Synovial sarcoma (SS) is typically diagnoses in young adults and usually appears in the extremities and soft tissues. However, it can sometimes arise in visceral organs. This study examines the differences in patient demographics, clinical features, and survival rates between soft tissue and visceral synovial sarcoma.

We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database spanning 2000-2018. ANOVA (analysis of variance) was used to identify significant factors for multivariate analysis. Cox regression modeling was used to determine independent risk factors for survival.

Of the 2,776 SS patients included, the median age was 39.0 years, predominating male (53.0 %) and white (81.3 %). Bone and soft tissue sarcomas were more common, accounting for 86.4 % of cases (p-value<0.001), while the rest were diagnosed as visceral sarcomas. Visceral SS patients were typically older (p-value<0.001), male (56.8 %), and white (84.8 %). They also presented more frequently with distant metastasis (HR 3.8, 95 % CI, 2.4-6.1), had larger tumors on average (HR for tumors >10 cm: 2.9, 95 % CI, 2.0-4.1), and were less likely to undergo surgery (HR 0.4, 95 % CI, 0.3-0.6). Despite receiving multimodal treatments, including surgery, radiation, and/or chemotherapy, visceral SS patients exhibited poorer overall survival compared to their bone and soft tissue SS counterparts (p-value<0.001).

Visceral SS often presents in older patients with advanced-stage and larger tumor size as compared to bone and soft tissue SS, which likely contributes to poorer survival. Advanced age, regional spread, and larger tumor size were all found to worsen outcomes, while surgery and radiation were found to be protective factors.

To investigate the MR imaging characteristics of intracranial synovial sarcoma by reviewing this case and literature, aiming to improve preoperative diagnostic accuracy for radiologists and neurosurgeons and guide appropriate treatment planning.

The clinical and MR images of 1 case with SS in the brain by pathology were retrospectively analyzed, and the causes of misdiagnosis were analyzed Combined with relevant literature.

MR showed a solid cystic mass in the right frontal lobe, isointense on T1WI, heterogeneous signal on T2WI, Elevated signal on DWI, obvious uneven enhancement on T1WI, and "triple signal sign" and "cobblestone sign" appearance.

SS in the brain is very rare. MR has certain imaging features, perfect MR examination is helpful for differential diagnosis.

Synovial sarcoma (SS) is the most common soft tissue sarcoma in children and adolescents. Despite the availability of new agents such as pazopanib and trabectedin, the prognosis after recurrence remains poor. Adoptive cell therapy is an emerging therapeutic strategy based on the modulation, manipulation, and selection of autologous T-cells in vitro to overcome immune system tolerance to tumor cells. Cancer-testis antigens are particularly attractive targets for immune therapy because male germ cells lack human leukocyte antigen class I molecules, limiting T-cell responses triggered by antigen presentation. T-cell receptor (TCR) engineered T-cell therapy targeting NY-ESO-1 and MAGE-A4 holds significant promise because of the high positive expression of these antigens in tumors. This approach facilitates the reprogramming of T lymphocytes by a transgenic TCR through gene transfer of TCR α and β chains specific to tumor antigens, offering potential therapeutic advances for patients with advanced SS. Clinical trials of TCR-engineered T-cell therapy targeting NY-ESO-1 and MAGE-A4 have been conducted, with an objective response rate reported to be 40-60% across several trials. This promising efficacy suggests that TCR-engineered T-cell therapy could become an attractive novel therapeutic option for advanced SS, which has limited treatment options in later stages. However, if TCR-engineered T-cell therapy is to be used in clinical practice, the standard approach following the failure of doxorubicin-based chemotherapy in patients with advanced SS must be defined. Future studies will be critical for establishing treatment strategies in this field.

Primary pericardial synovial sarcoma (PSS) is an extremely rare malignancy. Diagnosis and management primarily rely on multimodal imaging, with definitive diagnosis typically requiring a biopsy for histopathological confirmation. Although no established treatment protocol exists, complete tumour resection followed by adjuvant chemotherapy and radiotherapy is often considered.

A 68-year-old man presented with 1 month of shortness of breath and no significant medical history. Initial examination revealed cardiomegaly, a large pericardial effusion, and a solid mass adjacent to the right atrium. Multimodal imaging, including contrast-enhanced computed tomography and positron emission-T, identified a pericardial mass with metabolic activity. A thoracoscopic biopsy revealed atypical spindle-shaped cells, confirming the diagnosis of synovial sarcoma. This led to total tumour excision and lymph node dissection. Eighteen months post-surgery, imaging revealed recurrence, and the mass from the pericardium near the superior vena cava was resected via thoracotomy. Histopathological examination confirmed recurrent synovial sarcoma. Postoperative chemotherapy was administered; however, lung metastases developed, leading to further treatment 12 months post second surgery.

PSS is associated with poor prognosis and a high recurrence risk, highlighting the importance of regular follow-up imaging. While complete surgical resection remains the primary treatment, adjunct therapies may improve outcomes. This case underscores the need for multimodal imaging in diagnosing and monitoring PSS.

Background: Primary intrathoracic synovial sarcoma (SS) is a rare entity. The objective of this study was to evaluate survival outcomes for patients with intrathoracic SS presenting with localized disease at diagnosis. Methods: We conducted a retrospective review of 63 patients diagnosed with intrathoracic SS between 1997 and 2020. The Kaplan-Meier method and log-rank test were used to estimate the progression-free survival (PFS), overall survival (OS), local recurrence-free survival (LRFS), and metastasis-free survival (MFS). The hazard ratios were estimated by using Cox proportional hazards regression. Median follow-up time, age-at-diagnosis, and primary tumor size were 31 months (range: 4-218 months), 43 years (range: 18-77), and 7 cm (range: 1-23), respectively. Results: Sixty-two of sixty-three (98%) patients had their primary tumor resected, from whom eighteen (29%) and forty-three (69%) had received neo/adjuvant radiotherapy and chemotherapy, respectively. Median PFS, OS, and MFS were 1.2, 3.0, and 1.1 years, respectively. Based on multivariable analyses, patients with ≥5 cm tumor size had poorer OS (versus < 5 cm; HR: 2.66; 95% CI: 1.16, 6.11; LR-p = 0.014). Importantly, the receipt of neo/adjuvant chemotherapy was the only factor associated with both a more favorable PFS (HR: 0.33; 95% CI: 0.17, 0.65; LR-p = 0.0002) and a more favorable MFS (median 1.33 years versus no chemo 0.5 years; HR: 0.35; 95% CI: 0.17, 0.73; LR-p = 0.005). Conclusions: Outcomes associated with intrathoracic SS remain poor. Factors associated with poorer outcomes include larger tumors and omission of chemotherapy in the management of localized disease. We recommend providing perioperative chemotherapy to all patients with ≥5 cm tumor size to improve progression and metastasis-free survival.

Chromosomal rearrangement can be identified by direct methods or by using immunohistochemistry for a component of the fusion oncoprotein as a surrogate marker. Our aim was to gain insights into the staining profile using novel SS18-SSX and SSX c-terminus antibodies in SS18 fusion tumours and to investigate their potential use in soft tissue tumours harbouring SSX fusion partner outside the spectrum of synovial sarcoma. A retrospective analysis of 310 soft tissue sarcomas [via tissue microarray (TMA)] diagnosed at our Institution between 1999 and 2019 was performed. As controls, whole tissue sections from 14 genetically confirmed synovial sarcomas and one EWSR1::SSX2 rearranged sarcoma diagnosed between 2020 and 2023 were included. Two different antibodies for SSX locus were used: SSX c-terminus and SS18-SSX. Twenty-one of 310 (6.8%) and 25 of 310 (8.1%) sarcomas on the TMA showed nuclear staining with SS18-SSX and SSX, respectively. From the 24 synovial sarcomas, 17 (70.8%) stained positive for both antibodies, and in five of these cases, nuclear staining for SSX was weak. In four (16.7%) cases, only SS18-SSX was positive, and in three (12.5%) cases, only SSX staining was found. Furthermore, SSX nuclear expression was only found in four of 62 (6.5%) myxofibrosarcomas. In the control cohort, 11 of 14 synovial sarcomas (78.6%) showed positive staining for both antibodies. The remaining three cases were negative for SS18-SSX, but demonstrated at least focally strong positivity for SSX. The EWSR1::SSX2 rearranged sarcoma showed strong nuclear positivity for SSX. SS18-SSX and SSX c-terminus antibodies are reliable diagnostic markers that can be used as a surrogate marker for identification of a specific fusion. The SS18-SSX antibody is more specific and shows strong nuclear staining in synovial sarcomas, whereas SSX can present with weak staining and is less specific. However, the latter can be used in soft tissue tumours harbouring SSX fusion partner outside the spectrum of synovial sarcoma.

Synovial sarcoma (SS) is a rare and highly malignant soft tissue sarcoma. When SS occurs in atypical locations, it can present significant diagnostic challenges. We report a case of paraspinal SS initially misdiagnosed as spinal tuberculosis, highlighting the diagnostic difficulties and the importance of considering SS in the differential diagnosis.

A 23-year-old woman presented with progressively worsening lower left back pain over 3 weeks, accompanied by weakness and numbness in her left lower limb. She was initially misdiagnosed with spinal tuberculosis at 2 different hospitals based on weakly positive anti-tuberculosis antibodies and imaging findings. Despite ongoing anti-tuberculosis treatment, her condition continued to deteriorate.

The first surgery revealed findings inconsistent with spinal tuberculosis, but a tumor could not be excluded. However, the initial pathological biopsy was inconclusive. A second surgery confirmed the diagnosis of SS through histopathological examination.

The patient underwent a second surgery for mass resection and biopsy confirmation. Unfortunately, by the time the correct diagnosis was made, the disease had metastasized to her lungs, and the optimal window for surgical intervention had been missed.

The patient's delayed diagnosis resulted in extensive diffuse metastasis to both lungs, significantly impacting her survival.

This case underscores the need to consider malignancies such as SS in the differential diagnosis of spinal lesions, particularly when clinical response to treatment is poor. Early diagnosis and timely surgical intervention are critical to improving patient outcomes. Our literature review provides further insights into the characteristics of paraspinal SS and strategies to prevent misdiagnosis, emphasizing the importance of early and accurate diagnosis to enhance patient survival.

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor with intermediate malignant potential, and it rarely metastasizes. We encountered a unique AFH case where, the tumor was discovered initially in unusual locations-the left lung and the left 4th rib. Combined histological features with FISH and NGS analysis, the diagnosis of AFH was supported, however, it is difficult to determine which of these two is the primary lesion. Eight months after the initial surgery, multiple systemic metastases were detected, eventually leading to the patient's death 18 months later due to widespread metastasis. Our case signifies the first reported occurrence of systemic metastasis in either bone-originating or pulmonary-originating AFH, and it is the initial instance of mortality resulting from multifocal metastasis originating from an atypical site.

The purpose of this review is to clarify the terminology, possible cells of origin, and expected behavior of the most common synovial tumors in dogs. The synovial lining consists of 2 cell types, type A and type B. Type A synoviocytes are histiocytes of bone marrow origin that are immunoreactive with antibodies against typical markers of histiocyte origin, such as CD18, Iba-1, and CD204. Certain breeds and dogs with previous injury to a joint, especially cranial cruciate ligament rupture, are predisposed to synovial histiocytic sarcoma. Type B synoviocytes are mesenchymal cells that produce synovial fluid. There are no specific markers of type B synoviocytes, but based on their gross and microscopic appearance, synovial myxosarcomas (previously considered synovial myxomas) are presumed to be of type B synoviocyte origin. These can infiltrate into surrounding tissues, but are slow-growing and rarely metastasize, and then only to regional lymph nodes. Synovial histiocytic sarcomas and myxosarcomas can cause lysis in multiple bones surrounding the joint, but they have different prognoses and require histopathology and sometimes immunohistochemistry to diagnose them. Synovial sarcoma and synovial cell sarcoma are terms used in the human medical literature for a tumor that is not of synovial origin; these terms should not be used in veterinary medicine.

Sarcoma samples from 33 dogs, 25 subcutaneous and 8 articular, were submitted for cytokeratin immunohistochemistry. Eight of the 25 subcutaneous sarcomas (32%) expressed cytokeratin in 1% to 50% of the neoplastic cells. Of the 7 articular sarcomas evaluated, 1 (14%) expressed cytokeratin in 10% of neoplastic cells. The Kaplan-Meier survival analysis showed that the mean overall survival of dogs with subcutaneous sarcomas (28.1 months [confidence interval [CI]:17.8, 38.4]) did not significantly differ from those with articular sarcomas (24.8 months [CI = 0.5, 29.0]). Overall survival of dogs with sarcomas (both locations combined) immunoreactive for cytokeratin (31.2 months [CI = 17.8, 44.6]) did not differ from those not immunoreactive for cytokeratin (22.0 months [CI = 8.4, 35.6]). Therefore, cytokeratin expression does not indicate synovial origin (P = .64) and neither sarcoma location (P = .76) nor cytokeratin expression (P = .53) affects patient overall survival in this small study. The use of cytokeratin immunohistochemistry is not helpful to determine synovial origin of sarcomas in dogs.

Synovial sarcoma is a high-grade soft tissue sarcoma primarily affecting teenagers and young adults. Inguinal region involvement is rare, making diagnosis and treatment challenging.

A 35-year-old Tunisian man presented with a progressively enlarging right inguinal swelling. Imaging revealed a mass behind the inguinal ligament, confirmed as biphasic synovial sarcoma through biopsy. The patient underwent successful surgery with clear resection margins. Histopathological examination revealed a biphasic sarcoma with spindle cell and glandular components, supporting the diagnosis of synovial sarcoma. Following surgery, the patient received adjuvant radiotherapy. Regular outpatient follow-up is being conducted to monitor progress.

Synovial sarcoma is characterized by slow growth and local invasiveness, with potential for metastasis. It typically presents as a solid mass that can compress nearby structures such as blood vessels. Imaging studies offer valuable insights into tumor location, size, invasiveness, and potential metastases. Local tumor staging relies on MRI, while distant metastases are detected using chest CT or bone scans. Diagnosis is confirmed through histopathological examination and immunohistochemical analysis.

This case report highlights a rare presentation of inguinal synovial sarcoma and emphasizes the importance of individualized multimodal therapy in its management.

Synovialosarcoma is a mesenchymal tumor with soft tissue predilection, metastasizing to various organs, including the lung. Primary pulmonary involvement is rare and requires histological examination for confirmation. In early stages, the treatment is surgical followed by radiotherapy to avoid recurrence, while there's no consensus in chemotherapy. We present a case of a 54-year-old patient with primary pulmonary synovialosarcoma. The patient underwent successful treatment, achieving tumor control and complete excision. This case discusses diagnostic approaches, prognosis, treatment modalities for primary pulmonary synovialosarcoma, emphasizing the significance of early intervention for favourable outcomes.

Synovial Sarcomas (SS) are characterized by the presence of the SS18::SSX fusion gene, which protein product induce chromatin changes through remodeling of the BAF complex. To elucidate the genomic events that drive phenotypic diversity in SS, we performed RNA and targeted DNA sequencing on 91 tumors from 55 patients. Our results were verified by proteomic analysis, public gene expression cohorts and single-cell RNA sequencing. Transcriptome profiling identified three distinct SS subtypes resembling the known histological subtypes: SS subtype I and was characterized by hyperproliferation, evasion of immune detection and a poor prognosis. SS subtype II and was dominated by a vascular-stromal component and had a significantly better outcome. SS Subtype III was characterized by biphasic differentiation, increased genomic complexity and immune suppression mediated by checkpoint inhibition, and poor prognosis despite good responses to neoadjuvant therapy. Chromosomal abnormalities were an independent significant risk factor for metastasis. KRT8 was identified as a key component for epithelial differentiation in biphasic tumors, potentially controlled by OVOL1 regulation. Our findings explain the histological grounds for SS classification and indicate that a significantly larger proportion of patients have high risk tumors (corresponding to SS subtype I) than previously believed.

Primary synovial sarcoma originating in the pelvis is an extremely rare malignancy, and only a few cases have been reported. Usually, the tumor is detected at an advanced stage, making treatment more difficult. Lacking high-quality research, there are no consensus guidelines for the systemic treatment of the disease.

We admitted a 32-year-old male patient with an MRI suggestive of an 8.2 × 7.7 x 8.9 cm mass in the pelvis with bleeding. After a comprehensive evaluation, the patient underwent surgery, and postoperative pathology suggested biphasic synovial sarcoma. Once the diagnosis was clear, the patient was treated with chemotherapy, radiotherapy, and targeted therapy. Unfortunately, the patient died due to a recurrence of pelvic synovial sarcoma with multiple metastases throughout the body, with a survival period of 28 months.

Synovial sarcoma, a highly malignant soft tissue tumor, and primary intrapelvic synovial sarcoma are even rarer, with a poor prognosis. Ultrasound, Computed Tomography, and MRI can help doctors detect the tumor at an early stage and treat it aggressively, especially with surgical treatment, which can effectively improve the survival rate. Combined with the course of diagnosis and treatment of this case, it is possible to deepen the understanding of primary pelvic synovial sarcoma and discuss appropriate treatment strategies for this rare disease.

Synovial sarcoma (SS) is a rare soft-tissue cancer. Existing literature encompasses Surveillance, Epidemiology, and End Results (SEER) data-based research on SS explaining the incidence-prevalence in general, by subtypes, and by age at diagnosis. Therefore, this study aimed to fill in the gap of knowledge about measures of disease occurrence and burden of SS by tumor site using the SEER database.

In this cross-sectional study, primary SS patients were selected from SEER 17 Registries, Nov. 2021 (2000-2020) using ICD-O-3 codes 9040, 9041, 9042, and 9043. Patients with additional cancers were excluded. The primary tumor site was categorized into (1) head/neck, (2) internal thorax, (3) abdomen/pelvis, (4) upper extremity, and (5) lower extremity using ICD-10CM codes. Five outcomes were analyzed: age-adjusted incidence rate, 5-year limited-duration prevalence rate, incidence-based mortality, case-fatality rate, and overall survival.

From 2000-2020, the overall age-adjusted incidence rate was 0.15 per 100,000; the 5-year limited duration prevalence rate was 0.56 per 100,000; and the incidence-based mortality rate was 0.06 per 100,000 people. The case-fatality and 5-year OS rates were 39.2 % and 62.9 %, respectively. Lower extremity had the highest incidence of 0.07 (estimated 1166 cases), prevalence of 0.36 (estimated 224 cases), and mortality rate of 0.025 (estimated 429 deaths) per 100,000. The other four locations had much closer rates with each other. Intrathoracic SS had the highest case-fatality rate of 71.5 % (148/207) and lowest 5-year OS of 26.0 % (95 % CI: 19.6 %, 32.9 %) than other sites.

Based on the measures of disease frequency, the most common primary tumor site is the lower extremity, followed by the upper extremity, abdomen/pelvis, internal thorax, and head/neck. The least favorable primary location is the internal thorax. Those with a primary location of the upper extremity have the longest overall survival, followed by the head/neck, lower extremity, abdomen/pelvis, and internal thorax.

Mediastinal monophasic synovial sarcoma is a rare subtype that often lacks specific imaging characteristics, posing diagnostic challenges. This case report describes a mediastinal monophasic synovial sarcoma with vertebral metastasis, emphasizing imaging findings, differential diagnosis, and pathological features, thereby providing crucial support for accurate diagnosis and treatment planning.

Exosomes mediate cell-to-cell crosstalk involving a variety of biomolecules through an intricate signaling network. In recent years, the pivotal role of exosomes and their non-coding RNAs cargo in the development and progression of several cancer types clearly emerged. In particular, tumor bulk and its microenvironment co-evolve through cellular communications where these nanosized extracellular vesicles are among the most relevant actors. Knowledge about the cellular, and molecular mechanisms involved in these communications will pave the way for novel exosome-based delivery of therapeutic RNAs as well as innovative prognostic/diagnostic tools. Despite the valuable therapeutic potential and clinical relevance of exosomes, their role on sarcoma has been vaguely reported because the rarity and high heterogeneity of this type of cancer. Here, we dissected the scientific literature to unravel the multifaceted role of exosomal non-coding RNAs as mediator of cell-to-cell communications in the sarcoma subtypes.

Synovial sarcoma is a malignant soft tissue tumor of uncertain differentiation. It is typically seen in the deep soft tissue of the extremities; however, it has been reported to occur anywhere in the body. Synovial sarcoma by histomorphology has multiple subtypes, including monophasic spindle cell, biphasic and poorly differentiated subtypes. Synovial sarcomas measuring less than one centimeter in diameter are termed "minute" synovial sarcomas. "Minute" synovial sarcomas have only been reported so far in the acral region of the hands and feet. They are extremely rare and can often be misinterpreted as benign neoplasms. Herein, we report the findings in a 30-year-old female presenting with a palpable mass within the deep subcutaneous tissue along the anterior aspect of her right rectus abdominis muscle. The mass was excised and measured 0.6 cm in greatest dimension with histomorphology findings, immunohistochemical and molecular workup confirming the diagnosis of "minute" synovial sarcoma. Our findings represent the first documented case of a "minute" synovial sarcoma occurring at an extra-acral site. With such unique finding not yet reported in the literature, this case highlights the importance of considering synovial sarcoma in the differential diagnosis of subcutaneous abdominal masses.

Synovial sarcoma (SynSa) is one of the most common translocation-related soft tissue sarcomas. Patients with metastatic SynSa have limited treatment options and a very poor prognosis. Several novel experimental therapies are currently being explored in clinical trials, including T cell-based therapies targeting cancer testis antigens such as New York esophageal squamous cell carcinoma 1 (NY-ESO-1) or melanoma-associated antigen A4 (MAGE-A4), and degraders targeting bromodomain-containing protein 9 (BRD9). Preclinical studies investigate inhibitors of Yes associated protein 1 (YAP1), transcriptional co-activator with PDZ-binding motif (TAZ) and inhibitors of chemokine receptor 4 (CXCR4).

We explored the immunohistochemical expression of these targets using a tissue microarray (TMA) constructed from 91 clinical SynSa samples and correlated these findings with corresponding clinicopathological data.

Expression of MAGE-A4 and NY-ESO-1 was found in 69 % and 56 % of the samples, respectively. NY-ESO-1 was statistically higher expressed in samples from metastatic lesions as compared to samples from primary tumors. Nuclear expression of YAP1 and TAZ was observed in 92 % and 51 % of the samples, respectively. CXCR4 was expressed in the majority of the samples (82 %). BRD9 was highly expressed in all specimens. No prognostic role could be identified for any of the investigated proteins.

This study is a comprehensive study providing real-world data on the expression of several actionable proteins in a large proportion of SynSa samples. All evaluated markers were expressed in a clinically meaningful proportion of cases represented in our TMA, supporting the relevance of ongoing preclinical and clinical research with novel agents directed against these targets.

Synovial sarcomas are soft tissue tumours of uncertain origin, most commonly found in the upper or lower extremities. They are characterised by distinctive chromosomal rearrangements involving the gene SS18. Synovial sarcomas can occasionally arise also in visceral sites, but retroperitoneal SSs are very unusual. Among them, a few primary renal synovial sarcomas have been described in the scientific literature. Primary renal synovial sarcomas tend to be monophasic and often show cystic changes. Histologically, they can closely resemble other primary kidney tumours, mainly paediatric tumours such as nephroblastoma and clear cell sarcoma of the kidney. In the current work, a primary synovial sarcoma of the kidney with unusual morphological features (extensively myxoid stroma and immunohistochemical positivity for BCOR) is described. Molecular analysis, through targeted RNA sequencing, was of invaluable help in reaching the correct diagnosis. Despite locally advanced disease at presentation, the patient showed an unexpectedly brilliant response to chemotherapy.

Synovial sarcoma (SS) is an aggressive soft tissue sarcoma with poor prognosis due to late recurrence and metastasis. Metastasis is an important prognostic factor of SS. This study aimed to identify the core genes and mechanisms associated with SS metastasis. Microarray data for GSE40021 and GSE40018 were obtained from the Gene Expression Omnibus database. 186 differentially expressed genes (DEGs) were identified. The biological functions and signalling pathways closely associated with SS metastasis included extracellular matrix (ECM) organization and ECM-receptor interaction. Gene set enrichment analysis showed that the terms cell cycle, DNA replication, homologous recombination and mismatch repair were significantly enriched in the metastasis group. Weighted gene co-expression network analysis identified the most relevant module and 133 hub genes, and 31 crossover genes were identified by combining DEGs. Subsequently, four characteristic genes, EXO1, NCAPG, POLQ and UHRF1, were identified as potential biomarkers associated with SS metastasis using the least absolute shrinkage and selection operator algorithm and validation dataset verification analysis. Immunohistochemistry results from our cohort of 49 patients revealed visible differences in the expression of characteristic genes between the non-metastatic and metastatic groups. Survival analysis indicated that high expression of characteristic genes predicted poor prognosis. Our data revealed that primary SS samples from patients who developed metastasis showed activated homologous recombination and mismatch repair compared to samples from patients without metastasis. Furthermore, EXO1, NCAPG, POLQ and UHRF1 were identified as potential candidate metastasis-associated genes. This study provides further research insights and helps explore the mechanisms of SS metastasis.

Synovial sarcoma (SS) is a tumor known for its classic monophasic spindle cell or biphasic morphology. However, it exhibits a wide range of histologic variations, leading to diagnostic challenges. Here, we present four cases of molecularly confirmed, biphasic SS originating in the feet and displaying myoepithelial differentiation. The patients were two men and two women with an age range from 19 to 71 years (mean, 45 years). Each tumor showed foci with conventional spindle cell morphology. The epithelial components included areas with nests and cords of epithelioid cells set within a hyalinized and sclerotic stroma. The cytoplasm was clear to pale and eosinophilic. The nuclei were ovoid-round with fine chromatin and small to inconspicuous nucleoli. Mitotic figures were present (2-13 per 10 high-power fields; mean, 6.5). Immunohistochemical studies showed variable staining of the myoepithelial-like regions for low molecular weight keratins, EMA, p63, and S100 protein. Molecular studies confirmed the presence of SS18::SSX1/2 fusion in all four tumors. These cases highlight an unusual variant of synovial sarcoma with an apparent predilection for the distal lower extremity and suggest that differentiation of biphasic synovial sarcoma may be impacted by the anatomic site. Awareness of this variant is important to avoid misclassification and potential treatment and prognostic implications.

With great interest, we read the article by Manole et al [...].

Primary malignant cardiac tumors rarely occur, and cardiac synovial sarcoma (SS) is especially rare among such tumors. Herein, we present the case of a 35-year-old female with primary cardiac SS treated with surgery, chemotherapy, and radiotherapy. She presented with chest symptoms and underwent imaging examinations. A cardiac tumor was suspected, and an open biopsy was performed. The pathological findings suggested cardiac SS. Next, we performed a resection, and the tumors persisted at a macroscopic level. Immunohistochemistry was negative for SS18-SSX and positive for the SSX C-terminus and cytokeratin CAM5.2, a reduction of SMARCB1/INI1 was observed, and fluorescence in situ hybridization showed positive SS18 split staining. Owing to the FNCLCC grade 3 tumor and R2 margins, adjuvant chemotherapy with ifosfamide, doxorubicin, and radiotherapy was initiated, and the patient was diagnosed with cardiac SS. The differences in patients with cardiac SS compared with general SS include male predominance, larger tumor size, and poorer prognosis. Pathological findings of immunohistochemistry and fluorescence in situ hybridization were found to be more reliable than imaging findings for a correct diagnosis. Additionally, because incomplete resection is frequently performed, adjuvant therapy, including chemotherapy and radiation therapy, may be performed. The findings indicate that multiple therapies, including surgery, chemotherapy, and radiotherapy, are essential treatment strategies for improving the prognosis of patients with cardiac SS.

We report the case of a woman nearing 70 years old who was admitted to the hospital with a complaint of "epigastric distension for 1 month". Her main signs and symptoms were progressive abdominal distension and occasional abdominal pain. Computed tomography suggested an abdominal mass. She had a surgical history of synovial sarcoma (SS) of the lungs. After admission, she was diagnosed with jejunal SS following a puncture biopsy and laparoscopic surgery. This disease usually occurs in the soft tissues of the limbs, and it is extremely rare for SS to originate in the jejunum. The morphologic heterogeneity of SS overlaps with other tumors and makes the diagnosis particularly difficult. Imaging studies usually lack specificity; however, measuring multiple immunohistochemical markers can greatly assist in the diagnosis and differential diagnosis of SS. This case not only enriches our understanding of SS and describes a rare site of origin, but also emphasizes the importance and challenges of achieving an accurate diagnosis. Immunohistochemical and molecular biological testing have important roles in the definitive diagnosis, highlighting the need for precise and innovative diagnostic and therapeutic approaches in SS.

Prion-like domains (PLDs) are low-complexity protein sequences enriched within nucleic acid-binding proteins including those involved in transcription and RNA processing. PLDs of FUS and EWSR1 play key roles in recruiting chromatin remodeler mammalian SWI/SNF (mSWI/SNF) complex to oncogenic FET fusion protein condensates. Here, we show that disordered low-complexity domains of multiple SWI/SNF subunits are prion-like with a strong propensity to undergo intracellular phase separation. These PLDs engage in sequence-specific heterotypic interactions with the PLD of FUS in the dilute phase at sub-saturation conditions, leading to the formation of PLD co-condensates. In the dense phase, homotypic and heterotypic PLD interactions are highly cooperative, resulting in the co-mixing of individual PLD phases and forming spatially homogeneous condensates. Heterotypic PLD-mediated positive cooperativity in protein-protein interaction networks is likely to play key roles in the co-phase separation of mSWI/SNF complex with transcription factors containing homologous low-complexity domains.

Synovial sarcoma (SS) is a rare tumour of unknown origin with peak incidence between 10 and 35 years. Although it arises in juxta-articular location, SS is a misnomer and has no true relationship with synovium. In this case report, we present an elderly female patient with a long-standing history of thigh mass which was initially misdiagnosed as metastatic adenocarcinoma deposits on fine needle aspiration cytology, and again misdiagnosed as malignant adnexal skin tumour on core needle biopsy and referred for further management. Here, we discuss the challenges faced in the diagnosis of SS on a small biopsy and ways to differentiate it from other morphological mimickers. Therefore, we aim to increase the awareness of soft tissue tumours that microscopically appear like adenocarcinoma, which is a potential diagnostic pitfall. We also highlight the importance of morphological diagnosis and the utility of molecular testing using fluorescence in situ hybridisation, to arrive at the correct diagnosis of SS.

We report the clinicopathologic and immunohistochemical features of 18 cases of confirmed primary synovial sarcoma of the gastrointestinal tract. The neoplasms arose in 10 women and 8 men ranging in age from 23 to 81 years (mean: 50; median: 57.5 years). The tumors for which size was known ranged from 1.8 to 15.0 cm (mean: 5.2; median: 5.1 cm). Microscopically, 14 synovial sarcomas were of the monophasic type, 2 were biphasic, and 2 were poorly differentiated. Immunohistochemical analysis of 4 cases showed strong, diffuse staining for SS18::SSX (4/4 cases). Pancytokeratin and EMA immunohistochemistry were performed on 13 and 9 tumors, respectively, and each showed patchy-to-diffuse staining. By reverse-transcription PCR, 3 cases were positive for the SS18::SSX1, and 2 cases were positive for the SS18::SSX2 gene fusion. Six cases contained an SS18 gene rearrangement by fluorescence in situ hybridization, and next-generation sequencing identified an SS18::SSX2 gene fusion in one case. Clinical follow-up information was available for 9 patients (4 months to 4.6 years; mean, 2.8 y; median: 29 months), and one patient had a recent diagnosis. Three patients died of disease within 41 to 72 months (mean, 56 months) of their diagnosis. Five patients were alive without evidence of disease 4 to 52 months (mean, 17.6 months) after surgery; of whom 1 of the patients received additional chemotherapy treatment after surgery because of recurrence of the disease. A single patient was alive with intraabdominal recurrence 13 months after surgery. We conclude that synovial sarcoma of the gastrointestinal tract is an aggressive tumor, similar to its soft tissue counterpart, with adverse patient outcomes. It is important to distinguish it from morphologically similar gastrointestinal tract lesions that may have different treatment regimens and prognoses.

Soft tissue sarcomas are a group of rare, mesenchymal tumors characterized by dismal prognosis in advanced/metastatic stages. Knowledge of their molecular determinants is still rather limited. However, in recent years, epigenetic regulation - the modification of gene expression/function without DNA sequence variation - has emerged as a key player both in sarcomagenesis and sarcoma progression.

Herein, we describe and review the main epigenetic mechanisms involved in chromatin remodeling and their role as disease drivers in different soft tissue sarcoma histotypes, focusing on epithelioid sarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumors. Focusing on chromatin-remodeling complexes, we provide an in-depth on the role of BAF complex alterations in these soft tissue sarcoma histotypes. In parallel, we highlight current state-of-the-art and future perspectives in the development of rational, innovative treatments leveraging on epigenetic dysregulation in soft tissue sarcomas.

Therapeutic options for metastatic/advanced sarcomas are to date very limited and largely represented by cytotoxic agents, with only modest results. In the continuous attempt to find novel targets and innovative, effective drugs, epigenetic mechanisms represent an emerging and promising field of research, especially for malignant peripheral nerve sheath tumors, epithelioid and synovial sarcoma.

Synovial sarcoma is a rare and highly aggressive subtype of soft tissue sarcoma. The clinical challenge posed by advanced or metastatic synovial sarcoma, marked by limited treatment options and suboptimal outcomes, necessitates innovative approaches. The topoisomerase II (Topo II) inhibitor doxorubicin has remained the cornerstone systemic treatment for decades, and there is pressing need for improved therapeutic strategies for these patients. This study highlights the potential to enhance the cytotoxic effects of doxorubicin within well-characterized synovial sarcoma cell lines using the potent and selective DNA-PK inhibitor, peposertib. In vitro investigations unveil a p53-mediated synergistic anti-tumor effect when combining doxorubicin with peposertib. The in vitro findings were substantiated by pronounced anti-tumor effects in mice bearing subcutaneously implanted tumors. A well-tolerated regimen for the combined application was established using both pegylated liposomal doxorubicin (PLD) and unmodified doxorubicin. Notably, the combination of PLD and peposertib displayed enhanced anti-tumor efficacy compared to unmodified doxorubicin at equivalent doses, suggesting an improved therapeutic window-a critical consideration for clinical translation. Efficacy studies in two patient-derived xenograft models of synovial sarcoma, accurately reflecting human metastatic disease, further validate the potential of this combined therapy. These findings align with previous evidence showcasing the synergy between DNA-PK inhibition and Topo II inhibitors in diverse tumor models, including breast and ovarian cancers. Our study extends the potential utility of combined therapy to synovial sarcoma.

» Synovial sarcoma is a soft tissue sarcoma that most commonly presents in the extremity in a periarticular location.» As the history and physical examination of patients with synovial sarcoma can overlap considerably with those of patients with non-oncologic orthopedic conditions, it is important that orthopedic surgeons maintain a high level of suspicion when caring for patients with extremity masses.» Soft tissue sarcomas are best treated using a team approach. Early recognition and referral to a multidisciplinary sarcoma team are crucial to ensure the best clinical outcome for the patient.

Prion-like domains (PLDs) are low-complexity protein sequences enriched within nucleic acid-binding proteins including those involved in transcription and RNA processing. PLDs of FUS and EWSR1 play key roles in recruiting chromatin remodeler mammalian SWI/SNF complex to oncogenic FET fusion protein condensates. Here, we show that disordered low-complexity domains of multiple SWI/SNF subunits are prion-like with a strong propensity to undergo intracellular phase separation. These PLDs engage in sequence-specific heterotypic interactions with the PLD of FUS in the dilute phase at sub-saturation conditions, leading to the formation of PLD co-condensates. In the dense phase, homotypic and heterotypic PLD interactions are highly cooperative, resulting in the co-mixing of individual PLD phases and forming spatially homogeneous co-condensates. Heterotypic PLD-mediated positive cooperativity in protein-protein interaction networks is likely to play key roles in the co-phase separation of mSWI/SNF complex with transcription factors containing homologous low-complexity domains.

Synovial sarcomas are rare and highly aggressive soft-tissue sarcomas, primarily affecting adolescents and young adults aged 15-40 years. These tumors typically arise in the deep soft tissues, often near the large joints of the extremities. While the radiological features of these tumors are not definitely indicative, the presence of calcification in a soft-tissue mass (occurring in 30% of cases), adjacent to a joint, strongly suggests the diagnosis. Cross-sectional imaging characteristics play a crucial role in diagnosing synovial sarcomas. They often reveal significant characteristics such as multilobulation and pronounced heterogeneity (forming the "triple sign"), in addition to features like hemorrhage and fluid-fluid levels with septa (resulting in the "bowl of grapes" appearance). Nevertheless, the existence of non-aggressive features, such as gradual growth (with an average time to diagnosis of 2-4 years) and small size (initially measuring < 5 cm) with well-defined margins, can lead to an initial misclassification as a benign lesion. Larger size, older age, and higher tumor grade have been established as adverse predictive indicators for both local disease recurrence and the occurrence of metastasis. Recently, the prognostic importance of CT and MRI characteristics for synovial sarcomas was elucidated. These include factors like the absence of calcification, the presence of cystic components, hemorrhage, the bowl of grape sign, the triple sign, and intercompartmental extension. Wide surgical excision remains the established approach for definitive treatment. Gaining insight into and identifying the diverse range of presentations of synovial sarcomas, which correlate with the prognosis, might be helpful in achieving the optimal patient management.

Tumors of the lung with a spindle cell morphology require consideration of many entities in the differential diagnosis, including metastases. Ancillary immunohistochemical stains but also molecular studies are typically required to arrive at the proper diagnosis. We present a case of a 71-year-old woman with multiple lung nodules, mediastinal lymphadenopathy, and a history of uterine cancer who underwent endobronchial ultrasound-guided fine needle aspiration and biopsy of the lung and mediastinal lymph nodes. A sampling of the lung lesion showed a cytologically bland neoplasm with spindle cell morphology, lacking necrosis or brisk mitotic activity. In conjunction with the cytomorphology, strong and diffuse Transducin-like enhancer of split 1 (TLE1) reactivity in the tumor cells initially raised the diagnosis of synovial sarcoma; however, subsequent results of additional testing showed strong and diffuse expression with AE1/AE3, CK 8/18, TTF-1, synaptophysin and chromogranin and focal or negative staining with a large number of other antibodies. This warranted a diagnosis of a carcinoid tumor. This is the first report of TLE1 staining in a carcinoid tumor of the lung. Therefore, when evaluating tumors of the lung with spindle cell morphology in which the differential diagnosis may include both carcinoid tumor and synovial sarcoma, TLE1 expression should be interpreted with caution and in conjunction with an expanded immunohistochemical staining panel.

Background: Differential diagnosis of rhabdomyosarcoma (RMS) is challenging. Sineoculis homeobox homolog 1 (SIX1) is an oncogene involved in skeletal muscle differentiation. We compared protein expression patterns of SIX1 in RMS and its most common differential diagnoses. Methods: SIX1 immunohistochemistry in 36 RMS and in 33 tumors from seven differential diagnostic subtypes were evaluated. The fraction of SIX1 positive tumor cells was scored by three independent observers. Results: A majority (75%) of the evaluated RMS expressed SIX1 in at least 50% of tumor cells and all except one RMS had more than 25% positive tumor cells. Neuroblastoma had less than 1% SIX1 positive tumor cells. Gonadoblastoma, malignant rhabdoid tumor, and Ewing sarcoma had 10% or less positive tumor cells. Pleuropulmonary blastoma exhibited 26-50% positive tumor cells and synovial sarcoma >50% positive cells. Conclusion: SIX1 immunohistochemistry is positive in most RMS, and occasionally in some tumors within the differential diagnoses of RMS.

Synovial sarcoma (SS) is part of soft tissue sarcomas (STS). An incidence between 5% to 10% is estimated. The origin is mesenchymal mainly affecting the extremities. Being even rarer at the chest level and vertebral body, representing around 1%. Histologically, it consists of 3 variants: monophasic, biphasic, and poorly differentiated. Surgical resection is a priority when it comes to multidisciplinary management. The prognosis of patients with SS over the years has improved markedly.

Understand and evaluate the multidisciplinary management of SS considering that the SS has a lowe prevalence and highly malignancy.

We present a case of a 31-year-old male who has a history of monophasic synovial sarcoma diagnosed in 2019 and underwent surgery. Patient came back after two years without symptoms and posterior to a control MRI we observed a local recurrence of SS.

The literature was reviewed with a focus on best clinical and surgical strategy for recurrence of SS.

The patient recovered well with return to his normal daily activities. The review of the literature shows us the importance of the multidisciplinary management for the optimal clinical and surgical approach of SS recurrence.

SS represents a unique variant of STS, with malignant and metastatic potential. Being a rare pathology, an adequate multidisciplinary management is essential when providing optimal care for the patient.

Soft tissue sarcomas (STSs) are a heterogeneous group of malignancies that have long posed challenges in terms of diagnosis, treatment, and management. This narrative review provides a comprehensive exploration into the multifaceted realm of STS, spanning from its historical origins to the latest advancements in research and clinical care. We delve into the molecular intricacies of STS, highlighting the genetic and epigenetic aberrations that drive these tumors. The review emphasizes the neurological implications of STS, a relatively underexplored area, shedding light on the interplay between tumor biology and neural processes. The evolving therapeutic landscape is discussed, with a focus on the promise of targeted therapies, immunotherapy, and precision medicine. A significant portion is dedicated to the patient-centric approach, underscoring the importance of holistic care that addresses both the physical and psychological needs of STS patients. Furthermore, we highlight the gaps in current research and clinical practices, offering insights into potential avenues for future exploration. This review serves as a valuable resource for clinicians, researchers, and the broader scientific community, encapsulating the current state of STS knowledge and pointing toward future directions in this dynamic field.

Primary pericardial synovial sarcoma is an extremely rare malignant tumor, and affected patients have a poor prognosis. Only a few cases have been reported in the literature.

A 34-year-old man was admitted to our hospital with chest tightness and a cough. An echocardiogram revealed a heterogeneous mass with a large pericardial effusion. Further computed tomography (CT) of the chest and cardiac magnetic resonance imaging (CMRI) demonstrated an irregular pericardial mass abutting the left atrium and left ventricle and invading the mediastinal structures. Pathology results showed that the tumor was a monophasic synovial sarcoma. The patient underwent chemotherapy and survived for 17 months.

Many cardiac tumors are clinically asymptomatic or nonspecific, and they are frequently detected or diagnosed at an advanced stage of the disease. Multimodal cardiac imaging facilitates the detection and assessment of cardiac tumors. In particular, CMRI is considered as a superior imaging tool, because it provides high tissue contrast and can detect invasion of the myocardium. We describe the clinical details and multimodal imaging features of a rare primary pericardial synovial sarcoma, hoping to provide guidance for the diagnosis of similar cases in the future.

Synovial Sarcoma (SS) is a rare soft tissue sarcoma. Mean time to get a SS diagnosis from the onset of symptoms is 10 years, furthermore, SS is associated with late metastasis. Surgery is the main treatment option, whose quality deeply affects SS outcomes, and it can be associated to preoperative or post-operative radiotherapy. Chemotherapy is considered very effective in Children, while in adults its efficacy is still under debate. The aim of this study was to investigate the oncologic results in SS treatment and to identify the risk factors for local and systemic control of the disease.

From 1994 to 2018, 211 patients affected by SS were treated in 3 Referral Centres of Orthopaedic Oncology. One hundred seventy-seven patients were included in the study, the median follow-up length was 96 months (5-374).

Overall Survival on the Kaplan Meier Analyses was 80%, 70% and 56% at 5, 10 and 20 years. In multivariate analyses, OS correlated with tumour size and negative surgical margins. Chemotherapy use wasn't associated with better survival although patients who underwent CT had bigger and more aggressive tumours.

Our findings suggests that surgery with negative margins is the most important factor in Synovial Sarcoma. Adjuvant treatments as chemotherapy and radiation therapy didn't change the disease's course.

Synovial sarcomas are malignant soft tissue neoplasm representing 5 to 10 % of all Soft tissue sarcoma with incidence of 2.75 per 100,000. It is presented in particular along with extra articular location with no as such relation to synovial structures. Among various histological pattern biphasic synovial sarcoma (SS) is considered classical type. Involvement of neurovascular structures in synovial sarcoma is least noted and such invasion by malignant cells is considered an indication for amputation. However vessel reconstructive surgeries have also resulted in conservation of limb hence providing good quality of life.

13 years old Asian female presented with complaint of exposed synthetic vessel graft from her previous surgical site where femoral vessel reconstruction was carried out for SS of thigh with femoral vessel involvement. Following her (wide local excision) WLE and femoral vessel reconstruction in another center she suffered thrombosis of her femoral vessel following which emergency thrombectomy was also carried out. Later in our center vertical rectus abdominis myocutaneous flap (VRAM) flap was used to manage her exposed synthetic graft. At subsequent follow up patient was ambulating well with no signs of radiological metastasis.

Surgical resections of mass along with synthetic graft placement of the concomitant vascular bundle have also shown significant improvement in reducing the burden of the severe diseases such as synovial sarcoma.

SS with its malignant pathophysiology have impacted severely the quality of life of even among the pediatrics group of population. It is utmost need to set up proper and definitive muscular oncological care to reduce the morbidity and mortality associated with such malignancies.

To conduct an epidemiologic review, analyzing treatment, evolution, and survival of soft tissue sarcomas.

Retrospective study based on medical records of patient with STS treated by the Orthopedic Oncology Group at the Santa Casa de São Paulo, from 2006 to 2019. Data from 121 patients were analyzed according to age, sex, histological type, tumor location, treatment, previous surgery in a non-specialized service, local recurrences, lung metastases, and survival analysis.

The most frequent location was the thigh. Patients who underwent surgery with a non-specialized group had higher rates of local recurrence and those with pulmonary metastasis had a lower survival rate.

STS can occur at any age and the prevalence of the histological type depends on the patients' age group. Level of Evidence II, Prognostic Study.