A tour of the thymus: a review of thymic lesions with radiologic and pathologic correlation.

The thymus is routinely encountered on cross-sectional imaging studies of the chest. It has a variable appearance, undergoes dynamic changes during periods of stress, and demonstrates numerous different pathologic lesions. Understanding the imaging characteristics of these different lesions facilitates accurate radiographic diagnosis and can prevent unnecessary follow-up imaging and intervention. This article will review normal thymic anatomy and development, thymic hyperplasia and associated medical conditions, and the imaging and pathologic features of various benign and malignant thymic lesions.

Robotic thymectomy in thymic tumours: a multicentre, nation-wide study.

OBJECTIVES: Robotic thymectomy has been suggested and considered technically feasible for thymic tumours. However, because of small-sample series and the lack of data on long-term results, controversies still exist on surgical and oncological results with this approach. We performed a large national multicentre study sought to evaluate the early and long-term outcomes after robot-assisted thoracoscopic thymectomy in thymic epithelial tumours. METHODS: All patients with thymic epithelial tumours operated through a robotic thoracoscopic approach between 2002 and 2022 from 15 Italian centres were enrolled. Demographic characteristics, clinical, intraoperative, postoperative, pathological and follow-up data were retrospectively collected and reviewed. RESULTS: There were 669 patients (307 men and 362 women), 312 (46.6%) of whom had associated myasthenia gravis. Complete thymectomy was performed in 657 (98%) cases and in 57 (8.5%) patients resection of other structures was necessary, with a R0 resection in all but 9 patients (98.6%). Twenty-three patients (3.4%) needed open conversion, but no perioperative mortality occurred. Fifty-one patients (7.7%) had postoperative complications. The median diameter of tumour resected was 4 cm (interquartile range 3-5.5 cm), and Masaoka stage was stage I in 39.8% of patients, stage II in 56.1%, stage III in 3.5% and stage IV in 0.6%. Thymoma was observed in 90.2% of patients while thymic carcinoma occurred in 2.8% of cases. At the end of the follow-up, only 2 patients died for tumour-related causes. Five- and ten-year recurrence rates were 7.4% and 8.3%, respectively. CONCLUSIONS: Through the largest collection of robotic thymectomy for thymic epithelial tumours we demonstrated that robot-enhanced thoracoscopic thymectomy is a technically sound and safe procedure with a low complication rate and optimal oncological outcomes.

Surgical cytoreduction and hyperthermic intrathoracic chemotherapy for thymic tumours with pleural spread is effective on survival: results from the multicentre German hyperthermic intrathoracic chemotherapy study.

OBJECTIVES: Cytoreductive surgery and hyperthermic intrathoracic chemotherapy (HITOC) is effective on survival for patients with pleural metastatic thymic tumours. METHODS: Multicentre, retrospective analysis of patients with stage IVa thymic tumours treated with surgical resection and HITOC. Primary end point was overall survival, secondary end points were recurrence-/progression-free survival and morbidity/mortality. RESULTS: A total of n = 58 patients (thymoma, n = 42; thymic carcinoma, n = 15; atypical carcinoid of the thymus, n = 1) were included, who had primary pleural metastases (n = 50; 86%) or pleural recurrence (n = 8; 14%). Lung-preserving resection (n = 56; 97%) was the preferred approach. Macroscopically complete tumour resection was achieved in n = 49 patients (85%). HITOC was performed with cisplatin alone (n = 38; 66%) or in combination with doxorubicin (n = 20; 34%). Almost half of the patients (n = 28; 48%) received high-dose cisplatin > 125 mg/m2 body surface area. Surgical revision was required in 8 (14%) patients. In-hospital mortality rate was 2%. During follow-up, tumour recurrence/progression was evident in n = 31 (53%) patients. Median follow-up time was 59 months. The 1-, 3- and 5-year survival rates were 95%, 83% and 77%, respectively. Recurrence/progression-free survival rates were 89%, 54% and 44%, respectively. Patients with thymoma had significantly better survival compared to patients with thymic carcinoma (P-value ≤0.001). CONCLUSIONS: Promising survival rates in patients with pleural metastatic stage IVa in thymoma (94%) and even in thymic carcinoma (41%) were achieved. Surgical resection and HITOC is safe and effective for treatment of patients with pleural metastatic thymic tumours stage IVa.

Correlation of clinical and computed tomography features of thymic epithelial tumours with World Health Organization classification and Masaoka-Koga staging.

OBJECTIVES: Our goal was to investigate the correlation of clinical and computed tomography (CT) features of thymic epithelial tumours (TET) with the World Health Organization classification and the Masaoka-Koga staging system. METHODS: Clinical and CT imaging data from 159 patients surgically and pathologically diagnosed with TET (82 men, 77 women; mean [± standard deviation] age, 52.08 ± 11.76 years) were retrospectively collected and reviewed. CT features were evaluated by radiologists. Tumour size, morphology, margin, density, calcification, cystic necrosis, density of the fat layer around the tumour, invasion of surrounding tissues, mediastinal lymph node enlargement, pleural/pericardial effusion, metastasis, plain CT scans and enhanced CT values were analysed. RESULTS: Of the 159 patients with TET, 76 had low-risk thymoma, 55 had high-risk thymoma and 28 had thymic carcinomas. Age, maximum tumour diameter, myasthenia gravis, morphology, edges, density, fat around the lesion, mediastinal vascular, pericardial and lung tissue invasion, pleural/pericardial effusion, metastasis and arterial phase CT values were statistically different among the 3 groups (P < 0.05). Multivariate regression analysis revealed that edges, fat around the lesion, mediastinal vascular invasion and pericardial effusion were most relevant to TET classification. The 159 patients with TET were categorized into the non-invasion group (stage I; n = 58); the invasion of surrounding fat (stage II; n = 46); and the invasion of surrounding structures and metastasis group (stages III and IV; n = 55). Tumour diameter, morphology, margins, density, cystic degeneration and necrosis, invasion of surrounding fat and structure, pleural and pericardial effusion and lymph node enlargement were statistically different among the 3 groups (P < 0.05). Multivariate regression analysis revealed that edges, fat around the lesion, mediastinal vascular invasion and pleura invasion were the most relevant CT signs in relation to TET staging. CONCLUSIONS: Analysis of clinical and CT features before surgery may facilitate the preliminary classification and stage diagnosis of TET.

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.

Ectopic Cushing's Syndrome secondary to Recurrent Thymic Neuroendocrine Carcinoma with Bilateral Ovarian Metastases: A Case Report.

Cushing's syndrome due to ectopic adrenocorticotrophic hormone (ACTH) secretion is uncommon, accounting for 9 to 18% of cases; approximately 10% of ACTH producing tumours are caused by thymic carcinomas.1 We describe a young lady who presented with Cushing's syndrome secondary to a primary neuroendocrine tumour (NET) arising from the thymus. She had surgical resection of her primary tumour with remission of her Cushing's syndrome however subsequently went on to have locoregional recurrence followed by distant metastases to her bilateral ovaries. She underwent 6 surgeries including bilateral adrenalectomy and had 3 cycles of chemotherapy over the course of the 8 years since her diagnosis. Due to the rarity and highly aggressive nature of this disease, we highlight the need for a multidisciplinary team approach and use of multiple modalities in the management of our patient. Timely use of bilateral adrenalectomy particularly in young patients is important to prevent further complications and facilitate other treatment modalities.

Autoimmune disorders and paraneoplastic syndromes in thymoma.

Thymomas are counted among the rare tumour entities which are associated with autoimmune disorders (AIDs) and paraneoplastic syndromes (PNS) far more often than other malignancies. Through its complex immunological function in the context of the selection and maturation of T cells, the thymus is at the same time highly susceptible to disruptive factors caused by the development and growth of thymic tumours. These T cells, which are thought to develop to competent immune cells in the thymus, can instead adopt autoreactive behaviour due to the uncontrolled interplay of thymomas and become the trigger for AID or PNS affecting numerous organs and tissues within the human body. While myasthenia gravis is the most prevalent PNS in thymoma, numerous others have been described, be they related to neurological, cardiovascular, gastrointestinal, haematological, dermatological, endocrine or systemic disorders. This review article sheds light on the pathophysiology, epidemiology, specific clinical features and therapeutic options of the various forms as well as courses and outcomes of AID/PNS in association with thymomas. Whenever suitable and backed by the limited available evidence, the perspectives from both the thymoma and the affected organ/tissue will be highlighted. Specific issues addressed are the prognostic significance of thymectomy on myasthenia gravis and other thymoma-associated AID/PND and further the impact and safety of immunotherapies on AID and PND relating to thymomas.

The 100 most cited papers on thymic epithelial tumours: a bibliometric analysis.

Bibliometric analysis can help us analyse the most influential papers, authors, research institutions in a discipline or topic and analyse the impact of these papers on a specific field. Our purpose is to identify the 100 most cited papers about thymic epithelial tumours (TETs) and analyse their key characteristics. We use certain search terms in the Web of Science database to identify the 100 most cited papers, and analysed the first author, country of the first author, institution, journal, type of paper, number of citations, and citation rate. The search returned 26,497 results. The top 100 papers received 17,674 citations. The most cited paper was by Masaoka et al. (n=1,190 citations), in which, clinical staging criteria are proposed for thymoma with special emphasis on the therapy and prognosis. The paper with the highest citation rate was also by Masaoka et al. (citations rate =30.51). Osaka University published the most papers (n=6) and accrued the highest number of citations (n=2,122 citations). The United States was the country with the most published papers (n=45) and the highest number of citations (n=7,991 citations). Cancer is the journal with the most published papers (n=19) and the highest number of citations (n=5,017 citations). Through the analysis of the most influential papers, this study provides a reference for researchers trying to understand TETs, thus providing guidance for future research.

An in silico planning study comparing doses and estimated risk of toxicity in 3D-CRT, IMRT and proton beam therapy of patients with thymic tumours.

PURPOSE: To compare the dose distributions produced in patients (pts) treated for thymic tumours with spot-scanning proton beam therapy (PBT) implemented with single-field uniform dose (SFUD), intensity-modulated radiation therapy (IMRT) and three-dimensional conformal photon-beam based radiotherapy (3D-CRT). METHODS: Twelve pts, treated with 3D-CRT, were included. Alternative IMRT and SFUD plans were constructed. The IMRT plans were created using a setup with beams incident from 5 to 6 different angles. For the SFUD plans, a field-specific planning target volume (PTV) was created for each patient and a clinical target volume (CTV)-based robust optimization was performed. A robustness evaluation was performed for the CTV for all SFUD plans. A dosimetric evaluation was conducted for the doses to the CTV and organs at risk (OARs) for all plans. The normal tissue complication probability (NTCP), for different endpoints, was calculated using the Lyman-Kutcher-Burman (LKB)-model and compared between plans. RESULTS: SFUD was associated with significantly lower mean doses to the oesophagus, the heart, the left anterior descending coronary artery (LAD), lungs and breasts compared to 3D-CRT and IMRT. The maximum dose given to the spinal cord was significantly lower with SFUD. The risks for pneumonitis, esophagitis and myelopathy were significantly reduced in the SFUD plans. CONCLUSIONS: The present study showed dosimetric advantages of using scanned-beam PBT for the treatment of thymic tumours, as compared to 3D-CRT and IMRT, especially in regard to lower doses to the oesophagus and lungs. The risk of toxicity was reduced with SFUD.

Ectopic Cushing’s Syndrome secondary to Recurrent Thymic Neuroendocrine Carcinoma with Bilateral Ovarian Metastases: A case report / Journal of the ASEAN Federation of Endocrine Societies

@#Cushing’s syndrome due to ectopic adrenocorticotrophic hormone (ACTH) secretion is uncommon, accounting for 9 to 18% of cases; approximately 10% of ACTH producing tumours are caused by thymic carcinomas.1 We describe a young lady who presented with Cushing’s syndrome secondary to a primary neuroendocrine tumour (NET) arising from the thymus. She had surgical resection of her primary tumour with remission of her Cushing’s syndrome however subsequently went on to have locoregional recurrence followed by distant metastases to her bilateral ovaries. She underwent 6 surgeries including bilateral adrenalectomy and had 3 cycles of chemotherapy over the course of the 8 years since her diagnosis. Due to the rarity and highly aggressive nature of this disease, we highlight the need for a multidisciplinary team approach and use of multiple modalities in the management of our patient. Timely use of bilateral adrenalectomy particularly in young patients is important to prevent further complications and facilitate other treatment modalities.

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.