Thymoma: inter-relationships among World Health Organization histology, Masaoka staging and myasthenia gravis and their independent prognostic significance: a single-centre experience

Comparison of Efficacy and Safety of Different Second-line Therapies for Patients With Advanced Thymic Carcinoma

AIMS

Thymic carcinoma (TC) is a rare form of highly invasive tumors. Currently, the standard first-line therapy involves paclitaxel plus carboplatin treatment, while the recommended regimen for second-line therapy remains uncertain. The purpose of this study is to explore the second-line mode of TC patients.

MATERIALS AND METHODS

We evaluated the outcome of subjects with advanced TC between 2009 and 2023 in three medical centers, retrospectively. Tumor response was evaluated according to the Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1). Kaplan-Meier was used for calculating Progression-free survival (PFS) and overall survival (OS). The factors affecting survival in the real world were evaluated by Cox analysis.

RESULTS

Totally 136 patients were included in this study, the median PFS (mPFS) for all subjects was 5.97 months, and the median OS (mOS) was 25.03 months. According to patient's treatment modes, they are divided into monotherapy (n = 95) and combination therapy (n = 41), PFS manifested the difference between two groups (5.17 vs. 9.00 months, P = 0.043). OS also indicated a significant distinction (22.50 vs. 38.00 months, P = 0.017). Furthermore, there was a significant difference in PFS between patients using immunotherapy combined with chemotherapy and those with antivascular therapy (8.57 vs. 13.10 months, P = 0.047).

CONCLUSION

In the second-line therapy for advanced TC, the efficacy of combination therapy was better than monotherapy, especially for immunotherapy combined with antivascular therapy.

Differentiating low-risk thymomas from high-risk thymomas: preoperative radiomics nomogram based on contrast enhanced CT to minimize unnecessary invasive thoracotomy

BACKGROUND

This study was designed to develop a combined radiomics nomogram to preoperatively predict the risk categorization of thymomas based on contrast-enhanced computed tomography (CE-CT) images.

MATERIALS

The clinical and CT data of 178 patients with thymoma (100 patients with low-risk thymomas and 78 patients with high-risk thymomas) collected in our hospital from March 2018 to July 2023 were retrospectively analyzed. The patients were randomly divided into a training set (n = 125) and a validation set (n = 53) in a 7:3 ratio. Qualitative radiological features were recorded, including (a) tumor diameter, (b) location, (c) shape, (d) capsule integrity, (e) calcification, (f) necrosis, (g) fatty infiltration, (h) lymphadenopathy, and (i) enhanced CT value. Radiomics features were extracted from each CE-CT volume of interest (VOI), and the least absolute shrinkage and selection operator (LASSO) algorithm was performed to select the optimal discriminative ones. A combined radiomics nomogram was further established based on the clinical factors and radiomics scores. The differentiating efficacy was determined using receiver operating characteristic (ROC) analysis.

RESULTS

Only one clinical factor (incomplete capsule) and seven radiomics features were found to be independent predictors and were used to establish the radiomics nomogram. In differentiating low-risk thymomas (types A, AB, and B1) from high-risk ones (types B2 and B3), the nomogram demonstrated better diagnostic efficacy than any single model, with the respective area under the curve (AUC), accuracy, sensitivity, and specificity of 0.974, 0.921, 0.962 and 0.900 in the training cohort, 0.960, 0.892, 0923 and 0.897 in the validation cohort, respectively. The calibration curve showed good agreement between the prediction probability and actual clinical findings.

CONCLUSIONS

The nomogram incorporating clinical factors and radiomics features provides additional value in differentiating the risk categorization of thymomas, which could potentially be useful in clinical practice for planning personalized treatment strategies.

Thymic lipofibroadenoma: A case report

Lipofibroadenoma (LFA) is an epithelial tumor. It has been seen rarely in the thymus, and only a handful of cases have been reported. LFA is usually seen in the anterior mediastinum and is defined as a coalescence of epithelial thymic, adipose, and fibrotic tissue. We present a 30-year-old female who presented due to an unrelated traffic accident. An incidental mass was found in her left anterior superior mediastinum. After performing a complete excision, a histologic examination of the excised mass revealed it to be LFA of the thymus, which is extremely rare. The follow-up period was uneventful. LFA is a slow-growing benign tumor and is very similar to fibroadenoma of the breast. The etiology and clinical findings are yet to be well-defined. It was only seen in men in the prior cases. But recent cases, including this one, have also reported female patients. The tumor is mainly observed in the anterior mediastinum, which was also the case in our patient. The gold standard of diagnosis is pathologic examination. Our examination showed strands and nests of thymic parenchyma, including Hassall corpuscles, which separated fibro adipose tissue. Thymectomy is the treatment of choice. It can be performed by either video-assisted thoracic surgery or open surgery. We performed open surgery. The most important prognostic factor for this tumor is staging.

A Painless Right Anterior Neck Mass

A 58-year-old woman presents with a several-week history of a painless right-sided swelling on her anterior neck. What is your diagnosis?

Lobulated tumor contour as a predictor of preoperative tumor invasion of the lung or pericardium in thymoma patients

PURPOSE

Preoperative investigations to detect invasion to neighboring organs are important for deciding on the most appropriate surgical approach for thymoma. We evaluated preoperative computed tomography (CT) findings in thymoma patients to identify the CT features associated with tumor invasion.

METHODS

Clinicopathologic information on 193 patients who underwent surgical resection for thymoma at Chiba University Hospital between 2002 and 2016 was collected retrospectively. The surgical pathology identified invasion of thymoma in 35 patients: in the lung (n = 18), pericardium (n = 11), or both (n = 6). Contact lengths between the tumor contour and lung (CLTL) or pericardium (CLTP) were measured at the maximum section of the tumor on axial CT. Univariate and multivariate analyses were performed to analyze the relationship between pathological invasion of the lung or pericardium and the clinicopathologic features.

RESULTS

The mean CLTL and CLTP were significantly longer in patients with invasion of the neighboring organs than in those without invasion. A lobulated tumor contour was identified in 95.6% of the patients with invasion of the neighboring organs. A multivariate analysis revealed that a lobulated tumor contour was significantly associated with both lung and pericardial invasion.

CONCLUSIONS

A lobulated tumor contour was significantly associated with lung and/or pericardial invasion in thymoma patients.

Re-exploration of prognosis in type B thymomas: establishment of a predictive nomogram model

OBJECTIVE

To explore the risk factors for disease progression after initial treatment of type B thymomas using a predictive nomogram model.

METHODS

A single-center retrospective study of patients with type B thymoma was performed. The Cox proportional hazard model was used for univariate and multivariate analyses. Variables with statistical and clinical significance in the multivariate Cox regression were integrated into a nomogram to establish a predictive model for disease progression.

RESULTS

A total of 353 cases with type B thymoma were retrieved between January 2012 and December 2021. The median follow-up was 58 months (range: 1-128 months). The 10-year progression-free survival (PFS) was 91.8%. The final nomogram model included R0 resection status and Masaoka stage, with a concordance index of 0.880. Non-R0 resection and advanced Masaoka stage were negative prognostic factors for disease progression (p < 0.001). No benefits of postoperative radiotherapy (PORT) were observed in patients with advanced stage and non-R0 resection (p = 0.114 and 0.284, respectively).

CONCLUSION

The best treatment strategy for type B thymoma is the detection and achievement of R0 resection as early as possible. Long-term follow-up is necessary, especially for patients with advanced Masaoka stage and who have not achieved R0 resection. No prognostic benefits were observed for PORT.

WHO histological classification and tumor size are predictors of the locally aggressive behavior of thymic epithelial tumors

OBJECTIVE

The aim of this study was to explore the influencing factors that affect the local invasive behavior of thymic epithelial tumors (TETs).

METHOD

We retrospectively analyzed 524 patients with TETs who underwent surgical treatment at our center from January 2010 to January 2022. Cox regression analysis was applied to identify predictors associated with the prognosis of TET. Logistic regression analysis was used to analyze the factors associated with the locally invasive behavior of TETs. Receiver operating characteristic analysis and the Youden index were applied to determine the predictive efficiency and cutoff value.

RESULTS

There were 275 males and 249 females with a median age of 56 years. Seventy-seven patients had locally invasive behavior. The prognosis of local invasive TETs was significantly worse that of noninvasive TETs (P < 0.001). WHO classification and tumor size were two hazard factors for tumor invasive behavior. The risk of local invasion increased by 2.196 (OR (95 % CI): 1.813-2.659) times for each grade in WHO classification with a change from type A to thymic carcinoma. The tumor size cutoff of 6 cm represented a distinct boundary in predicting the hazard of local invasion (AUC: 0.784, specificity: 0.711, sensitivity: 0.726).

CONCLUSION

WHO classification and tumor size are important factors in predicting the locally aggressive behavior of TETs. The invasion capability of TETs is constantly increasing with an escalation in WHO classification. Tumors greater than 6 cm in size have a higher risk for local invasion.

Clinicodemographic characteristics and prognostic role of myasthenia gravis in thymoma: Experience from a Saudi population

OBJECTIVES

The objectives of the study were to determine the clinicodemographic characteristics and the prognostic role of myasthenia gravis (MG) in thymoma.

METHODS

The records of patients who underwent surgical resection of thymoma at King Faisal Specialist Hospital and Research Center in the past 23 years were reviewed. Seventy thymoma patients were finally included and were then categorized based on MG status into the MG group (39 patients) and the non-MG group (31 patients). Collected data included patients' demographic characteristics, tumor characteristics, and postoperative clinical outcomes. All analyses were conducted using SPSS. The comparison between both groups was tested using the Student t-test and Chi-square test for continuous and categorical variables, respectively. A P = 0.05 or less indicated statistical significance.

RESULTS

Patients' age ranged from 11 to 76 years, and female predominance was observed (55.7%). Compared to the non-MG group, no difference in patients' gender was observed (P = 0.058); however, MG patients had a younger age (39.30 vs. 48.77, P = 0.0095). No difference was noted between both groups based on the World Health Organization classification (P = 0.398), but MG patients tended to present with less-advanced tumors based on the TNM classification (P = 0.039) and lower stage based on the MASAOKA staging system (P = 0.017). No significant change in tumor size (P = 0.077), resectability (P = 0.507), and adjuvant therapy (P = 0.075) were observed. MG was not significantly associated with postoperative complications, morbidity, or mortality. However, it exhibited a prognostic protective role in terms of lower recurrence (2.56% vs. 35.48%, P = 0.0001) and longer survival duration (18.62 vs. 10.21 years, P < 0.001) as compared to non-MG patients.

CONCLUSIONS

MG occurrence in thymoma patients is more likely to occur at a younger age, higher TNM classification, and advanced MASAOKA stage. Although no significant association was noted between MG and complications and mortality, MG exhibited a protective role in thymoma by providing a lower recurrence rate and longer survival duration.

Evaluation of the relationship between the eighth edition of TNM staging, the mMasoaka, and World Health Organization histopathological classification for thymoma

AIM OF STUDY

The aim of this study was to describe the correlation between the eighth tumor, node, and metastasis (TNM), mMasaoka staging, and the World Health Organization (WHO) histopathologic classification and to identify prognostic values in predicting survival and recurrence of thymoma.

MATERIALS AND METHODS

Medical files of 90 patients with thymoma diagnosed between 1992 and 2018 were evaluated for this trial.

RESULTS

The distributions of patients were similar between mMasaoka and eighth TNM staging according to early (I, II) and advanced stages (IIIA, IIIB, IV). Interestingly, 55 of 63 stage I patients with TNM staging showed difference as 31 of them up-staged to stage IIA and 24 of them up-staged to stage IIB in mMasoaka staging. Both staging systems closely correlated with WHO classification (p < 0.001); stages I and II were associated with low-risk groups (type A, AB, B1), and stages III and IV were associated with high-risk groups (type B2, B3). WHO classification was not a prognostic factor for overall survival (OS) ( P = 0.13) and progression-free survival (PFS) (p = 0.08), but it was a prognostic factor for 10-year cancer-specific survival (CSS) (p = 0.04). Myasthenia gravis was associated to early stages (stage I, II) (p = 0.007) and related with better prognosis.

CONCLUSIONS

Our study showed a correlation between both staging system and WHO classification. A certain difference was found between eighth TNM staging and the mMasoaka staging in terms of stage I disease. Both staging systems effectively prognosticated OS, CSS, and PFS. To clarify the prognostic relevance and clinical usefulness of the WHO classification may be beneficial in clinical practice for the treatment decision.

Expression of Programmed Cell Death 1 Ligand 2 in Patients With Thymoma and Thymomatous Myasthenia Gravis

OBJECTIVES

This study aimed to examine the expression of programmed cell death 1 ligand 2 (PD-L2) in thymoma and thymomatous myasthenia gravis (MG).

METHODS

The records of 70 patients with thymoma receiving surgical resection between January 2017 and December 2018 were retrospectively reviewed. Thymoma PD-L2 expression was evaluated by immunohistochemistry staining. Associations between PD-L2 expression and clinicopathologic features were examined.

RESULTS

PD-L2 expression was positive in 41 patients (58.6%) and negative in 29 patients (41.4%). Of them, 33 had thymomatous MG. Patients with MG were more likely to be 50 years of age or younger (69.70% vs 35.14%); have more World Health Organization (WHO) type B thymomas (84.85% vs 64.86%); have tumors of smaller size (4.09 ± 2.33 cm vs 6.47 ± 2.42 cm); have positive PD-L2 expression (78.79% vs 40.54%); and have a higher percentage of PD-L2-positive cells, higher PD-L2 expression intensity, and score (all P < .05). Positive PD-L2 expression was associated with more type B thymomas, higher Masaoka-Koga stage, smaller tumor size, ectopic thymus, and MG (all P < .05). Factors significantly associated with MG were age under 50 years, tumor size less than 5 cm, and positive PD-L2 expression (all P < .05).

CONCLUSIONS

Thymoma PD-L2 expression is significantly associated with thymomatous MG and WHO histologic types B2 and B3.

Treatment outcomes and prognosis of immune checkpoint inhibitors therapy in patients with advanced thymic carcinoma: A multicentre retrospective study

BACKGROUND

Immunotherapy has demonstrated good efficacy and survival outcomes in solid tumours. However, efficacy data for immune checkpoint inhibitors (ICIs) in advanced thymic carcinoma are lacking. The present study aimed to assess the activity of ICIs in advanced thymic carcinoma.

METHODS

A multicentre retrospective study was conducted to explore the efficacy and safety of ICIs for advanced thymic carcinoma. Objective response rate (ORR), progression-free survival (PFS), overall survival, and immune-related adverse events (irAEs) were analysed. In addition, factors independently associated with treatment efficacy and survival outcomes were evaluated.

RESULTS

A total of 77 patients with advanced thymic carcinoma were enrolled between March 2016 and September 2021. The ORR was existing the difference between ICIs monotherapy (n = 23) and ICIs combined with chemotherapy (n = 54) (17.4% versus 44.4%, P = 0.024). The ICIs combination treatments were associated with better median PFS (mPFS) compared to ICIs monotherapy (12.7 months versus 2.1 months, P < 0.001). Notably, liver or brain metastasis was a poor prognostic factor of mPFS (1.8 months versus 3.5 months, P = 0.012) in the ICIs monotherapy group. In addition, mPFS for the first-line treatment (n = 27) was longer than that for ICIs as the second- or posterior-line treatment (n = 50) (P < 0.001). The incidence of irAEs was 54.5% (42/77) in the 77 enrolled patients. The incidence of grade 3-4 irAE was 15.6% (12/77).

CONCLUSIONS

Immunotherapy is effective in advanced thymic carcinoma, especially for combination with chemotherapy showed promising antitumour activity, which indicates worthy of combination treatment strategy for further study. IrAEs also require close monitoring and management.

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.

Small-sized type A thymoma with pulmonary metastasis: a case report

Background

Type A thymomas comprise a homogenous population of neoplastic epithelial cells that are characterized by a spindle/oval shape without nuclear atypia. They may be accompanied by few non-neoplastic lymphocytes. Most type A thymomas are detected in the earlier Masaoka stages. Compared to other thymoma subtypes, they rarely metastasize or recur. There have been some reports of patients with type A thymomas with pulmonary metastasis; however, these thymomas were 20 mm or more in size. Herein, we report the case of a patient who underwent surgical resection for a small-sized type A thymoma (12 mm) with pulmonary metastasis.

Case presentation

A 62-year-old patient presented with an abnormal shadow in the left lung on plain chest radiography during a medical checkup. Chest computed tomography revealed a 12-mm tumor in the anterior mediastinum and a 13-mm nodule in the left lower lobe. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography revealed uptake in the anterior mediastinal tumor, but did not show a significant uptake in the pulmonary nodule. The patient underwent surgical resection on two separate occasions, and was diagnosed with an atypical type A thymoma and pulmonary metastasis. The TNM classification was p-T1aN0M1b stage IVb, and it was stage IVb according to the Masaoka staging system. No recurrence was observed during the follow-up.

Conclusions

We report a case of the smallest type A thymoma with pulmonary metastasis. Pulmonary metastasis secondary to a type A thymoma should be considered even if the thymoma is small in size (< 20 mm).

Myasthenia is a poor prognostic factor for perioperative outcomes after robotic thymectomy for thymoma

OBJECTIVES

The goal of this study was to compare the early and intermediate surgical outcomes, including the survival of those with and without myasthenic thymoma, following robotic thymectomy.

METHODS

This is a retrospective analysis of prospectively maintained data of 111 patients who underwent robotic thymectomy for thymoma over 7 years in a thoracic surgery centre in India. We performed a comparative analysis of demographics, intraoperative variables and postoperative outcomes including survival of those with and without myasthenic thymoma.

RESULTS

Of 111 patients, 68 patients were myasthenic and 43 were non-myasthenic. The need to resect surrounding structures and conversions was greater in the myasthenic group (P = 0.02, P = 0.04). Postoperative complications were significantly higher in the myasthenic group (P = 0.02). No differences were observed in intensive care unit stay, the need for postoperative ventilation and the hospital stay. On correlation, a higher Masaoka stage [odds ratio 1.96, 95% confidence interval (CI) 1.22-3.15] and an aggressive World Health Organization histological diagnosis (odds ratio 1.58, 95% CI 1.10-2.26) were more likely in patients with myasthenia gravis. A total of 7 deaths (6.3%) occurred during the median follow-up of 4.2 years, 5 among those with myasthenic thymoma and 2 among patients with non-myasthenic thymoma. Due to the small number of deaths, there is insufficient evidence to draw any conclusion about the effect of myasthenia gravis on survival after surgery (hazard ratio 0.51, 95% CI 0.09-2.71; P = 0.43).

CONCLUSIONS

The presence of myasthenia with thymoma is associated with more adjacent structure resection, higher postoperative complications and more conversions. The use of robotic surgery for thymoma resection in patients with myasthenia could not overcome the early postoperative problems related to myasthenia gravis.

Myasthenia gravis affects overall survival in patients with thymoma: an analysis of multicentre database using propensity score matching

OBJECTIVES

About one-third of patients with thymoma have myasthenia gravis (MG). It remains controversial whether MG affects the prognosis of patients with thymoma. The aim of this study was to evaluate the effect of MG on the prognosis of patients with thymoma in a multicentre database.

METHODS

Patients with thymoma who underwent thymectomy were identified from 2 prospectively collected databases in 2 medical centres from 2010 to 2018. Kaplan-Meier curves and the log-rank test were used to assess overall survival and recurrence-free survival, and a Cox proportional hazards model was used to determine significant contributors to survival. Propensity score matching was performed to eliminate selection bias.

RESULTS

A total of 514 patients with thymoma were included in this study, of whom 320 patients were MG-free and 194 had MG. Patients with MG were younger (median age 50 vs 54 years, P = 0.001) and had smaller tumours (4.4 ± 2.0 vs 4.9 ± 2.3 cm, P = 0.020). Pathological analysis showed that type B tumours especially B2-B3 (B2 + B3 + mix B tumours, 55.2%) are more common in patients with MG, while type AB (37.2%) was the most common in patients without MG. A larger proportion of Masaoka III-IV stage tumour (25.7% vs 11.0%, P < 0.001) was seen in patients with thymoma and MG. Multivariable Cox regression analysis demonstrated that MG (hazard ratio [HR] = 3.729, 95% confidence interval [CI]: 1.398-9.947, P = 0.009), incomplete resection (HR = 5.441, 95% CI: 1.500-19.731, P = 0.010) and Masaoka stage III + IV (HR = 3.390, 95% CI: 1.196-9.612, P = 0.022) were negative prognostic factors of overall survival. Meanwhile, MG (HR =3.489, 95% CI: 1.403-8.680, P = 0.007) and Masaoka stage III + IV (HR = 6.582, 95% CI: 2.575-16.828, P < 0.001) were negative prognostic factors of recurrence-free survival. Propensity-matched analysis compared 148 patient pairs. K-M survival analysis demonstrated that MG was associated with worse overall survival and recurrence-free survival in propensity score-matched patients (log-rank, P = 0.034 and 0.017, respectively).

CONCLUSIONS

Thymoma patients with MG have smaller tumours and a higher percentage of late-stage tumours, which are mainly of WHO B types, especially B2-B3 types. In addition, MG is significantly associated with worse overall survival and recurrence-free survival in thymoma.

STAT3 activation in thymic epithelial tumors: correlation with cyclin D1, JAK3, and clinical behavior

OBJECTIVES

Thymic epithelial tumors are the most common adult mediastinal tumors; however, their growth mechanism remains relatively unknown. Among the JAK/STAT pathway-related proteins, which control various intracellular events, STAT3 is deeply involved in cell proliferation. Constitutive activation of STAT3 and the resulting overexpression of cyclin D1 have been confirmed in various tumors, but have not been thoroughly investigated in thymic epithelial tumors. In this study, we immunohistochemically examined STAT3 activation, cyclin D1 expression, and JAK3 activation in thymic epithelial tumors and statistically analyzed their correlation with clinicopathological features.

METHODS

Formalin-fixed paraffin-embedded specimens of 94 thymic epithelial tumors surgically resected at Kyorin University Hospital between 2005 and 2018 were included in this study. pSTAT3, cyclin D1, and pJAK3 were immunohistochemically examined, and the correlation with histology, Masaoka stage, and survival time was statistically analyzed.

RESULTS

Cyclin D1 was found to be significantly overexpressed in the STAT3-activated group. This phenomenon was associated with histology and Masaoka stage. JAK3 was also activated in thymic epithelial tumors; however, JAK3 and STAT3 activation were not always correlated. Using survival time analysis, the STAT3-activated group, cyclin D1-expressed group, and JAK3-activated group had significantly lower progression-free survival times than those for both the non-activated and non-expressed groups.

CONCLUSIONS

STAT3 activation may promote cyclin D1 overexpression in thymic epithelial tumors, and intracellular signaling pathways other than JAK3 may be involved in STAT3 activation. STAT3 activation, cyclin D1 overexpression, and JAK3 activation are biomarker candidates that indicate clinically poor prognosis.

Oncological resection, myasthenia gravis and staging as prognostic factors in thymic tumours: a Chilean case series

Background

Thymic epithelial tumours are rare and highly heterogeneous. Reports from the United States suggest an overall incidence of 0.15 per 100,000/year. In contrast, the incidence of these tumours in Latin America is largely unknown and reports are scarce, somewhat limited to case reports.

Methods

Herein, we report a series of 38 thymic tumours from a single institution, retrospectively incorporated into this study. Patient characteristics and outcomes including age, sex, stage, paraneoplastic syndromes, treatment regimens and the date of decease were obtained from medical records.

Results

Most cases in our series were females and young age (<50 years old) and early stage by Masaoka-Koga or the Moran staging systems. Also, a 34% of patients had myasthenia gravis (MG). Next, we analysed overall survival rates in our series and found that the quality of surgery (R0, R1 or R2), MG status and staging (Masaoka-Koga, Moran or TNM) were prognostic factors. Finally, we compared our data to larger thymic tumour series.

Conclusions

Overall, our study confirms complete surgical resection as the standard, most effective treatment for thymic epithelial tumours. Also, the Masaoka-Koga staging system remains as a reliable prognostic factor but also the Moran staging system should be considered for thymomas.

Epidemiology of thymic epithelial tumors: 22-years experience from a single-institution

Background

To assess the correlation of WHO histological classification and Masaoka–Koga staging system of thymic epithelial tumors (TETs) with prognosis.

Methods

We retrospectively analyzed 83 patients with TETs in the Instituto Nacional de Enfermedades Neoplasicas between 1996 to 2018. We analyzed the clinical stages, histological types and treatment modalities and attempted to determine the impact on overall survival. The data was retrieved from clinical files and reviewed by a pathologist who reclassificated according to the 2004 WHO classification system. The staging was performed with the Masaoka–Koga staging system. Survival curves were constructed with Kaplan‐Meir method.

Results

There was a total of 83 patients with a median age of 55 years old included in the study. The histological type corresponded to thymoma (T) in 63.8% (n = 53) and to thymic carcinoma (TC) in 36.1%. T were type A, AB, B1, B2 and B3 in 14.4%, 18%, 12%, 3.6%, 7.4% of cases, respectively. The proportion of advanced disease (Masaoka stage III–IV) was high (65%). With a median follow‐up of 88.4 months, median overall survival (OS) was 81.6 months for T and 12.3 months for TC (P = 0.01). Univariate analysis showed that sex, histological type, clinical stage and surgery (P = 0.01) were significant independent prognostic factors. On multivariate analysis, histology type and Masaoka–Koga staging had an effect on survival.

Conclusions

The results indicates a clear association between the WHO histological classification and Masaoka–Koga staging system with survival. We found a higher proportion of TETs with advanced disease at diagnosis. Further research are required and collaboration is important to foster knowledge focused on classification and treatment.

Key points

Significant findings of the study

The WHO histological classification, the Masaoka–Koga system and surgery treatment were associated with overall survival.

What this study adds

To determine prognosis factors in TETs.

Myasthenia Gravis Is Not an Independent Prognostic Factor of Thymoma: Results of a Propensity Score Matching Trial of 470 Patients

Objective

The association between the prognosis of thymoma and MG remains controversial. Differences in clinical characteristics and treatments between patients with and without MG may affect the findings of those studies. We designed this propensity score matching trial to investigate whether MG is an independent prognostic predictor in thymoma.

Methods

Patients with pathologically diagnosed thymoma and MG were enrolled in the MG group. Moreover, the propensity score matching method was used to select patients who were diagnosed with thymoma without MG from the database of two participating centers. Matched factors included sex, age, Masaoka stage, pathological subtypes, and treatments. Matched patients were enrolled in the non-MG group. Chi-squared test was used to compare the characteristics of the two groups. Overall survival, local-regional relapse-free survival, distant metastasis-free survival, progression-free survival, and cancer-specific survival were calculated from the diagnosis of thymoma using the Kaplan–Meier method.

Results

Between April 1992 and October 2018, 235 patients each were enrolled in the MG and non-MG groups (1:1 ratio). The median ages of patients in the MG and non-MG groups were 46 years old. The World Health Organization pathological subtypes were well balanced between the two groups (B2 + B3: MG vs. non-MG group, 63.0 vs. 63.4%, p = 0.924). Most patients in both groups had Masaoka stages I–III (MG vs. non-MG group, 90.2 vs. 91.5%, p = 0.631). R0 resections were performed in 86.8 and 90.2% of the MG and non-MG groups, respectively (p = 0.247). The median follow-up time of the two groups was 70.00 months (MG vs. non-MG group, 73.63 months vs. 68.00 months). Five-year overall survivals were 92.5 and 90.3%, 8-year overall survivals were 84.2 and 84.2%, and 10-year overall survivals were 80.2 and 81.4% (p = 0.632) in the MG and non-MG groups, respectively. No differences were found in the progression-free survival, distant metastasis-free survival, and local-regional relapse-free survival between the two groups.

Conclusion

MG is not an independent or direct prognostic factor of thymoma, although it might be helpful in diagnosis thymoma at an early stage, leading indirectly to better prognosis.

Video-assisted thoracoscopic surgery for myasthenia gravis with thymoma: A six-year single-center experience

OBJECTIVES

To investigate clinical and histopathological characteristics of Vietnamese patients with thymoma and myasthenia gravis (MG), and the outcomes of surgical management using video-assisted thoracoscopic surgery (VATS) thymectomy.

METHODS

A prospective study was carried out on 61 patients undergoing VATS thymectomy for MG class I, IIA with thymoma in the period from 10/2013 to 5/2019. The WHO histopathological classification, Masaoka's stages and MG grading using the guidelines of the Medical Scientific Advisory Board of the Myasthenia gravis foundation of America (MGFA) were used. All patients were followed up at 1 month, 6 months and over 1 year postoperatively.

RESULTS

The average patient age was 47.3 ± 10.8 years (21-70). The female/male ratio was 0.91.80.3% of patients had MG class IIA. Most of the patients were at Masaoka's stage I and stage II (75.4%). Only 1 patient (1.7%) had highly malignant type B3 thymoma. Conversion to open surgery was required in 8 patients. The surgical time was 91.8 ± 49.9 min and blood loss was 37.3 ± 31.5 ml. Most patients (68.9%) were extubated in the operating room. The postoperative hospital stay was 9.8 ± 5.9 days (5-37 days). 22.6% of patients relapsed after one-year. Refractory MG declined to 5.7% after surgical treatment.

CONCLUSION

VATS thymectomy for MG with thymoma was safe and effective, with a lower rate of intraoperative complications, shorter hospitalization, and better long-term outcomes. This approach could be applicable for patients of all age groups with thymomas at early Masaoka's stages.

18F-FDG-PET/CT predicts grade of malignancy and invasive potential of thymic epithelial tumors

PURPOSE

The aim of this study was to evaluate the ability of fluorine-18-fluorodeoxyglucose positron emission tomography coupled with computed tomography (18F-FDG-PET/CT) to predict the WHO malignancy grade, initial staging, and invasive potential of thymic epithelial tumors.

METHODS

We retrospectively reviewed the medical records of 56 patients with thymic epithelial tumors who were evaluated by PET/CT before surgery and underwent surgical resection. We analyzed the relationship of the maximum standardized uptake value (SUVmax) with the WHO histological classification, tumor invasion, TNM classification, and the Masaoka-Koga classification.

RESULTS

There were differences of SUVmax of the FDG-PET between thymic carcinoma (9.09 ± 3.34) and thymoma (4.86 ± 2.45; p < 0.01), thymic carcinoma (9.09 ± 3.34) and high-grade thymoma (6.01 ± 2.78; p < 0.01), and high-grade thymoma (6.01 ± 2.78) and low-grade thymoma (4.06 ± 1.86; p < 0.01). The cut-off value for the SUVmax was 7.40 and 5.40, and the sensitivity/specificity for predicting the histologic subtype of each group was 0.72/0.79 and 0.61/0.85, respectively. According to T classification, SUVmax was significantly higher in T3 (8.31 ± 2.57) than in T1a (4.45 ± 2.06; p < 0.01). Regarding Masaoka-Koga classification and WHO histological classification, a significantly higher SUVmax was detected in patients with stage III and IV disease than in those with stage I and II diseases (p < 0.01). The cut-off value for SUVmax was 5.40 in Masaoka-Koga stage and 5.60 in the WHO classification; the sensitivity/specificity for predicting the histologic subtype was 0.85/0.80 and 0.89/0.78, respectively.

CONCLUSIONS

FDG-PET is a useful tool to predict aggressiveness of thymic epithelial tumors.

Development of a deep learning model for classifying thymoma as Masaoka-Koga stage I or II via preoperative CT images

Background

Accurate thymoma staging via computed tomography (CT) images is difficult even for experienced thoracic doctors. Here we developed a preoperative staging tool differentiating Masaoka-Koga (MK) stage I patients from stage II patients using CT images.

Methods

CT images of 174 thymoma patients were retrospectively selected. Two chest radiologists independently assessed the images. Variables with statistical differences in univariate analysis were adjusted for age, sex, and smoking history in multivariate logical regression to determine independent predictors of the thymoma stage. We established a deep learning (DL) 3D-DenseNet model to distinguish the MK stage I and stage II thymomas. Furthermore, we compared two different methods to label the regions of interest (ROI) in CT images.

Results

In routine CT images, there were statistical differences (P<0.05) in contour, necrosis, cystic components, and the degree of enhancement between stage I and II disease. Multivariate logical regression showed that only the degree of enhancement was an independent predictor of the thymoma stage. The area under the receiver operating characteristic curve (AUC) of routine CT images for classifying thymoma as MK stage I or II was low (AUC =0.639). The AUC of the 3D-DenseNet model showed better performance with a higher AUC (0.773). ROIs outlined by segmentation labels performed better (AUC =0.773) than those outlined by bounding box labels (AUC =0.722).

Conclusions

Our DL 3D-DenseNet may aid thymoma stage classification, which may ultimately guide surgical treatment and improve outcomes. Compared with conventional methods, this approach provides improved staging accuracy. Moreover, ROIs labeled by segmentation is more recommendable when the sample size is limited.

Clinical prognostic scores for patients with thymic epithelial tumors

Several inflammation-based prognostic scores emerged in various types of cancer to predict clinical outcomes. So far, no accurate pre-treatment scoring systems exist for patients with thymic epithelial tumors (TETs), comprising thymomas and thymic carcinomas (TCs). Therefore, we sought to test the prognostic value of different clinical composite scores and their components, identify optimal cut-off values for TETs as well as combine predictive components to new suitable prognostic scores. One hundred eighty-four patients with TETs undergoing surgical tumor resection were analyzed. A significant advantage in Freedom-from-Recurrence and/or Cause-specific survival (CSS) was evident for patients with high Advanced-Lung- Cancer-Inflammation-Index, low CRP-Fibrinogen-Score (CFS), low Glasgow-Prognostic-Score (GPS), low high-sensitivity-modified GPS, low TET-adapted GPS (TET-aGPS) and low Systemic-Immune-Inflammation Index. On multivariable analysis high TET-aGPS (HR = 14.9;p = 0.001), incomplete resection status (HR = 13.5;p = 0.001) and TC (HR = 26.0;p = 0.001) were significant independent prognostic factors for worse CSS. The CFS had the highest coefficient of determination (R² = 0.188) to predict tumor recurrence of all composite scores, comprising CRP (R² = 0.141) and fibrinogen (R² = 0.158), the best single factor predictors. Inflammation-based prognostic scores and selected components are suitable to predict survival and/or tumor recurrence in TET patients undergoing primary surgery. Due to excellent long-term survival and frequent tumor recurrence, cut-off values were tailored to increase prognostic power.

A systematic review of paraneoplastic syndromes associated with thymoma: Treatment modalities, recurrence, and outcomes in resected cases

OBJECTIVE

Paraneoplastic syndromes associated with thymomas remain incompletely understood. The objective was to examine the association between surgically resected thymomas and paraneoplastic syndromes over the past half century.

METHODS

A primary PubMed/MEDLINE search was used to identify published articles describing paraneoplastic syndromes associated with thymomas from 1960 to 2019. A secondary search identified additional articles referenced in the articles found in the primary search. Kaplan-Meier and log-rank test were used for time-to-event data analyses.

RESULTS

From 407 articles describing 507 patients, 123 different paraneoplastic syndromes were associated with thymoma. The 5 most common paraneoplastic syndromes were myasthenia gravis, pure red cell aplasia, lichen planus, Good syndrome, and limbic encephalitis. Complete or partial resolution of paraneoplastic syndrome symptoms after surgery was noted in 76% of patients, of whom 21% had a relapse or new paraneoplastic syndrome onset after surgery. The most common adjunctive therapy associated with resolution of paraneoplastic syndrome was corticosteroids (30%). For all patients after surgery, thymoma recurrence was observed in 17% of cases, whereas recurrence of paraneoplastic syndrome was observed in 34% of cases, and both were observed in approximately 11% of cases. The 5- and 10-year overall survivals were 78% and 66%, respectively. Improved overall survival was associated with patients who had total resolution from paraneoplastic syndrome.

CONCLUSIONS

A comprehensive assessment of publications over the past half century suggests that a multimodal treatment approach that includes surgical resection of thymomas is able to achieve paraneoplastic syndrome resolution in a majority of patients. Onset of new paraneoplastic syndromes after surgery is associated with the recurrence of the first paraneoplastic syndrome, and resolution of paraneoplastic syndrome is associated with improved overall survival.

Radiofrequency in the treatment of primary hyperhidrosis: systematic review and meta-analysis

PURPOSE

To evaluate, via a systematic review, the effectiveness of radiofrequency (RF) for treatment of primary hyperhidrosis (PH).

METHODS

Experimental or observational studies were included where RF treatment (ablation or microneedling) was performed, comparing the periods before and after treatment.

RESULTS

Nine studies were considered eligible and included for analysis. In seven of nine studies, patients were subjected to RF only, and in two of nine studies RF was compared to video-assisted thoracoscopic sympathectomy (VATS). There was a reduction in the severity of PH in microneedling (three studies, mean difference -1.24, 95% CI -1.44 to -1.03). In a study that performed sympathetic RF ablation there was a greater reduction in PH severity compared to studies that performed microneedling (-2.42, 95% CI -2.55 to -2.29). There was improvement in the quality of life (QoL) after sympathetic RF ablation (two studies, mean difference -15.92, 95% CI -17.61 to -14.24). Regarding the microneedling procedure, there was a lower improvement in QoL, (two studies, -9.0, 95% CI -9.15 to -8.85). One study comparing sympathetic RF ablation with VATS applied the QoL questionnaire, and the VATS showed superior results. One of the two studies comparing compensatory sweating in RF ablation with VATS showed that compensatory hyperhidrosis was higher in VATS; however, the other study did not observe this difference. One study compared the recurrence of symptoms between VATS and RF ablation; symptom recurrence was shown to be higher in RF.

CONCLUSIONS

RF is effective for PH treatment, with superior results obtained with sympathetic ablation compared to microneedling.

Incidence and clinical variable inter-relationships of thymic epithelial tumors in northwest China

Background

Thymic epithelial tumors (TETs) are the most common primary thymus tumors, but neither the possible ethnical/regional differences in the incidence of TETs nor the inter-relationships among the clinical variables has been revealed in northwest China.

Methods

A retrospective chart review was performed among pathologically confirmed TET patients from January 2004 to December 2015 in a tertiary general hospital of northwest China and the incidence, clinical features and the inter-relationships among clinical variables were analyzed.

Results

A total of 603 pathologically confirmed TETs patients (age range, 5-78 years; 308 males) were enrolled and the most common lesion location was anterior mediastinum (98.5%), among them, 192 (31.8%) had myasthenia gravis (MG). Twenty-six (5.7%), 112 (24.6%), 83 (18.2%), 137 (30.1%), 74 (16.3%), and 23 (5.1%) patients fell into the World Health Organization (WHO) type A, AB, B1, B2, B3 and thymic carcinoma (TC), respectively. The incidence of TETs was slightly higher in the female population and the age group of 40-60 years old. In addition, MG predominantly coexisted with WHO types A-B3 TETs and the TETs with MG were smaller than those without MG. The correct diagnosis rates were 42.3% (77 out of 182), 61.1% (127 out of 208), 89.3% (250 out of 280) and 75.0% (3 out of 4) for chest X-ray, non-contrast computed tomography (CT), contrast CT scan and magnetic resonance imaging (MRI), respectively.

Conclusions

Distinct gender and age differences exist in the incidence of TETs and the A-B3 TETs are closely related with MG. Contrast CT scan plays more important role in diagnosing TETs.

[Clinical Study on the Prognosis of Patients with Thymoma with Myasthenia Gravis]

背景与目的

胸腺瘤常伴发重症肌无力（myasthenia gravis, MG），但是这些患者行胸腺切除的预后与MG的关系尚不明确。本研究旨在探讨影响胸腺瘤合并MG患者预后的因素。

方法

回顾性分析中国胸腺瘤协作组（Chinese Alliance for Research of Thymoma, ChART）数据库1992年-2012年875例随访20年资料完整的胸腺瘤病例，分析世界卫生组织（World Health Organization, WHO）组织学分型、Masaoka分期、术后辅助治疗与MG及预后的关系。

结果

胸腺瘤WHO组织学分型与MG有相关性，差异有统计学意义（χ²=24.908, P < 0.001）。MG发生率为22.7%，其中B2型（58/178, 32.58%） > B3型（65/239, 27.20%） > B1型（27/132, 20.45%） > AB型（43/267, 16.10%） > A型（6/59, 10.17%），Masaoka分期与MG无相关性（χ²=1.365, P=0.714）。生存分析表明WHO分型、Masaoka分期与预后有关（P < 0.05），而是否合并MG（χ²=0.113, P=0.736）、是否行胸腺扩大切除（χ²=1.548, P=0.213）、术后辅助放疗（χ²=0.380, P=0.538）与预后无相关，术后辅助化疗与差的预后相关（χ²=14.417, P < 0.001）。是否行胸腺扩大切除与MG的疗效有相关性（χ²=24.695, P < 0.001）。

结论

胸腺瘤患者是否合并MG和是否行胸腺扩大切除与预后无相关性，胸腺扩大切除可改善MG患者的疗效。

Surgical therapy of thymic tumours with pleural involvement: an ESTS Thymic Working Group Project

OBJECTIVES: Surgery for thymic epithelial tumours (TETs) with pleural involvement is infrequently performed. Thus, the value of surgical therapy for primary or recurrent TETs with pleural involvement is not sufficiently defined yet.

METHODS: Twelve institutions contributed retrospective data on 152 patients undergoing surgery (1977–2014) on behalf of the ESTS Thymic Working group. Outcome measures included overall (OS), cause-specific (CSS) and disease-free (DFS) survival as well as freedom from recurrence (FFR).

RESULTS: In 70.4% of cases, pleural involvement was present at the time of primary intervention, whereas 29.6% had surgery for recurrent disease involving the pleura. Pleural involvement resulted from thymomas (88.8%) and thymic carcinomas (11.2%). Forty extrapleural pneumonectomies (EPPs), 23 total pleurectomies (TPs), and 88 local pleurectomies (LPs) were performed (completeness of resection in 76.8%). OS for the entire patient population at 1, 3, 5 and 10 years was 96.4%, 91.0%, 87.2% and 62.7%, respectively. There was no statistically significant difference regarding FFR and OS for patients with local or advanced disease undergoing EPP, TP or LP. Thymic carcinomas in comparison with thymomas had a negative impact on OS [hazard ratio 6.506, P = 0.002], CSS and FFR. Incomplete resections predicted worse OS [hazard ratio 6.696, P = 0.003].

CONCLUSIONS: Complete resection remains the mainstay of treatment for TETs with pleural involvement. Study populations treated with EPP, TP and LP had similar survival that may be factual as observed, but in the presence of selection bias, we can further conclude from the results that EPP, TP and LP are equally effective procedures. Procedural choice depends upon the extent of tumour distribution. EPPs, TPs and LPs performed within a multimodality setting seem to be efficient procedures for local control of disease, as they yield excellent results regarding OS, DFS, CSS and FFR.

Inter-relationship among myasthenia gravis, WHO histology, and Masaoka clinical stage and effect on surgical methods in patients with thymoma: a retrospective cohort study

Background

The aim of study is to analyze the inter-relationship among WHO histology, myasthenia gravis (MG) and Masaoka stage and to assess the feasibility of thoracoscopic surgery in thymoma patients.

Methods

Data from 142 consecutive thymoma patients from January 2009 to March 2016 were retrospectively reviewed in our institution. Histological classification and clinical staging were assessed by WHO histology criteria and Masaoka stage. We investigated the clinical characteristics, inter-relationship among WHO histology, MG and Masaoka stage, and compared the feasibility and safety of thoracoscopic thymectomy by comparison of open thymectomy.

Results

Among 142 patients, the incidence of MG was 29.6%. Compared with A and AB-type thymomas, a higher prevalence of advance clinical stage was in B1 to C-type thymomas (37/63 vs. 9/43, P<0.001), and there was an increased trend of Masaoka stage from A to C-type thymomas (P<0.001). The incidence of MG was significantly higher in AB, B1 and B2-type thymomas than other type thymomas (23/63 vs. 6/44, P=0.009) and in early Masaoka clinical stage than advanced Masaoka clinical stage (29/80 vs. 12/59, P=0.042). Thoracoscopic surgery could significantly decrease blood loss in patients with (104.06±137.36 vs. 350.91±560.79 mL, P=0.001) or without MG (91.90±77.70 vs. 266.32±292.60 mL, P=0.02), with comparable complications. Additionally, thoracoscopic surgery could achieve an equal effect on the remission of MG with open surgery (7/11 vs. 10/14, P=1.000), and Masaoka stage was significantly associated with the remission of MG after thymectomy.

Conclusions

Our study suggests that WHO histology, MG, and Masaoka stage interrelate with one another, and Masaoka stage is an important prognostic factor in remission of MG after thymectomy in thymoma patients. Thoracoscopic thymectomy could achieve an equal efficacy to open thymectomy and should be recommended as a routine surgery for patients with early Masaoka stage.

Giant thymoma successfully resected via median sternotomy and anterolateral thoracotomy: a case report

Background

Some patients with thymoma present with a very large mass in the thoracic cavity. Although the most effective treatment for thymoma is surgical resection, it is difficult to perform because of the size of the tumor and the infiltration of tumor into the surrounding organs and vessels. We report a patient with a giant thymoma that was completely resected via a median sternotomy and left anterolateral thoracotomy.

Case presentation

A 63-year-old woman presented with a mass in the left thoracic cavity that was incidentally found on a chest X-ray. Chest computed tomography revealed a giant mass (16 × 10 cm) touching the chest wall and diaphragm and pressed against the heart and left upper pulmonary lobe. Complete resection was performed via a median sternotomy and left anterolateral thoracotomy. The tumor was histologically diagnosed as a WHO type B2 thymoma, Masaoka stage II.

Conclusions

Giant thymomas tend to grow expansively without invasion into surrounding organs and vessels. Surgical resection that employs an adequate approach must be considered, regardless of the size of the tumor.

Sclerosing thymoma: A rare case report and brief review of literature

RATIONALE

Sclerosing thymoma is an extremely rare mediastinal neoplasm; it was recognized for the first time in 1994 and to date only 15 cases have been reported.

PATIENT CONCERNS

The present study report a case of a 65-year-old man who was incidentally found to have an anterior mediastinal nodule, without clinical symptoms including fever, chest pain, and myasthenia gravis.

DIAGNOSES

The chest computed tomography (CT) revealed the nodule was 4.9 × 4.2 × 3.0 cm in size. And the microscopic and immunohistochemical findings indicated that the final diagnosis was sclerosing thymoma.

INTERVENTIONS

The anterior mediastinal nodule was completely removed.

OUTCOMES

No evidence of recurrence or complication was found in the second year after surgery.

LESSONS

The biologic behavior of the rare sclerosing thymoma is still largely mysterious; it is utmost importance to classify the sclerosing thymoma from other mediastinal tumors. Its prognosis is favorable and thymectomy is currently the mainstay of treatment.

[Postoperative Survival for Patients with Thymoma Complicating Myasthenia Gravis - Preliminary Retrospective Results of the ChART Database]

BACKGROUND

It is so far not clear that how myasthenia gravis (MG) affected the prognosis of thymoma patients. The aim of this assay is to compare the postoperative survival between patients with thymoma only and those with both thymoma and MG.

METHODS

The Chinese Alliance for Research in Thymomas (ChART) registry recruited patients with thymoma from 18 centers over the country on an intention to treat basis from 1992 to 2012. Two groups were formed according to whether the patient complicated MG. Demographic and clinical data were reviewed, Patients were followed and their survival status were analyzed.

RESULTS

There were 1,850 patients included in this study, including 421 with and 1,429 without MG. Complete thymectomy were done in 91.2% patients in MG group and 71.0% in non-MG group (P<0.05). There were more percentage of patients with the histology of thymoma AB, B1, or B2 (P<0.05) in MG group, and more percentage of patients with MG were in Masaoka stage I and II. The 5 year and 10 year OS rates were both higher in MG group (93% vs 88%; 83% vs 81%, P=0.034) respectively. The survival rate was significantly higher in patients with MG when the Masaoka staging was III/IV (P=0.003). Among patients with advanced stage thymoma (stage III, IVa, IVb), the constituent ratios of III, IVa, IVb were similar between MG and Non-MG group. Histologically, however, there were significantly more proportion of AB/B1/B2/B3 in the MG group while there were more C in the non-MG group (P=0.000). Univariate analyses for all patients showed that MG, WHO classification, Masaoka stage, surgical approach, chemotherapy and radiotherapy and resectability were significant factors, and multivariate analysis showed WHO Classification, Masaoka stage, and resectability were strong independent prognostic indicators.

CONCLUSIONS

Although MG is not an independent prognostic factor, the survival of patients with thymoma was superior when MG was present, especially in late Masaoka stage patients. Possible reasons included early diagnosis of the tumor, better histologic types, an overall higher R0 resection and less recurrence.
.

Evolution of Classification of Thymic Epithelial Tumors in the Era of Dr Thomas V. Colby

CONTEXT

-Numerous histomorphologic and staging classifications of thymic epithelial tumors (TETs) have been proposed during the last century, suggesting that the classification of these tumors is challenging and controversial. Difficulties of classifying TETs include various combinations of epithelial cells and lymphocytes and the paucity of these tumors. The prognostic significance, specifically of the histomorphologic classifications, has been debated. Early classifications were also challenged by the uncertainty of the neoplastic component(s) of the tumor.

OBJECTIVE

-To discuss the evolution of the histomorphologic classification and the staging system of TET. Controversies and problems of some classifications and their importance for therapeutic management and prognosis will be reviewed. Classifications that incorporated new concepts and approaches at the time or outcome studies will be highlighted. Current classifications will be discussed and the staging system that was recently proposed for the upcoming eighth American Joint Committee on Cancer staging will be described.

DATA SOURCES

-Search of literature database (PubMed) and current (2015) World Health Organization classification.

CONCLUSIONS

-Histomorphologic and staging classifications of TET have evolved during the last century and especially during the era of Thomas V. Colby, MD. Evidence supports that the staging system has prognostic implications independent of and superior to the histomorphologic classification. Histomorphology appears to be important for biologic features of TET.

Efficacy of computed tomography features in predicting stage III thymic tumors

Accurate assessment of the invasion of intrathoracic structures by stage III thymic tumors assists their appropriate management. The present study aimed to evaluate the efficacy of computed tomography (CT) features for the prediction of stage III thymoma invasion. The pre-operative CT images of 66 patients with confirmed stage III thymic tumors were reviewed retrospectively. The CT features of invasion into the mediastinal pleura, lungs, pericardium and great vessels were analyzed, and their sensitivity, specificity, positive predictive value (PPV), negative predictive value and accuracy were calculated. For mediastinal pleural and pericardial invasion, an absence of space between the tumor and the mediastinal pleura/pericardium with mediastinal pleural/pericardial thickening and pleural/pericardial effusion exhibited a specificity and PPV of 100%, respectively. For lung invasion, a multi-lobular tumor convex to the lung with adjacent lung abnormalities exhibited a specificity and PPV of 91.2 and 81.3%, respectively. For vessel invasion, the specificity and PPV were each 100% for tumors abutting ≥50% of the vessel circumference, and for tumor oppression, deformation and occlusion of the vessel. In conclusion, recognition of the appropriate CT features can serve as a guide to invasion by stage III thymic tumors, and can facilitate the selection of appropriate pre-operative treatment.

Invasive atypical thymic carcinoid: three case reports and literature review

Atypical thymic carcinoid is an extremely rare thymic neuroendocrine tumor derived from the neuroendocrine system. The aims of this paper were to investigate the clinical features of atypical thymic carcinoid and collate information and experience to improve the diagnosis and treatment of this disease. We describe three cases of atypical carcinoid of the thymus; clinical features, pathological data, treatment modalities, and short-term patient outcomes were summarized and analyzed. The initial clinical symptoms and signs of all three patients were nonspecific and an anterior mediastinal mass was found in each patient on chest computed tomography scan. All three patients underwent surgical resection (total thymectomy and complete excision of the tumor), followed by postoperative radiotherapy, with or without chemotherapy. The diagnoses of three patients were confirmed by pathological and immunohistochemical evaluation. We also present a review of the literature to collate as much information as possible and provide a reference for proper diagnosis and treatment of atypical thyroid carcinoid.

Preoperative misdiagnosis analysis and accurate distinguish intrathymic cyst from small thymoma on computed tomography

BACKGROUND

To evaluate the role of computed tomography (CT) in preoperative diagnosis of intrathymic cyst and small thymoma, and determine the best CT threshold for distinguish intrathymic cyst from small thymoma.

METHODS

We retrospectively reviewed the medical records of 30 patients (17 intrathymic cyst and 13 small thymoma) who had undergone mediastinal masses resection (with diameter less than 3 cm) under thoracoscope between January 2014 and July 2015 at our hospital. Clinical and CT features were compared and receiver-operating characteristics curve (ROC) analysis was performed.

RESULTS

The CT value of small thymoma [39.5 HU (IQR, 33.7-42.2 HU)] was significantly higher than intrathymic cyst [25.8 HU (IQR, 22.3-29.3 HU), P=0.004]. When CT value was 31.2 HU, it could act as a threshold for identification of small thymoma and intrathymic cyst (the sensitivity and specificity was 92.3% and 82.4%, respectively). The ΔCT value of enhanced CT value with the non-enhanced CT value was significantly different between small thymoma [18.7 HU (IQR, 10.9-19.0 HU)] and intrathymic cyst [4.3 HU (IQR, 3.0-11.7 HU), P=0.04]. The density was more homogenous in intrathymic cyst than small thymoma, and the contour of the intrathymic cyst was more smoothly than small thymoma.

CONCLUSIONS

Preoperative CT scans could help clinicians to identify intrathymic cyst and small thymoma, and we recommend 31.2 HU as the best thresholds. Contrast-enhanced CT scans is useful for further identification of the two diseases.

Thymic carcinoma with myasthenia gravis: Two case reports

•

Myasthenia gravis (MG) has been reported to correlate with earlier-stage thymoma and theoretically does not accompany thymic carcinoma.

•

We encountered two cases of thymic carcinoma with MG.

•

Very few reports have described MG associated with thymic carcinoma.

Introduction

Myasthenia gravis (MG) has been reported to correlate with earlier-stage thymoma, and theoretically does not accompany thymic carcinoma. However, we encountered two cases of thymic carcinoma with MG.

Presentation of cases

Case 1 involved a 54-year-old man who had been diagnosed with MG based on symptoms and detection of anti-acetylcholine receptor antibody (ARAB). Computed tomography (CT) revealed an anterior mediastinal tumor 30 mm in diameter. Prednisolone (PSL) and tacrolimus were administered without surgery at that time. Six years after diagnosis of MG, he was admitted to our hospital and underwent extended thymectomy. Pathological examination revealed type B2-B3 thymoma according to World Health Organization criteria, comprising 80% of the tumor with small cell carcinoma as 20%. Case 2 involved a 51-year-old woman. She had been diagnosed with MG based on eyelid ptosis and detection of ARAB. Ten years after diagnosis of MG, diaphragm elevation was detected on chest X-ray. CT revealed an anterior mediastinal tumor, 47 mm in diameter. We suspected tumor invasion to the right phrenic nerve, right atrium, and superior vena cava. We therefore performed extended thymectomy after preoperative radiotherapy (40 Gy). Pathological examination revealed squamous cell carcinoma.

Discussion

Most cases of thymic carcinomas appear to arise de novo, but appearance in thymomas has been described. In both our cases, MG was treated with pharmacotherapy alone without extended thymectomy, and thymic carcinoma was considered to have developed from the thymoma during long-term follow-up.

Conclusion

Thymic carcinoma can accompany MG.

Postoperative survival for patients with thymoma complicating myasthenia gravis-preliminary retrospective results of the ChART database

BACKGROUND

It is so far not clear that how myasthenia gravis (MG) affected the prognosis of thymoma patients. The aim of this assay is to compare the postoperative survival between patients with thymoma only and those with both thymoma and MG.

METHODS

The Chinese Alliance for Research in Thymomas (ChART) registry recruited patients with thymoma from 18 centers over the country on an intention to treat basis from 1992 to 2012. Two groups were formed according to whether the patient complicated MG. Demographic and clinical data were reviewed, patients were followed and their survival status were analyzed.

RESULTS

There were 1,850 patients included in this study, including 421 with and 1,429 without MG. Complete thymectomy were done in 91.2% patients in MG group and 71.0% in non-MG group (P<0.05). There were more percentage of patients with the histology of thymoma AB, B1, or B2 (P<0.05) in MG group, and more percentage of patients with MG were in Masaoka stage I and II. The 5- and 10-year overall survival (OS) rates were both higher in MG group (93% vs. 88%; 83% vs. 81%, P=0.034) respectively. The survival rate was significantly higher in patients with MG when the Masaoka staging was 3/4 (P=0.003). Among patients with advanced stage thymoma (stage 3, 4a, 4b), the constituent ratios of 3, 4a, 4b were similar between MG and non-MG group. Histologically, however, there were significantly more proportion of AB/B1/B2/B3 in the MG group while there were more C in the non-MG group (P=0.000). Univariate analyses for all patients showed that MG, WHO classification, Masaoka stage, surgical approach, chemotherapy and radiotherapy and resectability were significant factors, and multivariate analysis showed WHO classification, Masaoka stage, and resectability were strong independent prognostic indicators.

CONCLUSIONS

Although MG is not an independent prognostic factor, the survival of patients with thymoma was superior when MG was present, especially in late Masaoka stage patients. Possible reasons included early diagnosis of the tumor, better histologic types, an overall higher R0 resection and less recurrence.

Modified Masaoka stage and size are independent prognostic predictors in thymoma and modified Masaoka stage is superior to histopathologic classifications

INTRODUCTION

The prognostic value of histopathologic classifications of thymoma is debated. Problematic reproducibility might cause this controversy. We studied the prognostic significance of three histopathologic classifications of thymomas after three thoracic pathologists agreed upon thymoma subtype and invasion. We also compared the outcome to established prognostic parameters.

METHODS

Patients, surgically treated for thymic epithelial neoplasm at Mayo Clinic (1942-2008), were staged according to the modified Masaoka staging and the recently proposed staging by Moran. Three thoracic pathologists independently classified all cases according to the World Health Organization, Bernatz, and proposed Suster and Moran classification. Only thymoma that all three pathologists diagnosed as the same histopathologic subtype and extent of invasion were included in outcome analysis.

RESULTS

In 214 (proposed Suster and Moran classification), 145 (World Health Organization classification), and 120 cases (Bernatz classification), reviewers agreed upon subtype of thymoma and invasion and follow-up was available. Median follow-up time was 7.5-7.7 years (range between classifications). All histopathologic classifications were associated with overall survival (OS) and disease-free survival (p ≤ 0.0001 to p = 0.048); only Bernatz classification was independent of modified Masaoka staging associated with OS (p = 0.04). Modified Masaoka stage predicted outcome independent of all histopathologic classifications and resection status and strongly correlated with the proposed Moran stage (correlation coefficient, 0.95). Thymoma size and age were prognostic parameters for OS independent of any histopathologic classification.

CONCLUSIONS

Histopathologic classifications of thymomas are associated with prognosis but are in general not independent predictors of outcome. Modified Masaoka stage and proposed Moran staging are independent prognostic parameters for thymoma and superior to histopathologic classifications.

Pathologic Finding of Thymic Carcinoma Accompanied by Myasthenia Gravis

Background and Purpose

The World Health Organization (WHO) has classified thymic carcinoma and other thymomas (types A, AB, and B) as different neoplasms. Myasthenia gravis (MG) is an early sign of thymoma and theoretically does not accompany thymic carcinoma; however, cases of thymic carcinoma with MG have been reported. Whether thymic carcinoma can accompany MG has yet to be established.

Methods

The medical records of patients who underwent thymectomy for MG between 1990 and 2011 in a single hospital were reviewed. All cases with the diagnostic code of "thymic carcinoma" or "thymoma type C" (old terminology) were selected. A pathologist re-reviewed the pathologic specimens using the new WHO criteria. The rate of thymic carcinoma among these MG patients was then calculated.

Results

A total of 81 patients with MG had thymic tumors, 10 of whom had thymic carcinomas or thymoma type C. Seven cases of well-differentiated thymic carcinomas (type B3) were excluded, leaving three (3.7%) cases of thymic carcinoma with MG. All three of these cases were type B3 thymoma with a focal squamous cell carcinoma component that was very small and well demarcated. In addition, two out of the three tumors were found to be at an early clinical stage. All of the cases survived without recurrence over follow-up periods of at least 5 years.

Conclusions

Thymic carcinoma transformation from thymoma can occur during the early stages of thymoma. The association of this condition with MG is not as rare as was previously thought. Thymic carcinomas accompanying MG had a predominant B3 thymoma component with a focal thymic carcinoma area (squamous cell carcinoma).

Value of Computerized 3D Shape Analysis in Differentiating Encapsulated from Invasive Thymomas

Objectives

To retrospectively investigate the added value of quantitative 3D shape analysis in differentiating encapsulated from invasive thymomas.

Materials and Methods

From February 2002 to October 2013, 53 patients (25 men and 28 women; mean age, 53.94 ± 13.13 years) with 53 pathologically-confirmed thymomas underwent preoperative chest CT scans (slice thicknesses ≤ 2.5 mm). Twenty-three tumors were encapsulated thymomas and 30 were invasive thymomas. Their clinical and CT characteristics were evaluated. In addition, each thymoma was manually-segmented from surrounding structures, and their 3D shape features were assessed using an in-house developed software program. To evaluate the added value of 3D shape features in differentiating encapsulated from invasive thymomas, logistic regression analysis and receiver-operating characteristics curve (ROC) analysis were performed.

Results

Significant differences were observed between encapsulated and invasive thymomas, in terms of cystic changes (p=0.004), sphericity (p=0.016), and discrete compactness (p=0.001). Subsequent binary logistic regression analysis revealed that absence of cystic change (adjusted odds ratio (OR) = 6.636; p=0.015) and higher discrete compactness (OR = 77.775; p=0.012) were significant differentiators of encapsulated from invasive thymomas. ROC analyses revealed that the addition of 3D shape analysis to clinical and CT features (AUC, 0.955; 95% CI, 0.935–0.975) provided significantly higher performance in differentiating encapsulated from invasive thymomas than clinical and CT features (AUC, 0.666; 95% CI, 0.626–0.707) (p<0.001).

Conclusion

Addition of 3D shape analysis, particularly discrete compactness, can improve differentiation of encapsulated thymomas from invasive thymomas.