Primary Synovial Sarcomas of the Mediastinum

The Utility of Fine Needle Aspiration (FNA) Biopsy in the Diagnosis of Mediastinal Lesions

Fine needle aspiration is a minimally invasive, low-morbidity, and cost-efficient technique for the sampling of mediastinal lesions. Additionally, ancillary testing on FNA samples can be used for the refinement of diagnoses and for treatment-related purposes (flow cytometry, cytogenetics, immunohistochemistry, and molecular diagnostics). Mediastinal lesions, however, can show a variety of lineages and morphologic features, giving rise to diagnostic dilemmas. As a result, the differential diagnosis can vary widely and becomes especially challenging due to the smaller sample size on FNA and the variability in component sampling. For appropriate patient management and to determine the correct treatment strategies, accurate pathologic diagnoses are paramount. In this review, we present the cytomorphologic features together with the immunophenotypic findings of mediastinal lesions, with emphasis on the diagnostic challenges and pitfalls in FNA cytology samples, including smears and cell block sections.

Proton Beam Therapy for Unresectable Mediastinal and Pericardial Spindle Cell Sarcoma: A Case Report

Unresectable mediastinal soft tissue sarcomas are often aggressive and associated with a poor prognosis. A 17-year-old male presented with progressive fatigue, shortness of breath, and heart palpitations secondary to an extensive mass involving the mediastinum and pericardium. He was treated with chemotherapy per protocol Children's Oncology Group Protocol ARST0332 and proton beam therapy to the involved mediastinum, pericardium, and heart. At the 5-year follow-up evaluation, he remained disease-free on surveillance imaging. An echocardiogram revealed a 55% to 60% left ventricular ejection fraction. Given the patient's extended survival, we present the oncologic rationale for treatment and considerations of late toxicity.

A Case of Poorly Differentiated Synovial Sarcoma Arising in a Nasal Cavity Radiation Field: An Unusual Tumor in an Unusual Location

Synovial sarcomas are high-grade soft tissue sarcomas of primitive mesenchymal origin which are defined by a pathognomonic t(X;18)(p11,q11) translocation, and which occur in pediatric and adult populations. Herein we report a case of a 33-year-old female with a history of nasopharyngeal carcinoma status post radiotherapy, presenting with a poorly differentiated synovial sarcoma of the nasal cavity arising in the radiation field. While the development of radiation-associated sarcoma is a known complication of radiotherapy, to date only 10 cases of synovial sarcoma have been reported to occur in previously irradiated tissues. Moreover, only 1 case of poorly differentiated synovial sarcoma involving the nasopharynx has been described.

A Primary Mediastinal Monophasic Spindle-Cell Synovial Sarcoma with Superior Venacaval Obstruction

Primary mediastinal sarcoma is a rare tumour that usually presents with nonspecific symptoms such as hoarseness, dyspnoea, and chest pain. Superior vena cava (SVC) syndrome is an extremely uncommon complication that is caused by the compression, invasion, and thrombosis of the SVC or brachiocephalic veins. SVC syndrome can present as asymptomatic cases or as rare life-threatening emergencies with upper airway obstruction and increased intracranial pressure. This report describes the case of a 58-year-old female who presented with swelling of the face, neck, and upper limbs associated with dyspnoea on exertion. The radiological investigations revealed a large well-defined central necrotic peripherally enhancing lesion in the superior mediastinum extending anteriorly with the compression of brachiocephalic veins. A histopathological examination detected spindle cells arranged in fascicles with nuclear atypia with immunohistochemistry positive for creatine kinase (CK), smooth muscle actin (SMA), desmin and CD99. These findings established the diagnosis of a mediastinal monophasic synovial sarcoma with SVC obstruction. The patient was initiated on palliative radiotherapy for the management of the SVC, followed by systemic biological treatment with the tyrosine kinase inhibitor pazopanib, and was clinically improved. It is essential to promptly diagnose and treat this condition, especially when SVC syndrome manifests.

Solitary primary pulmonary synovial sarcoma: A case report

BACKGROUND

Synovial sarcoma (SS) is an uncommon and highly malignant soft tissue sarcoma in the clinic, with primary pulmonary SS (PPSS) being extremely rare. Here, we describe the clinical characteristics, diagnosis, and treatment of a solitary PPSS case confirmed via surgical resection and fluorescence in situ hybridization (FISH).

CASE SUMMARY

A 33-year-old man was admitted because of intermittent coughing and hemoptysis for one month, with lung shadows observed for two years. Whole-body positron emission tomography-computed tomography (PET-CT) revealed a solitary mass in the upper lobe of the right lung, with uneven radioactivity uptake and a maximum standardized uptake value of 5.6. The greyish-yellow specimen obtained following thoracoscopic resection was covered with small multi-nodulated structures and consisted of soft tissue. Hematoxylin and eosin staining revealed spindle-shaped malignant tumor cells. Immunohistochemistry indicated these tumor cells were CD99 and BCL-2-positive. Furthermore, the FISH test revealed synovial sarcoma translocation genetic reassortment, which confirmed the diagnosis of SS.

CONCLUSION

PPSS is extremely rare and tends to be misdiagnosed as many primary pulmonary diseases. PET-CT, histologic analysis, and FISH tests can be used to differentiate PPSS from other diseases. Surgical resection is regularly recommended for the treatment of solitary PPSS and is helpful for improving the prognosis.

Thymoma: Challenges and Pitfalls in Biopsy Interpretation

The interpretation of biopsy specimens in the diagnosis of thymoma is a subject that is generally not addressed in the literature. Even though the diagnosis of thymoma may seem to be an easy step in the assessment of these tumors, in reality, it is the biopsy specimen interpretation that will be use to determine course of action in any particular patient. It may determine whether a patient is a surgical candidate or on the contrary whether a patient may be benefited the most by medical therapy. In addition, there may be conditions in which all that is required is surgical resection without any further treatment, and that the evaluation of those conditions does not necessarily required the careful pathologic staging that thymomas need. In addition, it is important to highlight that in small biopsies, there are limitations not only in terms of the cellularity and other features that may not be present in such biopsy but also the limitation in term of immunohistochemical interpretation. Herein we have attempted to highlight numerous tumoral conditions that are frequently encountered in the daily practice of mediastinal pathology, some of them pose significant problems in separating them from thymomas. Needles to say, the entire spectrum of mediastinal pathology that may at any given time mimic thymoma is well beyond the scope of this review. Furthermore, we also herein emphasize the need for proper clinical and radiologic information and correlation in order to lead to a better interpretation of the biopsy specimen. The emphasis in this review is on thymoma and their possible pitfall and shortcomings while evaluating small biopsy specimens.

Mesenchymal Tumors of the Mediastinum: An Update on Diagnostic Approach

Mesenchymal tumors of the mediastinum are a heterogenous group of rare tumors with divergent lineages. Mediastinal mesenchymal tumors are diagnostically challenging due to their diversity and morphologic overlap with nonmesenchymal lesions arising in the mediastinum. Accurate histologic diagnosis is critical for appropriate patient management and prognostication. Many mediastinal mesenchymal tumors affect distinct age groups or occur at specific mediastinal compartments. Neurogenic tumors, liposarcoma, solitary fibrous tumor, and synovial sarcoma are common mesenchymal tumors in the mediastinum. Herein, we provide an update on the diagnostic approach to mediastinal mesenchymal tumors and a review of the histologic features and differential diagnosis of common benign and malignant mesenchymal tumors of the mediastinum.

The value of multidisciplinary team (MDT) management in the diagnosis and treatment of primary intrathoracic synovial sarcomas: a single-center experience

Background

Synovial sarcoma (SS) is a rare malignant soft tissue tumor. Primary intrathoracic SS is extremely rare, with limited diagnosis and treatment experiences. The aim of our study was to retrospectively study the clinicopathological characteristics, treatment and prognosis of primary intrathoracic SS and the impact of multidisciplinary team (MDT) management in diagnosis and treatment on patient prognosis.

Methods

The clinical and pathological characteristics, treatment, survival and prognosis of patients with primary intrathoracic SS admitted to the National Cancer Center from January 1999 to December 2018, as well as MDT intervention during diagnosis and treatment, were retrospectively analyzed.

Results

Thirteen patients were enrolled, including 7 (53.8%) males and 6 (46.3%) females, with primary intrathoracic SS in the lung (8/13, 61.5%), mediastinum (4/13, 30.8%) and pleura (1/13, 7.7%) as confirmed by morphological observation, immunohistochemical (IHC) staining and fluorescence in situ hybridization (FISH). Overall, 10/13 (76.9%) patients underwent surgery, and 6/10 (60.0%) received postoperative adjuvant therapy. Only 23.1% of patients received nonsurgical therapy. The MDT discussed and managed seven patients before and/or after surgery and one patient who did not undergo surgery. The estimated 3- and 5-year overall survival (OS) rates were 50.0% and 30.0%, respectively. Patients who were managed by an MDT had a longer median OS time than those who were not (46.0 vs. 18.0 months). Age (P=0.018), tumor location (P=0.029), and Ki-67 (P=0.020) were found to be significantly related to OS.

Conclusions

Monophasic morphology and fusion gene characteristics are the main features for the diagnosis of primary intrathoracic SS. MDT management can help obtain accurate diagnoses and provide reasonable therapeutic options.

The role of needle core biopsies in the evaluation of thymic epithelial neoplasms

Thymic epithelial neoplasms are rare tumors derived from thymic epithelium that most often present as large anterior mediastinal masses. The vast majority of thymic epithelial neoplasms fall under the diagnostic category of thymoma, with a smaller percentage qualifying for a diagnosis of thymic carcinoma. The ability to render a definitive diagnosis on these tumors is generally hampered by their deep location and close proximity to vital structures, which makes biopsy sampling for histopathologic evaluation difficult. In recent years, the trend in medicine has been to opt for the least invasive procedure to obtain tissue samples that, by definition, implies also obtaining smaller and smaller biopsies, resulting in lesser amounts of tissue available for examination. In the mediastinum, the most common modalities for procuring biopsy samples from mass lesions include fine-needle aspiration, percutaneous core needle biopsy and video-assisted thoracoscopic biopsy. In this review, we will deal only with the role and limitations of percutaneous core biopsies in the interpretation of thymic epithelial neoplasms.

Pleural malignant mesothelioma versus pleuropulmonary synovial sarcoma: a clinicopathological study of 22 cases with molecular analysis and survival data

The aim of this study was to carry out a comparative analysis by transducin-like enhancer of split 1 (TLE1) immunohistochemistry and molecular analysis of SYT-SSX, for 16 pleural predominantly sarcomatoid mesotheliomas and six cases of pleuropulmonary synovial sarcoma (five pleural in distribution only, with one case of a predominantly subpleural upper lobe synovial sarcoma), all of which were solely or predominantly monophasic. Our comparison included survival and some clinical data. We consider that the following points emerged from this study.

Mediastinal monophasic synovial sarcoma with pericardial extension causing hemodynamic instability

A 46-year-old man presented with mass on chest x-ray along with a 6-month history of weight loss, dyspnea and cough. He was hypotensive and an echocardiogram showed large extra-cardiac mass compressing the right ventricular outflow tract resulting in features of cardiac tamponade. Chest computed tomography revealed a mediastinal mass invading the pericardium adjacent to right ventricular outflow tract. Biopsy of the mass confirmed primary monophasic synovial sarcoma. Chemotherapy and radiotherapy along with anti-inflammatories were given as surgery was too high risk due to the location of the tumour and pericardial involvement. Patient responded briefly to the treatment with improvement in hemodynamic parameters but over next weeks he became less responsive to treatment with increasing size. He died 2 months after treatment commenced.

Stem cell transcription factor SOX2 in synovial sarcoma and other soft tissue tumors

BACKGROUND

SOX2 has gained considerable interest as a pluripotency inducing gene. Co-transfection of SOX2 together with NANOG, KLF4 and c-MYC into adult fibroblasts was able to generate pluripotent stem cells. SOX2 has been reported to be expressed in synovial sarcoma, a tumor being characterized by the SS18-SSX gene fusion forming part of the SWI/SNF chromatin remodeling complex that affects histone methylation. The role of SOX2 in this tumor type as well as other soft tissue tumor entities however is still poorly characterized. We analyzed SOX2 protein expression in soft tissue tumors. Alongside we tested Histone H3 expression (H3K27me3) in SOX2 positive cases to investigate this epigenetic mark and its correlation with the SOX2 status and clinicopathological parameters.

METHODOLOGY

In total, 60 samples of synovial sarcomas from the reference center for soft tissue tumors at the institute of pathology of the Jena University hospital were included into the study along with 343 other tissue tumors. Protein analysis was done by immunohistochemistry of tissue microarrays. All synovial sarcoma cases were confirmed by molecular testing using SS18 FISH break apart probes.

RESULTS

SOX2 reactivity was detectable in 35 synovial sarcoma cases (58.3%) while 25 (41.7%) were negative. Only 13 cases of the other 343 soft tissue tumors, varying from nodular fasciitis to undifferentiated pleomorphic sarcoma, revealed a SOX2 expression, 12 out of these were undifferentiated high grade sarcoma. There was no obvious correlation with the clinicopathological data. H3K27me3 immunohistochemistry of the synovial sarcoma cases revealed a high statistically significant correlation between SOX2 and H3K27me3 expression (p < 0,0005, Chi square test). Similar to SOX2, there was no correlation between H3K27me3 expression and tumor grade. Six SOX2 positive synovial sarcoma cases were analyzed by FISH using a SOX2/CEN3 dual color FISH probe. None of these cases revealed an amplification of the SOX2 gene.

CONCLUSION

The data confirms previous studies reporting SOX2 and H3K27me3 expression in synovial sarcoma and reveals that both biomarkers are related to each other. It strengthens the notion that the tumor type is driven by epigenetic processes similar to those that are operating in pluripotent stem cells. The relevance of these parameters in the pathway pathology of synovial sarcoma, i.e. the timing and dosing of SOX2 and H3K27me3 expression initiated by the SS18-SSX driver mutation together with the interplay of these events with other signaling pathways, cellular mechanisms and additional mutations in tumor progression, will require further studies.

Canine intrathoracic sarcoma with ultrastructural characteristics of human synovial sarcoma - case report

Background

Canine joint sarcomas, designated synovial sarcomas, are uncommon malignant mesenchymal neoplasms that occur in the large joints of the extremities of middle-aged, large-breed dogs. We report the diagnosis of an intrathoracic sarcoma with ultrastructural characteristics reminiscent of human synovial sarcoma in a dog.

Case presentation

A 7-year-old female spayed Tibetan terrier crossbred dog was presented for acute severe labored breathing and diagnosed with an intrathoracic neoplastic mass. The neoplasm resulted in the accumulation of substantial amounts of viscous pleural fluid that led to dyspnea. The neoplastic mass consisted of interweaving bundles of large pleomorphic mesenchymal cells, supported by an alcian blue positive myxomatous matrix. The neoplastic cells were immunohistochemically negative for cytokeratin and CD18. Transmission electron microscopy indicated that the neoplastic cells had desmosome junctions, short microvilli-like structures and ample amounts of rough endoplasmic reticulum resembling type B-like synoviocytes and synovial sarcoma as reported in people. Despite complete surgical excision of the neoplastic mass, clinical signs recurred after a month and led to the euthanasia of the dog.

Conclusion

Currently, there are no immunohistochemical markers specific for synovial sarcoma. Canine neoplasms with transmission electron microscopy characteristics resembling type B-like synoviocytes should be considered similar to the human sarcomas that carry the specific translocations between chromosomes X and 18.

Management of locally advanced primary mediastinal synovial sarcoma

Primary mediastinal synovial sarcoma (PMSS) is a relatively rare disease, and patients are treated predominantly with surgery for resectable disease. Management of locally advanced borderline resectable and unresectable PMSS is not only challenging but also lacks standard guidelines. We present three patients with PMSS, who were unresectable or borderline resectable at presentation and were treated with neoadjuvant chemotherapy followed by surgery and postoperative radiotherapy.

Primary Intraprostatic Synovial Sarcoma

Primary intraprostatic synovial sarcoma is a rare presentation of an otherwise well-studied disease, and it is one of the few primary sarcomas to occur in the prostate. Ancillary diagnostic techniques including immunohistochemistry and molecular genetics are useful to establish a definitive diagnosis. Despite its unorthodox location, it shares histologic and molecular genetic characteristics with tumors found elsewhere in the body. Most notably, the chromosomal translocation t(X;18)(p11;q11) encodes a chimeric transcription-activating protein, SS18-SSX, which has been identified as the primary driver mutation. The SS18-SSX fusion gene provides a consistent and dependable means of establishing a definitive diagnosis via reverse transcription-polymerase chain reaction or fluorescence in situ hybridization. Recent studies have continued to provide insight into the oncogenesis of this disease. The goal of this review is to elaborate on the clinicopathologic characteristics and underline those techniques that best facilitate the diagnosis of primary intraprostatic synovial sarcoma.

Morphological spectrum of mediastinal lesions with special emphasis on evaluation of needle biopsy: An experience from a tertiary care hospital

Background & objectives:

Mediastinal lesions are uncommon and are infrequently encountered in routine clinical practice. Hence, there is a need for more elaborate studies of mediastinal lesions to make the pathologists and clinicians aware of the large spectrum of these lesions. The present study describes the histomorphological spectrum of various mediastinal lesions in a tertiary care hospital in India, along with the discussion of some unusual and interesting cases. Considering the limited diagnostic material obtained in guided biopsies, the adequacy of such tissue for providing a definite opinion was also evaluated.

Methods:

This was a retrospective study performed on 125 mediastinal masses diagnosed on surgically resected specimens as well as needle biopsies over a period of two years (January 2012-December 2013). A few cases had inadequate diagnostic material, making a total of 116 cases which were further evaluated.

Results:

A total of 116 patients of mediastinal lesions were included in the study. Most of the lesions were in 21-30 yr age group, with male:female ratio of 1.7:1. Anterior mediastinal compartment was most commonly involved. Majority of the cases (62.1%) were of neoplastic nature, with benign tumours (34.5%) being more common than malignant ones (27.6%). Thymoma followed by lymphoma constituted the most common mediastinal tumours. One-third of the total cases were diagnosed on needle biopsy samples. All cases where needle biopsy was followed by resection specimen showed concordant diagnosis. The percentage adequacy of biopsy was 91.7 per cent and the diagnostic accuracy was 100 per cent.

Interpretation & conclusions:

This study provides the histomorphological spectrum and biological diversity of the mediastinal lesions. It also emphasizes that biopsy is sufficiently adequate, with the help of a comprehensive immunohistochemistry panel, for providing a definite diagnosis in majority of cases.

Primary Salivary Gland Type Tumors of the Thymus

The existence of primary salivary gland type tumors (SGTs), similar to those occurring in the major salivary glands, is well known in the thoracic cavity. When they occur in this anatomic area, these tumors more commonly arise from the lung. However, the existence of these tumors primarily affecting the thymus, although recognized in the literature, is rather not well documented or known. In addition, contrary to the primary lung SGTs, which are predominantly of the malignant type, these tumors when occur in thymus encompass a wider spectrum of biology ranging from benign to low grade, and high grade malignancy. The recognition of SGTs in the thymus, even though rare, is important to properly address treatment and prognosis. Herein, we will discuss the numerous benign a malignant SGTs that have been described in the thymus and highlight the difficulty that these tumors may pose when occurring in the thymic area.

Primary pleuropulmonary and mediastinal synovial sarcoma: a clinicopathologic and molecular study of 26 genetically confirmed cases in the largest institution of southwest China

BACKGROUND

Primary pleuropulmonary and mediastinal synovial sarcomas (PPMSSs) are extremely rare. The authors present the largest series in an Asian population.

METHODS

Between 2000 and 2015, 26 genetically confirmed PPMSSs were included. The clinicopathologic features of all of the cases were reviewed. Immunohistochemical staining was carried out using the following antibodies: TLE1, cytokeratin (AE1/AE3), EMA, CD99, Bcl-2, CK7, CD34, S-100 protein, and Ki-67. The chromosomal translocation t(X;18)(p11.2;q11.2) was detected by fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT-PCR). We compared the clinical, pathologic, immunohistochemical, and molecular features of this series with that of the previous series and soft tissue synovial sarcomas.

RESULTS

This series included 17 males and nine females. The median age was 36.5 years (range, 16-72 years). The tumors involved the lung (76.9 %), pleura (15.4 %), and mediastinum (7.7 %). The median tumor size was 6 cm (range 2.3 ~ 24 cm). The majority of the tumors were well-circumscribed. The tumors were classified as monophasic (84.6 %), biphasic (3.8 %), and poorly differentiated (11.5 %) types. The tumors were graded as French Federation of Cancer Centers (FNCLCC) grade 2 (62.5 %) and FNCLCC 3 (37.5 %). Diffuse immunostaining for TLE1, BCL-2, and CD99 was identified in 91.7, 95.7, and 56.0 % of the tumors, respectively. Focal positivity was seen with EMA (84.6 %), CK7 (55.6 %), cytokeratin (AE1/AE3) (68.0 %), CD34 (5.0 %), and S-100 protein (21.7 %). A high Ki-67 index (≥10 %) was observed in 91.3 % of the tumors. The fusion transcripts included SS18-SSX1 (15/22, 68.2 %), SS18-SSX2 including variants (6/22, 27.3 %), and SS18-SSX4 (1/22, 4.5 %) fusions. The remaining four cases showed positivity for SS18 rearrangement by FISH. Surgical excision of tumors or lobectomy were performed in 20 patients, and seven of the patients underwent adjuvant therapy. Clinical follow-up was available in 73.1 % cases, with a median follow-up of 12.0 months. The median survival time was 14.5 months. Tumor resection (p = 0.024) and no residual tumor (p = 0.004) were associated with an improved overall survival time.

CONCLUSIONS

PPMSS is a highly aggressive neoplasm. Extensive surgical resection of the tumor and more effective adjuvant therapy should be advocated. PPMSS must be differentiated from similar diseases.

Primary Pulmonary Synovial Sarcoma Showing a Prolonged Survival with Multimodality Therapy

A 54-year-old man was referred to our hospital due to a mass shadow noted on a chest X-ray. Thoracoscopic lobectomy yielded a diagnosis of primary pulmonary synovial sarcoma according to the histology and SYT-SSX1 gene analyses. Five months after the thoracic surgery, he developed brain metastasis; therefore, we performed resection of the brain metastatic focus followed by radiotherapy. As a local recurrence in the thoracic cavity concurrently emerged, systemic chemotherapy was also administered. These observations indicated that a multidisciplinary approach may be useful against primary pulmonary synovial sarcoma, although there is presently no established therapeutic strategy due to its rarity and highly aggressive nature.

Mesenchymal tumours of the mediastinum--part II

This is the second part of a two-part review on soft tissue tumours which may be encountered in the mediastinum. This review is based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart and provides an updated overview of mesenchymal tumours that have been reported in the mediastinum.

Primary Mediastinal Synovial Sarcoma Presenting as Superior Vena Cava Syndrome: A Rare Case Report and Review of the Literature

Primary mediastinal sarcomas are aggressive tumors with a very rare incidence. This report describes the case of a 35-year-old male patient who presented with acute symptoms of dyspnoea, facial puffiness, voice-hoarseness, and engorged neck veins. With the clinical picture consistent with the superior vena cava (SVC) syndrome, the patient was investigated with computed tomography of the chest. This revealed a large soft tissue density mass lesion compressing the SVC along with other critical superior mediastinal structures. Histopathological evaluation of the mass revealed features consistent with a soft tissue sarcoma and positive staining was observed for vimentin and S-100. Cytogenetic analysis by fluorescent in situ hybridisation (FISH) demonstrated the t(X:18) translocation. Thus diagnosis was established as primary mediastinal synovial sarcoma. Patient was treated with three cycles of neoadjuvant chemotherapy, to which there was a partial response as per the RECIST criteria. Surgical excision of the mediastinal mass was performed, and further postoperative treatment with adjuvant chemoradiotherapy was provided. Patient currently is free of disease. This is to the best of our knowledge the first report in the world literature of a successfully treated case of “primary mediastinal sarcomas presenting as SVC syndrome.” Patient is under regular surveillance at our clinic and remains free of recurrence one year after treatment completion.

Synovial sarcoma of the chest wall: a case report and literature review

Synovial sarcoma is a malignant soft-tissue tumor that most commonly occurs in the extremities of young adults. Synovial sarcoma arising from the chest wall is rare and only some cases had been reported in the literature. We present a 57-year-old woman who presented with chest pain. Radiologic evaluation revealed a right parietal tumor destructing the mid-portion of the 8(th) rib, with heterogeneous enhancement and invasion of the pectoral muscle and extra pleural fat. A surgical resection consisting in parietectomy was achieved. The histological and immunohistochemical findings were consistent with synovial sarcoma. An adjuvant chemotherapy was prescribed but the patient was lost of view. She presented 6 months later with a recurrent huge parietal mass.

Synovial sarcoma: defining features and diagnostic evolution

Synovial sarcoma (SS) is a malignant mesenchymal neoplasm with variable epithelial differentiation, with a propensity to occur in young adults and which can arise at almost any site. It is generally viewed and treated as a high-grade sarcoma. As one of the first sarcomas to be defined by the presence of a specific chromosomal translocation leading to the production of the SS18-SSX fusion oncogene, it is perhaps the archetypal "translocation-associated sarcoma," and its translocation remains unique to this tumor type. Synovial sarcoma has a variety of morphologic patterns, but its chief forms are the classic biphasic pattern, of glandular or solid epithelial structures with monomorphic spindle cells and the monophasic pattern, of fascicles of spindle cells with only immunohistochemical or ultrastructural evidence of epithelial differentiation. However, there is significant morphologic heterogeneity and overlap with a variety of other neoplasms, which can cause diagnostic challenge, particularly as the immunoprofile is varied, SS18-SSX is not detected in 100% of SSs, and they may occur at unusual sites. Correct diagnosis is clinically important, due to the relative chemosensitivity of SS in relation to other sarcomas, for prognostication and because of the potential for treatment with specific targeted therapies in the near future. We review SS, with emphasis on the diagnostic spectrum, recent immunohistochemical and genetic findings, and the differential diagnosis.

Lipomatous tumors of the anterior mediastinum with muscle differentiation: a clinicopathological and immunohistochemical study of three cases

Three cases of primary lipomatous tumors of the anterior mediastinum with prominent muscle differentiation are presented. The patients were two women and one man between the age of 52 and 68 years. All patients presented with progressive shortness of breath. Radiographically, all patients demonstrated anterior mediastinal tumors which were surgically resected. In two cases, the gross findings were those of circumscribed tumors, while one lesion was described as an ill-defined and unencapsulated neoplasm. Histologically, two cases corresponded to a well-differentiated liposarcoma, while the third was a thymolipoma. Extensive areas of smooth muscle were identified in one of the liposarcomas, while the other contained areas of mature skeletal muscle. The thymolipoma displayed a prominent myoid component. Immunohistochemical studies for muscle markers including smooth muscle actin, desmin, and myoglobin showed positive staining in the corresponding components. Follow-up information showed that one patient with liposarcoma died 60 months after initial diagnosis, while the other two patients remain alive and well 16 and 36 months after diagnosis, respectively. The current cases highlight the spectrum of muscle differentiation that can be seen in adipose tumors of the anterior mediastinum and also emphasize the difficulty that such a diagnosis can pose when confronted with limited mediastinoscopic biopsies.

Primary synovial sarcomas of the mediastinum: a systematic review and pooled analysis of the published literature

Background. The aim of this systematic review is to attempt to provide a descriptive analysis for cases of synovial sarcoma (SS) arising in the mediastinum and to analyze prognostic factors. Methods. We performed PubMed database search in July 2013. Twenty-two studies, which included 40 patients, form the basis of this review. Demographic and disease-related factors were analyzed for possible influence on survival. Findings were compared with extremity SS studies reported in literature. Results. Sixteen cases (40%) presented with locally advanced unresectable disease, 2 (5%) with metastatic disease, and 22 (55%) with localized resectable disease. Median tumor size was 11 cm (range: 5–20 cm). Thirty patients were assessable for survival and had a 5-year OS of 36%. Completeness of resection was the only factor associated with significant improvement in OS (5-year survival of 63% and 0% in favor of complete resection, P = 0.003). Conclusion. Mediastinal SS is associated with poor prognosis as more cases are diagnosed at an advanced stage and with larger tumor size compared to extremity SS. Complete surgical resection is the only identified factor associated with better prognosis and may result in survival outcomes that are comparable with those for localized SS of the extremity.

Primary mediastinal sarcoma: surgical outcomes of 21 cases

OBJECTIVES

Primary sarcomas of the mediastinum are relatively rare. This article reviews the surgical outcomes of 21 cases diagnosed with localized mediastinal sarcomas receiving multidisciplinary treatment modalities in Sichuan province, China, from January 1996 to January 2011.

METHODS

Twenty-one cases of histologically diagnosed primary mediastinal sarcoma undergoing surgical treatment were reviewed retrospectively. Disease-free survival (DFS) and overall survival (OS) were statistically analysed. All the patients presented with localized tumours consisting of 5 females and 16 males with a median age of 41.0 years (range: 9.0-68.0 years). Among all cases, 17 (81.0%) had an Eastern Cooperative Oncology Group performance status score of ≤1 at diagnosis. Eight (38.1%) underwent macroscopically complete resection (R0-R1) and 13 (61.9%) had incomplete resection (R2). Ten (47.6%) received postoperative radiotherapy and 7 (33.3%) postoperative chemotherapy.

RESULTS

The median DFS was 17 months (range: 0.4-79.8 months) and the median OS was 27.2 months (range: 0.4-79.8 months). Patients receiving complete resection showed significantly improved DFS (P = 0.031) and OS (P = 0.035) compared with those with incomplete resection. Neither postoperative radiotherapy nor chemotherapy significantly improved DFS (P = 0.770, P = 0.756) or OS (P = 0.905, P = 0.738). However, 7 patients (R2) and 2 (R0-R1 and grade 3) had improved local control with a local recurrence-free survival of 28.9 months (range: 7.6-73.2 months).

CONCLUSIONS

Complete resection should be preferentially attempted compared with incomplete resection and postoperative radiotherapy might yield good local control.

Primary monophasic synovial sarcoma of the liver in a 13-year-old boy

Synovial sarcoma originating in the liver is extremely rare, and thus far only 3 cases have been reported in the English literature. Herein, we report a primary hepatic synovial sarcoma in a 13-year-old Chinese boy. This patient present with a 10-day right upper quadrant pain, and a heterogeneous mass was documented in the right hepatic lobe by computed tomography. Subsequently, the patient underwent right hepatectomy. Histologically, the tumor exhibited classic features of monophasic synovial sarcoma. The diagnosis was confirmed by the presence of SS18 gene rearrangement and identification of SS18-SSX1 fusion transcript. Unfortunately, a relapsing mass was detected 11 months after the surgery. To the best of our knowledge, the current case is the 1st published example in the pediatric population.

Challenges and controversies in the diagnosis of malignant mesothelioma: Part 2. Malignant mesothelioma subtypes, pleural synovial sarcoma, molecular and prognostic aspects of mesothelioma, BAP1, aquaporin-1 and microRNA

Pleural malignant mesothelioma (MM) includes several unusual and even rare but distinctive histological subtypes, in addition to the usual subdivision into epithelioid, biphasic and sarcomatoid MM. Criteria for discrimination between fibrous pleuritis versus desmoplastic mesothelioma include evidence of neoplastic invasion for diagnosis of desmoplastic MM, but this histological assessment is complicated by the recently-described 'fake fat phenomenon' in cases of fibrous pleuritis. The distinction between biphasic and monophasic synovial sarcoma of the pleura versus biphasic and sarcomatoid MM can be problematical and is most cogently based upon molecular detection of the t(X;18) translocation, whereas a clear diagnosis of MM for a pleural tumour histologically resembling synovial sarcoma is favoured by a negative result for this translocation and, probably, microRNA evidence supportive of a diagnosis of MM. Aquaporin-1 (AQP1) is a molecule involved in the growth of MM cells, and yet is a factor reported to correlate with improved survival rates for MM with an epithelioid component, in comparison to AQP1-poor MM, as assessed from AQP1 expression by epithelioid MM cells only (apart from co-expression by stromal endothelial cells in addition to the tumour cells). Recent reports have also focused upon germline mutations in the BRCA1-associated protein 1 (BAP1), not only in cases of familial mesothelioma, but also BAP1 deletion in sporadic MM. Prognostic factors for MM include not only the histological subtypes, but other independent variables that include (among others), AQP1 expression by mesothelioma cells, the clinical status of the patient, the serum neutrophil:lymphocyte ratio and blood thrombocytosis.

Synovial sarcoma presenting with huge mediastinal mass: a case report and review of literature

Background

Synovial sarcoma presenting in the mediastinum is exceedingly rare. Furthermore, data addressing optimal therapy is limited. Herein we present a case where an attempt to downsize the tumor to a resectable state with chemotherapy was employed.

Case presentation

A 32 year female presented with massive pericardial effusion and unresectable huge mediastinal mass. Computed axial tomography scan - guided biopsy with adjunctive immunostains and molecular studies confirmed a diagnosis of synovial sarcoma. Following three cycles of combination Ifosfamide and doxorubicin chemotherapy, no response was demonstrated. The patient refused further therapy and had progression of her disease 4 months following the last cycle.

Conclusion

Synovial sarcoma presenting with unresectable mediastinal mass carry a poor prognosis. Up to the best of our knowledge there are only four previous reports where primary chemotherapy was employed, unfortunately; none of these cases had subsequent complete surgical resection. Identification of the best treatment strategy for patients with unresectable disease is warranted. Our case can be of benefit to medical oncologists and thoracic surgeons who might be faced with this unique and exceedingly rare clinical scenario.

The surprising outcome of a giant primary mediastinal synovial sarcoma treated with neoadjuvant chemotherapy

There are only a few cases of primary mediastinal synovial sarcoma in the literature. Normally, they do not respond well to chemotherapy. In our case, a 30-year-old patient was admitted due to thoracic pain, dyspnea, orthopnea, cough, hoarseness and weight loss over a 3-month period as well as a dramatic worsening a week before the admission. A chest radiography showed a completely white left hemithorax and contralateral mediastinal shift; in addition, a chest tomography revealed a giant heterogeneous mediastinal mass, lung atelectasia and a small pleural effusion. The patient was submitted to Chamberlain procedure (biopsy) under local anesthesia and the diagnosis of a synovial sarcoma was obtained after immunohistochemical analysis. Due to his poor general condition, he received chemotherapy first, with a dramatic response, after what, the mass that had been reduced was removed surgically. After a 5-year- follow-up period there are no signs of disease recurrence.

Primary intravascular synovial sarcoma: case report

Synovial sarcoma (SS), a mesenchymal spindle cell tumor, displays variable epithelial differentiation, including glandular formation, and features a specific chromosomal translocation, t(X;18)(p11;q11). SS accounts for 5% to 10% of soft-tissue sarcomas. These tumors occur mostly in the joints, especially near the knee, but they also occur in other locations. Primary intravascular SS (IVSS) are extremely rare; only 6 well-documented cases have been reported in the English literature. We describe a new case of primary IVSS of the superior vena cava (SVC) in a 16-year-old boy. A transthoracic echocardiogram confirmed a large (4.8 × 4.6 cm) circumscribed mass filling the right atrium, as well as a moderate pericardial effusion. The mass extended from the SVC to the tricuspid valve but did not prevent valve coaptation. Surgery via a transatrial approach revealed a huge mass (8 to 12 cm) attached to the SVC via a 5-mm pedicle. The tumor was excised, and the patient experienced an uneventful postoperative course. Fluorescence in situ hybridization analysis revealed the presence of the SS-specific translocation.

Thymic carcinoma, part 1: a clinicopathologic and immunohistochemical study of 65 cases

The clinicopathologic and immunohistochemical features of 65 primary thymic carcinomas are reported (43 men and 22 women; 19-81 years old). Thymectomy was performed in all cases. Masaoka staging for 53 patients showed 3 patients in stage I, 14 in stage II, 17 in stage III, and 19 in stage IV. Histologic studies revealed 9 carcinoma subtypes. Immunohistochemically, the tumors showed high rates of expression for cytokeratin, Pax8, and FoxN1. Follow-up for 62 patients revealed that 36 patients were alive (mean follow-up, 51.1 months) and 26 had died (mean survival, 47.5 months). The 3- and 5-year overall survival rates were 76.6% and 65.7%, respectively. Our findings suggest that thymic carcinomas may behave less aggressively than commonly believed. Lymph node status and tumor size seem to be important prognostic factors. The Masaoka staging system does not seem to reliably predict outcome.

Synovial sarcoma: CT imaging of a rare primary malignant tumour of the thorax

PURPOSE

This paper presents computed tomography (CT) features of three patients with primary synovial sarcoma of the lung (PSSL) who came to our attention and underwent surgery; reviews of the literature on this rare thoracic tumour are also presented.

MATERIALS AND METHODS

The patients, all men, with a mean age of 58 years, underwent clinical and radiological re-evaluation after receiving a histological diagnosis. None of the patients had multifocal disease or other concomitant neoplasms. All patients had undergone both chest X-rays and computed tomography, and two had also been studied with positron emission tomography (PET)-CT. Two patients underwent surgical removal of the tumour, whereas the third initially underwent surgery (following an incorrect diagnosis) and then thoracoscopic biopsy of the pleural lesions that subsequently arose.

RESULTS

In each case, chest X-rays showed changes, with the presence of pulmonary masses noted in all patients. In one patient, pleural effusion was also visible. CT scans showed parenchymal masses that were largely of a colliquative nature (in two out of three patients). Ipsilateral pleural effusion was present in two patients, associated in one with solid nodules within the pleura. Mediastinal lymphadenopathy, which was not radiologically significant, was present in only one patient. The two patients who also underwent PET-CT examination showed pathological tracer uptake confined to the lesion site without other thoracoabdominal or musculoskeletal localisations. CT-guided biopsy, performed in one patient only, was positive for mesenchymal tumour. In the two patients who underwent surgery, a definitive diagnosis of monophasic synovial sarcoma of the lung was made. The diagnosis of monophasic synovial sarcoma in the third patient was confirmed using thoracoscopic biopsy

DISCUSSION

Both in the cases described and in those identified in the literature review, standard chest X-rays mainly showed a parenchymal mass of pleural origin with either irregular or well-defined margins. CT characteristics are more definite, with evidence of a mass with regular and sharply defined margins, occasionally polycyclic, with inhomogeneous density due to the presence of colliquative areas within the tumour.

CONCLUSIONS

Although PSSL is a rare tumour, a pulmonary mass of inhomogeneous density, associated with pleural effusion but without lymphadenopathy, detected in an asymptomatic or poorly symptomatic patient, should lead to PSSL being considered in the differential diagnosis, provided that metastases from the more common synovial sarcomas of the musculoskeletal system have been excluded.

[Primary mediastinal sarcomas]

INTRODUCTION

Primary sarcomas of the mediastinum are rare and account for 2 to 8% of malignant mediastinal tumours. The aim of this study is to describe their clinical and pathological characteristics.

PATIENTS AND METHODS

Fifteen cases of primary mediastinal sarcoma, diagnosed between 1993 and 2009, were reviewed retrospectively, noting the clinical, radiological and pathological findings, and the treatment given.

RESULTS

The patient population consisted of eight females and seven males with mean age of 40 years (14 to 73 years). The symptomatology was predominately respiratory. Imaging showed a mediastinal mass invading adjacent organs in nine cases. The diagnosis was made in all cases by histological examination. These 15 mediastinal sarcoma comprised 12 malignant peripheral nerve tumours, two liposarcomas and one angiosarcoma. Three were grade III, six grade II and six grade I. Ten were treated surgically, of which seven had radical resections. Associated treatments were neoadjuvant (one case) or adjuvant (one case) chemotherapy and postoperative radiotherapy (five cases). Radiotherapy was undertaken alone in three inoperable tumours. Eight patients (53%) had died.

CONCLUSION

Management of primary mediastinal sarcoma needs a multidisciplinary approach, and is based mainly on radical resection. The prognosis is poor and depends mainly on surgical excision and histological grade.

Primary synovial sarcoma of the mediastinum : a case report

Synovial sarcomas commonly occur in the extremities of young adults. A primary occurrence in the mediastinum is very rare with only a few reported cases in the world literature. This paper is about a 42-year-old male who presented with chest pain and dyspnoea on exertion. Imaging showed an anterior mediastinal mass with adhesions to the lung. Pathological examination of the resected mass showed a biphasic neoplasm with a spindle cell component admixed with gland-like elements. The tumour showed positive staining with cytokeratin, epithelial membrane antigen, and Bcl-2 confirming the diagnosis of a biphasic synovial sarcoma. A wide range of neoplasms, both primary and metastatic, occur in the mediastinum, which pose considerable diagnostic difficulties. A synovial sarcoma should always be considered in the differential diagnosis, and immunohistochemistry is an important adjuvant tool in this situation. This paper highlights the importance of recognizing an unusual presentation of this aggressive neoplasm to aid appropriate clinical management.

Synovial sarcoma of the lung presenting late with compression of mediastinal structures and its successful resection: A case report

Synovial sarcoma accounts for 5-14% of all soft tissue tumours. We present a case of 35 year-old male who presented with five months history of progressively increasing shortness of breath and cough. On evaluation, there was no air entry on the left side. CAT scan chest showed a large necrotic mass involving the entire left hemi-thorax. The tru-cut biopsy of this mass was done and it showed synovial sarcoma. The entire tumour along with the lung and the pericardium was removed completely. The patient had an uneventful recovery and was discharged home in 10 days with follow-up for adjuvant chemotherapy. Due to the rarity of this disease, no guidelines for the treatment are available. Main existing treatment includes surgery followed by either radiation, chemotherapy or both. Synovial sarcoma should be considered in the differentials of an adolescent or adult male patient presenting with a mass in the thorax.

Synovial sarcoma of the thoracic spine

BACKGROUND CONTEXT

Synovial sarcoma is an uncommon malignant neoplasm occurring chiefly in young adults. It often presents as a solid well-circumscribed soft-tissue mass in the extremities of young adults. Despite its proximity to joints, it has been well established that the tumor cells do not display features of synovial differentiation but instead appear to have a primitive epithelial phenotype. There is no report of a lower thoracic paravertebral synovial sarcoma in an adult male.

PURPOSE

To describe our management in a patient with a synovial sarcoma of the thoracic spine and to review previously published cases.

STUDY DESIGN

Case report.

METHODS

A 60-year-old man presented with a 5-month history of right upper quadrant abdominal pain radiating to his back in a band-like fashion; shortness of breath on exertion; and increasing pain when standing, sitting, or walking. Magnetic resonance imaging (MRI) demonstrated a large right-sided paraspinal mass sitting on the eighth and ninth ribs, pressing on the T9 vertebrae and abutting the T7 and T8 vertebral level exhibiting "Triple Intensity." Plain films demonstrated a right-sided paraspinal mass extending from the T7-T8 level to T10. Bone scintigraphy showed increased uptake on the right thoracic spine at T7-T8 to T10. Computed tomography (CT) imaging revealed a right paraspinal mass with lytic changes in the T9 vertebral bodies. A right-sided thoracotomy was performed, and the patient underwent subsequent radiation therapy. Absence of the tumor was shown by an MRI scan after the operation.

RESULTS

Complete resolution of the patient's complaints was achieved. The diagnosis is supported by plain radiographs, bone scintigraphy, magnetic resonance and CT imaging studies, and histologic and immunohistochemical evidence.

CONCLUSIONS

Synovial sarcomas are rarely present in the paravertebral region of the thoracic spine. A careful radiographic study of the tumor permitted early preliminary diagnosis, confirmed upon histopathologic analysis. Despite lytic changes, removal of a periosteal layer permitted sparing of the vertebral bodies.

Primary mediastinal synovial sarcoma: a case report and review of the literature

Primary mediastinal synovial sarcoma is a rare malignancy with only a few cases reported so far. A 56-year-old woman was admitted to our hospital for an investigation of a nodule in the left middle lung on chest radiography. Computed tomography revealed a mediastinal mass first described as a solitary fibrous tumor. The diagnosis of synovial sarcoma was established by computed tomography-guided percutaneous needle biopsy. Work up showed no metastasis to distant organs or contralateral pleural cavity. The mass was surgically resected; pathological and immunohistochemical analyses confirmed the diagnosis of a monophasic spindle cell synovial sarcoma probably originating from phrenic nerve. The patient received adjuvant chemotherapy and radiation and is free of recurrence after a follow up of 16 months.