Thymic epithelial tumors represent the most common neoplasms of the anterior mediastinum, while atypical type A thymoma is a rare subtype of thymoma. On the morphological basis of type A thymoma, this tumor exhibits some atypical histological features, such as abundant cells, increased mitotic counts, tumor necrosis, and increased Ki67 index. At present, the clinical and pathological data of this tumor is still available. Since it was formally named, 16 cases have been reported around the world. In order to improve the understanding of the disease, this article reviews the related literature and tries to elaborate the atypical type A thymoma from the aspects of pathological features, clinical manifestations, epidemiology and differential diagnosis.
Objective To compare the differences in clinicopathological features, molecular phenotypes, and prognosis between atypical type A thymoma (AAT) and classic type A thymoma (TAT), and to clarify the aggressive nature of AAT. Methods The data of AAT patients (AAT group) and classic TAT patients (TAT group) who underwent surgical resection for thymoma at West China Hospital of Sichuan University between January 2016 and November 2024 were retrospectively collected. Comparisons on the clinical data, histopathology, immunohistochemistry (CD20, Ki-67), GTF2I mutation status, and survival outcomes were performed between the two groups. Results A total of 53 patients were enrolled, including 22 in the AAT group and 31 in the TAT group. There was no significant difference in age, sex, or initial presenting symptoms between the two groups (P>0.05). Compared with the TAT group, the AAT group had larger tumors [(5.6±2.7) vs. (4.1±2.0) cm, P=0.043], a lower proportion of Masaoka stage Ⅰ (31.6% vs. 61.3%, P=0.041), and worse survival outcomes [progression-free survival: hazard ratio (HR)=2.87, 95% confidence interval (CI) (1.42, 5.81), P=0.004; overall survival: HR=1.96, 95%CI (1.02, 3.78), P=0.013]. Pathologically, the AAT group showed more mitotic figures (mean 6/2 mm2), and tumor necrosis was observed in 45.5% of cases. There was no statistically significant difference in the CD20 expression rate (20.0% vs. 41.9%), Ki-67 index [(11.0±6.0)% vs. (8.0±6.9)%], or GTF2I mutation rate (86.7% vs. 92.3%) between the two groups (P>0.05). Conclusions AAT is a subtype of TAT with distinct aggressive pathological features, including higher mitotic activity, a tendency for necrosis, and a greater propensity for recurrence and metastasis. Pathological diagnosis should integrate morphology and molecular testing to guide more aggressive treatment and follow-up strategies.
Objective To systematically review the effectiveness of thoracoscopy surgery and thoracotomy for thymoma. Methods Databases including PubMed, EMbase, The Cochrane Library (Issue 3, 2016), Web of Science, CBM, WanFang Data and CNKI were searched to collect randomized controlled trials (RCTs) and cohort studies about thoracoscopy surgery versus thoracotomy for thymoma from inception to April 2016. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. Then meta-analysis was performed using RevMan 5.3 software. Results A total of 5 RCTs and 8 cohort studies involving 1 093 patients were included. The results of meta-analysis showed that, compared with thoracotomy, the thoracoscopy surgery could shorten operative time (MD= –22.2, 95%CI –32.92 to –12.52, P < 0.000 01), duration of ICU stay (MD= –0.76, 95%CI –0.21 to –0.30, P < 0.000 01), duration of hospital stay (MD= –3.71, 95%CI –4.47 to –2.96, P < 0.000 01) and duration of pleural drainage (MD= –1.80, 95%CI –2.42 to –1.18, P < 0.000 01), reduce volume of intraoperative blood loss (MD= –43.27, 95%CI –50.94 to –35.60, P < 0.000 01), and decrease the incidence of postoperative complications (OR=0.19, 95%CI 0.11 to 0.34, P < 0.000 01), but there was no significant difference in recurrence rate between two groups (OR=0.81, 95%CI 0.31 to 2.11, P=0.67). Conclusions Current evidence shows that, compared with thoracotomy, the thoracoscopy surgery for thymoma has shorter operative time, duration of ICU stay, duration of hospital stay, and duration of pleural drainage, as well as less blood loss and postoperative complications. Due to the limited quality of included studies, more high-quality studies are needed to verify the above conclusion.
Abstract： Objective To investigate the expression and correlation of phosphatase and tensin homologue deleted on chromosome ten(PTEN)， epidermal growth factor receptor(EGFR) and Ki-67 in human thymic tumors, and their possible role in tumor genesis， infiltration and metastasis. Methods The expression of PTEN， EGFR and Ki-67 were detected by using SP immunohistochemical technique in 45 cases of thymic tumors and 5 cases of normal thymic tissues. Results In 5 cases of normal thymic tissues, the expression of PTEN was bly positive, whereas EGFR and Ki -67 were weakly positive or negative. In 45 cases of thymic tumors, the positive ratio of PTEN were significantly reduced from benign thymoma， invasive thymoma to thymic carcinoma (χ2=7.808, P=0.020), but the positive ratio of EGFR and Ki-67 were gradually increased(χ2=8.032, 0.018，7.006；P=0.030). The positive ratio of PTEN， EGFR and Ki-67 protein were significantly related to Levine classification, Masaoka staging and lymph node metastasis (Plt;0.05). PTEN positive cases were negatively correlated with EGFR and Ki-67(r=－0.632，－0.653；Plt;0.01), EGFR positive cases were positively correlated with Ki-67 in thymic tumors(r=0.807,Plt;0.01). Conclusions Reduced or absent PTEN and increased EGFR and Ki-67 expression might play an important role in the genesis， invasiveness and metastasis of thymic tumors. The expression of PTEN is bly associated with the expression of abnormal EGFR and Ki-67. Detection of the three protein expressions simultaneously might be more helpful in making an early diagnosis of the tumors jndgement of theirs malignant degree，invasiveness and metastasis capacity, as well as the prognosis.
ObjectiveTo systematically evaluate the efficacy of adjuvant radiotherapy after thymoma resection. MethodsThe PubMed, EMbase, The Cochrane Library, Web of Science, Wanfang, VIP, CNKI databases were systematically searched to find relevant literature comparing the efficacy and effectiveness of thymoma resection and thymoma resection+postoperative radiation therapy (PORT) for treating thymoma published from inception to January 2024. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of included retrospective studies, and Review Manager 5.4 software was used to perform meta-analysis. ResultsA total of 23 articles were included, all of which were retrospective studies. There were a total of 13742 patients, including 6980 patients in the simple surgery group, with 3321 males and 3659 females, and an average age of 54.08 years; 6762 patients in the surgery+PORT group, with 3385 males and 3377 females, and an average age of 53.76 years. The NOS scores of the included literature were all≥7 points. The results of the meta-analysis showed that compared with the simple surgery group, the surgery+PORT group had higher 1-year overall survival rate [OR=0.32, 95%CI (0.25, 0.42), P<0.001], 3-year overall survival rate [OR=0.55, 95%CI (0.48, 0.64), P<0.001], 5-year overall survival rate [OR=0.66, 95%CI (0.58, 0.75), P<0.001], 10-year overall survival rate [OR=0.71, 95%CI (0.57, 0.88), P=0.002], 1-year disease-free survival rate [OR=0.47, 95%CI (0.23, 0.93), P=0.030], 5-year disease-free survival rate [OR=0.61, 95%CI (0.45, 0.84), P=0.003], 3-year disease-specific survival rate [OR=0.44, 95%CI (0.35, 0.55), P<0.001], 5-year disease-specific survival rate [OR=0.53, 95%CI (0.44, 0.63), P<0.001] and 10-year disease-specific survival rate [OR=0.53, 95%CI (0.35, 0.82), P=0.004]. But there was no statistically significant difference between the two groups in terms of 3-year disease-free survival rate [OR=0.86, 95%CI (0.61, 1.22), P=0.400], 10-year disease-free survival rate [OR=0.70, 95%CI (0.47, 1.05), P=0.080] and 1-year disease-specific survival rate [OR=0.83, 95%CI (0.55, 1.26), P=0.380]. ConclusionPORT after thymoma resection has more advantages than simple surgical treatment in terms of 1-, 3-, 5-, and 10-year overall survival, 1- and 5-year disease-free survival, and 3-, 5- and 10-year disease-specific survival.
National Comprehensive Cancer Network (NCCN) has updated and released the latest content of NCCN guidelines version 1. 2023 thymomas and thymic carcinomas (known as "guidelines"). The guideline sets standards for the diagnosis and treatment of thymoma and thymic carcinoma based on high quality clinical evidence and the latest advances in research. There have been some updates and revisions in the latest two versions of the guidelines, mainly focusing on the principles of radiotherapy, the principles of systematic therapy, multidisciplinary participation and the improvement of some footnotes, compared with the first version of the guidelines in 2022. In this paper, the contents of the new guideline will be interpreted in order to provide reference for the work of thymoma and thymic carcinoma in our country at the present stage.
ObjectiveTo investigate the long-term efficacy and the influencing factors of thymectomy for thymoma patients associated with myasthenia gravis. MethodsWe retrospectively analyzed the clinical and follow-up data of 126 thymoma patients associated with myasthenia gravis underwent extended thymectomy from June 2002 to December 2015 in our hospital. There were 26 males and 37 females at the mean age of 54.51±12.62 years. We built up survival analysis model to analyze the effect of those following factors on postoperative result:sex, the age when operated, the preoperative course of disease, the condition of associating with other diseases, history of critical illness, steroid administration time before operation, Osserman classification, Masaoka staging, WHO pathological type, surgical approach, tumor size and so on. Result The average follow-up time was 35(5-96) months. During follow-up period, 12 patients (19%) achieved complete remission, 39 patients (62%) achieved partial remission, 7 patients (11%) kept stable, 5 patients (8%) deteriorated and the total effective rate was 81%. The result of log-rank analysis showed that the preoperative course of disease (P=0.027), history of critical illness on myasthenia gravis (P=0.035) and Osserman classification (P=0.018) were related to incomplete remission, whlie the result of Cox regression analysis showed that the preoperative course of disease (P=0.001) and Osserman classification (P=0.012) were the independent risk factors for incomplete remission. ConclusionExtended thymectomy is an effective treatment for thymoma patients associated with myasthenia gravis, but the symptom of those patients whose preoperative course of disease are more than 12 months or Osserman classification is at ⅡB, Ⅲ and Ⅳ type of Osserman classification have poor effect after operation.
Objective To develop a radiomics nomogram based on contrast-enhanced CT (CECT) for preoperative prediction of high-risk and low-risk thymomas. Methods Clinical data of patients with thymoma who underwent surgical resection and pathological confirmation at Northern Jiangsu People's Hospital from January 2018 to February 2023 were retrospectively analyzed. Feature selection was performed using the Pearson correlation coefficient and least absolute shrinkage and selection operator (LASSO) method. An ExtraTrees classifier was used to construct the radiomics signature model and the radiomics signature. Univariate and multivariable logistic regression was applied to analyze clinical-radiological characteristics and identify variables for developing a clinical model. The radiomics nomogram model was developed by combining the radiomics signature and clinical features. Model performance was evaluated using area under the curve (AUC), sensitivity, specificity, accuracy, negative predictive value, and positive predictive value. Calibration curves and decision curves were plotted to assess model accuracy and clinical values. Results A total of 120 patients including 59 females and 61 males with an average age of 56.30±12.10 years. There were 84 patients in the training group and 36 in the validation group, 62 in the low-risk thymoma group and 58 in the high-risk thymoma group. Radiomics features (1 038 in total) were extracted from the arterial phase of CECT scans, among which 6 radiomics features were used to construct the radiomics signature. The radiomics nomogram model, combining clinical-radiological characteristics and the radiomics signature, achieved an AUC of 0.872 in the training group and 0.833 in the validation group. Decision curve analysis demonstrated better clinical efficacy of the radiomics nomogram than the radiomics signature and clinical model. Conclusion The radiomics nomogram based on CECT showed good diagnostic value in distinguishing high-risk and low-risk thymoma, which may provide a noninvasive and efficient method for clinical decision-making.
Objective To evaluate the risk factors of the patients with myasthenia gravis (MG) after resection of thymoma. Methods We retrospectively analyzed the clinical data of 126 thymoma patients without preoperative MG who underwent a thymectomy in our hospital from June 2002 through May 2015. There were 51 males and 75 females at age of 51.71±14.06 years. The risk factors for MG after resection of thymoma were evaluated. Results MG occurred in nine patients after resection of thymoma (7.1%). Incomplete resection (P=0.024), A and AB type of WHO classification (P=0.048), concomitant autoimmune diseases (P=0.024), postoperative pulmonary infection (P=0.036) were the risk factors for the MG after resection of thymoma. Postoperative radiotherapy and chemotherapy (P=0.011) reduced the risk for the patients with incomplete resection or invasive thymoma. Conclusion Incomplete resection, A and AB type of WHO classification, concomitant autoimmune diseases, postoperative pulmonary infection are considered as the risk factors for MG after resection of thymoma, and postoperative radiotherapy and chemotherapy should be performed for the patients with incomplete resection or invasive thymoma.