Genomic analysis and biomarker discovery of thymic cancer based on whole exome sequencing: A retrospective cohort study / 中国胸心血管外科临床杂志

@#Objective To examined gene mutations in thymic carcinoma (TC) patients and to explore prognostic correlates and potential targets for therapy. Methods We retrospectively included TC patients in Sichuan Cancer Hospital between January 2015 and Febuary 2021.Whole-exome sequencing was performed on tumor tissues from TC patients and their control peripheral blood samples, and the raw data were subjected to bioinformatics analysis and statistical analysis. Results We finally included 24 TC patients with 16 males and 8 females at a median age of 55 (42-74) years. The highest frequency of single nucleotide mutations in this cohort were in the TTN gene (42%), HSPG2 (29%), and OBSCN (29%). Higher frequency of copy number variations occurred in ZNF276 gene (54%, loss), BEND3 (50%, loss), DHODH (50%, loss), and VAC14 (50%, loss). Microsatellite instability (MSI) phenotype was found in 25% of the patients, and the mean tumor mutation burden (TMB) was 9.86. Conclusion This study is the first comprehensive analysis of the mutation profile of thymic carcinoma in China to date. The mutation frequencies of TTN, OBSCN, and ZNF276 genes were high. The biomarker analysis suggests that patients may benefit from immunotherapy and have a long effective survival.

Interpretation of NCCN guidelines version 1. 2023 thymomas and thymic carcinomas / 中国胸心血管外科临床杂志

@#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.

Clinical characteristics of intrathyroidal thymic carcinoma / 中华内分泌外科杂志

In this paper, the clinical case, pathological and immunohistochemical analyses were performed on 10 patients with intrathyroidal thymic carcinoma admitted to our hospital.Combined with relevant literature, it was found that tumour cells expressing CD5 and CD117 had differential diagnostic significance. Surgical resection of the tumour was the first choice for treatment, whether radiotherapy, chemotherapy and monotherapy were administered remained controversial.

Clinicopathological Features of Intrathyroid Thymic Carcinoma / 中国医学科学院学报

Objective To investigate the clinicopathological features,immunohistochemical characteristics,diagnosis,treatment and prognosis of intrathyroid thymic carcinoma.Methods Clinical data of 7 patients with intrathyroid thymic carcinoma were retrospectively reviewed.Histological examination and immunohistochemical staining were performed on the surgically resected tumors.The infection of Epstein-Barr virus(EBV)was detected by EBER in situ hybridization.Results The 7 patients included 5 males and 2 females.The age ranged from 40 to 71 years,with a median of 54 years.The tumors were located in the thyroid gland,with the maximum diameter ranging from 2.2 cm to 6.0 cm and the average maximum diameter of(4.0±1.2)cm.All the patients underwent thyroid gland resection and local lymph node dissection.After operation,all the cases were treated with radiotherapy and five of them additionally received chemotherapy.Six patients were followed up for 10-163 months,all of whom were still alive,including 2 patients with recurrence in situ,1 patient with homolateral cervical lymph node metastasis and the rest with no recurrence or metastasis.CK-pan,P63,CD5 and CD117 were expressed in all the cases,while TTF-1,TG,CT and PAX8 were negative.One case of them expressed SYN and CgA.Ki-67 proliferation index ranged from 10% to 90%.EBER in situ hybridization showed negative results in all 7 cases.Conclusions Intrathyroid thymic carcinoma is a relatively low-grade malignant tumor.The combination of immunohistochemical CD5,CD117 and monoclonal PAX8 is helpful in the diagnosis and differential diagnosis of intrathyroid thymic carcinoma.EBV may not be involved in the development of intrathyroid thymic carcinoma.Thyroid gland resection plus central lymph node dissection is an important treatment measure for intrathyroid thymic carcinoma.For patients with regional lymph node metastasis and obvious peripheral tissue invasion,postoperative radiotherapy with/without chemotherapy can effectively delay the disease progression.

Different Energy Spectrum CT Findings between Anterior Mediastinal Lymphoma and Thymic Carcinoma / 中国医学科学院学报

To investigate the differences in energy spectrum CT findings between anterior mediastinal lymphoma and thymic carcinoma. Twenty-two cases of anterior mediastinal lymphoma and 28 cases of thymic carcinoma confirmed by biopsy in Tangshan People's Hospital were selected.The CT values and changes of iodine content and water content in lesion sites were measured by energy spectrum analysis software.The differences between anterior mediastinal lymphoma and thymic carcinoma were compared. The single-energy CT value of 40-80 keV in thymus carcinoma was higher than that in anterior mediastinal lymphoma(=0.001,=0.037,=0.042,=0.034,=0.002;=0.016,=0.013,=0.018,=0.024,=0.012).The difference in the single-energy CT value of 90-110 keV between anterior mediastinal lymphoma and thymic carcinoma showed no statistical significance(all >0.05).The concentrations of water in the arterial and venous stages of thymic carcinoma were significantly lower than those in the anterior mediastinal lymphoma(=0.030,=0.037),whereas the iodine concentrations were significantly higher(=0.026,=0.000). Anterior mediastinal lymphoma and thymic carcinoma have remarkably different 40-80 keV single energy CT value and iodine concentration in arterial and venous phases,which may be helpful for the differential diagnosis of these two malignancies.

Tumores del timo: Experiencia del Instituto Nacional de Cancerología de Colombia / Thymic tumors: Experience of the National Cancer Institute of Colombia

Resumen Objetivos: Los tumores del timo tienen incidencia global de 0,13 por 100.000 habitantes, pero representan un importante porcentaje de tumores del mediastino. Hay poca literatura basada en nuestra población, por esto, hacemos un aporte de nuestra experiencia en el Instituto Nacional de Cancerología (INC). Métodos: Se hizo un estudio tipo series de caso, revisando las historias clínicas de los pacientes con tumores del timo tratados en el INC entre 2006 y 2017. Resultados: Desde el 2006 al 2017 se encontraron 31 pacientes con tumores del timo tales como timoma, hiperplasia tímica, quistes tímicos y carcinomas tímicos, predominando en el género femenino y con una mediana de 62 años de edad. 2 pacientes presentaron miastenia gravis (MG). 27 fueron sometidos a timectomía por medio de esternotomía, videotoracoscopia, toracotomía, entre otros, obteniendo una supervivencia global mayor al 90% a 5 años de seguimiento. Los estadios de Masaoka I, II y III tienen mejor pronóstico que los tipos IV independientemente de la histología. Conclusiones: La timectomía es el tratamiento de primera línea en los casos resecables, incluso en los que existe compromiso de estructuras vecinas que permiten una resección quirúrgica completa. Los resultados presentados describen conductas y resultados similares a los encontrados en la literatura mundial.

Abstract Objectives: Thymic tumors have an overall incidence of 0.13 per 100,000 inhabitants, but they represent a significant percentage of mediastinal tumors. There is little literature based on our population, we make a contribution of our experience in the National Cancer Institute. Methods: We did a case series study, reviewing the clinical histories of patients with thymic tumors treated at the National Cancer Institute from 2006 to 2017. Results: From 2006 to 2017, 31 patients with thymic tumors such as thymoma, thymic hyperplasia, thymic cysts and thymic carcinomas were found, mainly in the female gender and with a median of 62 years of age. 2 patients presented Myasthenia Gravis (MG). 27 patients underwent thymectomy through sternotomy, video-thoracoscopy, thoracostomy among others, obtaining an overall survival greater than 90% at 5 years of follow-up. The stages of Masaoka I, II and III have a better prognosis than type IV regardless of the histological type. Conclusions: Thymectomy is the first-line treatment in resectable cases, even when there is a compromise of nearby structures that allow a complete surgical resection. Our results describe behaviors and results similar to those found in the world literature.

Histotyping of Indian thymomas: A clinicopathologic study from north India

Background & objectives: Thymomas are rare, but most common anterior mediastinal lesions. The histomorphologic spectrum of thymic epithelial tumours (TETs) in Indian population has not been explored in depth. This study was aimed to assess the histomorphology of TETs in the Indian patients and correlate clinical parameters with pathological features. Methods: It was a retrospective study conducted in a tertiary referral hospital in north India. All morphologically confirmed cases of TETs since 2009 were included. Clinical details and histology slides were reviewed using the Modified Masaoka-Koga staging system and WHO 2015 classification. Clinicopathological correlation and survival analysis were done. A comparative review from other published Indian studies was performed. Results: A total of 219 cases of TETs (138 resections and 81 biopsies) were identified. The most common histomorphologic type was B2, and the most frequent stage was I. Types A/AB were common in older age (P<0.01). Clinically, higher stage tumours were found mostly in men (P<0.01), and these were Type B thymomas (P<0.01). Myasthenia gravis was more common in women (P<0.02) and in lower stages (P<0.05). Survival analysis revealed significant association between recurrence and tumour stage. Although thymic carcinoma was diagnosed on biopsy, no resectable case was identified. Interpretation & conclusions: Our findings showed that the thymomas in Indian patients were most commonly Stage I tumours of B2 and AB histotypes. Resected thymic carcinomas were conspicuously absent in our study. More studies need to be done to establish the frequency and biology of TETs from India.

Ultrasonographic and clinical pathological features of intrathyroid thymic carcinoma / 中华超声影像学杂志

Objective To investigate the ultrasonographic and clinical pathological features of intrathyroid thymic carcinoma( IT TC) . Methods T he ultrasonographic and clinical pathological features of 11 cases of pathologically confirmed intrathyroid thymic carcinoma were analyzed retrospectively . T he size , shape ,boundary ,internal echo ,calcification ,cystic change ,blood flow of the lesion and lymph nodes of the neck were recorded . T I‐RADS classification was performed on the lesion ,and the medical history ,clinical symptoms and treatment process of the patients were recorded . Results T he lesions of all 11 patients were solid and located in the lower pole or middle‐lower part of the thyroid ,8 cases were located in the right lobe of the thyroid gland ( 8/11 ,72 .7% ) ,and 3 cases were located in the left lobe ( 3/8 ,27 .3% ) . T he maximum diameter diameter of the lesions was ( 3 .55 ± 0 .51 ) cm . All the lesions were hypoechogenicity or marked hypoechogenicity and ill‐defined margin . T he internal echo of the lesions were heterogeneous . Ten lesions were characterized by striped hyperechogenicity interiorly on ultrasonograms . According to T I‐RADS classification ,2 cases were class 4a ,3 cases were class 4b ,2 cases were class 4c and 4 cases were class 5 . T here was no cystic component or calcifcation in all lesions ,and there was no taller‐than‐wide shape . T hree of 11 cases were accompanied by Hashimoto′s thyroiditis . Postoperative pathology showed that 5 cases had cervical lymph node metastasis ,5 had perithyroidal soft tissue in ltration ,of them , 3 cases had recurrent laryngeal nerve ,2 cases invaded the esophageal wall ,and 3 cases invaded the striated muscle of the neck . Immunohistochemistry showed that CD5 and CD117 of all lesions were positive . All patients underwent surgery ,and 3 of them underwent radiotherapy and chemotherapy after surgery . Conclusions There are common sonographic features of intrathyroid thymic carcinoma ,which are located at the lower pole or middle‐lower of the thyroid gland ,presenting a solid hypoechogenicity or marked hypoechogenicity ,with ill‐defined margin and striped hyperechogenicity interiorly on ultrasonograms . T hese sonographic features are helpful for the diagnosis of IT TC .

Surgical treatment and prognostic analysis of thymic carcinoma: a report of 38 cases / 中国胸心血管外科临床杂志

@#Objective    To evaluate the influence of clinical, pathological and treatment factors on the prognosis of thymic carcinoma patient accepted surgical treatment. Methods    Retrospective analysis was performed on 38 patients with thymic carcinoma undergoing surgical treatment between January 2008 and December 2017. The association between the prognostic factors including age, sex, thymectomy, radical resection, pathological type, TNM stage, Masaoka-Koga stage, tumor size, and survival was assessed using the Kaplan-Meier method. Results    The 5-year overall survival rate of our cohort was 51.9%. Kaplan-Meier univariate survival analysis showed that radical resection (P=0.003), TNM stage (P=0.038), Masaoka-Koga stage (P=0.033), and tumor size (P=0.030) were related to the prognosis of patients with thymic carcinoma. Radical resection was also validated as an independent prognostic factor in multivariate Cox analysis (P=0.009, hazard ratio 2.31, 95%CI 1.23-4.33). Conclusion    Radical surgical treatment could improve the prognosis of patients with resectable thymic carcinoma.

Carcinoma tímico en un adulto / Thymic carcinoma in an adult

Se presenta el caso clínico de un paciente de 50 años de edad, quien acudió a la consulta de Oncología del Hospital General Docente Dr Juan Bruno Zayas Alfonso de Santiago de Cuba, por presentar un tumor tímico de 4 meses de evolución. Se le realizó timectomía y linfadenectomía mediastinal, así como una biopsia que indicó la presencia de carcinoma tímico de tipo linfoepitelioma (II) de alto grado de malignidad, estadio IVA; por tal razón se decidió efectuar tratamiento con quimioterapia y radioterapia. Debido a la persistencia del tumor se planificó la segunda línea de quimioterapia, pero el paciente falleció.

The case report of a 50 year-old patient is presented who visited the Oncology department of Dr Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba, due to a 4 months thymic tumor. A thymectomy and mediastinal lymphadenectomy were carried out , as well as a biopsy which indicated the presence of thymic carcinoma, type II lymphoepithelioma of high degree of malignancy, stage IV A; for such a reason it was decided to carry out a treatment with chemotherapy and radiotherapy. Due to the tumor persistence the second chemotherapy line was planned, but the patient died.

A Whole-Tumor Histogram Analysis of Apparent Diffusion Coefficient Maps for Differentiating Thymic Carcinoma from Lymphoma

OBJECTIVE: To assess the performance of a whole-tumor histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating thymic carcinoma from lymphoma, and compare it with that of a commonly used hot-spot region-of-interest (ROI)-based ADC measurement. MATERIALS AND METHODS: Diffusion weighted imaging data of 15 patients with thymic carcinoma and 13 patients with lymphoma were retrospectively collected and processed with a mono-exponential model. ADC measurements were performed by using a histogram-based and hot-spot-ROI-based approach. In the histogram-based approach, the following parameters were generated: mean ADC (ADCmean), median ADC (ADCmedian), 10th and 90th percentile of ADC (ADC10 and ADC90), kurtosis, and skewness. The difference in ADCs between thymic carcinoma and lymphoma was compared using a t test. Receiver operating characteristic analyses were conducted to determine and compare the differentiating performance of ADCs. RESULTS: Lymphoma demonstrated significantly lower ADCmean, ADCmedian, ADC10, ADC90, and hot-spot-ROI-based mean ADC than those found in thymic carcinoma (all p values < 0.05). There were no differences found in the kurtosis (p = 0.412) and skewness (p = 0.273). The ADC10 demonstrated optimal differentiating performance (cut-off value, 0.403 × 10−3 mm2/s; area under the receiver operating characteristic curve [AUC], 0.977; sensitivity, 92.3%; specificity, 93.3%), followed by the ADCmean, ADCmedian, ADC90, and hot-spot-ROI-based mean ADC. The AUC of ADC10 was significantly higher than that of the hot spot ROI based ADC (0.977 vs. 0.797, p = 0.036). CONCLUSION: Compared with the commonly used hot spot ROI based ADC measurement, a histogram analysis of ADC maps can improve the differentiating performance between thymic carcinoma and lymphoma.

Clinicopathological analysis of five cases of intrathyroid thymic carcinoma / 上海交通大学学报（医学版）

Objective: To investigate the clinicopathological features of intrathyroid thymic carcinoma. Methods: Clinical data of 5 patients with intrathyroid thymic carcinoma were retrospectively reviewed. Histological examination and immunohistochemical staining were performed on the surgically resected tumors. The infection of EB virus (EBV) was detected by in situ hybridization of EBV-encoded RNAs (EBER). BRAF V600E mutation was examined by amplification refractory mutation system. Results: There were 3 males and 2 females with age between 51 and 69 years (average of 60.8 years). All 5 cases were intrathyroid tumors. The tumors were 2.0-3.5 cm in diameter. All 5 cases showed positive staining for CK, CK19, P40, CD5, CD117, Bcl-2, and Ki-67 at protein level, and negative staining for other related differential diagnosis markers including 34βE12, TPO, TG, TTF1, SYN, EBV, and BRAF. In situ hybridization of EBER showed negative results and no BRAF V600E mutation was found. Conclusion: Intrathyroid thymic carcinoma is a low-grade malignant tumor. Expressions of CD5 and CD117 in tumor cells play a very important role in the differential diagnosis.

Research advances in staging system of thymoma / 中国综合临床

It is difficult to define whether the thymoma is benign or malignant because of its morphological heterogeneity. The structure of the mediastinum is complex,and the tumor′s invasion of different structures will have different effects on the prognosis of the patients. These characteristics make it difficult for clinicians to assess their prognosis. The histology classification and clinical staging were used to determine the prognosis. But the existing staging types are complex and are not well matched with the prognosis.

Outcomes and prognostic factors of surgically treated thymic carcinoma / 中国胸心血管外科临床杂志

@#Objective     To evaluate the influence of resection status, pathological type, pathological stage and postoperative adjuvant therapy on prognosis of surgically treated thymic carcinoma. Methods     In this retrospective study, 56 patients with surgically treated thymic carcinoma in the Department of Thoracic Surgery, Peking Union Medical College Hospital from January 2005 to December 2015 were enrolled. There were 30 males and 26 females aged 52.1±11.5 years ranging from 22 to 81 years. The survival curve was performed by Kaplan-Meier method. The prognostic factors affecting overall survival (OS) and disease-free survival (DFS) were analyzed by one-way analysis of variance (ANOVA). Results     R0 resection was performed in 37 patients (67.9%), and other resections in 19 (32.1%); 13 patients suffered thymic carcinoma with Masaoka stage Ⅰ-Ⅱ, 26 Ⅲ, and 17 Ⅳ. Low-grade thymic carcinoma was found in 42 patients, and high-grade in 14. Postoperative radiotherapy, chemotherapy and chemoradiotherapy were performed on 17, 12 and 18 patients respectively and 9 patients were untreated. Forty-one patients was followed up for 1 to 10 years, and the follow-up rate was 73%. The 1-, 3- and 5-year OS rates were 93%, 74% and 61%, respectively. Resection status and pathological stage affected OS. Postoperative radiotherapy after R0 resection affected DFS, but did not affect OS. Conclusion     Most patients with thymic carcinoma after surgery can survive for a long period, and R0 resection is the most important prognostic factor of thymic carcinoma. Postoperative radiotherapy after R0 resection in patients with Masaoka stage Ⅱ-Ⅲ is recommended.

Epidural Metastasis in Malignant Thymoma Mimicking Epidural Abscess: Case Report and Literature Review

Thymoma and thymic carcinoma are rare epithelial tumors that originate from the thymus gland. Extrathoracic metastases occur in the liver, kidney, and bone in 1% to 15% of patients. Although thymoma and thymic carcinoma exhibit highly aggressive biological behavior, spinal metastasis is rare. We describe a 78-year-old man with left wrist and grasp weakness that occurred 7 days before admission. The patient underwent thymoma surgery 7 years ago and was cured. Magnetic resonance images showed a rim-enhanced mass in the C6–7–T1 epidural space. C6–7–T1 laminectomy was performed and the mass was removed. Histological examination was performed and patient was diagnosed with metastatic thymoma. The previous reported case occurred with involvement of the vertebral body or posterior element, but our case was mostly rim-enhanced and appeared as an abscess and intradural extramedullary tumor.

Thymic Carcinoma Treated with Video-assisted Thoracoscopic Surgery:Case Report / 中国微创外科杂志

[Summary] In this case report , a 44-year-old female patient complained of three years of tightness and chest pain , and was hospitalized in January 2016.The thymus and tumor were completely resected under video-assisted thoracoscopic surgery (VATS). Postoperative pathological examination presented a thymic mucoepidermoid carcinoma .The patient received 30 times of chemotherapy after operation and were followed up for 2 months.Postoperative recovery was smooth without symptoms .The CT scanning showed negative result .We consider that VATS was feasible and safe for the treatment of thymic carcinoma .

Thymic carcinoma presenting with an unusual and delayed metastasis to the neural foramen, mimicking thoracic spinal radiculopathy

We report a case of metastatic thymic carcinoma which presented as an enhancing mass located in the neural foramen of the thoracic spine. More common tumours which arise in the neural foramen would include a neurogenic tumour or developmental anomalies such as a foregut duplication cyst. This case is singular firstly because the lesion present as radiculopathy which mimics a neurogenic tumour. Secondly, the presentation was unusually delayed as the patient presented to our centre more than a decade after the resection of the primary tumour in another institution.

Chemotherapy and prognosis in advanced thymic carcinoma patients

OBJECTIVE: The role of chemotherapy in treating advanced thymic carcinoma is unclear. The purpose of the current study was to investigate the efficacy of chemotherapy and the prognostic factors for patients with advanced thymic carcinoma. METHODS: A retrospective review of the medical records of 86 patients treated with chemotherapy for advanced thymic carcinoma was conducted between 2000 and 2012 at our institution. The clinical characteristics, chemotherapy regimens and prognostic factors were analyzed. Survival curves were plotted using the Kaplan-Meier method and the Cox proportional hazard model was used for multivariate analysis. RESULTS: Of the 86 patients, 56 were male and 30 were female. The median survival time was 24.5 months. For the first-line chemotherapy treatment, the objective response rate was 47.7% and the disease control rate was 80.2%. The median progression-free survival for all patients was 6.5 months for first-line chemotherapy. No significant differences in progression-free survival were observed among the different chemotherapy regimens. Multivariate analyses revealed that the prognostic factors for overall survival included performance status (p=0.043), histology grade (p=0.048), and liver metastasis (p=0.047). CONCLUSION: Our results suggest that there is no difference in efficacy between multiagent and doublet regimens. The prognosis of patients with advanced thymic carcinoma can be predicted based on histological grade, liver metastasis and performance status.

Clinical prognosis with 71 thymic carcinoma patients / 安徽医科大学学报

Objective To explore the prognostic factor by analyzing clinical characters, pathologic features and treatment methods of thymic carcinoma. Methods From January 2000 to Deceber 2011, 71 patients received re-section of thymic carcinoma. They were analyzed retrospectively based on Masaoka stage(stageII 7,stageIII 33, stageIV 31). The clinical factors included histological classification, Masaoka stage, treatment and prognosis. Sur-vival rate was calculated and the survival curve was plotted by Kaplan-Meimer and Log-Rank method, Multi-analy-sis was carried out by COX regression. Results For these patients, the median survival time was 57. 2 months, the 5-year survival rate was 47. 9%. 25 patients received complete resection with 5-years survival rate 68%, 46 patients received partial resection with 5-years survival rate 36. 9%. 41 patients whose lump size was greater than or equal to 8 cm with 5-years survival rate 53. 6%, 40% with lower than 8 cm. Histology Masaoka staging with 5-years survival rate was stage II(57. 1%) , stage III(69. 7%) and stage IV(29. 0%) , respectively. Defferent his-tological type with 5-years survival rate squamous carcinoma(55. 1%) , adenocarcinoma (14. 3%) ,small cell car-cinoma ( 28. 6%) , adenosquamous carcinoma ( 33. 3%) , and carcinoid ( 100%) , respectively. The operation method, the maximum diameter, mass Masaoka stage and different pathology types for survival were statistically dif-ferent (P<0. 05). Preoperative treatment, postoperative radiotherapy and differentiation degree of survival had no statistical difference. Conclusion Surgical method, lump size, masaoka stage and histological type are the impor-tant factors affecting prognosis. Adjuvant radiotherapy maybe is not the poor prognosis factor of thymic tumors. Sur-gical method and lump size are the significant independent prognostic factors in patients with thymic tumors.

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).