A review of thymic tumours

Metastatic Thymic Mucoepidermoid Carcinoma: The Diagnostic Challenges and Role of CRTC1/MAML2 Translocation in Accurate Diagnosis and Treatment

Mucoepidermoid carcinoma (MEC) is a subtype of epithelial neoplasms commonly found in salivary glands, but can also be seen in the thymus. Diagnosing MEC of the thymus is sometimes challenging due to its histological similarities with adenosquamous carcinoma (ASC). This case report describes a 64-year-old female with a history of metastatic endometrial adenocarcinoma who presented to an oncology clinic with a thymic mass as well as multiple mass lesions in the liver, bone, and abdominal wall. Initially diagnosed as thymic ASC based on histopathology, further genomic profiling revealed a CRTC1/MAML2 translocation, leading to the diagnosis of metastatic MEC of the thymus. Comprehensive genomic testing played a crucial role in distinguishing MEC from ASC. This case highlights the importance of genetic testing in cases of uncertain primary origins and in differentiating between morphologically similar tumors.

Invasive thymoma metastases to the pancreas: A case report

INTRODUCTION AND IMPORTANCE

Thymoma is the most common type of tumor that develops in the thymic epithelial cells. Although thymomas can invade surrounding organs in the chest cavity, extrathoracic metastasis is very rare, and little is known about the prognosis and effective treatments for such tumors. Herein, we report a case of an invasive thymoma metastasizing to the pancreas after incomplete resection.

CASE PRESENTATION

A 47-year-old man presented to our hospital with an anterior mediastinal mass. Although a thymic tumor was suspected, complete resection was not achieved because the tumor had invaded the pulmonary artery trunk, superior pulmonary vein, and left brachiocephalic vein. The pathological diagnosis was a Type B3 thymoma. The patient underwent chemotherapy and radiotherapy after surgery. Three years after surgery, computed tomography indicated a pancreatic mass suggestive of pancreatic cancer. Distal pancreatectomy was performed after neoadjuvant chemotherapy and radiotherapy. The pancreatic mass was diagnosed as Type B3 thymoma metastasis. Thirteen months after surgery for the pancreatic lesion, the patient underwent resection of the bilateral lung metastases.

CLINICAL DISCUSSION

To the best of our knowledge, only four cases of metastatic thymic tumors in the pancreas have been reported. All patients who underwent surgical resection for pancreatic metastasis survived for >6 months including our case.

CONCLUSION

In cases of thymic tumors with metastasis to extra-thoracic organs, complete resection of the metastatic lesions can contribute to prolonged survival.

Efficacy and safety of treatments for advanced thymic carcinoma after failure of first-line platinum-based chemotherapy: A systematic literature review and meta-analysis

Thymic carcinoma (TC) is a rare cancer and patients failing initial chemotherapy (relapse/refractory) face limited therapeutic options given no approved options or consensus standard of care. This study aimed to identify and summarize clinical outcomes of all regimens evaluated in clinical trials of relapsed or refractory patients. Interventional trials enrolling advanced TC patients who failed first-line chemotherapy and reported outcomes in this group were eligible for inclusion in our systemic literature review (SLR). Between-study heterogeneity was assessed to determine the feasibility of pooling specific studies and treatments. Objective response rate (ORR), overall survival (OS), progression-free survival (PFS), and duration of response (DOR) endpoints were of interest for meta-analysis. Nineteen trials were identified in the SLR. Three trials with one or two TC patients were removed from our assessment to reduce publication bias. Response rates among studies with at least ten TC patients varied from 9 % to 38 %. Pooled ORRs in patients receiving S-1 (46 patients), sunitinib (46 patients), or pembrolizumab (66 patients) were 28 %, 24 %, and 21 %, respectively. Prolonged duration of response with pembrolizumab was observed with a pooled median of 23.8 months (95 % confidence interval [CI]: 12, not reached). Median PFS of five months or greater was reported in patients treated with sunitinib, lenvatinib, pembrolizumab, capecitabine + gemcitabine, everolimus, or S-1. Median OS of 20 months or greater was reported in trials evaluating S-1 or pembrolizumab; this endpoint was not reached in trials evaluating lenvatinib, regorafenib, or sunitinib. Generalizability of treatment effects is challenging in the research of rare diseases and meta-analysis of clinical outcomes may help to increase precision and relevance of results to the larger TC population. Our study found limited treatment options upon relapse, demonstrating a need for further investigations into novel therapeutics and well-powered clinical trials to better inform on optimal treatments.

Robotic vs. Transsternal Thymectomy: A Single Center Experience over 10 Years

Introduction: Thymomas are the most common tumors of the mediastinum. Traditionally, thymectomies have been performed through a transsternal (TS) approach. With the development of robot-assisted thoracic surgery (RATS), a promising, minimally invasive, alternative surgical technique for performing a thymectomy has been developed. In the current paper, the oncological and surgical outcomes of the TS vs. RATS thymectomies are discussed. Methods: For the RATS thymectomy, two 8 mm working ports and one 12 mm camera port were used. In the transsternal approach, we performed a median sternotomy and resected the thymic tissue completely, in some cases en bloc with part of the lung and/or, more frequently, a partial pericardiectomy with consequent reconstruction using a bovine pericardial patch. The decisions for using the TS vs. RATS methods were mainly based on the suspected tumor invasion of the surrounding structures on the preoperative CT scan and tumor size. Results: Between January 2010 and November 2020, 149 patients were submitted for an anterior mediastinal tumor resection at our institution. A total of 104 patients met the inclusion criteria. One procedure was performed through a hemi-clamshell incision. A total of 81 (78%) patients underwent RATS procedures, and 22 (21.1%) patients were treated using a transsternal (TS) tumor resection. Thymoma was diagnosed in 53 (51%) cases. In the RATS group, the median LOS was 3.2 ± 2.8 days and the median tumor size was 4.4 ± 2.37 cm compared to the TS group, which had a median LOS of 9 ± 7.3 days and a median tumor size of 10.4 ± 5.3 cm. Both differences were statistically significant (p < 0.001). Complete resection was achieved in all patients. Conclusion: While larger and infiltrating tumors (i.e., thymic carcinomas) were usually resected via a sternotomy, the RATS procedure is a good alternative for the resection of thymomas of up to 9.5 cm, and the thymectomy is a strong approach for myasthenia gravis. The oncological outcomes and survival rates were not influenced by the chosen approach.

Identification and Characterization of Non-Coding RNAs in Thymoma

BACKGROUND Thymoma is the most common tumor of the anterior mediastinum, and can be caused by infrequent malignancies arising from the epithelial cells of the thymus. Unfortunately, blood-based diagnostic markers are not currently available. High-throughput sequencing technologies, such as RNA-seq with next-generation sequencing, have facilitated the detection and characterization of both coding and non-coding RNAs (ncRNAs), which play significant roles in genomic regulation, transcriptional and post-transcriptional regulation, and imprinting and epigenetic modification. The knowledge about fusion genes and ncRNAs in thymomas is scarce. MATERIAL AND METHODS For this study, we gathered large-scale RNA-seq data belonging to samples from 25 thymomas and 25 healthy thymus specimens and analyzed them to identify fusion genes, lncRNAs, and miRNAs. RESULTS We found 21 fusion genes, including KMT2A-MAML2, HADHB-REEP1, COQ3-CGA, MCM4-SNTB1, and IFT140-ACTN4, as the most frequent and significant in thymomas. We also detected 65 differentially-expressed lncRNAs in thymomas, including AFAP1-AS1, LINC00324, ADAMTS9-AS1, VLDLR-AS1, LINC00968, and NEAT1, that have been validated with the TCGA database. Moreover, we identified 1695 miRNAs from small RNA-seq data that were overexpressed in thymomas. Our network analysis of the lncRNA-mRNA-miRNA regulation axes identified a cluster of miRNAs upregulated in thymomas, that can trigger the expression of target protein-coding genes, and lead to the disruption of several biological pathways, including the PI3K-Akt signaling pathway, FoxO signaling pathway, and HIF-1 signaling pathway. CONCLUSIONS Our results show that overexpression of this miRNA cluster activates PI3K-Akt, FoxO, HIF-1, and Rap-1 signaling pathways, suggesting pathway inhibitors may be therapeutic candidates against thymoma.

AB thymoma revealed by a huge intraparenchymal lung mass: a case report

Thymoma is an epithelial neoplasm of the thymus, which commonly lies in the anterior mediastinum. Unusually it can be found in other locations as well. Ectopic thymoma rarely presents as an intrathoracic tumor. We report a case of ectopic thymoma presenting as a giant right intrathoracic tumor, the patient was 51-year-old, and who was presented with heaviness in chest and breathlessness. Detailed investigation including chest computed tomography scan revealed a well-defined large solid tumor in the right thoracic cavity, in this case, immunohistochemical analysis demonstrated a thymome AB. The tumor was metastatic to the lung. Patient received a neoadjuvant chemotherapy, with favorable evolution.

Thymic carcinoma metastasize to the small intestine: a case report

BACKGROUND

Thymic carcinoma is a rare mediastinal neoplasm with a high malignant potential. It often shows pleural invasion and distant metastasis. The metastasis of thymic carcinoma to the small intestine is rarely reported and difficult to distinguish from other gastrointestinal tract tumors.

CASE PRESENTATION

An elderly man presented with lower abdominal pain for 2 months. Abdominal CT showed a mass communicated with the small intestinal lumen. After radical resection of the small intestinal tumor, resected specimens showed moderately differentiated squamous-cell carcinoma with lymph nodes metastases. The patient received chest CT and was found to have a mass in anterior mediastinum. Biopsies of the mass revealed thymic squamous-cell carcinoma.

CONCLUSIONS

We highlighted the metastasis of thymic carcinoma to the small intestine is rare and easily misdiagnosed. In patients with a mass communicated with the small intestinal lumen, a suspicion of thymic carcinoma metastasis should not be overlooked and we should make accurate differential diagnosis from the other small intestinal tumors.

Metabolic Characterization of Anterior Mediastinal Masses by 18F-FDG PET/CT

Objectives

To evaluate the role of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for the diagnosis of anterior mediastinal masses.

Methods

The oncological ¹⁸F-FDG PET/CT images of 41 patients (17 women, 24 men; age: 16-83 years, mean age: 50.5±19.5 years) who attended the nuclear medicine department between November 2016 and September 2017 were retrospectively evaluated for the metabolic characterization of their anterior mediastinal masses.

Results

Based on our results, the lesions of 4 patients were benign [maximum standard uptake value (SUV_max) <3] and that of 2 patients were non-tumoral (i.e., tuberculosis and sarcoidosis). The mean dimensions and the SUV_max levels of the malignant lesions were 6.4±3.7 cm and 11.9±9.6, respectively. The pathological results for the malign tumors were thymus tumors (n=8), lymphoma (n=8), lung cancer (n=11), carcinoid metastasis (n=2), thyroid carcinoma (n=2), germ cell carcinoma (n=1), schwannoma (n=1), and sarcoma (n=1). The degree of ¹⁸F-FDG accumulation could precisely identify the malign and benign tumors.

Conclusion

Thus, contrary to the known causes, it is possible that anterior mediastinal masses originate from structures other than the anterior mediastinal structures. In this study, the lymphoma and lung carcinoma pathology were more frequent than thymic lesions.

Midterm Results for Robotic Thymectomy for Malignant Disease

BACKGROUND

There are limited reports on robotic thymectomy for malignant disease. Our objectives are to review our experience and midterm outcomes.

METHODS

We reviewed a single-surgeon prospective database for patients who underwent planned robotic resection for malignancy from January 2010 to June 2019.

RESULTS

Two hundred thirteen patients underwent resection of an anterior mediastinal mass, all of which were planned for a robotic approach. Of these, 84 (39%) underwent robotic thymectomy for malignant disease. Thymoma was the most common pathology resected (68%). Median tumor size was 4.7 cm (interquartile range, 2.9-6.3), and median operative time was 81.5 minutes (interquartile range, 64-104). All except 1 patient had a complete (R0) resection (98.8%). There were 2 (2.3%) unplanned but elective conversions to open surgery, 1 of which required cardiopulmonary bypass. Median length of stay was 1 day (range, 0-9) with 1 readmission (1.2%). Major morbidity occurred in 3 patients (3.5%), and there were no 30- or 90-day mortalities. In patients with thymoma, follow-up was complete at a median of 32 months (range, 1-98), and 1 patient (1.8%) had an ipsilateral chest recurrence. To date there have been no patient deaths.

CONCLUSIONS

Robotic thymectomy for patients with malignant disease is safe with excellent perioperative outcomes. A robotic approach achieves a high rate of complete R0 resection, even for larger tumors. For patients with thymoma local recurrence is low after midterm follow-up, but longer-term analysis is needed to determine oncologic durability.

Comparing robotic and trans-sternal thymectomy for early-stage thymoma: a propensity score-matching study

OBJECTIVES

Minimally invasive techniques seem to be promising alternatives to open approaches in the surgical treatment of early-stage thymoma, although there are controversies because of lack of data on long-term results. The aim of the study was to evaluate the surgical and oncological results after robotic thymectomy for early-stage thymoma compared to median sternotomy.

METHODS

Between 1982 and 2017, 164 patients with early-stage thymoma (Masaoka I and II) were operated on by median sternotomy (108 patients) or the robotic approach (56 patients). Duration of surgery, amount of blood loss, complications, duration of chest drainage, postoperative hospital stay, oncological results and total costs were retrospectively evaluated. Data were analysed also after propensity score matching.

RESULTS

Compared to the trans-sternal group, robotic thymectomy had significantly longer average operative times (P < 0.001) but less intraoperative blood loss (P = 0.01), less perioperative complications (P = 0.03), shorter time to chest drainage removal and hospital discharge (P < 0.001). The median expense for the trans-sternal approach was significantly higher than the cost of the robotic procedure (P < 0.001), mainly due to longer hospitalization. From an oncological point of view, there were no differences in thymoma recurrence, although follow-up of the trans-sternal group was significantly longer (P < 0.001). Data were confirmed after propensity score matching.

CONCLUSIONS

Robotic thymectomy for early-stage thymoma is a technically safe and feasible procedure with low complication rate and shorter hospital stay compared to the trans-sternal approach. Cost analysis revealed lower expenses for the robotic procedure due to the reduced hospital stay. The oncological outcomes seemed comparable, but longer follow-up is needed.

Novel MRI of mediastinal masses: internal differentiation of a thymoma and lymphoma with T1 and T2 mapping

Routine imaging for mediastinal malignancies includes chest X-ray, CT or MRI. T1 and T2 mapping are novel MRI techniques which may have a role in expanding the assessment of internal tumour characteristics. This case report details two middle-aged women who had similar clinical presentations of mediastinal masses of comparable size and appearance when assessed with routine imaging. T1 and T2 maps were acquired on MRI to investigate whether these tumours could be further differentiated prior to surgery. T1 and T2 mapping supported suspicion for which tumour components were solid and cystic, as subsequently confirmed histologically. Furthermore, comparison between the two tumours showed native T1 values differed within the solid components by 37%, correlating to differences in proteinaceous material within the tumour types. This radiological-pathological correlation provides evidence that T1 and T2 mapping has clinical utility in the assessment and differentiation of mediastinal masses.

Chemotherapy with carboplatin and paclitaxel after failure of primary chemotherapy for advanced thymic carcinoma. A report of three cases and review of the literature

For patients with inoperable thymic carcinoma, multidrug chemotherapy containing cisplatin and an anthracycline is often used as first-line chemotherapy. A commonly applied regimen is cisplatin + doxorubicin + vincristine + cyclophosphamide (ADOC). There are relatively few reports on the use of carboplatin and paclitaxel as first-line chemotherapy for thymic carcinoma. In addition, little is known about its efficacy as second-line chemotherapy in patients with advanced thymic carcinoma. We here report on three patients with thymic carcinoma who were treated with carboplatin and paclitaxel as second-line chemotherapy after failure of ADOC. According to the Response Evaluation Criteria in Solid Tumors version 1.1, one patient achieved a partial response and two patients achieved stable disease. The median progression-free survival was 6.7 months and the median overall survival exceeded 3 years. Toxicities were well tolerated. Chemotherapy with carboplatin and paclitaxel appears to be effective as second-line chemotherapy for some persons with thymic carcinoma who fail ADOC.

Thymoma metastatic to liver and pancreas: case report and review of the literature

A 71-year-old man presented with a thymic mass involving the superior vena cava. A mediastinoscopical biopsy initially suggested a diagnosis of type A thymoma. After neoadjuvant chemotherapy, the patient underwent en-bloc thymectomy and vascular resection for a pathology-confirmed type B3 thymoma involving the superior vena cava, the left brachiocephalic vein and the distal part of the right brachiocephalic vein. Adjuvant radiotherapy was administered. Two years after the primary surgery, abdominal computed tomography (CT) and whole body fluorodeoxyglucose (18-FDG) positron emission tomography (PET) scans showed a single hepatic lesion that was treated with wedge liver resection. Pathological examination confirmed metastatic type B3 thymoma. Almost 4 years later, abdominal CT and 18-FDG PET revealed a 2.9-cm solid mass involving the body of the pancreas. Distal pancreatectomy with lymph node dissection was performed. Pathological examination showed a pancreatic metastasis from a type B3 thymoma, without lymph node involvement. The patient is alive and free of disease 6 months after the pancreatectomy (68 months after the initial thymectomy surgery). Intra-abdominal recurrence and pancreatic metastases are very uncommon manifestations of thymoma, but this event should be kept in mind when an abdominal mass is seen during follow-up.

Evaluation of metabolic response with 18F-FDG PET-CT in patients with advanced or recurrent thymic epithelial tumors

BACKGROUND

Patients with advanced or recurrent thymic epithelial tumors (TETs) often need several consecutive lines of chemotherapy. The aim of this retrospective monocentric study was to test whether ¹⁸F-Fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) is able to monitor standard chemotherapy efficacy in those patients and whether metabolic response correlates with morphovolumetric response as assessed by Response Evaluation Criteria in Solid Tumor (RECIST).

METHODS

We evaluated 27 consecutive patients with advanced (16 patients) or recurrent (11 patients) TETs. All patients underwent ¹⁸F-FDG PET-CT before and after at least 3 cycles of chemotherapy. Maximum standardized uptake value (SUV_max) of all detected lesions was recorded and the most ¹⁸F-FDG avid lesion in each patient was selected for determination of percentage change of SUV_max (ΔSUV_max) in pre- and post-treatment scans. Tumor response was assessed by contrast-enhanced computed tomography (CE-CT) using RECIST criteria. Receiver operating characteristic (ROC) curve analysis was performed to define the optimal threshold of ΔSUV_max discriminating responders from non-responders.

RESULTS

Metabolic response expressed as ΔSUV_max was significantly correlated with morphovolumetric response (Spearman's rank correlation, r = 0.64, p = 0.001). ROC curve analysis showed that a ΔSUV_max value of -25% could discriminate responders from non-responders with a sensitivity of 88% and a specificity of 80%. Conversely, basal SUV_max values were not predictive of morphovolumetric tumor response.

CONCLUSIONS

Our findings indicate that metabolic response assessed by ¹⁸F-FDG PET-CT, through evaluation of ΔSUV_max, may allow identification of responders and non-responders thus guiding adaptation of therapy in patients with advanced or recurrent TETs.

Robotic-assisted thymectomy: current perspectives

Thymectomy is the cornerstone in the treatment of thymic tumors and an accepted option for the management of myasthenia gravis. Different surgical approaches have been described, but the gold standard is represented by median sternotomy. In the last two decades, the development of minimally invasive surgery has led to an increased acceptance of thymectomy, especially for benign diseases. Robotic thymectomy seems a further step in the development and evolution of minimally invasive approaches. Since its introduction, different authors described their experience with robotic thymectomy, both for nonthymomatous myasthenia gravis and for thymic tumors. Available data show that robotic thymectomy may be considered a safe and feasible operation. In patients with nonthymomatous myasthenia, robotic thymectomy is effective and the long-term results are encouraging. The role of robotic thymectomy in patients affected by thymoma is still under evaluation, but the intermediate results seem promising both in terms of surgical and oncologic outcomes.

Loss of heterozygosity at the human leukocyte antigen locus in thymic epithelial tumors

Background

To study the relationship between loss of heterozygosity (LOH) at the human leukocyte antigen (HLA) locus and the pathogenicity and clinicopathological features of thymic epithelial tumors (TET).

Methods

Tumor and adjacent normal tissues were isolated from 36 TET patients. Five microsatellite loci (D6S1666, D6S265, D6S273, DS6276, and D6S291) within the HLA locus were amplified by polymerase chain reaction. DNA sequencing was used to measure the frequency of microsatellite LOH.

Results

LOH was identified in at least one locus in 83.6% of TET patients. LOH frequency at D6S1666, D6S265, D6S273, D6S276, and D6S291 was 44.4%, 16.7%, 30.5%, 38.9%, and 36.1% respectively. There was no significant association between LOH frequency in TET with tumor severity, or in the presence or absence of myasthenia gravis.

Conclusions

D6S1666, D6S265, D6S273, DS6S276, and D6S29 are sensitive loci for studying microsatellite LOH in TET. LOH within the HLA complex is implicated in the occurrence and development of TET, with the HLA-DQA1 gene likely involved. However, an understanding of the relationship between LOH and the clinicopathological features of TET requires a larger sample size than that of the present study.

Rare case of subcarinal thymic carcinoma in the middle mediastinum

We report an extremely rare case of a thymic carcinoma occurring in the subcarinal location of the middle mediastinum, masquerading as subcarinal adenopathy. A 6.2 × 5 cm mass was detected on computed tomography scan and found to be hypermetabolic on positron emission tomography scan. Transbronchial biopsy was performed and the mass was found to be suspicious for malignancy. A thoracoscopic resection of the mass was performed and found to be thymic carcinoma. The patient underwent a course of adjuvant radiation. To the best of our knowledge, this is the first reported case of a thymic carcinoma resected from the middle mediastinum.

[Retrospective analysis of 50 thymic epithelial tumors in Rennes university hospital]

BACKGROUND

Thymic epithelial tumors (TET), including thymomas and thymic carcinomas, are rare and characterized by very different evolutionary patterns depending on histology and invasion stage. The therapeutic management is not well defined but is a subject of increasing interest. The descriptive and analytic objectives of this retrospective monocentric study were to analyze the clinical characteristics of patients with TET, and to assess the management of these tumors in our centre.

METHODS

Adult patients with TET managed in the Rennes university hospital in the period 2000-2011 were selected via the pathology department. Their clinical and pathological features and survival were analyzed retrospectively.

RESULTS

Fifty TET were retrieved (46 thymomas and 4 thymic carcinomas). Their clinical and histological features and their invasion stages were concordant with published studies. Their diagnostic and therapeutic managements were also in accordance with current guidelines. In univariate analysis, myasthenia and surgery were associated with better survival rates.

CONCLUSION

Management of TET in Rennes university hospital is in accordance with guidelines.

Activating c-KIT mutations in a subset of thymic carcinoma and response to different c-KIT inhibitors

BACKGROUND

To analyze a multi-institutional series of type C thymic carcinomas (TCs) (including neuroendocrine tumors), focusing on the expression and mutations of c-KIT.

MATERIALS AND METHODS

Immunohistochemical expression of c-KIT/CD117, p63, CD5 and neuroendocrine markers, as well as mutational analysis of c-KIT exons 9, 11, 13, 14, 17 by direct sequencing of 48 cases of TCs. Immunohistochemical and molecular data were statistically crossed with clinicopathological features.

RESULTS

Overall, 29 tumors (60%) expressed CD117, 69% were positive for CD5 and 85% (41 cases) for p63. Neuroendocrine markers stained all six atypical carcinoids and five poorly-differentiated thymic squamous cell carcinomas. Overall, six CD117-positive cases (12.5%) showed c-KIT mutation. No mutation was detected in CD117-negative tumors and carcinoids. All the mutations were found in poorly-differentiated thymic squamous cell carcinomas expressing CD117, CD5, p63 and lacking neuroendocrine markers (6 of 12 cases with these features). Mutations involved exon 11 (four cases: V559A, L576P, Y553N, W557R), exon 9 (E490K) and exon 17 (D820E).

CONCLUSIONS

All TCs need an immunohistochemical screening with CD117, while c-KIT mutation analysis is mandatory only in CD117-positive cases, particularly when coexpressing CD5 and p63, lacking neuroendocrine differentiation. The finding of c-KIT mutation can predict efficacy with different c-KIT inhibitors.

Chronic shoulder pain referred from thymic carcinoma: a case report and review of literature

We report a case of thymic carcinoma presenting as unilateral shoulder pain for 13 months. Before an accurate diagnosis was made, the patient received conservative treatment, cervical discectomies, and myofascial trigger point injection, none of which relieved his pain. When thymic carcinoma was eventually diagnosed, he received total resection of the tumor and the shoulder pain subsided completely. Thymic carcinoma is a rare carcinoma, and our review of the literature did not show shoulder pain as its initial presentation except for one case report. The purpose of this report is to document our clinical experience so that other physiatrists can include thymic carcinoma in their differential diagnosis of shoulder pain.

Simultaneous double thymic carcinoids: a rare initial manifestation of multiple endocrine neoplasia type 1

A 53-year-old man was referred to our hospital for treatment of two anterior mediastinal tumors. The anterior mediastinal tumors were resected by thymectomy under the probable diagnosis of double thymomas. The final pathological diagnosis was multiple thymic carcinoids. Although 20%-25% of patients with thymic carcinoid have a family history of multiple endocrine neoplasia type 1 (MEN-1), radiographic screening just after the operation did not detect any endocrine tumors. However, the patient had a urinary calculus 4 months 7 months after the operation. Endocrinological examination then revealed mild hypercalcemia, hypophosphatemia, hyperinsulinemia, and hyperprolactinemia. Radiologically, a parathyroid tumor and a pancreatic tumor were found. The patient was referred to a university hospital and a mutation of MEN-1 gene was detected. The diagnosis of MEN-1 was confirmed about 1 year after the operation.

[(18)F]2-fluoro-2-deoxy-D-glucose PET/CT in mediastinal masses

Computed tomography (CT) and magnetic resonance imaging (MRI) are excellent modalities for the localization of mediastinal masses and there are often features that may allow the correct diagnosis to be made. However, CT and MRI cannot usually assess the aggressiveness of masses or identify viable tumour in residual masses after chemotherapy. Metabolic imaging using [¹⁸F]fluorodeoxyglucose (FDG)-positron emission tomography/CT, although not required in many cases, may be helpful for further characterization of masses and to guide the most appropriate site for biopsy.

Thirty-five-year follow-up analysis of clinical and pathologic outcomes of thymoma surgery

BACKGROUND

The impact of myasthenia gravis on patients with thymoma is still controversial when perioperative and long-term outcomes are analyzed. With the unique opportunity of a 35-year follow-up in a single institution, thymomatous myasthenia gravis cohort, we investigated the influence of early and long-term clinical predictors.

METHODS

We reviewed a surgical series of 317 (1972 to 2007) patients with thymoma: clinical and pathologic features were analyzed as prognostic factors matched against the short- and long-term survival and recurrence rates.

RESULTS

Male to female ratio was 153:164; median age, 49 years. Myasthenia gravis coexisted in 276 patients (87.1%). Thymomas were classified according to the Masaoka (42.0% stage I, 32.2% stage II, 21.5% stage III, and 4.4% stage IV) and the World Health Organization (3.5% type A, 9.5% type AB, 19.2% type B1, 57.7% type B2, 8.2% type B3, and 1.9% thymic carcinoma) staging systems. The resection was complete in 295 patients (93.1%). Operative mortality and morbidity were respectively 1.6% and 7.6%. No differences were recorded in postoperative outcome stratifying for myasthenia gravis or comorbidities. Mean follow-up was 144.7 +/- 104.4 months. The overall 5-, 10-, 20-, and 30-year survival rates were 89.9%, 84.1%, 73%, and 58.6%, respectively. The completeness of resection (p < 0.001), the Masaoka staging (p = 0.010), and the World Health Organization classification (p < 0.001) all significantly influenced the long-term survival (univariate analysis). Only completeness of resection was significantly correlated with a better prognosis (p < 0.001) in multivariate analysis. Masaoka staging (p < 0.001) and World Health Organization classification (p < 0.001) significantly correlated with the disease-free survival in the univariate and multivariate analyses as significant prognostic factors (Masaoka, p < 0.001; World Health Organization, p = 0.011). Myasthenia gravis patients showed a better prognosis in terms of long-term survival (p = 0.046) and disease-free survival (p = 0.012) in the univariate analysis.

CONCLUSIONS

We confirm the evidence that the clinical staging and the histologic classification influence long-term survival. The presence of myasthenia gravis was not significantly related to operative outcome, but prolongs both long-term survival and disease-free survival.

[Epithelial tumours of the thymus]

Epithelial tumours of the thymus include thymomas, thymic carcinomas and neuro-endocrine tumours. Rare, they nevertheless represent 20% of all mediastinal tumours and 50% of those located in the anterior mediastinum. Thymomas, in particular, can be associated to auto-immune disorders, among which predominates myasthenia gravis. Their clinical behaviour varies widely, from a relative indolence to the potential of lymph node and/or systematic metastases. However, even patients with an invasive disease may have a long clinical history, explaining that a 10-year or 20-year survival from diagnosis does not imply a definitive cure. In daily practice, both the clinical Masaoka's staging system and the WHO histological classification condition the treatment strategies and allow to anticipate the prognosis. The initial treatment, as well as that of the recurrence, is based mainly on a complete resection. Postoperative radiotherapy is systematically added to the treatment of invasive tumours and/or to those with an aggressive histological subtype. Inoperable or metastatic tumours require a cisplatine and anthracyclin-based chemotherapy, followed by radical surgery and/or radiotherapy.

Magnetic resonance imaging of radiation-induced thymic atrophy as a model for pathologic changes in acute feline immunodeficiency virus infection

The development of a protocol to reproducibly induce thymic atrophy, as occurs in feline immunodeficiency virus (FIV) infection and other immunosuppressive diseases, and to consistently estimate thymic volume, provides a valuable tool in the search of innovative and novel therapeutic strategies. Magnetic resonance imaging (MRI) using the short tau inversion recovery (STIR) technique, with fat suppression properties, was determined to provide an optimized means of locating, defining, and quantitatively estimating thymus volume in young cats. Thymic atrophy was induced in four, 8-10-week-old kittens with a single, directed 500 cGy dose of 6 MV X-rays from a clinical linear accelerator, and sequential MR images of the cranial mediastinum were collected at 2, 7, 14, and 21 days post irradiation (PI). Irradiation induced a severe reduction in thymic volume, which was decreased, on average, to 47% that of normal, by 7 days PI. Histopathology confirmed marked, diffuse thymic atrophy, characterized by reduced thymic volume, decreased overall cellularity, increased apoptosis, histiocytosis, and reduced distinction of the corticomedullary junction, comparable to that seen in acute FIV infection. Beginning on day 7 PI, thymic volumes rebounded slightly and continued to increase over the following 14 days, regaining 3-35% of original volume. These findings demonstrate the feasibility and advantages of using this non-invasive, in vivo imaging technique to measure and evaluate changes in thymic volume in physiologic and experimental situations. All experimental protocols in this study were approved by the Institutional Animal Care and Use Committee (IACUC) at Auburn University.

Long lasting response to the multikinase inhibitor bay 43-9006 (Sorafenib) in a heavily pretreated metastatic thymic carcinoma

Metastatic thymic carcinoma is an aggressive neoplasm for which multimodal therapies are often ineffective. We describe here a heavily pretreated patient with advanced thymic carcinoma responsive to multikinases inhibitor BAY 43-9006 (Sorafenib). Of note, a hitherto unreported c-kit missense mutation on exon 17 (D820E) identified in tumor cells seems to explain the clinical response and highlight the key role of molecular analysis in predicting efficacy of targeted therapies even in thymic neoplasms.