MG (one pre-treated with immunosuppressive drugs), four non-MG controls and five EOMG patients (not pretreated with immunosuppressive drugs). Immunohistochemistry of the Lrp4-MG thymi revealed normal architecture, with normal numbers and distribution of B-cells, lymphoid follicles and Hassall's corpuscles. Primary CD23+ lymphoid follicles were similarly infrequent in Lrp4-MG and control thymic sections. In none of the control or Lrp4-MG thymi did we find secondary follicles with CD10+ germinal centers. These were evident in 2 of the 5 EOMG thymi, where primary lymphoid follicles were also more frequent on average, thus showing considerable heterogeneity between patients. Even if characteristic pathological thymic changes were not observed in the Lrp4 subgroup, we cannot exclude a role for the thymus in Lrp4-MG pathogenesis, since one Lrp4-MG patient went into clinical remission after thymectomy alone (at one year follow-up) and one more improved after thymectomy in combination with immunosuppressive therapy. Highlights • Lrp4 thymi had normal thymic architecture. • Lrp4 thymi had few small primary lymphoid follicles, and no secondary follicles with germinal centers. • Fresh thymic cells from Lrp4-MG patient L1 spontaneously produced IgG in culture, indicating the presence of plasma cells. • Lrp4-MG patient L1 went into clinical remission after thymectomy without further therapy • Lrp4-MG patient L3 improved with post-operative immunosuppressive drugs. [ABSTRACT FROM AUTHOR]

Key Clinical Message: A surgical approach is the choice in young infants with MTH, who are furthest from the time of physiological involution of the thymus, and when the thymus achieves the largest relative size, a surgical approach is the choice. Steroid therapy has been shown to be ineffective (4, 9, 16, 18‐20). No surgical complications have been reported, and the outcome is excellent. Recurrence has been seen in only one case. A surgical approach is the choice in young infants with MTH, who are furthest from the time of physiological involution of the thymus, and when the thymus achieves the largest relative size, a surgical approach is the choice. Steroid therapy has been shown to be ineffective (4, 9, 16, 18‐20). No surgical complications have been reported, and the outcome is excellent. Recurrence has been seen in only one case. [ABSTRACT FROM AUTHOR]

Introduction: Thymectomy is the preferred standard treatment in younger non-thymoma patients with myasthenia gravis as well as in patients with early stage thymoma. Total thymectomy by median sternotomy has been the surgical approach since resection of the thymus with video-assisted thoracoscopic surgery (VATS). Aim: To compare the clinical outcomes of VATS thymectomy with conventional open thymectomy for neoplastic and non-neoplastic thymic diseases. Material and methods: Forty patients underwent thymectomy between October 2012 and January 2016. Fifteen patients were male and 25 patients were female. The mean age was 40.3 ±17.7 years. Seventeen (55%) patients underwent VATS thymectomy and 23 (45%) patients underwent an open procedure. We retrospectively reviewed the data of the patients and compared these two techniques. Results: The mean tumor size was 5.17 ±3.2 cm in the thymoma group (VATS 2.5 ±2.4 cm vs. open access 4.7 ±3.7 cm). None of the patients experienced a myasthenic crisis. Conversion to thoracotomy was required in 1 patient in the VATS group due to bleeding from the right internal mammary artery; therefore, the conversion rate was 2.5% among all the patients. No mortality occurred in either group. No significant difference was found in the perioperative blood loss, operative time or pain visual analogue scale scores. On the other hand, regarding postoperative drainage, duration of chest tube drainage and length of hospital stay, VATS thymectomy yielded better results and the differences were significant. Conclusions: Video-assisted thoracoscopic surgery thymectomy can be performed for both neoplastic and non-neoplastic thymic diseases with minimal morbidity and mortality. [ABSTRACT FROM AUTHOR]

Background and purpose: Myasthenia gravis (MG) is an autoimmune disease with muscular weakness as the only symptom, and often with immunosuppressive treatment. All these aspects could have relevance for the risk of infections as well as their prophylactic and curative treatment.Methods: This is a review article, where Web of Science has been searched for relevant key words and key word combinations. Full papers were selected first by title and then by abstract.Results and conclusions: MG can be triggered and worsened by infections. No virus or other pathogen has been proven to have a specific link to MG. Treatment with immunosuppressive drugs and thymectomy implies a slightly increased risk for infections. Infections should be actively treated, but a few antibiotics are avoided due to potential interference with neuromuscular transmission. Hospitalization and intensive care may be necessary during infections because of MG deterioration and risk of insufficient respiration. Vaccinations are generally recommended in MG, but live microorganisms should be avoided if possible in immunosuppressed patients. [ABSTRACT FROM AUTHOR]

The processes regulating peripheral naive T-cell numbers and clonal diversity remain poorly understood. Conceptually, homeostatic mechanisms must fall into the broad categories of neutral (simple random birth–death models), competition (regulation of cell numbers through quorum-sensing, perhaps via limiting shared resources), adaptation (involving cell-intrinsic changes in homeostatic fitness, defined as net growth rate over time), or selection (involving the loss or outgrowth of cell populations deriving from intercellular variation in fitness). There may also be stably maintained heterogeneity within the naive T-cell pool. To distinguish between these mechanisms, we confront very general models of these processes with an array of experimental data, both new and published. While reduced competition for homeostatic stimuli may impact cell survival or proliferation in neonates or under moderate to severe lymphopenia, we show that the only mechanism capable of explaining multiple, independent experimental studies of naive CD4+ and CD8+ T-cell homeostasis in mice from young adulthood into old age is one of adaptation, in which cells act independently and accrue a survival or proliferative advantage continuously with their post-thymic age. However, aged naive T cells may also be functionally impaired, and so the accumulation of older cells via ‘conditioning through experience’ may contribute to reduced immune responsiveness in the elderly. [ABSTRACT FROM AUTHOR]

With increasing knowledge that the immune system has a major impact on reproductive health, the potential for cells arising in organs such as the thymus to alleviate oxidative stress has been revealed. This study addresses the impact of neonatal thymectomy on male reproductive function in pubertal and adult animals. Neonatal Sprague Dawley rats were allotted to four treatments consisting of fully thymectomized, partially thymectomized, intact, and sham-operated rats. Half of the rats in each treatment were sacrificed at 40 and the other half at 80 days of age. Testicular volume, ventral prostate and spleen weight, several sperm attributes (concentration, motility, livability, membrane integrity, sperm penetration into mucus, total antioxidant capacity, mitochondrial dehydrogenase activity), plasma superoxide dismutase, glutathione, and testosterone level as well as fertility decreased in thymectomized rats. Adrenal gland weight, sperm malondialdehyde level, indices of oxidative stress, sperm abnormality, testicular and sperm lipid peroxidation, protein carbonylation, and sperm reactive oxygen species generation increased in thymectomized rats. In thymectomized rats, the testes contained high levels of malondialdehyde but low levels of glutathione and ferric-reducing antioxidant power. Epididymal sperm reactive oxygen species, blood lipid peroxidation, and oxidative stress indices in blood and spermatozoa were highest in fully thymectomized, intermediate in partially thymectomized, and lowest in both pubertal and mature control rats. Blood levels of superoxide dismutase, lipid peroxidation indices, and testosterone, and mitochondrial adenosine triphosphate and dehydrogenase activities in epididymal spermatozoa were lowest in fully thymectomized, intermediate in partially thymectomized, and highest in both pubertal and mature control rats. The data indicated that increased oxidative stress and mitochondrial dysfunction might play a role in the mechanism of immunosuppression-induced testicular and sperm abnormalities. [ABSTRACT FROM AUTHOR]

The thymus plays an important role in the development of the immune cell pool; it serves as the primary location for T-lymphocyte maturation. Early cardiac surgical interventions for congenital heart defects are necessarily associated with thymectomy, i.e. the partial or complete removal of the thymus. A newborn infant already has a functioning thymus and developed cells of the immune system. However, thymectomy eliminates the primary location where T cells differentiate and mature. This study summarizes the current knowledge of the cellular disturbances and potential clinical consequences associated with performing thymectomy in children treated surgically for congenital heart defects. [ABSTRACT FROM AUTHOR]

Background: We believe the merit of preservation of a part of the thymus following surgery for thymoma. We evaluated the efficacy of partial or subtotal thymectomy for early-stage thymoma in the prospective study. Methods: The Japanese Association for Research on the Thymus conducted a multiple institutional study of thymectomy for thymoma localized in the thymus without total thymectomy. Patients without autoimmune disease who had an anterior mediastinal tumor that had been clinically diagnosed as an early-stage thymoma were enrolled in the study. Patients who were positive for anti-acetylcholine receptor antibodies were excluded. Results: Sixty-three patients were enrolled preoperatively; 27 patients were judged as being inappropriate based on the other thymic pathologies or tumor invasion. The remaining 36 cases were diagnosed as early-staged thymoma and analyzed. The mean age of the patients was 61 years. The mean maximal tumor diameter in the resected specimens was 3.6 cm. The most common pathological types of thymoma were AB ( n = 10) and B1 ( n = 10). The Masaoka stages were classified as stage I ( n = 22) and II ( n = 14). The mean observation period was 63 months. Two patients died due to respiratory dysfunction, which was not related to thymoma. One hundred percent of the patients remained recurrence-free. Conclusions: This prospective study suggested the efficacy of partial or subtotal thymectomy for early-stage thymoma in patients without any apparent evidence of autoimmune disease. We can preserve a part of the thymus even following surgery for thymoma to prepare the possible second malignancies or diseases in future. [ABSTRACT FROM AUTHOR]

The contribution of the decline in thymic activity for the emergence of autoimmunity is still debatable. Immune-competent adults submitted to complete thymectomy early in life provide a unique model to address this question. We applied here strict criteria to identify adults lacking thymic activity based on sjTREC levels, to exclude thymic rebound and/or ectopic thymuses. In agreement, they featured severe naïve CD4 T-cell depletion and contraction of T-cell receptor diversity. Notwithstanding this, there was neither increased incidence of autoimmune disease in comparison with age-matched controls nor significant changes in their IgG/IgA/IgM/IgE autoreactivity profiles, as assessed through extensive arrays. We reasoned that the observed relative preservation of the regulatory T-cell compartment, including maintenance of naïve regulatory CD4 T-cells, may contribute to limit the emergence of autoimmunity upon thymectomy. Our findings have implications in other clinical settings with impaired thymic activity, and are particularly relevant to studies of autoimmunity in ageing. [ABSTRACT FROM AUTHOR]

Although myasthenia gravis (MG) is a classic autoantibody-mediated disease, T cells are centrally involved in its pathogenesis. In recent years a number of studies have analyzed the role of CD4 + FoxP3 + regulatory T cells (T reg ) in the disease with contradictory results. Here, the generation of T reg was significantly reduced in thymoma as compared to thymic hyperplasia and normal thymus tissue (p = 0.0002). In the peripheral blood, T reg subsets classified according to CD49d, HELIOS and CD45RA expression changed after thymectomy and in the long-term course of immunosuppression. Compared to healthy volunteers the frequency of CD45RA + FoxP3 low T reg was reduced in MG patients in general (p = 0.037) and in particular in patients without immunosuppression (p = 0.036). In our study, thymectomy and immunosuppressive treatment were associated with changes in T reg subpopulations. The reduced frequency of CD45RA + FoxP3 low T reg we observed in MG patients might play a role in MG pathogenesis. [ABSTRACT FROM AUTHOR]

Myasthenia Gravis is an autoantibody-mediated, neuromuscular junction disease, and is usually associated with thymic abnormalities presented as thymic tumors (~10%) or hyperplastic thymus (~65%). The exact role of thymus in Myasthenia Gravis development is not clear, yet many patients benefit from thymectomy. The apoptotic ligand TNF-Related Apoptosis-Inducing Ligand is thought to be involved in the regulation of thymocyte counts, although conflicting results are reported. We investigated differential expression profiles of TNF-Related Apoptosis-Inducing Ligand and its transmembrane receptors, Nuclear Factor-kB activation status, and apoptotic cell counts in healthy thymic tissue and pathological thymus from Myasthenia Gravis patients. All tissues expressed TNF-Related Apoptosis-Inducing Ligand and its receptors, with hyperplastic tissue having the highest expression levels of death receptors DR4 and DR5. No detectable Nuclear Factor-kB activation, at least via the canonical Protein Kinase A-mediated p65 Ser276 phosphorylation, was evident in any of the tissues studied. Apoptotic cell counts were higher in MG-associated tissue compared to the normal thymus. Possible use of the TNF-Related Apoptosis-Inducing Ligand within the concept of an apoptotic ligand-mediated medical thymectomy in thymoma- or thymic hyperplasia-associated Myasthenia Gravis is also discussed. [ABSTRACT FROM AUTHOR]

Introduction: Myasthenia gravis (MG) occurs globally, and many studies have indicated that there are regional differences in epidemiology, biomarkers, and prognosis of MG.Methods: A total of 478 patients with MG who visited hospitals in the Henan Province between January 2010 and February 2014 were included. Age, gender, age at onset, serum antibody, thymus pathology, treatment information, and Myasthenia Gravis Foundation of America (MGFA) classification were assessed.Results: Compared with previous reports from other areas, we found some differences in MG patients from Henan. The proportion of childhood MG in our study was lower than other reports of Oriental patients with MG. There seems to be an association between onset age, muscle involvement, and acetylcholine receptor antibody levels. Thymectomy improved the symptoms in 78.5% of thymectomy-treated patients.Conclusions: These differences are likely related to geographical, environmental, and ethnic differences. Understanding these differences will help us to define more specific treatment. [ABSTRACT FROM AUTHOR]

Objectives: Neuroendocrine differentiation in carcinomas of the nonneuroendocrine type has been observed in various organ systems. Awareness of this phenomenon is important since such tumors need to be separated from true neuroendocrine neoplasms because of therapeutic and prognostic consequences. To investigate this occurrence in thymic carcinomas, 27 cases of different histologies were analyzed using neuroendocrine immunohistochemical markers.Methods: Twenty-seven conventional thymic carcinomas from thymectomies were studied immunohistochemically with antibodies directed against synaptophysin, chromogranin A, and CD56 in addition to the standard markers for these tumors.Results: Focal expression of at least one neuroendocrine marker was identified in a total of 12 (44%) cases. Chromogranin A was positive in five (19%) cases, synaptophysin in eight (30%), and CD56 in 10 (37%). All three markers were coexpressed in four (15%) cases.Conclusions: Neuroendocrine differentiation in conventional thymic carcinomas is a common occurrence. It is imperative to separate these tumors from true neuroendocrine neoplasms of the thymus-especially large cell neuroendocrine carcinoma-since both entities require different treatment modalities and likely show different biologic behavior. Contrary to prior suggestions, neuroendocrine differentiation should not be used to distinguish thymic carcinomas from thymomas, and these tumors should not be regarded as "mixed carcinomas." [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is an autoimmune disease characterized by autoantibody mediated postsynaptic failure of neuromuscular transmission. The thymus gland has a role in the pathogenesis of MG. The aim of this study was to determine (1) the prevalence of different thymic pathologies in the MG patient population of Latvia; (2) the potential impact of different thymus pathologies on the clinical course of MG; and (3) the effectiveness of surgical treatment of thymic pathologies in Latvia. The results showed that the most common thymus pathology among the patients with MG in Latvia is thymoma. Compared to the published data, the proportion of MG patients diagnosed with thymus hyperplasia in Latvia is very small. Thymus hyperplasia is uncommon among patients 60 years of age and older. MG onset for patients with thymoma is significantly later than that of patients with thymus hyperplasia. Almost all patients with thymoma or thymus hyperplasia develop a generalised form of MG. The presence of a thymus pathology does not significantly affect the electrophysiological test results, clinical symptom severity, frequency of disability or hospitalisation of the patients with MG. Thymectomy in patients with thymoma or thymus hyperplasia has no significant effect on relieving MG symptoms [ABSTRACT FROM AUTHOR]

OBJECTIVES: Thymectomy is a recognized treatment for myasthenia gravis (MG), but the optimal surgical approach is yet to be determined. This study analysed the results in non-thymomatous MG patients treated at our institution using an extended transcervical access with partial upper sternotomy (TC-US), in order to describe cumulative incidence of remission and its predictors. METHODS: In the period 1988-2012, 215 non-thymomatous MG patients underwent thymectomy using the TC-US approach. There were 61 males and 154 females (median age: 33 years). Primary end points were complete stable remission (CSR) and pharmacological remission (PR). Clinico-pathological predictors of CSR/PR were analysed including age, gender, preoperative MG symptom duration, preoperative immunosuppression therapy and disease severity. RESULTS: The median follow-up period was 127 months. The median preoperative duration of MG symptoms was 9 months (interquartile range 4-13). The median operative time was 65 min (range: 45-135). There was no postoperative death. Morbidity rate was 7% (14 patients, no major complication). Ten patients died at the follow-up (3 of MG). MG symptoms improved in 85% (150/176) of the patients. CSR rate was 34%, PR rate was 4%. Cumulative incidence of CSR/PR was 27, 37 and 46% at 5, 10 and 15 years, respectively. Independent predictors of increased CSR/PR rate were age (P = 0.028) and MG symptom duration <6 months (P = 0.013). CONCLUSIONS: Our data suggest that in patients with non-thymomatous MG, thymectomy by TC-US has a remission rate not inferior to those reported after trans-sternal or video-assisted thoracic surgery techniques. The short duration of MG symptoms before thymectomy is a predictor of remission. The technique strikes a reasonable balance between the extent of thymic resection, operative and anaesthesia time, patient acceptance, neurological outcome and costs. [ABSTRACT FROM AUTHOR]

The objective of this study was to describe the clinical characteristics, outcome and factors that may affect the outcome of childhood-onset myasthenia gravis (CMG) patients in China. We have followed up 424 patients with CMG for at least 5 years at Tongji Hospital. At the end of follow-up, the outcome of all the patients was measured according to MGFA Post-intervention Status. In this study, the patients have been followed up for 9.8 ± 5.4 years. The mean onset age was 5.4 ± 3.6 years. Ocular myasthenia gravis (OMG) was the major type of CMG within 2 years after onset (95 %). Thymic hyperplasia was found in 116 patients, and thymoma was confirmed in 6 patients. Acetylcholine receptor antibodies were elevated in 69.5 % of the patients. All the patients were routinely treated. Thymectomy was performed in 34 patients (8.0 %). At the end of follow-up, seventy-one patients (16.7 %) were significantly improved, 66 patients (15.6 %) remained unchanged, 53 patients (12.5 %) were worsened, and 234 patients (55.2 %) were exacerbated. Importantly, fifty OMG patients (12.4 %) had transformed into generalized myasthenia gravis (GMG) over 2 years after onset. Thymectomy did not effectively reduce the transformation from OMG to GMG. However, GMG cases significantly benefited from the surgery. This study indicated that the cases with autoimmune CMG account for over 50 % in Chinese MG population. The long-term follow-up discloses that CMG patients have a low percentage of improvement, and a high percentage of worsening and exacerbation. The treatment should not be withdrawn too early after the patients obtain complete stable remission. More studies are needed to gain better control of CMG symptoms. [ABSTRACT FROM AUTHOR]

Background Complete surgical excision is the most important long-term prognostic factor of thymomas. Although video-assisted thoracoscopic surgery (VATS) has been reported as an effective treatment to excise mediastinal thymic lesions, it has not replaced median sternotomy as the standard approach because of the lack of long-term follow-up studies. The objective of this study was to analyze and to compare the outcome of VATS extended thymectomy with the traditional open approach. Methods This is a single center's retrospective study of 27 patients submitted to surgery for early stage thymomas between 1995 and 2007. Histologic subtype and clinicopathologic staging were classified, respectively, according to World Health Organization and Masaoka criteria. Patients with preoperative computed tomography scan evidence of clinical Masaoka stage 1 thymomas were selected for VATS thymectomy with unilateral technique. Results All patients successfully underwent surgery: 3 with VATS and 4 with an open approach. There were no differences in time of surgery and postoperative complication between the two groups. Patients who had VATS had shorter postoperative hospital stay than patients who had open technique. After a median follow-up of 123 months, there were no postoperative recurrences. Conclusion VATS is a safe operation and has comparable effectiveness to the open technique in terms of oncological radicality for small, early stage thymoma. [ABSTRACT FROM AUTHOR]

Background Thymectomy is an essential component in the treatment of myasthenia gravis (MG) and the best treatment for localized thymoma. Minimally invasive thymectomy has advanced to include robotic-assisted techniques. The acceptance of this approach is growing rapidly, while the debate on the adequate technique for thymectomy remains open. Methods We describe the technique of robotic-assisted thymectomy and its modifications. The worldwide registries and the literature are reviewed. The experience from the largest single-center database is analyzed. Results The unilateral three-trocar approach for robotic thymectomy from either left or right side has been standardized. More than 100 centers worldwide perform robotic thymectomy. The annual number of this procedure increased steadily and reached 1,000 in 2012, while the largest single-center experiences comprise almost 500 cases. The end points improvement of MG and recurrence of thymoma are comparable to open procedures. There are special advantages of robotic assistance for complete mediastinal dissection. The perioperative complication rate is below 2%. Conclusion Robotic thymectomy combines minimal incisional discomfort with extensive mediastinal dissection. As its use expands, robotic thymectomy may become the standard for all indications of thymectomy. [ABSTRACT FROM AUTHOR]

The therapeutic effect of thymectomy on myasthenia gravis is not completely understood. Several types of thymectomy varying in approach and extent have been performed. None of these disclosed a neat superiority over others. Patients desire thymectomy through small, painless, and cosmetically favorable operations. Videoassisted thoracoscopic surgery (VATS) thymectomy fits all these requests as well as that of the surgeon. Indeed, this approach allows for ample operative space, easy maneuverability, and extended thymectomy. No mortality, low morbidity, faster recovery, short hospital stay, and small economical costs are undoubtedly advantages of VATS over transsternal and transcervical thymectomy. In the near future, the introduction of robotic devices will lead to a new era in the surgery of the thymus. Herein we analyzed our comprehensive experience. [ABSTRACT FROM AUTHOR]

Background In myasthenia gravis (MG) both native and ectopic thymic tissue containing germinal centers should show greater metabolism compared to adjacent tissues. We evaluated whether preoperative standardized uptake value (SUV) of 18fluoro-deoxy-glucose on Positron Emission Tomography (PET) might be increased and correlated with the presence of native or ectopic germinal centers. Methods From 2005 to 2012 we performed extended thymectomy in 68 patients with nonthymomatous MG. All patients underwent PET-scan preoperatively and one-year postoperatively. SUVs were assessed in thymic and perithymic regions. Then it was matched with same-age, non-MG and non-neoplastic control group and finally correlated with presence of germinal centers in native thymus or in the ectopic tissue found in the surgical specimens. Results Mean SUV was significantly increased in MG patients compared to control group. Thymic SUV was significantly higher in presence of thymic germinal centers [3.5 (2.4-5.0) Vs 2.1 (1.4-2.5), p = 0.021] while perithymic SUV was significantly higher in presence of ectopic germinal centers [3.1 (2.7-3.5) Vs 1.3 (0.9-1.7), p = 0.001]. SUV was significantly correlated with MG score (rho = 0.289, p = 0.017) and marginally with antibodies anti-acetylcholine receptors (rho = 0.129, p = 0.05). At Kaplan Meier analysis, ectopic thymic tissue (p = 0.045) and ectopic germinal centers (p = 0.036) were significant predictors of complete stable remission, but preoperative dichotomized thymic (3.5 or more Vs less) (p = 0.083) and perithymic (2.1 or more Vs less) (p = 0.052) SUVs did not. Conclusions Thymic and perithymic SUVs were significantly higher in patients with MG than non-MG and non-neoplastic patients. Thymic SUV was significantly correlated with the presence of germinal centers. Perithymic SUV resulted significantly correlated with the discovery of ectopic active thymic tissue. Neither thymic nor perithymic high SUVs predicted remission. [ABSTRACT FROM AUTHOR]

Background: This study aimed to compare the perioperative outcomes for patients who underwent transsternal or robot-assisted thymectomy and to determine the feasibility of robot-assisted thymectomy for the treatment of Masaoka stages 1 and 2 thymomas. Methods: The study evaluated the short-term outcomes for 74 patients undergoing surgery for Masaoka stages 1 and 2 thymomas without myasthenia gravis between January 2009 and December 2012. Of these 74 patients, 23 underwent thymoma resection using unilateral robot-assisted thoracoscopic surgery (RATS group), and 51 underwent transsternal thymectomy (TST group). Duration of surgery, amount of intraoperative blood loss, duration of chest drainage, duration of postoperative hospital stay, and postoperative complications were evaluated. Results: The intraoperative blood loss was significantly less in the RATS groups (61.3 ml) than in the TST group (466.1 ml) ( p < 0.01). The postoperative hospital stay was significantly shorter in the RATS group (3.7 vs 11.6 days; p < 0.01). No patients in the RATS group underwent conversion to open surgery. No severe surgical complications (e.g., bleeding caused by injury to the left brachiocephalic vein) and only one case of pulmonary atelectasis (appearing in a male patient 2 days after surgery) were detected in this series. Conclusion: Robot-assisted thoracoscopic thymectomy for early-stage thymomas is technically feasible, safe, and less invasive for the patient. [ABSTRACT FROM AUTHOR]

The MGTX trial is the first prospective, randomized clinical trial that aims to evaluate the impact of extended transsternal thymectomy on myasthenic symptoms, prednisone requirements, and quality of life in patients with nonthymomatous, anti-acetylcholine receptor autoantibody-positive myasthenia gravis (MG). Here, we give an overview of the rationale of thymectomy and the standardized macroscopic and histopathological work-up of thymectomy specimens as fixed in MGTX standard operating procedures, including the grading of thymic lymphofollicular hyperplasia and the morphometric strategy to assess thymic involution. [ABSTRACT FROM AUTHOR]

The clinicopathologic and immunohistochemical features of 65 primary thymic carcinomas are reported (43 men and 22 women; 19-81 years old). Thymectomy was performed in all cases. Masaoka staging for 53 patients showed 3 patients in stage I, 14 in stage II, 17 in stage III, and 19 in stage IV. Histologic studies revealed 9 carcinoma subtypes. Immunohistochemically, the tumors showed high rates of expression for cytokeratin, Pax8, and FoxN1. Follow-up for 62 patients revealed that 36 patients were alive (mean follow-up, 51.1 months) and 26 had died (mean survival, 47.5 months). The 3- and 5-year overall survival rates were 76.6% and 65.7%, respectively. Our findings suggest that thymic carcinomas may behave less aggressively than commonly believed. Lymph node status and tumor size seem to be important prognostic factors. The Masaoka staging system does not seem to reliably predict outcome. [ABSTRACT FROM AUTHOR]

OBJECTIVES The aim of the study was to investigate the distribution of ectopic thymic tissue in the mediastinum and to evaluate the possible relevance of this distribution to the therapeutic yield of thymectomies in patients with myasthenia gravis. METHODS In this prospective autopsy study, mediastinal dissections were performed on 50 cadavers without any previously known intrathoracic pathology. The initial dissection was performed in the same way as during the maximal thymectomy. The second stage consisted of dissecting areas of fatty tissue located out of reach of the standard maximal thymectomy, such as the perithyroid, periaortic, peritracheal and retrotracheal areas, as well as the areas adjacent to the right and left phrenic and recurrent laryngeal nerves. Each specimen was independently examined by two pathologists for ectopic thymic tissue. RESULTS There were 41 (82%) male and 9 (18%) female cadavers, with a mean age of 44.3 years (range: 15–75). Ectopic thymic tissue was detected in 32 out of 50 cadavers (64%). In 10 (20%) cadavers thymic foci were found in locations accessible to the standard surgical intervention and in 22 (44%)—in inaccessible locations. Thymic tissue incidence in individual locations was as follows: retrothyroid, 3 (6%); peritracheal, 5 (10%); retrotracheal, 1 (2%); right phrenic nerve, 2 (4%); left phrenic nerve, 14 (28%); right recurrent laryngeal nerve, 2 (4%); left recurrent laryngeal nerve, 2 (4%) and periaortic, 0. CONCLUSIONS The incidence of ectopic thymic tissue in the mediastinum is common. Although some improvements in the results of thymectomies may be expected with more extensive dissection, the frequent presence of thymic foci in anatomical locations hardly accessible to surgical intervention may be the true limitation for surgical treatment of myasthenia. [ABSTRACT FROM PUBLISHER]