Thymoma Group Research Articles

Robotic-assisted extended thymectomy for large resectable thymoma: 21 years’ experience

ObjectiveThis study aims to evaluate the perioperative and midterm oncological outcomes of robotic-assisted thoracic surgery extended thymectomy for patients with large resectable thymomas compared with small thymomas. MethodsThis retrospective single-center study included 204 patients with thymomas who underwent robotic-assisted thoracic surgery extended thymectomy between January 2003 and February 2024. Patients were divided into 2 groups based on the thymoma size (5-cm threshold). ResultsThe study comprised 114 patients (55.9%) in the small thymoma group and 90 patients (44.1%) in the large thymoma group. No significant differences were found between the groups regarding gender, age, proportion of elderly patients, or pathologic high-risk classifications. Apart from a longer operative time (P = .009) in the large thymoma group, no differences were observed between the 2 groups regarding surgical parameters and postoperative outcomes. No deaths occurred within 30 days in either group. During a median follow-up of 61.0 months (95% CI, 48.96-73.04), 4 patients experienced recurrence (1.96%). No significant differences in the 5-year overall survival (P = .25) or recurrence-free survival (P = .43) were observed between groups. ConclusionsRobotic-assisted thoracic surgery extended thymectomy is technically feasible, safe, and effective for treating large resectable thymomas. Moreover, midterm outcomes for patients with completely resected large thymomas were comparable to those with small thymomas during a median follow-up period of up to 5 years.

Distribution of multi-level B cell subsets in thymoma and thymoma-associated myasthenia gravis

B-cell subsets in peripheral blood (PB) and tumor microenvironment (TME) were evaluated to determine myasthenia gravis (MG) severity in patients with thymoma-associated MG (TMG) and the distribution of B cells in type B TMG. The distribution of mature B cells, including Bm1–Bm5, CD19+ and CD20+ B cells and non-switched (NSMBCs) and switched (SMBCs) memory B cells, were determined in 79 patients with thymoma or TMG. Quantitative relationships between the T and TMG groups and the TMG-low and TMG-high subgroups were determined. NSMBCs and SMBCs were compared in TME and PB. Type B thymoma was more likely to develop into MG, with types B2 and B3 being especially associated with MG worsening. The percentage of CD19+ B cells in PB gradually increased, whereas the percentage of CD20+ B cells and the CD19/CD20 ratio were not altered. The (Bm2 + Bm2′)/(eBm5 + Bm5) index was significantly higher in the TMG-high than in thymoma group. The difference between SMBC/CD19+ and NSMBC/CD19+ B cell ratios was significantly lower in the thymoma than TMG group. NSMBCs assembled around tertiary lymphoid tissue in thymomas of patients with TMG. Few NSMBCs were observed in patients with thymoma alone, with these cells being diffusely distributed. MG severity in patients with TMG can be determined by measuring CD19+ B cells and Bm1-Bm5 in PB. The CD19/CD20 ratio is a marker of disease severity in TMG patients. Differences between NSMBCs and SMBCs in PB and TME of thymomas can synergistically determine MG severity in patients with TMG.

Risk of Infection in Patients with Myasthenia Gravis With and Without Thymoma (P2-8.008)

<h3>Objective:</h3> To assess the risk of infection in patients with myasthenia gravis (MG) with thymoma compared to MG patients without thymoma. <h3>Background:</h3> MG is treated with multiple immunosuppressive agents and is sometimes associated with thymoma, which may increase the risk of infection further. Understanding infection risk may help with degree of immunosuppression and attempts to prevent infection with prophylactic vaccination/antibiotic treatments. <h3>Design/Methods:</h3> Retrospective analysis of all adult patients with AChR+ve MG at our center from 2015 to 2022 was performed. Rates of herpes zoster, pneumonia, UTI, meningitis, pneumocystis jirovecii pneumonia, sepsis, CMV infections, and morbidity were analyzed in MG patients with or without a history of thymoma. We used descriptive statistics and propensity score (PS) matching for comparative analysis. Infections within 6 months of chemotherapy were excluded. <h3>Results:</h3> We identified 141 patients diagnosed with AChR+ve MG, 30 with thymoma, and 111 without thymoma. The thymoma group had a higher percentage of females and patients of Asian descent, but similar ages. Comorbidity scores were similar, but the thymoma group had higher rates of chronic pulmonary disease. Baseline measures were notable for more neurologic diagnoses and higher immunosuppressant use in the thymoma group. The unadjusted rates of all infections during the follow up period were 37% in the thymoma group and 11.7% in the non-thymoma group; this was significant in the unmatched and basic-matched analyses (OR 16.1, 95% CI: 2.04 to 744, p = 0.002) but not after PS-matched analysis (OR 1.75, 95% CI: 0.52–5.87, p=0.36). Rates of pneumonia and sepsis were significantly higher in the thymoma group in unmatched, but not in the PS-matched, analysis. Rates of CMV, Zoster, UTI, and death were similar. <h3>Conclusions:</h3> The rates of all non-chemotherapy related infections in patients with MG and thymoma are higher compared to MG patients without thymoma but are similar after adjusting for comorbidities and observable confounders. <b>Disclosure:</b> Dr. Clifford has nothing to disclose. Dr. McKeen has nothing to disclose. Dr. Yuan has received personal compensation for serving as an employee of Atropos Health. Dr. Muppidi has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alexion. Dr. Muppidi has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for argenx. Dr. Muppidi has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB/Ra Pharma. Dr. Muppidi has received publishing royalties from a publication relating to health care.

Prognostic CT features in patients with untreated thymic epithelial tumors

To determine the prognostic CT features in patients with untreated thymic epithelial tumors (TETs). Clinical data and CT imaging features of 194 patients with pathologically confirmed TETs were retrospectively reviewed. The subjects included 113 male and 81 female patients between 15 and 78 years of age, with a mean age of 53.8 years. Clinical outcomes were categorized according to whether relapse, metastasis or death occurred within 3 years after the first diagnosis. Associations between clinical outcomes and CT imaging features were determined using univariate and multivariate logistic regression analyses, while the survival status was analyzed by Cox regression. In this study, we analyzed 110 thymic carcinomas, 52 high-risk thymomas and 32 low-risk thymomas. Percentages of poor outcome and patient death in thymic carcinomas were much higher than those in patients with high-risk and low-risk thymomas. In the thymic carcinomas groups, 46 patients (41.8%) experienced tumor progression, local relapse or metastasis and were categorized as having poor outcomes; vessel invasion and pericardial mass were confirmed to be independent predictors by logistic regression analysis (p < 0.01). In the high-risk thymoma group, 11 patients (21.2%) were categorized as having poor outcomes, and the CT feature pericardial mass was confirmed to be an independent predictor (p < 0.01). In survival analysis, Cox regression showed that CT features of lung invasion, great vessel invasion, lung metastasis and distant organ metastasis were independent predictors for worse survival in the thymic carcinoma group (p < 0.01), while lung invasion and pericardial mass were independent predictors for worse survival in high-risk thymoma group. No CT features were related to poor outcome and worse survival in the low-risk thymoma group. Patients with thymic carcinoma had poorer prognosis and worse survival than those with high-risk or low-risk thymoma. CT can serve as an important tool for predicting the prognosis and survival of patients with TETs. In this cohort, CT features of vessel invasion and pericardial mass were related to poorer outcomes in those with thymic carcinoma and pericardial mass in those with high-risk thymoma. Features including lung invasion, great vessel invasion, lung metastasis and distant organ metastasis indicate worse survival in thymic carcinoma, whereas lung invasion and pericardial mass indicate worse survival in high-risk thymoma.

The role of surgery in advanced thymic tumors: A retrospective cohort study.

There is no definitive and detailed treatment guideline for advanced thymic tumors, thus when lymph node and other organ metastasis are present, clinical guidelines recommend chemotherapy-based multidisciplinary treatment. A consensus has been reached that surgery has beneficial effects on partial patients with stage IVA whose metastatic lesions were isolated and resectable, but because of few cases of advanced thymic tumor s and the scarcity of reports, the role of surgery in stage IVB is still unknown. The current study aimed to systematically analyze the role of surgery in advanced thymic tumors based on the Surveillance, Epidemiology, and End Results (SEER) database, with a sufficient number of cases. A secondary aim was to clarify the prognostic value of surgery in advanced thymic tumors. Data derived from a total of 979 patients with advanced thymoma or advanced thymic carcinoma were collected from the SEER database. Propensity score matching was performed to eliminate confounding factors, and Cox regression analyses were conducted to assess prognoses. Patients were assigned to four groups based on pathology and whether surgery was performed; thymoma (surgery), thymoma (no surgery), thymic carcinom a (surgery), and thymic carcinoma (no surgery). Disease-specific survival differed significantly in the thymoma (surgery) and thymoma (no surgery) groups, both before and after propensity score matching (both p < 0.001). Similarly, disease-specific survival differed significantly in the thymic carcinoma (surgery) and the thymic carcinoma (no surgery) groups (p < 0.001 before and p = 0.003 after). No total resection, distant metastasis, and thymic carcinoma were all unfavorable prognostic factors. In the present study surgery had positive effects on advanced thymoma and advanced thymic carcinoma patients who could undergo surgical resection, significantly improving survival times. Total resection of the primary site was the most advantageous form of surgery. The study provides a reference for the clinical treatment of advanced thymic tumors.

Integrated proteomics and metabolomics analysis reveals hubs protein and network alterations in myasthenia gravis.

Background: Thymoma-associated myasthenia gravis (TAMG) is a well-described subtype of Myasthenia gravis (MG). Nevertheless, the detailed proteins and bioprocess differentiating TAMG from TAMG (−) thymoma have remained unclear.Methods: The proteomics and metabolomics were carried out on serum samples from thymoma group (n = 60, TNMG), TAMG (+) thymoma group (n = 70, TAMG (+)), and TAMG (−) thymomas group (n = 62, TAMG (−)), and controls (n = 159). groups. Proteomics and metabolomics analyses, including weighted gene co-expression network analysis (WGCNA), was conducted to detect the hub proteins and metabolomics processes that could differentiate TAMG (+) from TAMG (−) thymomas. MetaboAnalyst was used to examine the integration of proteomic and metabolomic analysis to differentiate TAMG (+) from TAMG (−) thymomas.Results: The of module–trait correlation of WGCNA analysis identified KRT1, GSN, COL6A1, KRT10, FOLR2, KRT9, KRT2, TPI1, ARF3, LYZ, ADIPOQ, SEMA4B, IGKV1-27, MASP2, IGF2R was associated with TAMG (+) thymomas. In addition, organismal systems-immune system and metabolism-biosynthesis of other secondary metabolites were closely related to the mechanism of TAMG (+) pathogenesis.Conclusion: Our integrated proteomics and metabolomics analysis supply a systems-level view of proteome changes in TAMG (+), TAMG (−) thymomas and exposes disease-associated protein network alterations involved in.

Can MRI chemical shift imaging replace thymic biopsy in myasthenia gravis patients?

BackgroundMyasthenia gravis is a neuromuscular junction autoimmune condition characterized by muscle weakness. Many people with myasthenia gravis have thymic abnormalities, such as thymic lymphoid hyperplasia and thymic tumors, therefore, the thymus plays a significant role in the disease. The imaging properties of thymic hyperplasia and thymoma on CT and conventional MRI are very similar, yet, MRI has recently revealed promising capability by adding novel sequences. Chemical shift MRI was demonstrated to consistently distinguish thymic hyperplasia from thymus gland tumors. The aim of this study was to determine the value of chemical shift MRI imaging in characterizing thymic lesions in patients diagnosed with myasthenia gravis and its ability to differentiate thymic hyperplasia from thymoma.ResultsMRI showed that thymic lymphoid hyperplasia was more common to be convex in shape while thymoma was more likely to be round or irregular (P = 0.004). Paired comparison between histopathology and chemical shift MRI showed that MRI had 90% sensitivity and 100% specificity in detecting thymoma with overall diagnostic accuracy 93.3% (P = 0.5). MRI chemical shift ratio showed 100% sensitivity by using > 0.85 as a cut off value for diagnosis of thymoma, with specificity 83.3% (P = 0.0001). There was statistically significant difference in chemical shift ratio between thymic lymphoid hyperplasia and thymoma groups, as thymoma group had a higher chemical shift ratio of 1.06 ± 0.06 compared to 0.48 ± 0.13 in thymic hyperplasia group (P = 0.0001).ConclusionMRI chemical shift imaging with chemical shift ratio offers a highly sensitive and specific tool in assessment of thymus lesions in myasthenia gravis patients and it can differentiate between thymic hyperplasia and thymoma using cutoff value of > 0.85, hence, unwarranted invasive procedures as thymic biopsy or thymectomy can be avoided and proper management could be planned.

Characteristics of genomic mutations and signaling pathway alterations in thymic epithelial tumors.

BackgroundTo elucidate the mechanisms of thymic epithelial tumor (TET) canceration by characterizing genomic mutations and signaling pathway alterations.MethodsPrimary tumor and blood samples were collected from 21 patients diagnosed with TETs (thymoma and thymic cancer), 15 of whom were screened by nucleic acid extraction and whole exon sequencing. Bioinformatics was used to comprehensively analyze the sequencing data for these samples, including gene mutation information and the difference of tumor mutation burden (TMB) between thymoma and thymic carcinoma groups. We performed signaling pathway and functional enrichment analysis using the WebGestalt 2017 toolkit.ResultsZNF429 (36%) was the gene with the highest mutation frequency in thymic carcinoma. Mutations in BAP1 (14%), ABI1 (7%), BCL9L (7%), and CHEK2 (7%) were exclusively detected in thymic carcinoma, whereas ZNF721 mutations (14%) and PABPC1 (14%) were found exclusively in thymoma. The mean TMB values for thymic carcinoma and thymoma were 0.722 and 0.663 mutations per megabase (Mb), respectively, and these differences were not statistically significant. The ErbB signaling pathway was enriched in the thymoma and intersection groups, and pathways of central carbon metabolism in cancer, longevity regulating and MAPK signaling were only found in the thymoma group, while pathways in cancer (hsa05200) was found in the thymoma and thymic carcinoma groups.ConclusionsMultiple differences in somatic genes and pathways have been identified. Our findings provide insights into differences between thymoma and thymic carcinoma that could aid in designing personalized clinical therapeutic strategies.

Clinicopathological Analysis of Anterior-Superior Mediastinal Masses

Background: The mediastinum is the space between the two lungs, bounded anteriorly by the sternum and posteriorly by the vertebral column. A spectrum of neoplastic and non-neoplastic lesions can arise in the mediastinum.&#x0D; Methods: A total of 14 cases were retrospectively retrieved from the Histopathology department. The cases had histopathological diagnosis either in image guided, thorocoscopic, transbronchial or excision biopsies.&#x0D; Results: The majority of cases (43% n=6) were of thymic origin, which included both neoplastic lesions of thymoma group and non-neoplastic lesion like thymic cysts. The thymoma group included 3 cases of thymoma B3 and 1 case of thymoma AB. The lymphoid lesions include Hodgkin lymphoma (14.3%; n=2) and non-Hodgkin lymphoma (7.1%; n=1). The mesenchymal lesions (21.4%; n=3) included lipoma, solitary fibrous tumor and schwannoma which accounts for one case each. A rare case of ectopic parathyroid adenoma (7.1%; n=1). and a case of metastatic papillary carcinoma (7.1%; n=1) were also reported.&#x0D; Conclusion: The diagnosis of mediastinal mass lesions can pose difficulties due to its wide clinicopathologic spectrum to the clinician, radiologists and pathologist. A multimodal approach with histopathological examination and immunohistochemistry can help in arriving at an accurate diagnosis.

CT imaging-based machine learning model: a potential modality for predicting low-risk and high-risk groups of thymoma: \u201cImpact of surgical modality choice\u201d

IntroductionRadiomics methods are used to analyze various medical images, including computed tomography (CT), magnetic resonance, and positron emission tomography to provide information regarding the diagnosis, patient outcome, tumor phenotype, and the gene-protein signatures of various diseases. In low-risk group, complete surgical resection is typically sufficient, whereas in high-risk thymoma, adjuvant therapy is usually required. Therefore, it is important to distinguish between both.This study evaluated the CT radiomics features of thymomas to discriminate between low- and high-risk thymoma groups.Materials and methodsIn total, 83 patients with thymoma were included in this study between 2004 and 2019. We used the Radcloud platform (Huiying Medical Technology Co., Ltd.) to manage the imaging and clinical data and perform the radiomics statistical analysis. The training and validation datasets were separated by a random method with a ratio of 2:8 and 502 random seeds. The histopathological diagnosis was noted from the pathology report.ResultsFour machine-learning radiomics features were identified to differentiate a low-risk thymoma group from a high-risk thymoma group. The radiomics feature names were Energy, Zone Entropy, Long Run Low Gray Level Emphasis, and Large Dependence Low Gray Level Emphasis.ConclusionsThe results demonstrated that a machine-learning model and a multilayer perceptron classifier analysis can be used on CT images to predict low- and high-risk thymomas. This combination could be a useful preoperative method to determine the surgical approach for thymoma.

Clinical importance and configuration of collateral vessel systems in patients with Takayasu arteritis or with thymoma visualized by three-dimensional volume rendering computed tomographic angiography

Abstract Background Collateral vessels form after gradual blood vessel occlusion. We speculate that in Takayasu arteritis (TA) and thymoma patients, before planning surgical procedures, a complex artery/venous system should be examined using three dimensional (3D) volume rendering computed tomographic (CT) angiography. Purpose To seek the clinical importance and actual complex configuration of collateral vessel systems in patients with TA or with thymoma using 3D volume rendering CT angiography with special acquisition method. Methods We performed 3D CT angiography in patients with Takayasu arteritis (TA) with occluded arteries (N=6) or thymoma (N=2) with occluded superior-vena-cava (SVC), respectively. For CT angiography in thymoma patients, diluted (1/4) iodinated-contrast was injected in right and left medial cubital-veins simultaneously, and images acquired 10 seconds after contrast-injection. Results Occluded and collateral-arteries (TA group) and occluded SVC and collateral-veins (thymoma group) were successfully visualized (Figures a-h). Collateral-arteries form from the inferior mesenteric artery (Figure a) or de novo arteries from the abdominal aorta (Figure b) after superior mesenteric artery occlusion (Figure c, d). In patients with thymoma, an SVC thymoma disrupts venous return in the neck and upper extremities; a complex venous system forms on the abdominal surface (Figure e-h). Conclusion In TA and thymoma patients, before planning surgical procedures, a complex artery/venous system should be examined using 3D volume rendering CT angiography. For CT in thymoma, diluted (1/4) iodinated contrast should be injected in both medial cubital veins, and images should be acquired 10 seconds after contrast-injection. 3D volume rendering CT angiography Funding Acknowledgement Type of funding source: None

Рівень адренокортикотропного гормону периферичної крові як предиктор локалізації та поширення нейроендокринних пухлин грудної клітки, що супроводжуються ектопічним синдромом Кушинга

Попри стрімкий розвиток і вдосконалення діагностичних можливостей в онкології та ендокринології діагностика синдрому неопластичного гіперкортицизму залишається однією з найскладніших та остаточно не вирішених проблем сучасної медицини. Мета — виявити можливість залежності рівня адренокортикотропного гормону периферичної крові від локалізації та поширення нейроендокринних пухлин грудної клітки, що супроводжуються ектопічним синдромом Кушинга на ранньому, пре-візуальному етапі діагностики. Матеріал і методи. Проаналізовано дані літератури, які містили інформацію про зміну рівня адренокортикотропного гормону та ступінь поширення пухлинного процесу 71 хворого із не-йроендокринними пухлинами грудної клітки. Відповідно до локалізації пухлин хворих розподілили на 3 клінічні групи. Перша група (бронхолегеневий карциноїд) включала 30 пацієнтів, із них 23 пацієнти з обмеженим пухлинним процесом; друга група (дрібноклітинний рак легень) — 4 пацієнти, усі з поширеним процесом; третя група (карциноїд/карцинома тимуса) — 37 пацієнтів, із них з обмеженим процесом 17 хворих. Показник рівня адренокортикотропного гормону в периферичній крові пацієнтів представлений у вигляді співвідношення: рівень адренокортикотропного гормону пацієнта / значення верхньої межі норми. Результати. Найвище значення рівня адренокортикотропного гормону було в групі дрібноклітинного раку легень — підвищення в 11,2±9,89 раза, натомість у групі тимом — у 7,4±7,7 раза (р&lt;0,05), причому в підгрупі тимом обмеженої стадії рівень був дещо вищим, ніж за поширеної стадії — підвищення у 8,6±8,43 раза та 6,38±7,08 раза відповідно (р&lt;0,05). У групі бронхолегеневого карциноїду — середнє підвищення рівня адренокортикотропного гормону в 3,28±2,54 раза в загальній групі, у підгрупі з обмеженим пухлинним процесом середній рівень адренокортикотропного гормону був вищим, ніж у групі з поширеним процесом — підвищення в 3,45±2,78 раза та 2,72±1,53 раза відповідно (р&lt;0,05). Висновок. Отримані дані дають можливість модифікації діагностичного алгоритму в кожному конкретному клінічному випадку в пацієнтів із даною патологією, що дозволяє зробити економічно та радіологічно обґрунтований вибір подальшого діагностичного етапу.

Clinicopathologic Significance and Immunogenomic Analysis of Programmed Death-Ligand 1 (PD-L1) and Programmed Death 1 (PD-1) Expression in Thymic Epithelial Tumors.

Objectives: Thymic epithelial tumors (TETs) are rare malignant tumors that exhibit heterogeneous histology and clinical behavior. As immune check point inhibitors, drugs targeting anti-programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have shown remarkable results against many cancers; thus, the importance of PD-1/PD-L1 immunohistochemistry as a predictive or prognostic biomarker has grown. However, limited data on PD-L1 and PD-1 expression in TETs have been reported; moreover, these results have been variable. Here, we examined the expression of PD-1/PD-L1 proteins in TETs and analyzed the clinicopathologic significance of this expression.Patients and Methods: A tissue microarray was constructed using 368 samples of TETs, each in triplicate. Immunohistochemistry for PD-L1 (SP263 assay) and PD-1 in TETs and CD8 in thymic carcinoma (TC) was performed; next, correlations with clinicopathologic characteristics were analyzed. PD-L1high was designated as ≥50% of tumor proportion score; PD-1high and CD8high were defined as ≥5% and 1% of tumoral immune cells, respectively.Results: The cohort consisted of 308 patients with thymomas and 60 patients with TC. PD-L1 positivity was identified in 90.6% (328/362, ≥1%) of TETs, PD-1 expression of intra-/peritumoral T cells was identified in 53.6% (194/362) of TETs and CD8 positivity was identified in 11% (7/60, ≥1%) of TC. Of the 362 patients, 141 (39.0%) exhibited high PD-L1 expression (PD-L1high). The PD-L1high thymoma group was correlated with high Masaoka-Koga stage (p < 0.001), type B3 histology (p < 0.001), and myasthenia gravis (p < 0.001). This group exhibited poor overall survival (OS, p = 0.003, log-rank) and worse disease-free survival (DFS, p = 0.042, log-rank). No survival differences were detected between PD-L1high and PD-L1low groups in TC. Additionally, there was no correlation between PD-1 expression and survival in patients with TETs. Multivariate analysis revealed that PD-L1high expression was an independent poor prognostic factor (p = 0.047, HR 2.087, 95% CI, 1.009–4.318) in thymomas.Conclusions: To our knowledge, this is the largest study on TETs published in English literature. This study provides useful information regarding the prognosis of and potential therapeutic options for patients with TETs.

Myasthenia gravis: perioperative complications of 1002 transsternal thymectomies - historical overwiev of 34 years long practice at one institution

Introduction: Thymectomy became an important part of the treatment of myasthenia gravis, since Alfred Blalock reported about his first surgery 80 years ago. Despite of several different surgical techniques already accepted abroad, sternal approach was the almost exclusive exposure for thymectomy in Hungary till 2006. In this publication, we analyze the direct surgical consequences and complications of this method. Methods: At the Surgical Department of Budai MÁV Hospital, 1002 transsternal thymectomies were performed during 34 years on patients suffering from myasthenia gravis. Surgeries were performed for neurological indications, following careful medical investigations, involving specialists in neurology and internal medicine. In cases associated with thymoma, surgery was indicated for two reasons: removal of the thymus and the tumor at the same time. Neurological indications, patient preparation, perioperative treatment and surgical technique have considerably changed during these 34 years. We interpret the results according to the two eras based on the most frequently applied surgical techniques (simple and extended thymectomy); we publish the data separately of the patients with thymoma and those who underwent repeated surgery, focusing basically on breath-related complications. Results: The patients' age was 32 years on the average (8-73 years). Women/men ratio: 3.5:1. Myasthenia gravis was associated with thymoma in 12.7% of the patients. Repeated thymectomy was necessary in case of 11 patients; further two patients required repeated sternotomy after cardiac surgery. Respiratory failure occurred in 21,3% out of 525 myasthenic patients operated in the first 19-year-old era, emergency re-intubation and tracheostomy happened in 12,8% and in 11,2% as well. In the second 15-year-old period postoperative respiratory failure occurred in 12,7% with emergency re-intubation in 7,1% and tracheostomy only in 1,2% out of 338 myasthenic patients. Respiratory failure occurred in 19.1% out of 126 patients operated for thymoma; re-intubation was necessary in 12.8% of the cases and tracheostomy was performed in 20.6% of the patients. Respiratory failure occurred in 13 patients, who underwent repeated surgery (46.1%); the ratio of re-intubation was 15.4% and that of tracheostomies 46.1%. Serious surgical complications were infrequent also in the entire group of patients: 2 patients required repeated surgery due to sternal bleeding; one more patient underwent repeated surgery due to rupture of the drainage tube, 4 cases of mediastinitis in the first group, two cases of heart injury and one case of sternal disruption occurred in the second period. The overall mortality was 1.4%: 1.3% in the first period, 0.3% in the second period, 4% in the thymoma group and 7.7% after repeated surgeries. Conclusions: In a historical overview, the ratio of serious respiratory and airway complications and the mortality after transsternal thymectomies has considerably decreased, but the postoperative respiratory failure and the surgical risk of transsecting the sternum still pose a real risk.

The tumor doubling time is a useful parameter for predicting the histological type of thymic epithelial tumors.

We assessed the utility of the tumor doubling time (TDT) for predicting the histological type of thymic epithelial tumors. We retrospectively reviewed 130 patients with thymic epithelial tumors who underwent computed tomography two or more times before surgery. The patients were divided into low-risk thymoma (types A, AB and B1), high-risk thymoma (types B2 and B3) and thymic carcinoma (thymic carcinoma and thymic neuroendocrine tumor) groups. In the 96 patients who showed tumor enlargement, the relationship between the histological type and the TDT of the tumor was investigated. The study population included 55 men and 41 women from 26 to 82years of age. The TDT of the thymic carcinoma group (median 205days) was significantly shorter in comparison to the low-risk thymoma (median 607days) and high-risk thymoma (median 459days) groups. No significant differences were observed between the low-risk thymoma and high-risk thymoma groups. When we set the cutoff time for differentiating thymic carcinoma group from thymoma at 313days, the sensitivity and specificity were 83.8% and 82.1%, respectively. The TDT is a useful parameter for differentiating between thymoma and thymic carcinoma group.

Comparative study of video-assisted thoracoscopic surgery versus open thymectomy for thymoma and myasthenia gravis.

IntroductionThymectomy 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).AimTo compare the clinical outcomes of VATS thymectomy with conventional open thymectomy for neoplastic and non-neoplastic thymic diseases.Material and methodsForty 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.ResultsThe 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.ConclusionsVideo-assisted thoracoscopic surgery thymectomy can be performed for both neoplastic and non-neoplastic thymic diseases with minimal morbidity and mortality.

Histogram analysis of apparent diffusion coefficient maps for assessing thymic epithelial tumours: correlation with world health organization classification and clinical staging.

To investigate the value of apparent diffusion coefficients (ADCs) histogram analysis for assessing World Health Organization (WHO) pathological classification and Masaoka clinical stages of thymic epithelial tumours. 37 patients with histologically confirmed thymic epithelial tumours were enrolled. ADC measurements were performed using hot-spot ROI (ADCHS-ROI) and histogram-based approach. ADC histogram parameters included mean ADC (ADCmean), median ADC (ADCmedian), 10 and 90 percentile of ADC (ADC10 and ADC90), kurtosis and skewness. One-way ANOVA, independent-sample t-test, and receiver operating characteristic were used for statistical analyses. There were significant differences in ADCmean, ADCmedian, ADC10, ADC90 and ADCHS-ROI among low-risk thymoma (type A, AB, B1; n = 14), high-risk thymoma (type B2, B3; n = 9) and thymic carcinoma (type C, n = 14) groups (all p-values <0.05), while no significant difference in skewness (p = 0.181) and kurtosis (p = 0.088). ADC10 showed best differentiating ability (cut-off value, ≤0.689 × 10-3 mm2 s-1; AUC, 0.957; sensitivity, 95.65%; specificity, 92.86%) for discriminating low-risk thymoma from high-risk thymoma and thymic carcinoma. Advanced Masaoka stages (Stage III and IV; n = 24) tumours showed significant lower ADC parameters and higher kurtosis than early Masaoka stage (Stage I and II; n = 13) tumours (all p-values <0.05), while no significant difference on skewness (p = 0.063). ADC10 showed best differentiating ability (cut-off value, ≤0.689 × 10-3 mm2 s-1; AUC, 0.913; sensitivity, 91.30%; specificity, 85.71%) for discriminating advanced and early Masaoka stage epithelial tumours. ADC histogram analysis may assist in assessing the WHO pathological classification and Masaoka clinical stages of thymic epithelial tumours. Advances in knowledge: 1. ADC histogram analysis could help to assess WHO pathological classification of thymic epithelial tumours. 2. ADC histogram analysis could help to evaluate Masaoka clinical stages of thymic epithelial tumours. 3. ADC10 might be a promising imaging biomarker for assessing and characterizing thymic epithelial tumours.

Clinical and pathological aspects of microscopic thymoma with myasthenia gravis and review of published reports.

Microscopic thymomas, defined as epithelial proliferations smaller than 1 mm in diameter, characteristically occur in patients with myasthenia gravis without macroscopic thymic epithelial tumors. However, some clinical and pathological aspects of this entity are still unclear. This retrospective study includes five consecutive patients who had undergone extended thymectomy for myasthenia gravis at our institution from April 2007 to March 2016 and in whom microscopic thymomas were diagnosed by histopathological examination of the resected specimens. During the same period, we performed 32 extended transsternal thymothymectomies/thymectomies in patients with myasthenia gravis, including the above five cases. We here review 18 cases of microscopic thymoma, including our five cases and 13 previously reported cases. The incidence of previously undiagnosed microscopic thymoma in patients undergoing thymectomy for myasthenia gravis in our institution is 15.2%. Serum preoperative anti-acetylcholine receptor antibody (anti-AchR Ab) titers were abnormally high in all of our five cases h (74.4±53.3 nmol/L) and decreased significantly after surgery (11.7±13.5 nmol/L, P=0.037). We divided our cases into the following three groups: microscopic thymoma group (Group M), thymoma group (Group T) and non-thymic tumor group (Group N). The mean preoperative anti-AchR Ab titers of these groups were 74.4, 26.5, and 368 nmol/L, respectively. All these values decreased postoperatively. The mean anti-AchR Ab titer was significantly higher in Group M than in Group T (P=0.034). All five cases in Group M were found by post-operative pathological examination to have multifocal type A thymomas. Microscopic thymomas tend to be multifocal type A thymomas. Anti-AchR Ab titers decreased significantly in all groups. It is very important to both perform complete extended thymectomies in patients with myasthenia gravis and pathological examination of thin slices of thymic tissue to maximize detection of microscopic thymomas.

Effect of thymectomy for thymic atrophy in myasthenia gravis: A retrospective study on 93 patients

To clarify the efficacy of thymectomy among myasthenia gravis (MG) patients with and without thymoma. We classified MG patients who underwent thymectomy into 3 groups, such as thymic atrophy group, thymic follicular hyperplasia (TFH) group and thymoma group. We compared the data of clinical features and postoperative prognosis at very short-term, short-term, and medium-term. The clinical course of MG patients with atrophic thymus after thymectomy was even better than those of TFH or thymoma, in this retrospective study. However, we found no significant differences in the comparison of mean dose of prednisolone between the 3 groups at each time point.

Comparison of CT and chemical-shift MRI for differentiating thymoma from non-thymomatous conditions in myasthenia gravis: value of qualitative and quantitative assessment

To evaluate the usefulness of computed tomography (CT) and chemical-shift magnetic resonance imaging (MRI) in patients with myasthenia gravis (MG) for differentiating thymoma (THY) from thymic lymphoid hyperplasia (TLH) and normal thymus (NT), and to determine which technique is more accurate. Eighty-three patients with generalised MG who underwent surgery were divided into the TLH/NT group (A; 65 patients) and THY group (B; 24 patients). Differences in qualitative characteristics and quantitative data (CT: radiodensity in Hounsfield units; MRI: signal intensity index [SII]) between groups were tested using Fisher's exact test and Student's t-test. Logistic regression models were estimated for both qualitative and quantitative analyses. At quantitative analysis, discrimination abilities were determined according to the area under the receiver operating characteristic (ROC) curve (AUROC) with computation of optimal cut-off points. The diagnostic accuracies of CT and MRI were compared using McNemar's test. At qualitative assessment, MRI had higher accuracy than CT (96.4%, 80/83 and 86.7%, 72/83, respectively). At quantitative analysis, both the radiodensity and SII were significantly different between groups (p<0.0001). For CT, at quantitative assessment, the AUROC of the radiodensity in discriminating between groups was 0.904 (optimal cut-off point, 20 HU) with an accuracy of 77.1% (64/83). For MRI, the AUROC of the SII was 0.989 (optimal cut-off point, 7.766%) with an accuracy of 96.4% (80/83), which was significantly higher than CT (p<0.0001). By using optimal cut-off points for cases with an erroneous diagnosis at qualitative assessment, accuracy improved both for CT (89.2%, 74/83) and MRI (97.6%, 81/83). Quantitative analysis is useful in evaluating patients with MG and improves the diagnostic accuracy of CT and MRI based on qualitative assessment. Chemical-shift MRI is more reliable than CT in differentiating THYs from non-thymomatous conditions.