Thymoma and thymic carcinomas

Postoperative clinical outcomes of patients with thymic epithelial tumors after over-3-year follow-up at a single-center

BACKGROUND

To evaluate postoperative clinical outcomes and analyze influencing factors for patients with thymic epithelial tumors over 3 years after operation.

METHODS

Patients with thymic epithelial tumors (TETs) who underwent surgical treatment in the Department of Thoracic Surgery at Beijing Hospital from January 2011 to May 2019 were retrospectively enrolled in the study. Basic patient information, clinical, pathological, and perioperative data were collected. Patients were followed up by telephone interviews and outpatient records. Statistical analyses were performed using SPSS version 26.0.

RESULTS

A total of 242 patients (129 men, 113 women) with TETs were included in this study, of which 150 patients (62.0%) were combined with myasthenia gravis (MG) and 92 patients (38.0%) were not. 216 patients were successfully followed up and their complete information was available. The median follow-up period was 70.5 months (range, 2-137 months). The 3-year overall survival (OS) rate of the whole group was 93.9%, and the 5-year OS rate was 91.1%. The 3-year relapse-free survival (RFS) rate of the whole group was 92.2%, and the 5-year relapse-free survival rate was 89.8%. Multivariable COX regression analysis indicated that recurrence of thymoma was an independent risk factor for OS. Younger age, Masaoka-Koga stage III + IV, and TNM stage III + IV were independent risk factors for RFS. Multivariable COX regression analysis indicated that Masaoka-Koga staging III + IV, WHO type B + C were independent risk factors for postoperative improvement of MG. For patients with MG, the postoperative complete stable remission (CSR) rate was 30.5%. And the result of multivariable COX regression analysis showed that thymoma patients with MG with Osserman staging IIA + IIB + III + IV were not prone to achieving CSR. Compared with patients without MG, MG was more likely to develop in patients with WHO classification type B, and patients with myasthenia gravis were younger, with longer operative duration, and more likely to develop perioperative complications.

CONCLUSIONS

The 5-year overall survival rate of patients with TETs was 91.1% in this study. Younger age and advanced stage were independent risk factors for RFS of patients with TETs, and recurrence of thymoma were independent risk factors for OS. In patients with MG, WHO classification type B and advanced stage were independent predictors of poor outcomes of MG treatment after thymectomy.

Clinicogenomic Landscape of Metastatic Thymic Epithelial Tumors

BACKGROUND

Despite favorable clinical outcomes, a subset of patients with thymic epithelial tumors (TETs) develop metastasis. The Cancer Genome Atlas (TCGA) provides genomic data on primary TETs (pTETs). This study assessed the molecular alterations and uncovered targetable pathways in metastatic TETs (mTETs).

METHODS

From 2015 to 2020, 49 patients with stage IV TETs underwent Clinical Laboratory Improvement Amendments-based sequencing using whole-exome sequencing (n = 33), panel-based testing (n = 12), and/or liquid biopsy (n = 24). Specimens were obtained from a metastatic organ (n = 36) or relapsed primary mediastinal mass (n = 10), whereas four patients underwent a liquid biopsy only. Data on pTETs were derived from the TCGA.

RESULTS

Compared with the pTET data set, patients with mTETs were younger (54 years v 60.5 years, P = .009) and had more aggressive histologies, with the most common tumor type being thymic carcinoma (n = 22, 40.7%) and B3 thymoma (n = 15, 27.8%). GTF2I was the most altered gene in primary thymomas (48.80%, n = 60). In metastatic thymoma and thymic carcinoma, TP53 was the most common genetic alteration (31% and 36%, respectively). In mTETs, the genomic alteration occurred in the TP53/CDK, EGFR/RAS, and PI3K/mTOR pathways. Biopsies obtained from distant metastasis were more commonly found to contain targetable mutations. There was an overlap of 61% (22 of 36) between tissue and liquid biopsy genomic alterations.

CONCLUSION

Clinically actionable genomic alterations are frequently observed in mTETs, indicating a value of repeat biopsy (preferably from a metastatic site of TETs for sequencing at the time of recurrence (TCGA data).

Clinicopathologic characteristics of thymic clear cell carcinoma: a case report with literature review

BACKGROUND

Thymic clear cell carcinoma is a rare mediastinal neoplasm, with only 25 reported cases to date. We report a case of a 45-year-old man with thymic clear cell carcinoma. We think imaging and laboratory tests may be helpful for differential diagnosis.

CASE PRESENTATION

A 45-year-old male was admitted to a local hospital for chest distress with cardiopalmus. CT showed a mediastinal mass. Laboratory examination results were all in the normal range. Histologically, the tumor cells had a clear cytoplasm, and immunohistochemically, the tumor cells were positive for epithelial markers. We performed abdominal and pelvic CT and further examined serum levels of thyroxine, parathyroid hormone and AFP postoperatively, which were normal. The patient received postoperative radiotherapy, and CT showed left adrenal metastasis at 20 months after surgery.

CONCLUSION

Thymic clear cell carcinoma is a rare malignant neoplasm. Adrenal metastasis can occur. Patients undergo thymectomy with chemotherapy or with radiotherapy have better outcoming. Metastasis, direct invasion of parathyroid carcinoma and other primary tumors in the mediastinum should be excluded. Immunohistochemical markers, imaging and laboratory examination can help to exclude metastasis.

Epigenetics of Thymic Epithelial Tumors

Thymic epithelial tumors (TETs) arise from the epithelial cells of the thymus and consist in the 1% of all adult malignancies, despite the fact that they are the most common lesions of the anterior mediastinum. TETs can be divided mainly into thymomas, thymic carcinomas, and the rarest ad aggressive neuroendocrine forms. Despite the surgical resection is quite resolving, the diagnosis of TETs is complicated by the absence of symptoms and the clinical presentation aggravated by several paraneoplastic disorders, including myasthenia gravis. Thus, the heterogeneity of TETs prompts the search for molecular biomarkers that could be helpful for tumor characterization and clinical outcomes prediction. With these aims, several researchers investigated the epigenetic profiles of TETs. In this manuscript, we narratively review the works investigating the deregulation of epigenetic mechanisms in TETs, highlighting the need for further studies combining genetic, epigenetic, and expression data to better characterize the different molecular subtypes and identify, for each of them, the most relevant epigenetic biomarkers of clinical utility.

Neoadjuvant radiotherapy plus single-incision thoracoscopic surgery in the treatment of type B3 thymomas

Background

Although minimally invasive surgery is the standard treatment for thymomas, minimally invasive thymectomy is difficult for patients with type B3 thymomas, especially for giant or aggressive lesions. These tumors are frequently treated with radical radiation therapy or surgery plus adjuvant radiotherapy. Few studies, however, have tested the efficacy of neoadjuvant radiotherapy prior to thoracoscopic surgery.

Methods

Patients with type B3 thymomas >5 cm or with infiltrates into vital organs on CT-guided puncture biopsy who underwent neoadjuvant radiotherapy followed by single-incision minimally invasive thymectomy from March 2016 to July 2020 were retrospectively evaluated. Reduction ratios, TNM stage changes according to WHO stage criteria, resectability, long-term survival, and the response in terms of RECIST v1.1 criteria achieved by preoperative RT were analyzed.

Results

The 11 patients who underwent neoadjuvant radiotherapy plus minimally invasive thymectomy included five men and six women, of mean age 49.5 years. Four patients had myasthenia gravis. Neoadjuvant radiotherapy consisted of 50 Gy in 25 fractions, with all patients showing varying degrees of lesion reduction after radiotherapy. Surgery was performed about 1 month after neoadjuvant radiotherapy, with none of these patients having severe radiation pneumonitis. All patients underwent radical resection of the tumor and adjacent tissue, with none experiencing tumor seeding or rupture during surgery. The median postoperative hospital stay was 3 days (range: 2-6 days) and the frequency of additional regular analgesics (including those for wound pain and neuralgia) was 2.5 times per person. On follow-up, one patient experienced pleural metastasis and one experienced pulmonary metastasis, with the other nine patients showing no evidence of tumor recurrence.

Conclusion

Neoadjuvant radiotherapy followed by minimally invasive surgery was a safe and efficacious procedure for the treatment of type B3 thymomas, with less postoperative pain and faster recovery. This strategy, of tumor shrinkage prior to surgery, may make possible the easier removal of type B3 thymomas by single-incision thoracoscopy.

Myasthenia gravis with achalasia secondary to thymoma: a case report and literature review

Background

Myasthenia gravis is an autoimmune neuromuscular junction disorder characterized by fatigable muscle weakness and autoantibodies. Frequent associations exist between myasthenia gravis and thymic abnormalities, including hyperplasia and thymoma. Several autoimmune illnesses have been identified to be associated with thymoma; however, a few case reports have linked thymoma and achalasia, and the underlying mechanism is unknown.

Case report

A 43-year-old man with thymoma-associated myasthenia gravis presented with dysphagia that was refractory to conventional treatment of myasthenia gravis. This dysphagia was challenging to diagnose even after multiple gastroenterology consults and upper endoscopy. The diagnosis of achalasia type II was established after a comprehensive evaluation, including upper endoscopy, barium swallow, and high-resolution esophageal manometry. The patient underwent elective pneumatic balloon dilatation, which successfully alleviated his dysphagia.

Conclusion

This case confirmed the association between myasthenia gravis secondary to thymoma and achalasia and showed how the diagnosis of achalasia was challenging. Awareness of this association is crucial for early diagnosis and treatment, improving affected patients' quality of life.

Evaluation of the role of postoperative radiotherapy in locally invasive thymoma: A propensity-matched study based on the SEER database

OBJECTIVES

No consensus was reached on the efficacy of postoperative radiotherapy (PORT) in locally invasive thymomas because of the rarity of the thymic epithelial and the variations of study results. Therefore, we aimed to explore the efficacy of PORT in locally invasive thymomas using the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Patients diagnosed with thymomas from 2004 to 2016 were identified using the SEER database. Prognostic factors of cancer-specific survival (CSS) and overall survival (OS) were identified using univariate and multivariate Cox regression analyses.Propensity score matching (PSM) was performed to balance the baseline characteristics.

RESULTS

A total of 700 eligible patients were identified. After PSM, 262 paired patients were selected from the two groups, those who received or did not receive PORT. Receiving PORT improved CSS and OS before and after PSM. In the matched population, the multivariate analyses showed that tumour invasion into adjacent organs/structures and non-utilisation of PORT were independent poor prognostic factors for CSS, whereas age ≥62 years,tumour invasion into adjacent organs/structures, and non-utilisation of PORT were independently associated with poorer OS. The subgroup analysis revealed that PORT improved CSS and OS in Masaoka-Koga stage III thymoma, but showed no OS benefit in Masaoka-Koga stage IIB thymoma.

CONCLUSION

Based on the SEER database, we found that PORT provides a significant survival benefit in Masaoka-Koga stage III thymoma with complete or incomplete resection. The role of PORT in thymoma requires further evaluation.

Nomogram based on TNM stage to predict the prognosis of thymic epithelial tumors (TETs) patients undergoing extended thymectomy

Background

Thymomas and thymic carcinoma are thymic epithelial tumors (TETs) of the anterior mediastinum. On the basis of The AJCC 8th Edition of TNM classification, no prognostic prediction model has been established for TETs patients undergoing surgical resection. In this study, based on data from Qilu Hospital of Shandong University, we identified prognostic factors and developed a nomogram to predict the prognosis for TETs patients undergoing extended thymectomy.

Methods

Patients with TETs who underwent thymectomy between 2010 and 2020 were consecutively enrolled. An analysis of multivariate Cox regression and stepwise regression using the Akaike information criterion (AIC) was conducted to identify prognostic factors, and a nomogram for TETs was derived from the results of these analyses. The model was validated internally with the Kaplan-Meier curves, ROC curves and calibration curves.

Results

There were 350 patients with TETs enrolled in the study, and they were divided into a training group (245,0.7) and a validation group (105,0.3). Age, histological type, tumor size, myasthenia gravis, and TNM stage were independent prognostic factors for CSS. The Kaplan-Meier curves showed a significant difference between high nomorisk group and low nomorisk group. A nomogram for CSS was formulated based on the independent prognostic factors and exhibited good discriminative ability as a means of predicting cause-specific mortality, as evidenced by the area under the ROC curves (AUCs) of 3-year, 5-year, and 10-year being 0.946, 0.949, and 0.937, respectively. The calibration curves further revealed excellent consistency between the predicted and actual mortality when using this nomogram.

Conclusion

There are several prognostic factors for TETs. Based on TNM stage and other prognostic factors, the nomogram accurately predicted the 3-, 5-, and 10-year mortality rates of patients with TETs in this study. The nomogram could be used to stratify risk and optimize therapy for individual patients.

Comparison of Efficacy and Safety of Platinum-Based Chemotherapy as First-Line Therapy between B3 Thymoma and Thymic Carcinoma

BACKGROUND

B3 type thymoma is defined as a well-differentiated thymic carcinoma and is similar to a thymic carcinoma. However, the differences between them are not well defined. In addition, the data to compare the efficacy and safety of platinum-based chemotherapy as first-line therapy between B3 thymoma and thymic carcinoma are lacking.

METHODS

The efficacy and safety of platinum-based chemotherapy as first-line therapy was retrospectively compared between a group of 36 patients with type B3 thymoma and a group of 127 patients with thymic carcinoma treated between January 2009 and March 2022 at the Zhejiang Cancer Hospital. Objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and treatment-related adverse events were analyzed.

RESULTS

The ORRs for B3 thymoma and thymic carcinoma were 36.1% and 28.3%, respectively (p = 0.370). Among all patients, the difference in PFS between B3 thymoma and thymic carcinoma was not significant (11.3 vs. 10.1 months, p = 0.118). The squamous carcinoma subgroup did not exhibit any differences in PFS compared to B3 thymoma (11.7 vs. 11.3 months, p = 0.161). The result for the non-squamous carcinoma subgroup was similar (6.5 vs. 11.3 months, p = 0.128). Furthermore, the OS values for B3 thymoma and thymic carcinoma were not significantly different (58.3 vs. 35.1 months, p = 0.067). However, there were differences in OS between B3 thymoma and non-squamous carcinoma (58.3 vs. 30.6 months, p = 0.031).

CONCLUSIONS

B3 thymoma and especially squamous carcinoma patients may be treated using a similar therapy scheme as that utilized for thymic carcinoma.

Quantitative texture analysis based on dynamic contrast enhanced MRI for differential diagnosis between primary thymic lymphoma from thymic carcinoma

To evaluate the value of texture analysis based on dynamic contrast enhanced MRI (DCE-MRI) in the differential diagnosis of thymic carcinoma and thymic lymphoma. Sixty-nine patients with pathologically confirmed (thymic carcinoma, n = 32; thymic lymphoma, n = 37) were enrolled in this retrospective study. Ktrans, Kep and Ve maps were automatically generated, and texture features were extracted, including mean, median, 5th/95th percentile, skewness, kurtosis, diff-variance, diff-entropy, contrast and entropy. The differences in parameters between the two groups were compared and the diagnostic efficacy was calculated. The Ktrans-related significant features yielded an area under the curve (AUC) of 0.769 (sensitivity 90.6%, specificity 51.4%) for the differentiation between thymic carcinoma and thymic lymphoma. The Kep-related significant features yielded an AUC of 0.780 (sensitivity 87.5%, specificity 62.2%). The Ve-related significant features yielded an AUC of 0.807 (sensitivity 75.0%, specificity 78.4%). The combination of DCE-MRI textural features yielded an AUC of 0.962 (sensitivity 93.8%, specificity 89.2%). Five parameters were screened out, including age, Ktrans-entropy, Kep-entropy, Ve-entropy, and Ve-P95. The combination of these five parameters yielded the best discrimination efficiency (AUC of 0.943, 93.7% sensitivity, 81.1% specificity). Texture analysis of DCE-MRI may be helpful to distinguish thymic carcinoma from thymic lymphoma.

MC-ViT: Multi-path cross-scale vision transformer for thymoma histopathology whole slide image typing

OBJECTIVES

Accurate histological typing plays an important role in diagnosing thymoma or thymic carcinoma (TC) and predicting the corresponding prognosis. In this paper, we develop and validate a deep learning-based thymoma typing method for hematoxylin & eosin (H&E)-stained whole slide images (WSIs), which provides useful histopathology information from patients to assist doctors for better diagnosing thymoma or TC.

METHODS

We propose a multi-path cross-scale vision transformer (MC-ViT), which first uses the cross attentive scale-aware transformer (CAST) to classify the pathological information related to thymoma, and then uses such pathological information priors to assist the WSIs transformer (WT) for thymoma typing. To make full use of the multi-scale (10×, 20×, and 40×) information inherent in a WSI, CAST not only employs parallel multi-path to capture different receptive field features from multi-scale WSI inputs, but also introduces the cross-correlation attention module (CAM) to aggregate multi-scale features to achieve cross-scale spatial information complementarity. After that, WT can effectively convert full-scale WSIs into 1D feature matrices with pathological information labels to improve the efficiency and accuracy of thymoma typing.

RESULTS

We construct a large-scale thymoma histopathology WSI (THW) dataset and annotate corresponding pathological information and thymoma typing labels. The proposed MC-ViT achieves the Top-1 accuracy of 0.939 and 0.951 in pathological information classification and thymoma typing, respectively. Moreover, the quantitative and statistical experiments on the THW dataset also demonstrate that our pipeline performs favorably against the existing classical convolutional neural networks, vision transformers, and deep learning-based medical image classification methods.

CONCLUSION

This paper demonstrates that comprehensively utilizing the pathological information contained in multi-scale WSIs is feasible for thymoma typing and achieves clinically acceptable performance. Specifically, the proposed MC-ViT can well predict pathological information classes as well as thymoma types, which show the application potential to the diagnosis of thymoma and TC and may assist doctors in improving diagnosis efficiency and accuracy.

Subtotal Pleurectomy with Intrathoracic Chemo Hyperthermia (HITHOC) for IVa Thymomas: De Novo Versus Recurrent Pleural Disease

INTRODUCTION

Stage IVa thymoma is a rare disease without a standard of care. Subtotal pleurectomy and HITHOC introduced in highly selected patients may provide interesting oncologic results. The purpose of this study was to distinguish de novo stage IVa tumors (DNT) from distant relapse (DR) with respect to post-operative and long-term outcomes to provide the procedure efficacy.

METHODS

From July 1997-December 2021, 40 patients with IVa pleural involvement were retrospectively analyzed. The surgical procedure was subtotal pleurectomy and HITHOC (cisplatin 50 mg/m2, mitomycin 25 mg/m2, 42 °C, 90 min). The post-operative outcome, disease-free interval (DFI) and overall survival (OS) were analyzed.

RESULTS

Mean age was 52 ± 12 years. B2 and B3 thymomas were preponderant (27; 67.5%). The median number of pleural nodes were nine (4-81) vs. five (1-36); p = 0.004 * in DNT and DR, respectively. Hospital mortality rate was 2.5%. There were four specific HITHOC complications (10%). DFI were 49 and 85 months (p = 0.02 *), OS were 94 and 118 months (NS), in DNT and DR, respectively.

CONCLUSIONS

Subtotal pleurectomy with HITHOC in IVa offers satisfying results in highly selected patients, for both DNT and DR. Due to the disease rarity, multicentric studies are needed to define HITHOC as a standard of care.

Prognostic Value of Preoperative Serum Carcinoembryonic Antigen for Overall Survival and Recurrence-Free Survival in Resectable Thymic Epithelial Tumors

Introduction: Tumor markers have been shown to be closely related to the long-term survival of patients with cancer and the recurrence of various malignant tumors. However, their role in thymic epithelial tumors (TETs) remains to be elucidated. We aimed to investigate whether the preoperative tumor biomarkers carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) could serve as independent predictors of postoperative prognosis in patients with TETs. Materials and Methods: We retrospectively included a total of 111 patients with TETs who underwent thymectomy at our hospital. Cox regression analysis was used to evaluate the statistical significance of CEA and NSE as independent predictors of overall survival (OS) and recurrence-free survival (RFS). Kaplan-Meier curves were used to present the results of our survival analyses. Results: Cox regression analysis showed that T stage, World Health Organization (WHO) histologic type, tumor size, and CEA levels served as independent prognostic factors for OS (P < .05). Whereas for RFS, multivariate analysis showed that only T stage, WHO histologic type, and drinking history were independently associated with it (P < .05). Conclusion: Our study found that preoperative serum CEA levels and tumor size may be strong predictors of postoperative OS in patients with TETs.

Fatal toxicity induced by anti-PD-1 immune checkpoint inhibitor in thymic epithelial tumor

A standard treatment for advanced thymic epithelial tumors (TETs) after initial treatment remains unavailable to date. Targeted immune checkpoint inhibitors (ICIs) of the programmed cell death-1 (PD-1) pathway may produce objective responses in TETs, notably thymic carcinoma. Findings of clinical trials suggested ICIs are a practical choice. However, the risk of severe immuno-related adverse events is higher in TETs. Concerning histologic subtypes, thymomas are more frequently associated with autoimmune disorders than carcinomas, so close monitoring is needed for thymomas. In this article, we describe four cases of fatal toxicity caused by anti-PD-1 therapy in TETs. Four patients with metastatic thymomas or carcinoma difficult to treat with first-line standard chemotherapy were treated with the anti-PD-1 drug pembrolizumab or sintilimab. The association of PD-1 inhibitors with a high proportion of severe immuno-related adverse events in TETs necessitates attentive monitoring during treatment.

Purulent pericarditis in advanced thymoma: A case report

Thymoma is the most common primary anterior mediastinum mass with various clinical manifestations, and one of the manifestations is pericardial effusion. While pericardial effusion in thymoma is usually serous, it can become purulent when an infection occurs in a nearby organ, albeit rare. In this report, we present a rare case of a 27-year-old woman who had purulent pericarditis secondary to an advanced thymoma. The patient came to the emergency department with the chief complaints of worsening chest discomfort, non-productive cough, and fever in the past 2 weeks. The patient was diagnosed with thymoma 5 months prior. Based on the examinations, it was discovered that the patient had pericarditis. After the pericardiocentesis was performed and the fluid was examined, the patient was diagnosed with purulent pericarditis secondary to thymoma. The patient was then treated with intravenous antibiotic and pericardial drain. Unfortunately, the patient's condition deteriorated, and the patient died on the fifth day of hospitalization. This case highlights an infrequent but potentially life-threatening complication of thymoma. In addition, thymic pathologies should be included as a rare etiology in the differential diagnosis of purulent pericardial effusion.

Prognostic factors for overall survival after surgical resection in patients with thymic epithelial tumors: A systematic review and meta-analysis

BACKGROUND

Thymic epithelial tumors (TETs) originate in the thymic epithelial cell, including thymoma and thymic carcinoma. Surgical resection is the first choice for most patients. However, some studies have shown that the factors affecting the prognosis of these patients are not consistent. To evaluate prognostic factors in patients with surgically resected thymic epithelial tumors, we performed a meta-analysis.

METHODS

We searched the Chinese biomedical literature database, Pubmed, Embase, Cochrane Library and other electronic databases. Studies including postoperative overall survival (OS) and predictors of TETs were included. We made a comprehensive analysis the hazard ratios (HRs) through a single proportional combination. HRs were combined using single proportion combinations.

RESULTS

The meta-analysis included 11,695 patients from 26 studies. The pooled OS was 84% at 5 years and 73% at 10 years after TETs operation. The age as continuous-year (HR 1.04, 95% confidence interval (CI) 1.02-1.04), incomplete resection (HR 4.41, 95% CI 3.32-5.85), WHO histologic classification (B2/B3 vs A/AB/B1 HR 2.76, 95% CI 1.25-6.21), Masaoka Stage (stage III/IV vs I/II HR 2.74, 95% CI 2.12-3.55,) were the poor prognostic factors.

CONCLUSIONS

For patients with TETs after surgical resection, advanced age, incomplete resection, WHO classification B2/B3, and higher Masaoka stage are risk factors for poor prognosis.

Multiparameter diagnostic model based on 18F-FDG PET and clinical characteristics can differentiate thymic epithelial tumors from thymic lymphomas

OBJECTIVE

To evaluate the diagnostic performance of combined multiparametric ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸FDG PET) with clinical characteristics in differentiating thymic epithelial tumors (TETs) from thymic lymphomas.

PATIENTS AND METHODS

A total of 173 patients with 80 TETs and 93 thymic lymphomas who underwent ¹⁸F-FDG PET/CT before treatment were enrolled in this retrospective study. All patients were confirmed by pathology, and baseline characteristics and clinical data were also collected. The semi-parameters of ¹⁸F-FDG PET/CT, including lesion size, SUVmax (maximum standard uptake value), SUVmean (mean standard uptake value), TLG (total lesion glycolysis), MTV (metabolic tumor volume) and SUVR (tumor-to-normal liver standard uptake value ratio) were evaluated. The differential diagnostic efficacy was evaluated using the receiver operating characteristic (ROC) curve. Integrated discriminatory improvement (IDI) and net reclassification improvement (NRI), and Delong test were used to evaluate the improvement in diagnostic efficacy. The clinical efficacy was evaluated by decision curve analysis (DCA).

RESULTS

Age, clinical symptoms, and metabolic parameters differed significantly between patients with TETs and thymic lymphomas. The ROC curve analysis of SUVR showed the highest differentiating diagnostic value (sensitivity = 0.763; specificity = 0.888; area under the curve [AUC] = 0.881). The combined diagnostics model of age, clinical symptoms and SUVR resulted in the highest AUC of 0.964 (sensitivity = 0.882, specificity = 0.963). Compared with SUVR, the diagnostic efficiency of the model was improved significantly. The DCA also confirmed the clinical efficacy of the model.

CONCLUSIONS

The multiparameter diagnosis model based on ¹⁸F-FDG PET and clinical characteristics had excellent value in the differential diagnosis of TETs and thymic lymphomas.

Nomogram predicts the prognosis of patients with thymic carcinoma: A population-based study using SEER data

BACKGROUND

Thymic carcinoma (TC) is a rare malignant tumor that can have a poor prognosis, and accurate prognostication prediction remains difficult. We aimed to develop a nomogram to predict overall survival (OS) and cancer-specific survival (CSS) based on a large cohort of patients.

METHODS

The Surveillance Epidemiology and End Results (SEER) database was searched to identify TC patients (1975-2016). Univariate and multivariable Cox regression analyses were used to identify predictors of OS and CSS, which were used to construct nomograms. The nomograms were evaluated using the concordance index (C-index), calibration curve, receiver operating characteristic curve, and decision curve analysis (DCA). Subgroup analysis was performed to identify high-risk patients.

RESULTS

The analysis identified six predictors of OS (Masaoka stage, surgical method, lymph node metastasis, liver metastasis, bone metastasis, and radiotherapy) and five predictors of CSS (Masaoka stage, surgical method, lymph node metastasis, tumor size, and brain metastasis), which were used to create nomograms for predicting three-year and five-year OS and CSS. The nomograms had reasonable C-index values (OS: 0.687 [training] and 0.674 [validation], CSS: 0.712 [training] and 0.739 [validation]). The DCA curve revealed that the nomograms were better for predicting OS and CSS, relative to the Masaoka staging system.

CONCLUSION

We developed nomograms using eight clinicopathological factors that predicted OS and CSS among TC patients. The nomograms performed better than the traditional Masaoka staging system and could identify high-risk patients. Based on the nomograms' performance, we believe they will be useful prognostication tools for TC patients.

Does Myasthenia Gravis Affect Long-Term Survival in Thymic Carcinomas? An ESTS Database Analysis

Background: Thymic carcinoma is a rare and highly malignant tumor with a dismal prognosis, which occasionally coexists with myasthenia gravis (MG). This study aims to investigate the MG incidence on a surgical cohort of patients with thymic carcinoma and to explore its influence on long-term survival. Methods: the prospectively collected data from the ESTS database on thymic epithelial tumors were reviewed. Clinical, pathological, and survival information on thymic carcinoma were analyzed. Results: the analysis was conducted on 203 patients, with an equal gender distribution (96 males and 107 females). MG was detected in 22 (10.8%) patients, more frequently elderly (>60 years, p = 0.048) and male (p = 0.003). Induction therapy was performed in 22 (10.8%) cases. After surgery, 120 (59.1%) patients had a Masaoka stage II−III while complete resection (R0) was achieved in 158 (77.8%). Adjuvant therapy was performed in 68 cases. Mean follow-up was 60 (SD = 14) months. The 3-year, 5-year and 10-year survival rates were 79%, 75% and 63%, respectively. MG did not seem to influence long-term survival (5-year survival in non-MG−TCs 78% vs. 50% in MG−TCs, p = ns) as age < 60 years, female gender, early Masaoka stage, and postoperative radiotherapy did, conversely. Conclusions: myasthenia occurred in about 10% of thymic carcinomas and it did not seem to affect significantly the long-term prognosis in surgically treated thymic carcinoma-patients.

Secondary coronary artery ostial lesions: Three case reports

BACKGROUND

Atherosclerosis is one of the main causes of coronary artery ostial lesions seen clinically. Secondary coronary artery ostial lesions are rare, and cases reported previously were associated with syphilitic vasculitis and aortic dissection. Here, we report three rare cases of secondary coronary ostial lesions. Due to their rareness, these lesions can easily be neglected, which may lead to misdiagnosis and missed diagnosis.

CASE SUMMARY

We present three patients with acute myocardial infarction and unstable angina caused by secondary coronary artery ostial lesions. In Case 1, coronary angiography (CAG) revealed 90% stenosis of the left main coronary ostium. Chest contrast computed tomography (CT) suggested thymic carcinoma invading the left main coronary ostium. Coronary artery bypass grafting and tumor resection were performed. In Case 2, echocardiography revealed a sinus of Valsalva aneurysm (SVA)-like dilatation. CAG showed a right coronary sinus giant aneurysm and complete obstruction of the right coronary artery (RCA) ostium. Aortic contrast CT confirmed these findings. The Bentall procedure was performed. In Case 3, CT CAG identified an anomalous origin of the right coronary artery (AORCA) from the left sinus of Valsalva coursing between the aorta and pulmonary trunk, causing severe RCA ostium stenosis by compression. Surgical correction of the AORCA was performed.

CONCLUSION

The cases reported here suggest that we should consider other causes of coronary ostial lesions other than atherosclerosis.

Unraveling the Immune Microenvironment of Thymic Epithelial Tumors: Implications for Autoimmunity and Treatment

Thymic Epithelial Tumors (TETs) represent a rare tumor family, originating from the epithelial component of the thymus gland. Clinicopathologically, they are segregated into six major subtypes, associated with distinct histological features and clinical outcomes. Their emergence and evolution are accompanied by the generation of a complex tumor microenvironment (TME), dominated by phenotypically and functionally divergent immune cellular subsets, in different maturation states and in analogies that vary significantly among different subtypes. These heterogenous leukocyte populations exert either immune-permissive and tumor-suppressive functions or vice versa, and the dynamic equilibrium established among them either dictates the tumor immune milieu towards an immune-tolerance state or enables the development of a productive spontaneous tumoricidal response. The immunologically “hot” microenvironment, defining a significant proportion of TETs, makes them a promising candidate for the implementation of immune checkpoint inhibitors (ICIs). A number of phase I and II clinical trials have already demonstrated significant, type-specific clinical efficacy of PD-L1 inhibitors, even though substantial limitations in their utilization derive from their immune-mediated adverse effects. Moreover, the completed clinical studies involved relatively restricted patient samples and an expansion in the enrolled cohorts is required, so that more trustworthy conclusions regarding the benefit from ICIs in TETs can be extracted.

Comparison of perioperative outcomes between robotic-assisted and video-assisted thoracoscopic surgery for mediastinal masses in patients with different body mass index ranges: A population-based study

Background

The effectiveness of robotic-assisted thoracoscopic surgery (RATS) for mediastinal masses has not been fully evaluated. This study aimed to compare the perioperative outcomes between RATS and video-assisted thoracoscopic surgery (VATS) for mediastinal masses, and then explore which group of people would benefit more from RATS.

Methods

This retrospective study compared the perioperative outcomes of patients with mediastinal masses who underwent RATS and VATS from September 2018 to December 2021. Subgroup analysis were performed according to body mass index (BMI) ranges.

Results

A total of 212 patients with mediastinal masses (106 RATS cases and 106 VATS cases) were included. Compared with the VATS group, the RATS group had a significantly reduced incidence of overall postoperative complications (5.7% vs. 14.2%, p = 0.039), complications of grade II or less (3.8% vs. 12.3%, p = 0.023), and pneumonia (2.8% vs. 9.4%, p = 0.045). Hospitalization costs were significantly higher in the RATS group (¥ 49350.0 vs. ¥ 32551.9, p < 0.001). There was no significant difference in operation duration, intraoperative estimated blood loss, postoperative chest tube drainage volume, NRS pain score, day of chest tube removal, complications of grade III or more, or in-hospital mortality rate (p > 0.05). Subgroup analysis indicated that the incidence of overall postoperative complications (3.1% vs. 15.2%, p = 0.017), complications of grade II or less (1.5% vs. 12.1%, p = 0.033) and postoperative length of stay (4 days vs. 4.5 days, p = 0.046) were significantly reduced in the RATS group for overweight and obese patients (BMI ≥ 24 kg/m²), while these differences became insignificant in the BMI < 24 kg/m² subgroup.

Conclusion

RATS could reduce the incidence of postoperative complications, shorten the postoperative length of stay and might be a more cost-effective surgical treatment for overweight and obese patients with mediastinal masses.

Characterization of IL-10-producing regulatory B cells in thymoma

BACKGROUND

Regulatory B cells (Bregs) are a subset of B cells that secrete interleukin 10 (IL-10) and play a vital role in suppressing the immune response. The aim of this study was to evaluate the proportion of Bregs in patients with thymoma.

METHODS

The proportions of subgroups of Bregs in 23 patients with thymoma and 15 healthy controls were detected by flow cytometry. The serum IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α levels of the subjects were measured using a cytometric bead array (CBA).

RESULTS

The proportions of circulating IL-10⁺ B cells, IL-10⁺CD24^hiCD38^hi Bregs, and IL-10⁺CD24^hiCD27⁺ Bregs and the serum IL-10 level were significantly higher in patients with thymoma than in the control group and were negatively correlated with the Karnofsky Performance Scale (KPS) score. The serum levels of cytokines IL-2, IL-6, IFN-γ, and TNF-α were higher and serum IL-17A level was lower in patients with thymoma. Patients with advanced-stage thymoma exhibited significantly higher proportions of IL-10-producing Bregs and a higher serum IL-10 level. After tumour resection, the frequency of circulating IL-10⁺CD24^hiCD38^hi Bregs and the serum IL-10 level were significantly decreased in patients with thymoma. The serum IL-10 levels exhibited the best accuracy in assessing the risk of thymoma occurrence in this study.

CONCLUSIONS

The expression of IL-10 produced by Bregs is increased in patients with thymoma, particularly those with advanced-stage disease, which may suggest that Bregs are involved in the pathogenesis and progression of thymoma.

Metabolomic and Transcriptomic Profiling Identified Significant Genes in Thymic Epithelial Tumor

Thymomas and thymic carcinomas are malignant thymic epithelial tumors (TETs) with poor outcomes if non-resectable. However, the tumorigenesis, especially the metabolic mechanisms involved, is poorly studied. Untargeted metabolomics analysis was utilized to screen for differential metabolic profiles between thymic cancerous tissues and adjunct noncancerous tissues. Combined with transcriptomic data, we comprehensively evaluated the metabolic patterns of TETs. Metabolic scores were constructed to quantify the metabolic patterns of individual tumors. Subsequent investigation of distinct clinical outcomes and the immune landscape associated with the metabolic scores was conducted. Two distinct metabolic patterns and differential metabolic scores were identified between TETs, which were enriched in a variety of biological pathways and correlated with clinical outcomes. In particular, a high metabolic score was highly associated with poorer survival outcomes and immunosuppressive status. More importantly, the expression of two prognostic genes (ASNS and BLVRA) identified from differential metabolism-related genes was significantly associated with patient survival and may play a key role in the tumorigenesis of TETs. Our findings suggest that differential metabolic patterns in TETs are relevant to tumorigenesis and clinical outcome. Specific transcriptomic alterations in differential metabolism-related genes may serve as predictive biomarkers of survival outcomes and potential targets for the treatment of patients with TETs.

Prognostic value of systemic inflammatory markers and the nutrition status in thymic epithelial tumors with complete resection

Background

Recent studies have shown that several systemic inflammatory markers and the nutrition status, including the neutrophil‐to‐lymphocyte ratio (NLR), monocyte‐to‐lymphocyte ratio (MLR), platelet‐to‐lymphocyte ratio (PLR), and prognostic nutritional index (PNI), are useful prognostic factors in several malignant tumors. The present study explored the prognostic value of the NLR, MLR, PLR, and PNI in thymic epithelial tumor (TET) patients who underwent complete resection.

Methods

A total of 158 TET patients who underwent complete resection were involved in the analysis. Their NLR, MLR, PLR, and PNI values were obtained from a blood examination within one month before the initiation of treatment. A receiver operating characteristic curve analysis was conducted to determine the optimal cutoff values.

Results

The enrolled patients were stratified by cutoffs of 4.35 for the NLR, 0.22 for the MLR, 130.18 for the PLR, and 44.02 for the PNI. A univariate analysis revealed that high‐grade malignant TET, including type B2 and B3 thymoma, thymic carcinoma, and thymic neuroendocrine tumor; an advanced Masaoka stage; a high NLR; a high MLR; and a low PNI were significant predictors of a poor disease‐free survival (DFS). A multivariate analysis confirmed that an advanced Masaoka stage (HR = 5.5557, p = 0.0007) and a high MLR (HR = 3.3371, p = 0.0264) were independent predictors of a poor DFS.

Conclusions

Our study demonstrated that the pretreatment MLR was an independent predictor of the DFS in patients with TETs who underwent complete resection.

Identification of Immune-Related Hub Genes in Thymoma: Defects in CD247 and Characteristics of Paraneoplastic Syndrome

Background: Thymomas (Ts) and thymic carcinomas (TCs) are rare primary tumors of the mediastinum. Paraneoplastic syndrome (PNS) is an important feature of thymoma, which presents great challenges to clinicians.

Methods: The present study uses the weighted gene co-expression network analysis (WGCNA) to identify possible immunologic mechanisms of thymoma. RNA sequencing data from thymoma samples were downloaded from the TCGA. Core genes were taken from the module that is closely related to the WHO’s stage of classification. Enhanced analysis using the online database “Metascape” and an overall survival (OS) analysis were carried out via the Kaplan–Meier method. The hub genes were obtained from the protein–protein interaction (PPI) network. In addition, we jointly analyzed multiple sets of PNS data related to thymomas from other sources to verify the correlation between thymomas and PNS. The impact of hub genes on the prognosis of PNS was evaluated via the ROC curve, with simultaneous analysis of immune infiltration by CIBERSORT.

Findings: The 14 immune hub genes closely related to thymomas were found to be jointly involved in the T-cell receptor signaling pathway. Compared to the normal thymus and type B1/B2 thymoma, there is a lower number of T-cells in type A/B3 thymoma and thymic carcinoma. The expression of genes related to the T-cell receptor signaling pathway appeared defective. The low expression of CD247 and the decrease in the number of mature T-cells are common features among thymomas, specific pulmonary fibrosis, rheumatoid arthritis, and systemic lupus erythematosus.

Langerhans Cell Histiocytosis Involving the Thymus and Heart With Simultaneous Thymoma: A Case Report

Langerhans cell histiocytosis (LCH) is a rare disease characterized by clonal expansion of CD1a+/CD207+ cells in lesions. The most frequent sites involved are bone and, less commonly, lymph nodes, lungs, and skin. The thymus or heart is rarely involved with LCH. In this case, we present a 73-year-old woman with a mediastinal mass. Histopathology after thymectomy identified this mass as type AB thymoma; notably, subsequent immunohistochemical tests showed lesions of LCH scattered in the region of thymoma. 18-Fluorodeoxyglucose PET/CT (18-FDG-PET/CT) was performed to make an overall assessment of the extent of this disease, which demonstrated suspicious cardiac involvement of LCH. This report highlights the importance of differentiating abnormalities of the thymus or mediastinal mass from LCH and the necessity of comprehensive evaluation for patients with LCH.

Long Non-Coding RNAs in the Cell Fate Determination of Neoplastic Thymic Epithelial Cells

Thymic Epithelial Tumors (TETs) arise from epithelial cells of the thymus and are very rare neoplasms comprising Thymoma, Thymic carcinoma, and Thymic Neuroendocrine tumors that still require in-depth molecular characterization. Long non-coding RNAs (lncRNAs) are emerging as relevant gene expression modulators involved in the deregulation of several networks in almost all types of human cancer, including TETs. LncRNAs act at different control levels in the regulation of gene expression, from transcription to translation, and modulate several pathways relevant to cell fate determination under normal and pathological conditions. The activity of lncRNAs is strongly dependent on their expression, localization, and post-transcriptional modifications. Starting from our recently published studies, this review focuses on the involvement of lncRNAs in the acquisition of malignant traits by neoplastic thymic epithelial cells, and describes the possible use of these molecules as targets for the design of novel therapeutic approaches specific for TET. Furthermore, the involvement of lncRNAs in myasthenia gravis (MG)-related thymoma, which is still under investigation, is discussed.

Construction of immune-related LncRNAs classifier to predict prognosis and immunotherapy response in thymic epithelial tumors

The primary objective of this study was to construct an immune-related long non-coding RNAs (IRLs) classifier to precisely predict the prognosis and immunotherapy response of patients with thymic epithelial tumors (TET).Based on univariable Cox regression analysis and Lasso regression, six prognosis-related IRLs (AC004466.3,AC138207.2, AC148477.2, AL450270.1, HOXB-AS1 and SNHG8) were selected to build an IRL classifier. Importantly, results of qRT-PCR validated that higher expression levels of AC138207.2, AC148477.2, AL450270.1 and SNHG8 as well as lower expression levels of AC004466.3, and HOXB-AS1 in TETs samples compared to normal controls. The IRL classifier could effectively classify patients into the low-risk and high-risk groups based on the different survival parameters. In terms of predictive ability and clinical utility, the IRL classifier was superior to Masaoka staging system. Additionally, IRL classifier is significantly associated with immune cells infiltration (dendritic cells, activated CD4 memory T cells and tumor-infiltrating lymphocyte (TIL), T cell subsets in particular), immune microenvironment (immune score and immune checkpoint inhibitors), and immunogenicity (TMB) in TETs, which hints that IRL classifier is tightly correlated with immune characteristics and might guide more effective immunotherapy strategies for TETs patients. Encouragingly, according to TIDE algorithm, there were more immunotherapy responders in the low-risk IRL subgroup and the IRL score was robustly negatively linked to the immunotherapeutic response. To sum up, the IRL classifier was established, which can be used to predict the prognosis, immune infiltration status, immunotherapy response in TETs patients, and may facilitate personalized counseling for immunotherapy.

A predictive model of lymph node metastasis for thymic epithelial tumours

OBJECTIVES

Thymic epithelial tumours (TETs) are relatively rare indolent malignancies in the mediastinum. Lymph node metastasis (LNM) is an important prognostic indicator for TETs; however, the pattern of LNM involved in TETs has yet to be elucidated.

METHODS

Patients diagnosed with histologically confirmed thymoma (A-B3), thymic carcinomas and thymic neuroendocrine tumours, between 1988 and 2016 were identified from the Surveillance, Epidemiology, and End Results database. Univariable and multivariable logistic regression analyses were applied to identify the predictors for LNM. The predictive nomogram was built from the independent risk factors and measured using the concordance statistic.

RESULTS

The overall proportion of TETs with LNM was 18.5% (200/1048). The rate of LNM in thymoma, thymic carcinomas and thymic neuroendocrine tumours was 6.8% (42/622), 30.2% (100/331) and 61.1% (58/95), respectively. According to the logistic regression analysis, histology type and T stage were independent factors correlated with LNM. A predictive nomogram model was developed with a concordance statistic of 0.807 (95% confidence interval: 0.773-0.841), which was significantly better than the T stage (P < 0.001) while had limited benefit to the histology type (P = 0.047). The calibration curve for the nomogram comparing the predicted and actual probabilities after bias correction showed good agreement.

CONCLUSIONS

Nodal involvement was not uncommon in TETs. Main factors related to LNM in TETs were histology type and T stage. The probability of LNM could be well calculated using the predictive model.

Transformation from Small Cell to Squamous Cell Carcinoma in a Thymic Carcinoma Patient with a Durable Response to Anlotinib: A Case Report

The most common pathologic type of thymic carcinoma (TC) is squamous cell carcinoma (SCC). Small cell carcinoma is relatively rare, accounting for approximately 2% to 5% of all thymic tumors. Histologic transformation of TC has not yet been reported. Available treatments for TC patients who progress after first-line therapy are limited, which contributes to their poor prognosis. We reported an extraordinary case of a 66-year-old man who was diagnosed with thymic small cell carcinoma that transformed into SCC after third-line treatment. Surprisingly, the patient had a progression-free survival (PFS) of 25 months and an overall survival (OS) of 10 years on anlotinib as fourth-line therapy. The tolerance was well. Thus, anlotinib may be a safe and promising treatment for TC patients, especially those who undergo histologic transformation.

The Use of Sunitinib as Maintenance Therapy in a Pediatric Patient With a Poorly Differentiated Thymic Carcinoma

BACKGROUND

Thymic carcinomas are rare aggressive mediastinal tumors with a median survival of 2 years.

OBSERVATION

We present a pediatric patient who was diagnosed with metastatic thymic carcinoma and showed continuous improvement of his primary mass and lung metastases with a regimen of cisplatin/docetaxel followed by long-term maintenance therapy with sunitinib for over 5 years.

CONCLUSIONS

This report demonstrates a long-term positive treatment effect using chemotherapy followed by sunitinib in an advanced thymic carcinoma. We are not aware of other reports of pediatric patients with metastatic thymic carcinoma treated with sunitinib maintenance who maintained a durable response for this prolonged period of time.

Combined clinical and specific positron emission tomography/computed tomography-based radiomic features and machine-learning model in prediction of thymoma risk groups

OBJECTIVES

In this single-center study, we aimed to propose a machine-learning model and assess its ability with clinical data to classify low- and high-risk thymoma on fluorine-18 (18F) fluorodeoxyglucose (FDG) (18F-FDG) PET/computed tomography (CT) images.

METHODS

Twenty-seven patients (14 male, 13 female; mean age: 49.6 ± 10.2 years) who underwent PET/CT to evaluate the suspected anterior mediastinal mass and histopathologically diagnosed with thymoma were included. On 18F-FDG PET/CT images, the anterior mediastinal tumor was segmented. Standardized uptake value (SUV)max, SUVmean, SUVpeak, MTV and total lesion glycolysis of primary mediastinal lesions were calculated. For texture analysis first, second, and higher-order texture features were calculated. Clinical information includes gender, age, myasthenia gravis status; serum levels of lactate dehydrogenase (LDH), alkaline phosphatase, C-reactive protein, hemoglobin, white blood cell, lymphocyte and platelet counts were included in the analysis.

RESULTS

Histopathologic examination was consistent with low risk and high-risk thymoma in 15 cases and 12 cases, respectively. The age and myasthenic syndrome were statistically significant in both groups (P = 0.039 and P = 0.05, respectively). The serum LDH level was also statistically significant in both groups (450.86 ± 487.07 vs. 204.82 ± 59.04; P < 0.001). The highest AUC has been achieved with MLP Classifier (ANN) machine learning method, with a range of 0.830 then the other learning classifiers. Three features were identified to differentiate low- and high-risk thymoma for the machine learning, namely; myasthenia gravis, LDH, SHAPE_Sphericity [only for 3D ROI (nz>1)].

CONCLUSIONS

This small dataset study has proposed a machine-learning model by MLP Classifier (ANN) analysis on 18F-FDG PET/CT images, which can predict low risk and high-risk thymoma. This study also demonstrated that the combination of clinical data and specific PET/CT-based radiomic features with image variables can predict thymoma risk groups. However, these results should be supported by studies with larger dataset.

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

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

Novel Tumor-Specific Antigens for Immunotherapy Identified From Multi-omics Profiling in Thymic Carcinomas

Thymic carcinoma (TC) is the most aggressive thymic epithelial neoplasm. TC patients with microsatellite instability, whole-genome doubling, or alternative tumor-specific antigens from gene fusion are most likely to benefit from immunotherapies. However, due to the rarity of this disease, how to prioritize the putative biomarkers and what constitutes an optimal treatment regimen remains largely unknown. Therefore, we integrated genomic and transcriptomic analyses from TC patients and revealed that frameshift indels in KMT2C and CYLD frequently produce neoantigens. Moreover, a median of 3 fusion-derived neoantigens was predicted across affected patients, especially the CATSPERB-TC2N neoantigens that were recurrently predicted in TC patients. Lastly, potentially actionable alterations with early levels of evidence were uncovered and could be used for designing clinical trials. In summary, this study shed light on our understanding of tumorigenesis and presented new avenues for molecular characterization and immunotherapy in TC.

Canine Epithelial Thymic Tumors: Outcome in 28 Dogs Treated by Surgery

Simple Summary

Thymoma is a tumor of the cranial mediastinum rarely reported in dogs and should be differentiated from mediastinal lymphoma. CT and fine-needle aspirates or core biopsies are helpful in differential diagnosis, but flow cytometry may improve the pre-operative diagnostic ability. In thymomas, paraneoplastic syndromes such as myasthenia gravis and hypercalcemia may develop concurrently with the tumor. Their role as prognostic factors is not well determined. Surgical excision is the treatment of choice, but adjuvant radiotherapy and/or chemotherapy may prolong survival in cases of incomplete excision or if a thymic carcinoma is diagnosed. Local recurrence and metastasis are infrequently reported; therefore, a long survival is expected if the tumor is completely excised or if adjuvant therapy is undertaken. This article reports the authors’ experience with 28 dogs affected by 18 thymomas and 10 thymic carcinomas surgically treated from January 2000 to August 2021. The median overall survival time of the entire population was 1137 days; the median disease-free time was 903 days. Dogs with thymic carcinomas had significantly shorter disease-free intervals and shorter, although not statistically significant, survival times. Dogs with Masaoka Stage III tumors had worse outcomes.

Abstract

Thymoma is a tumor rarely reported in dogs and should be differentiated from mediastinal lymphoma. Clinical signs may have a late onset, and thymoma is often diagnosed when symptoms related to the space-occupying effect or paraneoplastic syndromes occur. CT and fine-needle aspirates or core biopsies are helpful in differential diagnosis, but flow cytometry may improve the pre-operative diagnostic ability. Concurrent paraneoplastic syndromes such as myasthenia gravis and hypercalcemia have been reported; however, their role as prognostic factors is not well determined. Surgical excision is the treatment of choice; adjuvant radiotherapy and/or chemotherapy may prolong survival in cases of incomplete excision or when a thymic carcinoma is diagnosed. Local recurrence and metastasis are infrequently reported; therefore, a long survival time is expected if the tumor is completely excised or if adjuvant therapy is undertaken. This article reports the authors’ experience with 28 dogs affected by 18 thymomas and 10 thymic carcinomas. The median overall survival in this series was 1173 days, and the median disease-free interval was 903 days. Dogs with thymic carcinoma had significantly shorter disease-free intervals and shorter, although not statistically significant, survival times. Dogs with Masaoka Stage III tumors had worse outcomes.

Post-thymectomy myasthenia gravis: a case report and systematic review of literature

Myasthenia gravis (MG) is an autoimmune condition affecting the neuromuscular junction characterised by weakness and fatiguability, carrying a high morbidity if treatment is delayed. A clear association with thymoma has led to management with thymectomy as a common practice, but MG presenting post-thymectomy has rarely been reported. We present a case of an 82- year-old woman developing fatigue, ptosis and dysarthria 3 months after thymectomy. After a clinical diagnosis of MG was made, she responded well to prompt treatment with prednisolone and pyridostigmine. Her anti-acetylcholine receptor antibody (anti-AChR) subsequently came back positive. Our systematic review reveals that post-thymectomy MG can be categorised as early-onset or late-onset form with differing aetiology, and demonstrated correlation between preoperative anti-AChR titres and post-thymectomy MG. The postulated mechanisms for post-thymectomy MG centre around long-lasting peripheral autoantibodies. Clinicians should actively look for MG symptoms in thymoma patients and measure anti-AChR preoperatively to aid prognostication.

The First Reported Case of Neurotrophic Tyrosine Receptor Kinase Fusion-Positive Thymoma Treated Successfully With Entrectinib

We present the first reported case of stage 4 thymoma with pleural metastases that was found to be driven by the neurotrophic tyrosine receptor kinase (NTRK)-fusion gene. The patient was started on chemotherapy but it was discontinued due to intolerable side effects. Alternative options in such patients with rare diseases are limited; in fact, many concerns exist regarding the safety and efficacy of newly approved agents for the treatment of advanced thymomas, such as pembrolizumab and sunitinib. Due to NTRK-fusion gene positivity, entrectinib, a novel NTRK-fusion inhibitor, was then initiated. This drug has shown an objective response of 57% in treating NTRK fusion-positive solid tumors of 19 different histological subtypes, predominantly sarcomas, non-small cell lung cancer (NSCLC), and mammary analogue secretory carcinoma of the salivary gland. However, it has never been assessed in the treatment of thymomas. After 10 months of follow-up, the patient showed a significant response with mild adverse events, which was managed by temporary discontinuation of the drug. This case highlights the crucial role of whole-genome sequencing and tissue-agnostic antineoplastics in the future of cancer treatment.

Diagnostic and Prognostic Significances of SOX9 in Thymic Epithelial Tumor

Background

Thymic epithelial tumors (TETs) are rare tumors originating from the thymic epithelial cells. SOX9, a member of the family of SOX (SRY-related high-mobility group box) genes, has been considered as an oncogene and therapeutic target in various cancers. However, its role in TETs remains uncertain.

Methods

Using the immunohistochemistry method, the expression of SOX9 was analyzed in TETs tissues, including 34 thymoma (8 cases with type A, 6 with type AB, 6 with type B1, 9 with type B2, and 5 with type B3 thymomas) and 20 thymic cancer tissues and the clinicopathologic and prognostic significances were evaluated. Further bioinformatics analysis of gene expression profiles of thymomas with high and low SOX9 expressions and the corresponding survival analyses were based on the thymoma cases identified in The Cancer Genome Atlas (TCGA) database, with the median expression level of SOX9 selected as cutoff.

Results

Immunohistochemistry staining showed that SOX9 was highly expressed in the nuclei of the epithelial cells of the Hassall’s corpuscles and of the TET tumor cells. SOX9 expression was significantly associated with histological type and high expression indicated unfavorable clinical outcomes of thymomas. Bioinformatics analysis revealed that genes positively associated with SOX9 expression were mapped in proteoglycans in cancer, cell adhesion molecules, and molecules involved in extracellular matrix-receptor interaction and the TGF-β signaling pathway, and that genes negatively associated with SOX9 expression were mapped in molecules involved in primary immunodeficiency, the T cell receptor signaling pathway, Th17 cell differentiation, PD-L1 expression, and the PD-1 checkpoint pathway in cancer. In addition, SOX9 expression was positively associated with POU2F3 and TRPM5 expressions, the master regulators of tuft cells, suggesting that high SOX9 expression might be associated with the tuft cell phenotype of thymomas. Moreover, high SOX9 expression was associated with immune dysregulation of thymoma, and M2 macrophage significantly dominated in the high SOX9 expression group.

Conclusion

SOX9 may serve as a diagnostic and prognostic marker for TETs. Notably, high SOX9 expression in TETs may indicate a tuft cell phenotype and an immune suppressive microenvironment of thymomas.

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

BACKGROUND

To elucidate the mechanisms of thymic epithelial tumor (TET) canceration by characterizing genomic mutations and signaling pathway alterations.

METHODS

Primary 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.

RESULTS

ZNF429 (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.

CONCLUSIONS

Multiple 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.

Correlation Between Thymoma and Soluble Interleukin-2 Receptor Expression in a Patient with Good Syndrome

Good syndrome is a rare condition characterized by the presence of thymoma in combination with adult-onset hypogammaglobulinemia. Immunological features of Good syndrome include various immunodeficiencies accompanied with hypogammaglobulinemia. In patients with thymoma, paraneoplastic syndromes including hypogammaglobulinemia worsen the prognosis. We herein describe a patient with advanced-stage type A thymoma who was effectively treated with chemotherapy and exhibited a parallel decrease in the serum level of soluble interleukin-2 receptor (sIL-2R), which depends on cellular immunity. The present case suggests the efficacy of sIL-2R as a potential prognostic biomarker in a subset of patients with Good syndrome.

Future Perspective of Chemotherapy and Pharmacotherapy in Thymic Carcinoma

Simple Summary

Thymic carcinoma is a rare cancer, and its biology remains largely unknown. Although complete surgical resection is a standard treatment for thymic carcinoma, systemic chemotherapy is frequently administered in metastatic or recurrent cases. Given the rarity, therapeutic agents are often confirmed on the basis of the results of phase II trials or retrospective studies. Platinum-based combination chemotherapy has long been employed for treating thymic carcinoma. Recently, biomarkers have been explored, and molecular profiles and major oncogenic pathways have gradually been revealed by next-generation sequencing, resulting in the development of targeted therapies. Moreover, clinical trials assessing combination therapy with immune checkpoint inhibitors are ongoing and are expected to be efficacious for treating thymic epithelial tumors. We reviewed the current role of systemic chemotherapy, including targeted therapies and immune checkpoint inhibitors, considering recent findings regarding its biology.

Abstract

Thymic carcinoma is a rare cancer that arises from thymic epithelial cells. Its nature and pathology differ from that of benign thymoma, presenting a poorer prognosis. If surgically resectable, surgery alone or surgery followed by chemoradiotherapy or radiotherapy is recommended by the National Comprehensive Cancer Network Guidelines. Metastatic and refractory thymic carcinomas require systemic pharmacotherapy. Combined carboplatin and paclitaxel, and cisplatin and anthracycline-based regimens have been shown a fair response rate and survival to provide a de facto standard of care when compared with other drugs employed as first-line chemotherapy. Cytotoxic agents have been pivotal for treating thymic carcinoma, as little is known regarding its tumorigenesis. In addition, genetic alterations, including driver mutations, which play an important role in treatments, have not yet been discovered. However, molecular pathways and biomarker studies assessing thymic epithelial tumors have been reported recently, resulting in the development of new agents, such as molecular targeted agents and immune checkpoint inhibitors. As treatment options are currently limited and the prognosis remains poor in metastases and recurrent thymic carcinoma, genetic alterations need to be assessed. In the present review, we focused on the current role of targeted therapies and immune checkpoint inhibitors in treating thymic carcinoma.

GHSR methylation-dependent expression of a variant ligand and receptor of the ghrelin system induces thymoma tumorigenesis

Our previous study reported that the DNA methylation of growth hormone secretagogue receptor (GHSR) was significantly higher in thymoma or thymic carcinoma (TC) than in normal thymic tissue samples. Thymic epithelial tumors (TETs) with higher GHSR DNA methylation were associated with significantly worse prognosis than those with lower levels of DNA methylation. Diversified components of the ghrelin-GHSR axis may exert opposing effects in cancer progression, depending on the cancer type in question. However, the precise function of the axis remains unclear. In the present study, the mRNA expression of five key components of the ghrelin system [native ligand ghrelin, variant ligand In-1 ghrelin, native receptor GHSR1a, variant receptor GHSR1b and acylation enzyme ghrelin O-acyltransferase (GOAT)] were examined in 58 TET samples by reverse transcription-quantitative PCR, and protein expression of GHSR1a and GHSR1b was assessed in 20 TETs using immunohistochemistry. The results revealed that In-1 ghrelin, GHSR1b (variant forms) and GOAT were more strongly expressed in thymoma compared with thymic-adjacent tissue. By contrast, no significant differences were observed in the expression of ghrelin and GHSR1a (native forms) between thymoma and thymic tissue. The mRNA expression of In-1 ghrelin and GHSR1b (variant forms) was positively associated with GHSR methylation in thymoma tissue samples. However, a relationship was not found between ghrelin, GHSR1a or GOAT expression (native forms) and GHSR methylation in thymoma. Immunohistochemical analysis revealed that mRNA expression of GHSR1a and GHSR1b generally correlated with expression of the corresponding protein, and that the expression of GHSR1b was increased in advanced-stage TETs. These results indicate that the DNA methylation of GHSR is associated with a shift from native expression (ghrelin and GHSR1a) to variant expression (In-1 ghrelin and GHSR1b), which induces the tumorigenesis of thymoma, but not TC.

Two types of immune infiltrating cells and six hub genes can predict the occurrence of myasthenia gravis in patients with thymoma

Thymoma is the most common primary mass in anterior mediastinum. Although associated with low malignancy, it is often accompanied by myasthenia gravis resulting in poor prognosis. Due to the dual factors of tumor immune tolerance and autoimmune reaction, it is urgent to understand the immune status of MG with thymoma. In this study, RNA sequencing data were obtained from the TCGA and GEO cohorts to identify differentially expressed messenger RNAs and infiltrated immune cells. A total of 121 samples in TCGA and 43 samples in GEO were screened out. The infiltrated immune cells were identified by CIBERSORT, in which Tfh cells and activated DC cells were abnormal in thymoma patients. The differently expressed genes were performed by package LIMMA. The functional characteristics of differently expression genes were analyzed by GO and KEGG; one GO and seven KEGG pathways were both found in both TCGA and GEO cohorts. Meanwhile, 27 common differently expressed genes were obtained and were displayed by a Venn diagram. The TRRUST was used to screen the hub genes for the common 27 different genes and 6 genes were found. Then, PPI networks were constructed. Subsequently, the relationship between SCNAs of common genes and related immune cells tested by TIMER. Kaplan–Meier plots, ROC curve and Cox’s expression model for immune infiltration and hub genes were also tested. In conclusion, we found that two types of immune infiltrated cells and six hub genes can predict the occurrence of myasthenia gravis in thymoma patients.

Intrathoracic myolipoma from parietal pleura with oestrogen and progesterone receptor

Myolipoma is a rare benign lipomatous soft tissue neoplasm, occurring most frequently in adults in the abdomen, pelvis or retroperitoneum. We presented a case of a 39-year-old female with an epipleural lesion at the left paraspinal region identified using computed tomography. Magnetic resonance imaging revealed a fat-containing lesion attached to the pleura over the left paraspinal region. Surgical resection was performed, and histopathological analysis revealed a tumour composed of interlacing bundles of neoplastic smooth muscle cells with low cellularity and rare mitotic figures intermixing with mature adipocytes. The presence of oestrogen and progesterone receptors in smooth muscle cells was noted. The mass was reported as myolipoma. To the best of our knowledge, this case is the first description of an intrathoracic myolipoma.

Elevated serum CYFRA 21-1 level as a diagnostic marker for thymic carcinoma

Background

No useful tumor markers have been identified for the diagnosis of thymic carcinomas. Serum cytokeratin 19 fragment, measured using the CYFRA 21‐1 immunoassay, is used as a tumor marker for squamous cell carcinomas in various malignant tumors. Here, we evaluated the value of CYFRA 21‐1 in diagnosing thymic carcinoma.

Methods

We retrospectively reviewed 94 patients with pathological diagnoses of thymic carcinoma or thymoma (32 and 62 patients, respectively) who were referred to our departments between January 2000 and March 2019. Primary outcomes included tumor marker levels and their diagnostic accuracy.

Results

Patients with thymic carcinoma were significantly more likely to be male (thymic carcinoma, 68.8%; thymoma, 40.3%; p = 0.02), have an advanced TNM stage (p < 0.01), and a significantly higher CYFRA 21‐1 level than those with thymoma (thymic carcinoma: median = 4.2 ng/ml; interquartile range [IQR] = 2.1–6.1 ng/ml vs. thymoma: median = 1.2 ng/ml; IQR = 0.9–1.7 ng/ml; p < 0.01). Receiver operating characteristic curves demonstrated that the area under the curve for CYFRA 21‐1 to distinguish thymic carcinoma from thymoma was 0.86 (95% confidence interval [CI]: 0.74–0.93; cutoff = 2.7 ng/ml; sensitivity = 68.8%; specificity = 95.2%). Multivariable analysis demonstrated that CYFRA 21‐1 (odds ratio = 25.6; 95% CI: 4.6–141.6; p < 0.01) was an independent predictor for thymic carcinoma after adjusting for TNM stage.

Conclusions

Serum CYFRA 21‐1 level may help in diagnosing thymic carcinoma.