Tonsillar synovial sarcoma, unusual anatomical location: case report and literature review.

BACKGROUND: Synovial sarcoma is a rare soft tissue malignancy, occasionally found in the head and neck region. The diagnosis necessitates a multidisciplinary approach involving the clinical presentation, proper imaging studies and histological confirmation, with molecular testing for definitive identification. Treatment entails surgical resection with adjuvant therapies as needed. CASE PRESENTATION: A 33-year-old male patient presented with globus sensation concomitant with right-sided neck swelling. He was clinically found to have right tonsil enlargement with posterior extension. Therefore, he underwent right tonsillectomy with pharyngoplasty. Histopathological examination revealed a biphasic tumor consistent with synovial sarcoma, confirmed by immunohistochemistry and fluorescence in situ hybridization. CONCLUSIONS: Tonsillar synovial sarcoma represents a diagnostic challenge, requiring a high index of suspicion and comprehensive evaluation. With only twenty previously published cases documented in the literature, awareness of this rare presentation is crucial for prompt diagnosis and appropriate management. Collaboration among multidisciplinary healthcare teams and ongoing research efforts are essential for optimizing diagnostic accuracy, treatment efficacy, and patient outcomes in this rare malignancy.

A minute primary gastric synovial sarcoma with ulcer: a case report.

BACKGROUND: Synovial sarcomas are a rare type of high-grade sarcomas with unknown cell origin. They arise predominantly in the soft tissues but rarely in the stomach. We recently encountered a rare case of minute gastric synovial sarcoma. CASE PRESENTATION: A 61-year-old Japanese woman was pointed out edematous erosion at the body of the stomach. Biopsy specimen showed dense proliferation of spindle-shaped tumor cells mixed with smooth muscle fibers of the muscularis mucosae. Although the definite histological diagnosis was undetermined, the patient underwent laparoscopic wedge resection of the stomach. Histological examination of the resected sample revealed that the maximum diameter of the tumor was only 6 mm and that dense proliferation of rather uniform spindle tumor cells were observed mainly in the submucosa. Immunohistochemistry showed that they were positive for pan-keratin, CD99 and TLE1. SS18-SSX fusion-specific antibody gave diffuse positive staining to the tumor cells, and analysis using mRNA extracted from paraffin sections revealed that the tumor had SS18-SSX1 fusion gene. Thus, it was diagnosed as gastric synovial sarcoma, monophasic fibrous type. CONCLUSIONS: Primary synovial sarcoma of the stomach is rare and only 47 cases have been reported in the English literature to date. The maximum diameter of the lesion of our case was 6 mm which is the smallest among them.

Usefulness of SS18-SSX antibody as a diagnostic marker for pulmonary metastatic synovial sarcoma.

BACKGROUND: The novel SS18-SSX fusion-specific antibody is reported to have high sensitivity and specificity for the diagnosis of primary synovial sarcoma (SS), which often metastasizes to the lung. Thus far, no study has validated the diagnostic efficacy of SS18-SSX antibody for pulmonary metastatic SS. Therefore, we aimed to investigate the usefulness of the SS18-SSX antibody in the diagnosis of pulmonary metastatic SS. METHODS: We evaluated the immunohistochemistry of SS18-SSX fusion-specific antibody (E9X9V) in 10 pulmonary metastatic SS cases and the corresponding five primary sites (four limbs and one mediastinum) in five patients, for whom SS was already diagnosed and confirmed by fluorescence in-situ hybridization in the metastatic and primary sites, and in 93 clinical and histologic mimics including 49 non-SS, pulmonary metastatic sarcomas, 39 primary lung cancers, and five intrathoracic solitary fibrotic tumors. All specimens were surgically resected at Shinshu University Hospital during 2001-2019. For primary and metastatic SS, we also evaluated SS18-SSX immunohistochemistry using needle biopsy and touch imprint cytology specimens from the primary site. RESULTS: SS18-SSX staining was diffusely-strongly positive in all 10 pulmonary metastatic SS cases and the corresponding five primary sites; whereas, it was negative in all 93 clinical and histologic mimics (100% sensitivity and 100% specificity). Further, SS18-SSX staining was also sufficiently positive in the biopsy and cytology specimens. CONCLUSIONS: Immunohistochemistry of the SS18-SSX fusion-specific antibody is useful for the differential diagnosis of pulmonary metastatic SS in clinical practice. This simple and reliable method has the potential to replace traditional genomic tests. However, further studies are warranted in this regard.

Primary cardiac synovial sarcoma: a clinicopathological, immunohistochemical, and molecular genetics study of five clinical cases.

BACKGROUND: Primary cardiac synovial sarcoma was an exceedingly rare tumor that less reported. The study investigated the clinicopathologic, immunohistochemical, and molecular features of primary cardiac synovial sarcoma. METHODS: A total of five cardiac synovial sarcoma cases were assessed and reviewed using H&E, immunohistochemical and fluorescence in situ hybridization staining methods. Clinicopathological data were retrospectively analyzed and followed up. RESULTS: The cases occurred in four males and one female ranging in age from 23 to 48 years (mean, 32 years). The tumors were grossly large and solid (7.4-13.7 cm; mean 8.6 cm). Microscopically, clinical cases were biphasic (n = 2) and monophasic (n = 3) types and were diffusely immunoreactive for EMA, vimentin, and BCL-2. All cases demonstrated SS18 rearrangement by fluorescence in situ hybridization staining. Clinically, three patients died within 1 year after surgery, while one patient had bone metastasis and still carried the disease. One last patient underwent a heart transplant and survived without evidence of the disease. CONCLUSION: Cardiac synovial sarcoma was an aggressive tumor whose differentiation may be a continuous and complex morphologic spectrum. SS18 rearrangement demonstration by fluorescence in situ hybridization was decisive in our study for differential diagnosis of cardiac synovial sarcoma and other tumors. Cardiac synovial sarcoma usually endured poor survival rates. Patients in advanced stages may undergo heart transplantation as a means of improving their survival rates.

Exploring Two Protocols of FISH Using Cytocell SYT-SSX Probe on Formalin Fixed Paraffin Embedded Tissue Sections.

BACKGROUND: Chromosomal translocation t(X;18)(p11.2;q11.2) is the cytogenetic hallmark of synovial sarcoma and have been identified as an alternative diagnostic strategy in differentiating synovial sarcoma from other histologic mimics. This study was carried out to test the efficacy of two FISH protocols using the SYT-SSX break apart probe from Cytocell. METHODOLOGY: Representative paraffin blocks of synovial sarcoma were utilized in this study. FISH study was performed on formalin-fixed paraffin embedded tissue sections using the SYT-SSX break apart probe from Cytocell, to detect two form of SYT-SSX transcript, SYT-SSX1 and SYT-SSX2. FISH protocol, including the hybridization was done following two different protocols, Cytocell FISH protocol and Optimized Dako FISH protocol. RESULTS: Tissue samples subjected to FISH using Cytocell FISH protocol showed the absence of signal corresponding to the probe used. Utilizing Optimized Dako FISH protocol, the two signals (red and green) corresponding to the break-apart probes was detected. These findings suggested that Optimised Dako FISH protocol is more suited for use with the tested probe on paraffin embedded tissues in comparison to Cytocell FISH protocol. CONCLUSION: Optimised Dako FISH protocol was noted to be more suited for detecting SYT-SSX FISH signals on paraffin embedded tissues in comparison to Cytocell FISH protocol.

Primary thyroid biphasic synovial sarcoma and synchronous papillary carcinoma: report of a remarkable case.

Synovial Sarcoma (SS) is the fourth most common soft tissue sarcoma, characterized by translocation t(X;18) (p11.2;q11.2). Although its histological features have been extensively described, this entity is characterized by a wide morphological spectrum so that the recognition can be very challenging at atypical anatomical localization, like the thyroid. We describe a case of a 42-ys-old female patient complaining a cervical swelling due to left intrathyroid nodule, measuring 35 mm in its greatest dimension. A Fine Needle Aspiration Cytology (FNAC) was performed and diagnosis of indeterminate neoplastic lesion, indefinite whether primary or metastatic, was formulated. After complete thyroidectomy, the histological picture of the nodule was characterized by a dual cellular population: several glandular structures composed by columnar cells with clear cytoplasm were embedded in a highly cellular stroma composed of spindle-shaped elements. Immunohistochemistry and molecular biology confirmed the morphological suspicion of SS identifying the fusion transcript SYT-SSX1 and thus ruling out several differential diagnoses which include more common thyroid malignancies. Moreover a synchronous papillary microcarcinoma was detected in the controlateral lobe.This case is noteworthy since it describes the synchronous presence in the thyroid of two completely different malignancies, the first one belonging to the soft tissue neoplasm category and the other one originating from the thyroid follicular epithelium.

[Primary Pulmonary Synovial Sarcoma;Report of a Case].

A 66-year-old man was referred to our hospital for an abnormal shadow. Chest computed tomography (CT)showed a heterogeneous mass with well-defined border in the right S10and ipsilateral pleural effusion. Fluorodeoxyglucose-positron emission tomography(FDG-PET)showed the accumulation in the mass and pleural effusion. Right lower lobectomy with lymphnode dissection was performed for diagnosis and treatment. Histologically,the tumor was mainly composed of complicated spindle-shaped cells with extensive necrosis, showing a large number of nuclear fission images. Immunohistochemistry showed the tumor cells to be positive for cytokeratin AE1/AE3, Bcl-2, EMA, vimentin and negative for TTF-1, S-100, calretinin, CD34, being compatible with monophasic fibrous synovial sarcoma.

Primary Synovial Sarcoma of the Kidney: A Rare Presentation.

Primary renal synovial sarcoma (PRSS) is a rare entity. It should be considered as one of the differential diagnoses of spindle cell tumors of the kidney. Immunohistochemistry and genetic translocation studies should be used to confirm the diagnosis. Because of a lack of consistent literature data regarding the treatment options, management of PRSS remains a therapeutic challenge. In view of the chemosensitive nature of the tumor, we propose a multimodality treatment in form of surgery and chemotherapy in patients with PRSS. Here we report a rare case of PRSS in a 17-year-old adolescent.

Primary dura-based synovial sarcoma of the parafalcine region of brain.

Dura-based intracranial neoplasms include a wide range of primary and metastatic tumors, varying in their clinical, radiologic, morphologic, and immunophenotypic characteristics. At this anatomic location, sarcomas are rare, however, they exhibit close morphologic resemblances to meningioma. Herein we describe the third case of primary synovial sarcoma of the parafalcine region in a50-years-old female, who presented with left-sided hemiplegia. The radiologic survey revealed a 5.5cm×5.8cm contrast enhancing dura-based mass at the right parafalcine region with meningeal enhancement and edema in the surrounding areas. Morphologic evaluation exhibited a high-grade spindle cell neoplasm, with focal hemangiopericytomatous pattern. The tumor cells were diffusely immunoreactive for CD99, Bcl2, TLE-1, and vimentin. The Ki-67 proliferation index was 40%. Pancytokeratin was focally positive. Epithelial membrane antigen, progesterone receptor, CD34, S-100, and glial fibrillary acidic protein were negative. Fluorescence in situ hybridization confirmed tumor specific translocation t(X;18)(p11.2;q11.2). Hence, final diagnosis of synovial sarcoma was rendered. Primary meningeal synovial sarcoma should be considered in the differential of aggressive and high-grade dura-based tumors in view of their relative chemosensitivity and future prospect of a molecular target-based therapy. The index case highlights the importance of an extensive pathologic analysis of high-grade mesenchymal lesions of the meninges to arrive at a definitive diagnosis and differentiate such tumors from other usual dura-based tumors, which has important therapeutic and prognostic implications.

Biphenotypic sinonasal sarcoma: an expanded immunoprofile including consistent nuclear ß-catenin positivity and absence of SOX10 expression.

Biphenotypic sinonasal sarcoma (BSNS) is a recently recognized low-grade sarcoma that exhibits both neural and myogenic differentiation. This unique dual phenotype stems from recurrent rearrangements in PAX3, a transcription factor that promotes commitment along both lineages. While identification of PAX3 rearrangements by fluorescence in situ hybridization (FISH) can confirm a BSNS diagnosis, this assay is not widely available. This study evaluates whether an expanded immunohistochemical panel can facilitate recognition of BSNS without molecular analysis. Eleven cases of BSNS were identified from the surgical pathology archives of two academic medical centers. In 8 cases, the diagnosis was confirmed by FISH using custom probes for PAX3. In 3 cases, FISH failed but histologic and immunophenotypic findings were diagnostic for BSNS. All 11 BSNS (100%) were at least focally positive for S100 as well as calponin and/or smooth muscle actin. In addition, 10 (91%) of 11 expressed nuclear ß-catenin, 8 (80%) of 10 expressed factor XIIIa, 4 (36%) of 11 expressed desmin, and 3 (30%) of 10 expressed myogenin. All 11 tumors were negative for SOX10. While no single marker resolves immunohistochemical overlap between BSNS and its histologic mimickers such as nerve sheath tumors, an extended immunohistochemical panel that includes ß-catenin and SOX10 helps to support the diagnosis of BSNS without the need for gene rearrangement studies.

Rare presentation of four primary pediatric cardiac tumors.

Pediatric cardiac tumors are extremely rare and usually benign. We selected four unique cases of pediatric cardiac tumors from a 15-year period at our institution. The four chosen cases represent unique, rare primary tumors of the heart. Our selection includes a case of Rosai Dorfman disease without systemic involvement, which is, to our knowledge, the second case of isolated cardiac Rosai Dorfman disease in a child. We present a case of subtotal replacement of myocardium by granulocytic sarcoma with minimal bone marrow involvement, representing the first reported case in a child manifested as hypertrophic cardiomyopathy, as well as a case of a primary synovial sarcoma arising from the atrioventricular (AV) node, representing the fourth reported pediatric case of a cardiac synovial sarcoma, and it is the first to arise from the AV node. Finally, we present a primary congenital infantile fibrosarcoma of the heart, which is, to our knowledge, the first confirmed cardiac congenital infantile fibrosarcoma. These four cases represent the need for continued inclusion of rare cardiac conditions in a clinician's differential diagnosis. Furthermore, they present the need for more in-depth molecular and genomic analysis of pediatric cardiac tumors in order to identify their etiopathogenesis.

Primary pulmonary monophasic synovial sarcoma: Evading diagnosis.

Primary pulmonary synovial sarcoma is a very rare tumor, thus there is no consensus as to the most appropriate management. A 78-year-old man presented with nonspecific symptoms of weight loss and shortness of breath. Imaging confirmed a large right-sided mass and accompanying pleural effusion. Strong 18F-fluorodeoxyglucose uptake was found on positron-emission tomography. The preoperative work-up and intraoperative frozen section were inconclusive. Immunohistochemistry and molecular analysis confirmed the diagnosis of primary pulmonary monophasic synovial sarcoma.

The diagnostic utility of reduced immunohistochemical expression of SMARCB1 in synovial sarcomas: a validation study.

Synovial sarcoma is a malignant mesenchymal neoplasm of uncertain histogenesis, characterized by a specific SS18-SSX fusion. The diagnosis of synovial sarcoma can be challenging based on morphology and conventional immunohistochemistry alone, and identification of the fusion gene by molecular genetics may be necessary for diagnosis. Several recent studies have demonstrated the diagnostic utility of the reduced expression of SMARCB1 in synovial sarcomas as measured using immunohistochemistry. Therefore, we undertook a validation study using synovial sarcomas and other spindle or round cell tumors that could enter differential diagnosis of monophasic or poorly differentiated synovial sarcomas. Among 36 synovial sarcomas that were successfully evaluated, the expression of SMARCB1 was diffusely reduced in 33 cases (92%) at variable degrees. In contrast, the expression of SMARCB1 was not reduced in any of the 93 evaluable non-synovial sarcoma tumors (5 thymomas, 5 sarcomatoid mesotheliomas, 10 schwannomas, 9 mesenchymal chondrosarcomas, 20 solitary fibrous tumors, 19 Ewing sarcomas, and 25 malignant peripheral nerve sheath tumors). A few schwannomas and malignant peripheral nerve sheath tumors showed mosaic or complete loss of SMARCB1 expression. Reduced expression of SMARCB1 immunoreactivity was therefore found to be highly sensitive and specific for synovial sarcoma, and can be useful for rapidly and accurately confirming the diagnosis of synovial sarcoma. This reduction in SMARCB1 expression likely reflects the BAF47 ejection mechanism of the SS18-SSX fusion product and can therefore be viewed as an indirect visualization of this fusion product.

Transducer-like Enhancer of Split 1 as a Novel Immuno- histochemical Marker for Diagnosis of Synovial Sarcoma.

BACKGROUND: Synovial sarcoma is a mesenchymal neoplasm that accounts for around 10% of all soft tissue sarcomas. The diagnosis of synovial sarcoma can be a challenging task, particularly with small biopsy specimens. AIM: We investigated transducer-like enhancer of split 1 (TLE1), monoclonal antibody, expression by immunohistochemical analysis in a group of 74 synovial sarcoma cases, 20 cases of MPNST, 12 cases of neurofibroma, 15 cases of schwannoma, 5 cases of MFH, 10 cases of lieomyosarcoma and 10 cases of solitary fibrous tumor. MATERIALS AND METHODS: Whole tissue sections were examined: (39 biphasic and 35 monophasic). Nuclear immunoreactivity was scored as negative (<5% of cells positive), 1+(mild /5-25%), 2+ (moderate/25-50%), and 3+ (strong >50%). RESULTS: Overall, 71 (96%) of 74 synovial sarcomas were positive for TLE1, including 37 biphasic (95%) and 34 monophasic (97%) tumors. Other spindle cell tumors showed very low or absent staining of TLE1. CONCLUSIONS: We conclude that TLE1 is a sensitive marker and can be a useful diagnostic marker for synovial sarcoma, particularly the monophasic forms.

Primary synovial sarcoma of the kidney.

Primary synovial sarcoma (SS) of the kidney is a very rare disease as well as a diagnostic dilemma. Here, we present a case of a 60-year-old male clinically diagnosed as renal cell carcinoma. The radical nephrectomy specimen showed a well-circumscribed renal mass of approximately 13 cm × 9 cm × 7 cm. The cut-surface of the mass was tawny and firm, with cystic areas, and also showed focal hemorrhage and necrosis. Histologically, the tumor was composed of spindle cells arranged in the intersecting fascicles, alternating with hypocellular areas suggestive of monophasic synovial sarcoma. Morphological and immunohistochemical features were compatible with the diagnosis of SS of the kidney.

Primary synovial sarcoma of the right heart involving the tricuspid valve in an elderly Chinese woman: a case report.

Described herein is a 51-year-old woman with abdominal discomfort who was found to have a pericardial effusion and a large mass in her right heart by computed tomography scan and who then underwent tumour resection surgery. The tumour was so extensive that it involved the right atrium, the right ventricle and the tricuspid valve, and encompassed the right coronary artery. The patient had no significant medical history, and no tumour was found at any other site. The morphology of the tumour mimicked carcinosarcoma, exhibiting mixed epithelioid and spindle elements and it was difficult to differentiate the diagnosis even by immunohistochemical stains. Then, the final diagnosis of primary biphasic synovial sarcoma of the heart was established based on the finding of SS18 rearrangement. This is a highly intriguing rare case that may represent a diagnostic pitfall, particularly regarding frozen section. The patient will receive chemotherapy, and we will pursue follow-up.

Primary pleuropulmonary synovial sarcoma: a case report.

Pleuropulmonary synovial sarcoma (PPSS) is an extremely rare malignant tumor, which is increasingly recognized as a subtype of sarcoma with a distinctive chromosomal translocation specific to synovial sarcoma. It is often presents like any thoracic tumor with symptoms such as chest pain or cough. Here we report a case of PPSS in a 49-year-old woman presenting with cough, shortness of breath and chest pain. And who were found upon histologic examination of the resection specimen to have cystic primary pleuropulmonary synovial sarcoma.

Prognostic significance of bcl-2, c-myc, survivin and tumor grade in synovial sarcoma.

OBJECTIVE: We aimed to determine the prognostic value of bcl-2, c-myc and survivin in synovial sarcoma cases and to evaluate the relationship between the conventional morphological findings with prognosis. MATERIAL AND METHOD: In this study, we evaluated 81 synovial sarcoma cases referred to our tertiary tumor center during a period of 20 years. We applied bcl-2, c-myc and survivin immunohistochemically and investigated the relationship with prognosis for those 65 cases with follow-up. The relationship between the conventional morphological findings (mitosis, necrosis, grade) with prognosis was also investigated. RESULTS: Five-year disease free survival rate was 44% and ten-year progression free survival rate was 38%, reflecting the aggressive behavior of synovial sarcoma. Tumor grade (according to FNCLCC) was the most significant prognostic input in this study. We obtained a significant difference between grade II (40 cases) and grade III (24 cases) group regarding progression-free survival and overall survival (p < 0.001 and p < 0.001 respectively). Grade II was divided into two groups according to mitotic index and necrosis (grade IIa and IIb) and there was a significant difference between them regarding prognosis (p=0.013 for progression free survival, p=0.003 for overall survival). There was a significant relationship between bcl-2 negative plus focally weak positive cases (9 cases) and focally strong cases (21 cases) and diffuse strong cases (35 cases) (p=0.042 and p=0.016 respectively). There was a significant relation between c-myc negative cases (25 cases) and nuclear positive cases (17 cases) regarding overall survival (p=0.043) and between c-myc negative cases and cytoplasmic positive cases (23 cases) regarding progression free survival (p=0.05). The relation between survivin and prognosis was not significant. CONCLUSION: Tumor grade was the most significant prognostic parameter in this study. The grade IIa group (with less than 10 mitoses in 10 HPF, without necrosis) had a better prognosis than both the grade IIb and III groups. The grade IIb group was closer to grade III regarding the prognosis. Bcl-2 and c-myc (nuclear and/or cytoplasmic) immunohistochemical positivity had prognostic value but this finding has to be confirmed by large series.

Fine needle aspiration of primary mediastinal synovial sarcoma: cytomorphologic, immunohistochemical, and molecular study.

The cytologic diagnosis of synovial sarcoma (SS) can be difficult when it occurs in unusual locations, atypical age groups, and/or have unusual morphology. We report a case of primary mediastinal SS in a 65-year-old male with a long smoking history who presented with increasing shortness of breath and was found to have a 14.2 cm mediastinal mass. Smears from the endobronchial ultrasound guided fine needle aspiration of the mass were moderately cellular consisting of loosely cohesive clusters, some of which demonstrated nuclear molding, and dispersed single cells. The relatively uniform tumor cells had a high nuclear-to-cytoplasmic ratio, finely granular chromatin, and inconspicuous nucleoli. Some of the single cells had spindled morphology with unipolar wispy tails and naked nuclei. Based on the clinical presentation and the cytomorphologic features, our initial differential diagnoses included atypical carcinoid, small cell carcinoma, basaloid squamous cell carcinoma, sarcoma, and lymphoma. Immunohistochemical studies on the cell block sections revealed that the tumor cells were focally positive for cytokeratin and diffusely positive for CD56, while negative for CD45, synaptophysin and chromogranin. Ultimately, an immunohistochemical stain for TLE-1 demonstrated diffusely strong nuclear positivity and molecular studies showed the presence of the t(X; 18) SYT/SSX1 translocation confirming the diagnosis of SS. In this report, we describe the cytomorphologic features of SS, its diagnostic pitfalls, and potential mimics in the mediastinum.