Complete resection of a giant intrapericardial cardiac synovial sarcoma

Synovial sarcoma of the heart is a rare tumor. Herein we would like to report a case of giant intrapericardial cardiac synovial sarcoma that originated from the right ventricle and grew outward near the diaphragm. After making adequate preoperative preparation, we performed the surgery as quickly as possible and resected the tumor completely. Based on the identification of the translocation on chromosome 18 rearrangement, the tumor can be diagnosed as a primary cardiac synovial sarcoma. Through this study, we aim to afford more information about cardiac synovial sarcomas as well as a reference for similar cases.

[Primary cardiac synovial sarcoma: a clinicopathological analysis of five cases]

Objective: To assess the clinicopathological features, immunophenotype, molecular characteristics and differential diagnosis of primary cardiac synovial sarcoma (PCSS). Methods: Five cases of PCSS were collected at Guangdong Provincial People's Hospital from 2008 to 2023, and their clinicopathological features were summarized. Immunohistochemical staining, fluorescence in-situ hybridization (FISH) and next-generation sequencing (NGS) were performed, and relevant literatures were reviewed. Results: The cases were found in four males and one female, ranging in ages from 16 to 51 years (median 30 years). Two cases were located in the pericardium, two in the right ventricle, and one in the left ventricle. Follow-up data were available in four cases. All the four patients died of disease at 3, 7, 13 and 26 months, respectively, after diagnosis. The tumor maximum diameter ranged from 6.0 to 14.0 cm in (mean 10.0 cm). Microscopically, three cases were monophasic and two cases were biphasic. Immunohistochemically, all cases were immunoreactive for EMA, vimentin, bcl-2 and CD56. The tumor cells were variably positive for pan-cytokeratin, SS18-SSX, SOX2, TLE1, CD99, synaptophysin, calretinin and calponin. FISH showed the presence of SS18 rearrangement in all the cases. NGS detected SS18-SSX gene fusion in three cases (SS18-SSX1 in one and SS18-SSX2 in two). Conclusions: PCSS is an exceedingly rare neoplasm, and should be distinguished from other various malignant epithelial and mesenchymal tumors. The clinical history, histopathological and immunohistochemical features, and molecular findings are all essential to the definitive diagnosis of PCSS.

Diagnostic Utility of GATA3 and ISL1 in Differentiating Neuroblastoma From Other Pediatric Malignant Small Round Blue Cell Tumors

Accurate diagnosis of neuroblastoma may be challenging, especially with limited or inadequate specimen and at the metastatic sites due to overlapping imaging, histopathologic, and immunohistochemical (immunohistochemistry [IHC]; infidelity among various lineage-associated transcription factors eg FLI1, transducin-like enhancer 1, etc) features. GATA3 and ISL1 have recently been described as markers of neuroblastic differentiation. This study aims at determining the diagnostic utility of GATA3 and ISL1 in differentiating neuroblastoma from other pediatric malignant small round blue cell tumors.

We evaluated GATA3 and ISL1 expression in 74 pediatric small round blue cell tumors that included 23 NMYC-amplified neuroblastomas, 11 EWSR1-rearranged round cell sarcomas, 7 SYT::SSX1-rearranged synovial sarcomas, 5 embryonal rhabdomyosarcomas, 10 Wilms tumors (nephroblastomas), 7 lymphoblastic lymphoma, 7 medulloblastoma, and 4 desmoplastic small round cell tumor.

All 23 neuroblastomas (moderate to strong staining in >50% of the tumor cells), 5 T-lymphoblastic lymphomas (moderate to strong staining in 40%-90% of the tumor cells), and 2 desmoplastic small round cell tumors (weak to moderate staining in 20%-30% of the tumor cells) expressed GATA3, while other tumors were negative. ISL1 immunoreactivity was observed in 22 (96%) neuroblastomas (strong staining in in >50% of the tumor cells, n  =  17; moderate to strong staining in 26%-50% of the tumor cells, n  =  5), 3 embryonal rhabdomyosarcoma (moderate to strong staining in 30%-85% of the tumor cells), 1 synovial sarcoma (weak staining in 20% of the tumor cells), and 7 medulloblastoma (strong staining in 60%-90% of the tumor cells). Other tumors were negative. Overall, GATA3 showed 86% specificity, 100% sensitivity, and 90% accuracy for neuroblastoma, with a positive predictive value (PPV) and negative predictive value (NPV) of 77% and 100%, respectively. ISLI showed 72% specificity, 96% sensitivity, and 81% accuracy for neuroblastoma, with a PPV and NPV of 67% and 97%, respectively. After the exclusion of T-lymphoblastic lymphoma and desmoplastic small round cell tumors, GATA3 had 100% specificity, sensitivity, accuracy, and PPV and NPV for neuroblastoma. Similarly, in pediatric small round blue cell tumors, ISL1 had 100% specificity, sensitivity, accuracy, PPV, and NPV for neuroblastoma, after embryonal rhabdomyosarcoma, synovial sarcoma, and medulloblastoma were excluded.

CONCLUSIONS

GATA3 and ISL1 may be valuable in the diagnostic work-up of neuroblastoma and may reliably be used to support the neuroblastic lineage of pediatric small round blue cell tumors. Furthermore, dual positivity helps in challenging scenarios, when there is equivocal imaging, overlapping IHC features, limited specimen, and the lack of facility for a molecular work up.

Synovial sarcoma of the viscera (lung and jejunum): a case report

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.

Small gastric synovial sarcoma diagnosed and treatment by laparoscopic-endoscopic cooperative surgery: a case report

We report a case of small gastric synovial sarcoma (SS) finally diagnosed after laparoscopic-endoscopic cooperative surgery (LECS). A 50 year-old male underwent medical examination for a chief complaint of epigastric pain. Endoscopic examination showed a 20 mm submucosal tumor (SMT) located in the anterior wall which extended to the lesser curvature of the middle stomach. The biopsy tissue did not yield a definitive diagnosis. During 6 months of follow-up for this lesion suspected to be an inflammatory tumor, neither the shape nor the size of the tumor changed. We performed LECS for both diagnosis and treatment. Histologically, the tumor was composed of fascicles of spindle cells. Immunohistochemically, the tumor cells were focally positive for epithelial membrane antigen, cytokeratin (AE1/AE3) and S100 protein, while being negative for desmin, α-smooth muscle actin, CD34, c-kit and DOG1. The expression of INI1 was reduced. Fluorescence in situ hybridization (FISH) detected SS18 rearrangement. The SMT was diagnosed as primary SS. A SMT measuring < 20 mm might be malignant potential tumor such as SS even if there are no typical malignant findings by endoscopy. Surgical resection should be considered for SMT measuring < 20 mm with atypical findings even in the absence of definitive high-risk features.

Biphasic synovial sarcoma with epithelial predominance reminiscent of adenocarcinoma: a diagnostic challenge

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.

Recurrent Synovial Sarcoma with Breast and Pulmonary Nodule: A Case Report

Synovial sarcoma is a mesenchymal tumour with partial epithelial differentiation. About 85-90% of SS occur in the extremities. We present a case of a 44-year-old woman diagnosed with recurrent synovial sarcoma with breast and pulmonary nodules. The primary treatment for synovial sarcoma is wide surgical excision, while chemotherapy is reserved for metastatic cases. In the first-line metastatic setting, combination treatment with adriamycin and ifosfamide is administered. Despite the unfavourable prognosis, the patient's extended survival is fortunately not the typical outcome.

Keywords

case reports; chemotherapy; immunohistochemistry; synovial sarcoma.

Utility of Immunohistochemistry With Antibodies to SS18-SSX Chimeric Proteins and C-Terminus of SSX Protein for Synovial Sarcoma Differential Diagnosis

Synovial sarcoma is a relatively common soft tissue tumor characterized by highly specific t(X;18)(p11;q11) translocation resulting in the fusion of SS18 with members of SSX gene family. Typically, detection of SS18 locus rearrangement by fluorescence in situ hybridization or SS18 :: SSX fusion transcripts confirms the diagnosis. More recently, immunohistochemistry (IHC) for SS18-SSX chimeric protein (E9X9V) and C-terminus of SSX (E5A2C) showed high specificity and sensitivity for synovial sarcoma. This study screened a cohort of >1000 soft tissue and melanocytic tumors using IHC and E9X9V and E5A2C antibodies. Three percent (6/212) of synovial sarcomas were either negative for SS18-SSX or had scattered positive tumor cells (n=1). In these cases, targeted RNA next-generation sequencing detected variants of SS18 :: SSX chimeric transcripts. DNA methylation profiles of 2 such tumors matched with synovial sarcoma. A few nonsynovial sarcoma tumors (n=6) revealed either focal SS18-SSX positivity (n=1) or scattered positive tumor cells. However, targeted RNA next-generation sequencing failed to detect SS18 :: SSX transcripts in these cases. The nature of this immunopositivity remains elusive and may require single cell sequencing studies. All synovial sarcomas showed positive SSX IHC. However, a mosaic staining pattern or focal loss of expression was noticed in a few cases. Strong and diffuse SSX immunoreactivity was also seen in epithelioid sclerosing osteosarcoma harboring EWSR1 :: SSX1 fusion, while several sarcomas and melanocytic tumors including cellular blue nevus (5/7, 71%) revealed focal to diffuse, mostly weak to intermediate SSX staining. The SS18-SSX and SSX IHC is a useful tool for synovial sarcoma differential diagnosis, but unusual immunophenotype should trigger molecular genetic testing.

Synovial Sarcoma of the Gastrointestinal Tract

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.

Indolent Multinodular Synovial Sarcoma of Peripheral Nerves Mimicking Schwannoma: A Case Report and Literature Review

BACKGROUND/AIM

Most cases of synovial sarcoma (SS) are aggressive and large-sized; only few show indolent behavior, having a small size. Nerves are rare sites of SS occurrence. An atypical case of SS can lead to its misdiagnosis as a benign tumor and delay its treatment.

CASE REPORT

Here, we report a case of primary SS of indolent multinodular synovial sarcoma of peripheral nerves. Considering the clinical and imaging findings at the first visit, we suspected a benign tumor and continued careful follow-up. Three years later, marginal resection was performed and SS was suspected. We then performed an additional wide resection using a free flap. Histopathologically, the proximal tumor showed a diffuse proliferation of spindle cells without pleomorphism, whereas the distal tumor showed a similar histology with more hypercellularity. Additional wide-resection specimens showed remnant tumors derived from the peripheral nerve. Immunohistochemistry (IHC) showed positive staining for SS18:SSX and SSX in both tumors and fluorescence in situ hybridization showed positive staining for the SS18 split in both tumors. Finally, SS of the peripheral nerve was diagnosed. Owing to FNCLCC grade 2 tumor and tumor size, adjuvant chemotherapy was not performed.

CONCLUSION

In cases of SS or other sarcomas with atypical clinical courses, with imaging findings mimicking benign tumors, we recommend marginal resection along with pathological examination for correct diagnosis.

Sarcoma care in the era of precision medicine

Sarcoma subtype classification is currently mainly based upon histopathological morphology. Molecular analyses have emerged as an efficient addition to the diagnostic workup and sarcoma care. Knowledge about the sarcoma genome increases, and genetic events that can either support a histopathological diagnosis or suggest a differential diagnosis are identified, as well as novel therapeutic targets. In this review, we present diagnostic, therapeutic, and prognostic molecular markers that are, or might soon be, used clinically. For sarcoma diagnostics, there are specific fusions highly supportive or pathognomonic for a diagnostic entity-for instance, SYT::SSX in synovial sarcoma. Complex karyotypes also give diagnostic information-for example, supporting dedifferentiation rather than low-grade central osteosarcoma or well-differentiated liposarcoma when detected in combination with MDM2/CDK4 amplification. Molecular treatment predictive sarcoma markers are available for gastrointestinal stromal tumor (GIST) and locally aggressive benign mesenchymal tumors. The molecular prognostic markers for sarcomas in clinical practice are few. For solitary fibrous tumor, the type of NAB2::STAT6 fusion is associated with the outcome, and the KIT/PDGFRA pathogenic variant in GISTs can give prognostic information. With the exploding availability of sequencing technologies, it becomes increasingly important to understand the strengths and limitations of those methods and their context in sarcoma diagnostics. It is reasonable to believe that most sarcoma treatment centers will increase the use of massive-parallel sequencing soon. We conclude that the context in which the genetic findings are interpreted is of importance, and the interpretation of genomic findings requires considering tumor histomorphology.

Team Approach: Extremity Soft Tissue 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.

Primary synovial sarcoma and acinar adenocarcinoma of prostate rarely occur simultaneously: A case report

RATIONALE

Primary synovial sarcoma of the prostate is an extremely rare mesenchymal malignant soft tissue tumor with unique morphological features. Synovial sarcoma often occurs in the pararticular tissues of limbs in young people, but rarely occurs in prostate. Because it is very rare, it is easily misdiagnosed as benign prostatic hyperplasia or prostate cancer clinically. A case of synchronous acinar adenocarcinoma of the prostate has not been reported. In this article, we report a unique case of primary prostatic synovial sarcoma with acinar adenocarcinoma.

PATIENT CONCERNS

A 58-year-old male patient was found to have a prostate mass during physical examination. Prostate ultrasound examination showed an increase in prostate volume of 5.2 × 3.3 × 3.3 cm, mixed echo mass can be seen on the left side of the prostate, with a size of approximately 4.9 × 4.3 cm, left seminal vesicle compressed.

DIAGNOSES

Prostatic synovial sarcoma (biphasic type) combined with prostatic acinar adenocarcinoma (Gleason 3 + 3).

INTERVENTION

The patient received radical prostatectomy, followed by adjuvant chemotherapy and radiotherapy.

OUTCOME

After 2 months of follow-up, at the time of writing this article, the patient received a comprehensive treatment plan of adjuvant chemotherapy and radiotherapy for 2 months, and no recurrence or metastasis was found.

LESSONS

Primary prostatic synovial sarcoma (biphasic type) combined with prostatic acinar adenocarcinoma is a very unique and rare case, and effective treatment guidelines are not yet clear, posing new challenges to clinical treatment. Making full use of pathological and imaging examinations, early diagnosis and radical surgery combined with multidisciplinary treatment seem to be still a positive method.

Successful reconstruction using a buccal fat pad flap in misdiagnosed buccinators intramuscular synovial sarcoma: A case report

INTRODUCTION

Synovial sarcoma (SS) is a subtype of soft tissue sarcoma that primarily usually occurs in the lower extremities but rarely arises in the head and neck areas, including the oral cavity. Due to its variable presentation and similarity to benign masses in terms of age at onset, growth rate, and favorable outcomes, SS is often misdiagnosed as a benign tumor. However, it is a malignant tumor.

PATIENT CONCERNS

We report the case of intramuscular SS in the oral cavity. Initially, the lesion was clinically suspected as a benign mass but was ultimately confirmed as malignant SS.

DIAGNOSIS

Although histopathological examination is the first step in diagnosing SS, molecular testing to confirm the presence of SYT-SSX fusion can provide a definitive diagnosis when the histopathology is inconclusive. In this patient as well, the postoperative pathological report confirmed the diagnosis of biphasic SS, and molecular testing revealed positive SYT/SSX fusion.

THERAPEUTICS INTERVENTIONS

Following the recommendation of multidisciplinary care system, a wide excision was performed including the buccinators muscle, and reconstruction was performed using a buccal fat pad flap to prevent cheek depression.

OUTCOMES

On the final pathologic report, SS was removed margin-free, and there were no metastatic lymph nodes. No evidence of cheek dimpling was observed, and follow-up neck CT showed no significant changes in the lymph nodes. As a result of observation up to several months after surgery, there were no functional and aesthetic complications.

CONCLUSIONS

We report a successful case of intramuscular SS resection, initially misdiagnosed as a benign mass, using a buccal fat pad flap. We also highlight the importance of correctly diagnosing SS, especially in the craniofacial region where it can be mistaken for benign masses.

[Primary synovial sarcoma of lung: a clinicopathological analysis of 12 cases]

Objective: To investigate the clinicopathological features, immunophenotype, molecular features and differential diagnosis of primary synovial sarcoma of the lung (PSSL). Methods: Twelve cases of PSSL were collected at Henan Provincial People's Hospital, during May 2010 and April 2021, and their clinicopathological parameters were summarized. SS18-SSX, H3K27Me3, and SOX2 were added to the original immunomarkers to evaluate their diagnostic value for PSSL. Results: The age of 12 patients when diagnosed ranged from 32 to 75 years (mean of 50 years). There were 7 males and 5 females, 2 left lung cases and 10 right lung cases. Of the 6 patients who underwent surgical resection, five cases were confined to lung tissue (T1), one case had mediastinal invasion (T3), two cases had regional lymph node metastasis (N1), and none had distal metastasis. Microscopically, 11 cases showed monophasic spindle cell type and one case showed biphasic type composed of mainly epithelial cells consisting of cuboidal to columnar cells with glandular and cribriform structures. It was difficult to make the diagnosis by using the biopsy specimens. Immunohistochemistry (IHC) showed CKpan expression in 8 of 12 cases; EMA expression in 11 of 12 case; TLE1 expression in 8 of 12 cases; S-100 protein expression in two of 12 cases; various expression of bcl-2 and vimentin in 12 cases, but no expression of SOX10 and CD34 in all the cases. The Ki-67 index was 15%-30%. The expression of SS18-SSX fusion antibody was diffusely and strongly positive in all 12 cases. SOX2 was partially or diffusely expressed in 8 of 12 cases, with strong expression in the epithelial component. H3K27Me3 was absent in 3 of 12 cases. SS18 gene translocation was confirmed by fluorescence in situ hybridization (FISH) test in all 12 samples. Six cases underwent surgery and postoperative chemotherapy, while the other six cases had chemotherapy alone. Ten patients were followed up after 9-114 months, with an average of 41 months and a median of 26 months. Five patients survived and five died of the disease within two years. Conclusions: PSSL is rare and has a broad morphological spectrum. IHC and molecular tests are needed for definitive diagnosis. Compared with current commonly used IHC markers, SS18-SSX fusion antibody has better sensitivity to PSSL, which could be used as an alternative for FISH, reverse transcription-polymerase chain reaction or next generation sequencing in the diagnosis of PSSL.

SS18-SSX Expression in a Contemporary Cohort of Primary Renal Synovial Sarcoma: A Multi-Institutional Experience of Fourteen Patients

Primary renal synovial sarcoma is a rare aggressive mesenchymal neoplasm of the kidney that accounts for less than 1% of renal sarcomas. Herein, we describe the clinicopathologic and molecular findings of 14 renal synovial sarcoma patients in one of the largest case series to date and to our knowledge, the only renal synovial sarcoma series to use novel SS18-SSX IHC. Clinicopathologic, IHC, molecular, management, and follow-up data were reviewed and analyzed. Macroscopically, the tumors had either homogeneous, tan-white, and solid (n = 10), variegated and solid (n = 3), or variegated and solid-cystic (n = 1) cut surfaces. Spindle cell (n = 10), round cell (n = 3), and round to epithelioid morphologies (n = 1) were observed. SS18-SSX IHC was positive in all 14 tumors (diffuse, n = 10; multifocal, n = 2; focal, n = 2). All the tumors harbored SS18::SSX1/2 gene rearrangement. Metastases to the liver, brain, and lung (n = 1); liver and bone (n = 1); liver and diaphragm (n = 1) were identified. Adjuvant chemotherapy was administered in 11/12 patients. Follow-up was available for 10 patients (time period range: 5 to 24 months). Four patients died of disease, and six patients are alive with no recurrence or metastasis. As SS18-SSX IHC showed an excellent concordance with the FISH results, this may reliably be used in the IHC panel of spindle/round cell sarcomas of the kidney and as a molecular surrogate for renal synovial sarcoma, particularly in a resource-limited setting. Also, the tumors with focal SS18-SSX expression had lower break apart signals in the FISH assay (19% and 23% in two tumors with focal SS18-SSX IHC positivity).

Primary Synovial Sarcoma of the Bone: A Case Report and Literature Review

BACKGROUND/AIM

Synovial sarcoma (SS), a spindle cell sarcoma, typically occurs in the soft tissues of the extremities and rarely develops in the bones as a primary tumor. To our knowledge, no case of SS in the metacarpal bone has been reported.

CASE REPORT

We report a case of primary SS of the metacarpal bone. Considering the clinical and imaging findings, SS was difficult to diagnose; therefore, we performed an open biopsy. Next, we performed a wide resection following the management guidelines for SS of the soft tissue. Immunohistochemistry (IHC) showed positive staining for SS18:SSX and SSX, and fluorescence in situ hybridization showed positive staining for the SS18 split. Owing to FNCLCC grade 3 tumor and the R1 margin, adjuvant chemotherapy with ifosfamide and doxorubicin was initiated. Finally, SS of the bone was diagnosed. Furthermore, we reviewed a total of 37 published cases of primary bone SS, including our case. Age and sex were almost the same in all cases of bone SS, and the most frequent site was the long bone in the lower extremity.

CONCLUSION

IHC for SS18::SSX and SSX antibodies are beneficial for diagnosing general SS and SS of the bone. Moreover, SS of the bone should be considered in the differential diagnosis of spindle cell sarcomas of the bone. Wide resection and chemotherapy are recommended as current treatment strategies, although further studies are required regarding treatment validity.

Two Cases of Biphasic Synovial Sarcoma With Expression of PAX8 and ER: A Diagnostic Pitfall

Synovial sarcoma (SS) is a high-grade malignant neoplasm frequently arising in the deep soft tissue of the lower and upper extremities of young adults. Primary SS in the pelvis is extremely rare with scattered case reports. It often causes a diagnostic challenge in small biopsy and/or with aberrant expression of immunohistochemical markers. Here, we report 2 unusual cases of SS in the pelvis. Microscopically both cases present with biphasic morphology including spindle and epithelioid cells. In addition, the tumor cells in both cases expressed PAX8 and estrogen receptor. PAX8 is a transcription factor usually expressed in tumors of thyroid gland, kidney, and Müllerian system origin. The expression of PAX8 especially with co-expression of estrogen receptor can be misleading and result in a diagnosis of Müllerian tumors in female patients with pelvic masses. The diagnosis of SS for both cases was confirmed either with the fluorescence in situ hybridization or reverse transcription polymerase chain reaction showing a SS18 (SYT) (18q11) gene rearrangement. It is imperative to include SS in the differential diagnosis for malignant neoplasms exhibiting monotonous spindle cells (monophasic SS) and biphasic mixed monotonous spindle and epithelioid tumor cells in female patients with a pelvic mass. Molecular study for SS18 translocation is essential for the diagnosis in such cases.

Relapsed Synovial Sarcoma: Treatment Options

OPINION STATEMENT

Synovial sarcoma (SS) is a fusion-driven subtype of sarcoma that is a more chemo-sensitive subtype of soft tissue sarcoma. While chemotherapy options are currently standard of care, our fundamental understanding of the biology of SS is driving new therapies. We will review the current standard of care, as well as the current therapies showing promise in a clinical trial. It is our hope that by encouraging participation in clinical trials, the fundamental therapies available for SS will change the current treatment paradigm.

Primary Pulmonary Synovial Sarcoma with Hemothorax: a Case Report

Background

Synovial sarcoma is a rare and aggressive soft tissue malignancy most commonly arises from periarticular tissue of the extremities. Although several cases in the literature have reported different origins, primary pulmonary synovial sarcoma (PPSS) is an exceedingly rare and underrecognized entity, accounting for 0.5% of all lung malignancies. Clinical presentation includes chest pain, dyspnea, cough, and hemoptysis. The finding of hemothorax is a rare presentation and was barely reported in the literature. Due to its rarity and aggressive nature, the optimal treatment is unclear, while the mainstay remains surgical resection with chemo- and/or radiation therapy.

Objective

To report a case of hemorrhagic effusion subsequently diagnosed with primary pulmonary synovial sarcoma with the main objective of enriching the literature regarding this rare malignancy.

Case report

A 52-year-old male smoker with a background of coronary artery disease, hypertension, and diabetes mellitus was referred to our hospital. The patient presented with a history of chest pain, dyspnea, and massive right-sided pleural effusion. Laboratory investigations were unremarkable except for anemia. Chest x-ray showed a complete opacity on the right lower zone with right-sided pleural effusion. Thoracentesis was done and revealed hemorrhagic exudative effusion. Computed tomography (CT) scan showed a right heterogeneous lung mass compressing the medial segment of the middle lobe. Subsequently, the patient underwent bronchoscopy, which showed compression and edema on the right middle lobe bronchus with traces of blood coming from the right lower lobe. The patient underwent a right posterolateral thoracotomy, a fungating mass eroding the medial segment of the middle lobe was resected that was diagnosed as high-grade primary pulmonary synovial sarcoma. Radiotherapy was instituted. The patient died after two years due to recurrence.

Conclusion

PPSS is an aggressive disease with poor prognostic outcomes, and Its presentation is almost similar to other lung malignancies. Meanwhile, there is no definitive management guideline, and most management depends on surgical resection if feasible with adjuvant chemo-radiation therapy.

A rare lung tumor: Primary pulmonary synovial sarcoma

ABSTRACT

Synovial sarcoma is one of the rare soft tissue sarcomas occurring in the periarticular region originating from synovia. Synovial sarcomas occur less frequently in the neck, tongue, larynx, mediastinum, heart, lung, abdominal wall, small intestine, mesentery, and retroperitoneum. Primary pulmonary synovial sarcoma is a poor pathological condition without extrapulmonary involvement. In these rapidly progressing tumors, making quick decisions is important and performing complete resection is the best treatment that contributes to survival. Herein, we present a case of primary pulmonary synovial sarcoma in which we were able to achieve long-term survival with the multimodal approach after complete resection.

[Oncological outcomes and prognostic factors in surgically treated patients with synovial sarcoma]

INTRODUCTION

Synovial sarcoma is an unusual tumor with an incidence of 1-3 cases per million. It is more frequent in teenagers and young adults under 30. It develops anywhere, but the extremities are the most frequent place of appearance (80% extremities, 20% other locations: 8% trunk, 7% retroperitoneal/abdominal, 5% head and neck). Oncological results are different depending on the study. Survival rate free of local recurrence, survival rate free of events and global survival rate vary upon published studies. The same happens with the disease's prognostic factors.

METHODS

The objective was to analyze a group of 43 patients with diagnosis of synovial sarcoma of the extremities treated surgically and determine (1) global survival rate, (2) survival rate free of events, (3) local recurrence rate and (4) oncological risk factors.

RESULTS

The global survival rate at 2 years was 90% (IC95%: 76 - 96%) and 67% (IC95%: 49-80%) at 5 years. The survival rate free of events at 2 years was 68% (IC95% 51-80%) and 48% (IC95% 32-52%) at 5 years. The recurrence rate at 2 years was 9% (IC95% 3-25%) and 25% (IC95% 13-46%) at 5 years. The histological grade and metastatic presence were bad prognostic factors.

DISCUSSION

We can conclude that our oncological results are in line with those published in previous series and that there were two factors associated with poor prognosis.

Expanding the Use of an SS18-SSX Antibody for Molecular Assays in Synovial Sarcoma

Synovial sarcoma is an aggressive malignancy that generally affects adolescents and young adults and is characterized by high rates of recurrence and metastasis, with a 10-year survival rate of about 50%. The fusion oncoprotein SS18-SSX, the product of a pathognomonic chromosomal translocation t(X;18), is the oncogenic driver of this sarcoma, disrupting differentiation through widespread epigenetic dysregulation. Experimental research into SS18-SSX biology has been limited by the lack of an antibody that specifically detects the endogenous fusion oncoprotein as opposed to its native SS18 or SSX components. Recently, a rabbit monoclonal antibody was developed and made commercially available, which specifically detects the fusion junction site epitope of SS18-SSX as found in at least 95% of synovial sarcomas. Here, we characterize a suite of molecular biology assays using this new antibody, both confirming existing and reporting on novel applications. We demonstrate its high sensitivity and specificity for synovial sarcoma diagnosis on patient samples through positive immunohistochemical staining on synovial sarcoma, tissue microarray, and full face sections. In addition, we demonstrate detection of the human SS18-SSX protein when expressed in a genetically engineered mouse model of synovial sarcoma. We also demonstrate nuclear staining of SS18-SSX in synovial sarcoma cells using immunofluorescence, and visualize the interaction between SS18-SSX and the BAF complex member BRG1 through a proximity ligation assay. Lastly, we confirm the interaction between SS18-SSX and promoter regions of target genes through chromatin immunoprecipitation. This antibody represents a breakthrough in sarcoma research and has value in multiple applications to expand the knowledge of synovial sarcoma biology.

Primary pulmonary synovial sarcoma: A clinicopathological study of 22 cases

INTRODUCTION

Primary pulmonary synovial sarcoma (PPSS) is a rare mesenchymal tumour with characteristic translocation SS18-SSX1/2/rarely 4 fusion transcripts, and presents most often in adolescents and young adults. According to the World Health Organization (WHO) classification, synovial sarcoma is a malignant tumour of uncertain differentiation.

AIMS

To present a case series of PPSS with clinical, pathological and molecular analysis at a rare primary site.

SETTING AND DESIGN

Retrospective study conducted in a tertiary care hospital.

MATERIALS AND METHODS

Twenty-two cases of PPSSs were retrieved from electronic database between January 2009 to December 2018. Metastatic tumours from soft tissue primaries were excluded. Immunohistochemistry (IHC) and reverse transcription polymerase chain reaction (RT-PCR) were performed. Statistical analysis was performed using Mann-Whitney non-parametric test.

RESULTS

Among 22 patients, the male-female ratio was 3.4:1 and the median age was 31.5 years. The tumours were classified as monophasic (90.9%) and biphasic (9.1%) subtypes and graded as grade 2(77.3%) and grade 3(22.7%). IHC demonstrated expression of TLE1 (17/17 cases), Bcl-2 (7/8 cases), focal EMA (16/17 cases), CD99 (10/11 cases), focal pancytokeratin (8/12 cases) and CD56 (14/14 cases). The fusion transcripts included SYT-SSX1(4/11, 36.4%) and SYT-SSX2 (2/11, 18.2%). The remaining five cases were negative for SS18 rearrangement by RT-PCR. Only 8 patients had localised tumour. Surgical excision was performed in 5 patients. The median follow-up period was 6 months and 21 days.

CONCLUSIONS

Monophasic SS was the most common subtype. Small core biopsies pose a diagnostic challenge, in such a scenario, a combination of clinical, histomorphological, immunomarkers and genetic studies help confirm the diagnosis of PPSS.

[Clinical analysis of 24 cases of synovial sarcoma of head and neck]

Objective: To investigate the pathological characteristics, treatment and prognosis of synovial sarcoma of head and neck. Methods: The clinical data of 24 patients with synovial sarcoma of the head and neck treated in the First Affiliated Hospital of Zhengzhou University from January 2012 to December 2020 were retrospectively analyzed. There were 16 males and eight females, aged 17 to 75 years. The pathological features, treatment and follow-up were summarized. Cumulative survival was estimated by Kaplan-Meier method. Results: All patients' diagnoses were confirmed by pathological examinations. Most cases showed the tumors were composed of spindle cells under microscope, with the characteristics of malignant tumor cells, and some tumors also showed epithelioid cell morphology, forming the typical pathological characteristics of biphasic differentiation. Except for one patient who could not tolerate surgery and the diagnosis was only confirmed by biopsy, the remaining 23 patients received surgical treatment, including three patients receiving surgical treatment alone, five patients receiving post-operative adjuvant radiotherapy, seven patients receiving post-operative adjuvant chemotherapy, and eight patients receiving post-operative adjuvant radiotherapy. Follow-up time was 3.0-114.1 months (median follow-up time: 25.2 months), including two cases of loss to follow-up, 10 cases of recurrence, five cases of lung metastases, one case of bone metastasis, and 12 cases of death. The 1-year, 3-year and 5-year survival rates for the 24 patients with synovial sarcoma of head and neck were 74.4%, 58.9% and 39.2%, respectively. Conclusion: Synovial sarcoma of the head and neck has a high recurrence rate, common distant metastasis and poor prognosis. Histopathology and immunohistochemical examinations are an important basis for diagnosis, if necessary, combined with molecular genetics. Surgical resection is the main treatment, preferring radical or expanded resection.

Primary cardiac synovial sarcoma mimicking SARS-CoV-2 associated pericarditis

Primary cardiac synovial sarcoma is an extremely rare tumor with a higher incidence in young men. The mean age of occurrence is 32 years. Synovial sarcomas are tumors with high aggressiveness, proliferate rapidly and metastasize to regional and distant lymph nodes or surrounding organs. The typical location of synovial sarcoma of the heart is the atrial and ventricular septum. Its size, the degree of infiltration of the surrounding tissues and the presence of metastases influence clinical symptoms, which are very non-specific. The low specificity of the symptoms complicates the clinical diagnosis and in most cases the tumor is detected during its progression or incidentally. The final diagnosis is based on histological examination. The primary and only method of treatment is a surgical solution with an effort to completely resect the tumor, followed by aggressive palliative chemotherapy. In the following paper, we present a case report of a 32-year-old man who was diagnosed with synovial cardiac sarcoma only on the basis of exacerbation of non-specific subjective complaints due to the complication in the form of of aneurysmal bleeding of the tumor mass.

Primary Synovial Sarcoma of the Orbit: A Case Report and Update on Diagnostic Techniques

Synovial sarcoma is a malignant mesenchymal tumor that most commonly occurs in the deep soft tissue of the extremities in adolescents and young adults. Primary periocular synovial sarcoma is extremely rare with only 11 previously reported cases. We describe a 23-year-old woman who presented with a 1-year history of painful, progressive right upper eyelid swelling. She was subsequently found to have a superomedial orbital mass on CT scan. Pathologic evaluation revealed a spindle cell neoplasm with SS18 (SYT) rearrangement by fluorescence in situ hybridization studies, consistent with a monophasic synovial sarcoma. This case describes the clinical, radiographic, histopathologic, and molecular cytogenetic features of this rare orbital neoplasm, with an emphasis on the emerging diagnostic techniques and novel therapies.

Primary monophasic breast synovial sarcoma in a female patient

Synovial sarcoma (SS) is a rare soft tissue sarcoma usually arising in the deep soft tissues of the limbs, trunk, and head and neck region. Due to its rarity, diagnosis can be difficult to establish, especially when it involves an uncommon location like the breast. In this case report, we describe a young woman who was found to have primary SS of the breast. Initial immunohistochemistry staining was focally positive for cytokeratin and S100 and she was misdiagnosed with atypical spindle cell carcinoma. Due to the unusual presentation, further testing was performed which showed TLE1 and epithelial membrane antigen positivity, establishing the diagnosis of SS of the breast. A FISH was later sent out and was positive for SS18-SSX fusion transcript. This case highlights the importance of considering rare histopathology in breast lesions and using additional staining and cytogenetics to confirm diagnosis.

A Plum On Thumb: A Rare Presentation Of Synovial Sarcoma

Synovial sarcoma (SS) is a rare and aggressive mesenchymal tumour accounting for around 5-10% soft tissue neoplasms usually found in joints of upper and lower extremities. A 35years old healthy looking male patient from Afghanistan presented with swelling on palmar side of base of thumb from last one year. Seven months back excisional biopsy was taken report of which showed neurofibroma/dermatofibroma with. No evidence of malignancy seen. From last 5months mass reappeared and gradually increased in size with itching sensation and mild pain. On local examination there was 5×4×5 cm reddish mass on palmar surface of base of thumb with extension into mid thenar eminence with diffuse margins. X-ray showed soft tissue density mass with spikes of calcification. Ultrasound showed 4.2×4×4.5 cm heterogeneous solid lesion on anteromedial surface of root of right thumb without any remarkable intralesional calcification and remarkable intralesional vasculature. MRI reported lobulated well defined soft tissue mass eliciting low to intermediate signal on T1 and WIs and bright signal on T2and STIR Vividly enhancing mass. Case was operated mass was excised and biopsy sent. Post op status was unremarkable. Biopsy reported poorly differentiated biphasic synovial sarcoma. No recurrence seen till 3months.

Development and Validation of the Nomograms for Predicting Overall Survival and Cancer-Specific Survival in Patients With Synovial Sarcoma

BACKGROUND

The study aimed to build and validate practical nomograms to predict overall survival (OS) and cancer-specific survival (CSS) for patients with synovial sarcoma (SyS).

METHODS

A total of 893 eligible patients confirmed to have SyS between 2007 and 2015 were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were randomly divided into the training cohort (n = 448) and validation cohort (n = 445). Clinically independent prognostic and important factors were determined according to the Akaike information criterion in multivariate Cox regression models when developing the nomograms with the training cohort. The predictive accuracy of nomograms was bootstrapped validated internally and externally with the concordance index (C-index) and calibration curve. Decision curve analysis (DCA) was performed to compare the clinical usefulness between nomograms and American Joint Commission on Cancer (AJCC) staging system.

RESULTS

Two nomograms shared common indicators including age, insurance status, tumor site, tumor size, SEER stage, surgery, and radiation, while marital status and tumor site were only included into the OS nomogram. The C-index of nomograms for predicting OS and CSS was 0.819 (0.873-0.764) and 0.821 (0.876-0.766), respectively, suggesting satisfactory predictive performance. Internal and external calibration curves exhibited optimal agreement between the nomogram prediction and the actual survival. Additionally, DCA demonstrated that our nomograms had obvious superiority over the AJCC staging system with more clinical net benefits.

CONCLUSIONS

Two nomograms predicting 3- and 5-year OS and CSS of SyS patients were successfully constructed and validated for the first time, with higher predictive accuracy and clinical values than the AJCC staging system regarding OS and CSS.

Synovial sarcoma of the spine in the lumbar vertebral body: A rare case report

RATIONALE

Synovial sarcoma (SS) is a soft tissue neoplasm that rarely occurs in the vertebral body and should be considered in the differential diagnosis in patients with SS and vertebral lesions. SS often presents as a painless mass in the spine, which may undergo slow enlargement, resulting in sustained symptoms of neurologic deficit and pain. Due to the difficulty in differentiating between SS from other soft tissue tumors and metastatic tumors, careful histological confirmation is required for definite diagnosis. Furthermore, due to its malignancy, the appropriate treatment procedure for SS should be carefully considered.

PATIENT CONCERNS

A 56-year-old female patient had low back pain. Radiological examination revealed bony erosion of the L-2 vertebral body, and no soft tissue mass around the lumbar spine.

DIAGNOSIS

Histopathological and immunohistochemical examination revealed SS.

INTERVENTIONS

The initial treatment of posterior laminectomy decompression and percutaneous vertebro plasty (PVP) was performed, however, this initial treatment course was inappropriate, but she eventually underwent L-2 complete resection and internal fixation. After the second surgery, she was treated by external beam radiation therapy.

OUTCOMES

operation radiotherapy was finally performed. No local recurrence in L-2 vertebral body or distant metastasis was found at 1-year follow up postoperation; the neurologic symptom gradually relieved, and no other symptom was noted. And no local recurrence in L-2 vertebral body and distant metastasis was found in 1 year follow up postoperation.

LESSONS

Solitary spinal SS is extremely rare. Early surgery for total resection and adjuvant radiotherapy/chemotherapy should be emphasized.

Primary renal synovial sarcoma: A case report

RATIONALE

Synovial sarcoma (SS) is a malignant neoplasm that arises from soft tissues proximal to the joints. It occurs primarily at the major joints of the extremities, but may also occur in the deep soft tissues around the joints. While primary renal synovial sarcoma (PRSS) is extremely rare, it is important to have a better understanding of their imaging and clinical features to establish an effective treatment plan. Correct identification of PRSS is also useful for treating renal neoplasms.

PATIENT'S CONCERNS

A 56-year-old Chinese man was admitted to our hospital due to moderate, paroxysmal left-sided loin pain.

DIAGNOSIS

Renal enhanced computed tomography (CT) scanning showed a relatively hypovascular lesion with calcification in the left kidney. A radical nephrectomy was performed in the left kidney. Postoperative pathology indicated SS with necrosis. The immunohistochemical findings were as follows: 34βE12 (Epithelium+), Bcl-2(+), CD99(+), CK-pan((Epithelium+), EMA(Epithelium+), Ki-67(+60%), and Vimentin(+), CD34(-).

INTERVENTIONS

The patient underwent radical left nephrectomy with no complications.

OUTCOMES

After discharge, a close review for 3 months showed no evidence of recurrence.

LESSONS

PRSS should be considered for the differential diagnosis of renal hypovascular tumors. When problems arise in distinguishing renal hypovascular tumors, surgical pathology is helpful in the final diagnosis and further treatment of the disease.

Primary Synovial Sarcoma of the Thyroid: Challenges in Cytologic Diagnosis and Review of the Literature

BACKGROUND

Primary synovial sarcoma (SS) of the thyroid (PSST) is extremely rare. Its differential diagnosis from other neoplasms is essential since it has different management protocols and prognosis.

CASE

A 26-year-old man with a 4.5-cm solid lobulated mass was seen at an outside hospital. Fine needle aspiration (FNA) was interpreted as a papillary carcinoma, and a total thyroidectomy was performed. The final histologic diagnosis was spindle epithelial tumor with thymus-like differentiation (SETTLE). No metastases were detected at that time, and the patient received radioactive iodine treatment. Two years post-surgery, he was seen at our hospital with a local recurrence, and FNA was considered as consistent with SETTLE. The mass was resected, and a left modified radical neck dissection was performed. The tumor revealed necrosis and a high mitotic index. Following histologic, immunohistochemical, and molecular studies, the tumor was classified as a PSST. The patient received chemotherapy and targeted immunotherapy, but he died 41 months after the initial presentation.

CONCLUSION

The main diagnostic pitfall of PSST is SETTLE. The presence of mitotic figures and basal lamina material, negative staining for smooth muscle actin, and positive staining for transducer-like enhancer of split 1 antibody favor SS over SETTLE. SYT gene rearrangement is essential to establish the definitive diagnosis of PSST.

[Synovial sarcoma - a rare and highly malignant, tumor with an ambiguous clinical picture at times]

A characteristic feature of soft tissue sarcomas is the absence of alarm symptoms such as pain or abnormal laboratory findings. We present two patients where the diagnostic difficulties delayed the definitive diagnosis, in one case with lethal outcome. The two patients highlight the difficulties a clinician may encounter with this particular disease. Even though synovial sarcoma represents around 0,1 % of all cancer forms, we recommend a high degree of awareness and - when in doubt - prompt contact with a Sarcoma center for consultation.

Primary pulmonary synovial sarcoma with calcification: A case report

The lung is the organ most commonly affected by primary synovial sarcoma. Intratumoral calcification is less common in this organ versus soft tissue. Meanwhile, the presence of calcification in a lung nodule reduces the risk of lung cancer. Here, we report a case of pulmonary synovial sarcoma which manifested as a nodule with calcification, depicted on computed tomography (CT). A 52-year-old asymptomatic male was referred to Saitama Medical University International Medical Center and CT revealed a well-defined nodule (1.8 cm), with punctate and eccentric calcification in the right lower lobe. Enhanced CT and 18F-fluorodeoxyglucose positron-emission tomography suggested a malignant tumor, and surgery was performed. Histology provided a preliminary diagnosis of monophasic spindle-cell synovial sarcoma with hyalinized collagen bands and calcifications. Genetically, the presence of the SYT-SSX2 fusion gene was consistent with the features of this disease. We conclude that primary pulmonary synovial sarcoma should be listed as a differential diagnosis for solitary pulmonary nodules with calcification.

Pericardial Synovial Sarcoma: Case Report, Literature Review and Pooled Analysis

BACKGROUND

Pericardial synovial sarcomas (PSS) are very rare tumors, with dismal prognosis and limited data. We describe the clinical features and identify prognostic factors of primary PSS.

CASE REPORT

We describe the case of a 56-year-old male patient with PSS managed by the multidisciplinary team of thoracic oncology. The therapeutic plan comprised surgery, chemotherapy, stereotactic radiosurgery and targeted therapy, with excellent results.

MATERIALS AND METHODS

Data from 37 cases reported in English during the past 20 years were gathered and analyzed. PSS was found to occur at a mean age of 36±17.082 (range=13-67) years. Survival analysis was performed on 20 cases with follow-up of at least 6 months.

CONCLUSION

Only complete resection of the tumor seems to be an independent prognostic factor. To our knowledge, this is the first report on the safety and effectivity of pazopanib in PSS and may provide guidance for similar cases in the future.

Biphasic chest wall synovial sarcoma with epithelial pleural effusion: a diagnostic challenge

Synovial sarcoma (SS) is a rare malignancy that most commonly involves the extremities and large joints. We describe a 67-year-old woman who presented with shortness of breath and flu-like symptoms, and a chest wall mass. On resection of the mass biphasic morphology of SS was noted, as well as confirmatory immunostains including TLE1 and bcl2. An SS18/SSX2 fusion transcript was detected by reverse transcriptase-DNA amplification. A year later, following chemotherapy, the patient developed a right-sided pleural effusion. Cytological examination of the fluid showed an epithelial population forming clusters and groups. TLE1 was positive, as well as fluorescent in situ hybridization analysis for the SS18/SSX2 fusion transcript. SS can be a challenging diagnosis in fluid-filled cavities, when the epithelial component predominates and its original biphasic quality is not seen. We discuss the diagnostic challenges of monophasic and biphasic SS, and updates to ancillary testing.

Primary Synovial Sarcoma of the Mediastinum with Long-term Follow-up

Chest radiography showed a right posterior mass on the mediastinum of an 84-year-old woman. The mass had been growing gradually for four years. Surgical excision was performed, and a pathological examination found the mass to be consistent with primary synovial sarcoma (SS) of the mediastinum. To our knowledge, this is a rare case in which follow-up imaging was able to be performed over a period of four years. This disease is aggressive, and its early diagnosis is key to achieving a cure. It is important to consider primary SS in the differential diagnosis of a primary intra-thoracic tumor, even if the tumor grows slowly.

Primary Synovial Sarcoma of the Mediastinum in an 18-year old male: A case report

Primary mediastinal synovial sarcomas are very rare occurrences with only a few cases reported in literature to date. We present a similar case in an 18-year old male which proved challenging to diagnose and treat. Radiological imaging and tru-cut biopsy results gave rise to suspicion of an unusual malignancy. The sarcoma under went en bloc resection and subsequent immunohistochemical staining confirmed the diagnosis of synovial sarcoma. The patient was put on adjuvant chemotherapy after surgery to prevent recurrence. The purpose of this case report is to assist oncologists in the diagnosis and clinical management of this rare tumour.

The role of immunohistochemistry in the diagnosis and management of synovial sarcoma

Synovial sarcoma (SS) is a malignant soft tissue tumor representing 5-10% of all soft tissue sarcomas. Most synovial sarcomas are found at the extremities, especially in the lower limbs. A 28-year-old female presented at the Department of Plastic and Reconstructive Surgery, "Dr. Pius Brînzeu" Clinical Hospital, Timişoara, Romania, for evaluation of a mass located in the anterior region of the elbow. Imagistic, histological and immunohistochemically evaluations established the diagnosis of monophasic spindle cell SS G2. Block excision of the tumor with oncological safety margins was performed followed by total elbow arthroplasty. The patient then received radio- and chemotherapy. The case was followed-up at regular intervals for local recurrence and metastases and was free of symptoms at two years. Early diagnosis of SS, multimodal therapies and performing an arthroplasty of the elbow allowed the patient to resume daily activities. The unpredictable evolution requires regular follow-up for a long period of time.

A primary gastric synovial sarcoma: A case report and literature review

RATIONALE

When a gastric spindle cell tumor is observed, the possibility of synovial carcinoma, besides common mesenchymal tumor, should also be considered.

PRESENTING CONCERNS OF THE PATIENT

The patient is a 51-year-old American woman who underwent medical check-up at a general hospital. Upper endoscopy showed a 2-cm sized mass covered with intact mucosa, and a central depression located on the posterior wall of the mid body. Biopsy of the mass showed focal atypical cells proliferation in mucosa on hematoxylin & eosin (H&E) staining. Endoscopic ultrasound showed a 17-mm homogenously hypoechoic mass within the submucosal layer.

INTERVENTIONS

After diagnostic endoscopic submucosal dissection was performed, H&E and immunohistochemical staining showed synovial sarcoma (SS). To confirm the diagnosis, reverse transcriptase-polymerase chain reaction was performed, revealing a chimeric transcript of the SYT-SSX1 fusion gene. The diagnosis of primary gastric SS was confirmed because no evidence of possible primary lesions or metastatic lesions was observed. Therefore, the patient underwent distal gastrectomy.

OUTCOMES

After surgery, the surgical specimen demonstrated no residual tumor cells. The patient received no adjuvant therapy, and there has been no evidence of local recurrence or distant metastasis for 2 months after the operation.

LESSONS

When gastric subepithelial tumor is suspicious, we should also consider gastric SS.

Diagnosis, Classification, and Management of Soft Tissue Sarcomas

BACKGROUND

Soft tissue sarcomas are challenging to oncologists due to their unique character, the infrequency of their occurrence, and the difficulties in predicting outcomes. Advances in imaging, as well as improvements in surgical techniques and adjunctive treatment methods, have improved care for patients with these unusual disorders.

METHODS

The various types of soft tissue tumors are defined, and the statistics for the Orthopaedic Oncology Group in relation to them are reviewed and compared with literature references.

RESULTS

The overall survival rate for 1,220 tumors treated at our institute from June 1972 to June of 2001 was 72%, with a wide range. Patients with leiomyosarcomas, clear cell sarcomas, and malignant fibrous histiocytomas had a poorer survival rate, while those with fibrosarcomas, liposarcomas, and neurofibrosarcomas fared better. Outcome was affected by patient age, tumor anatomic site, tumor stage, and a history of recurrence.

CONCLUSIONS

Competent imaging, predictive immunological and genetic studies, improved surgery, and newer methods of adjunctive and neoadjunctive treatment should result in improvements in outcomes for patients with these tumors.

Whorling cellular perineurioma: A previously undescribed variant closely mimicking monophasic fibrous synovial sarcoma

The authors present a distinctive perineurioma (PN) variant which morphologically strongly resembles monophasic fibrous synovial sarcoma (MSS). The patients were 3 males and 1 female. The age ranged from 15 to 61years (mean: 44years). Locations included the sole, lower jaw, palm and foot. The tumor size ranged from 1.3cm to 2.5cm in the largest dimension (mean 1.8cm). Morphologically, all tumors had an identical, monotonous appearance. The perineurial cells were closely packed and created a confluent cellular whorls and/or sheets in a scarce stroma, with only focally discernible long, slender cytoplasmic processes typical for perineurial differentiation. The nuclei were rounded or slightly elongated to tapered, without nuclear atypia. Mitoses were rare to completely absent. Atypical mitoses, hemorrhage, necrosis or calcifications were not present. The proliferative index (Ki-67) was 1-3%. All analyzed tumors were positive for EMA, Claudin-1, GLUT-1 and negative with S100 protein, CD34, OSCAR, CK7 and TLE-1. Two cases were tested by fluorescence in situ hybridization and neither showed alterations of the SYT gene. One case studied by electron microscopy showed characteristic features of perineurial differentiation. Follow-up was available for two patients both of which showed no evidence of disease at 8years and 6months, respectively. Based on their bland morphology, perineurial features and presumably benign clinical outcome we propose the term "whorling cellular perineurioma" for these tumors, which may represent an extremely cellular variant of sclerosing PN. Awareness of this PN subtype and its distinction from MSS is of utmost clinical significance.

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.

[Primary Pulmonary Synovial Sarcoma Confirmed by Demonstration of SYT-SSX Fusion Gene Translocation by Fluorescence In Situ Hybridization]

A 58-year-old man was referred to our hospital due to a mass shadow noted on a chest X-ray. Chest computed tomography showed a 3 cm nodule in the left lung. Thoracoscopic left upper lobectomy was performed to remove the lesion, and the postoperative diagnosis was primary pulmonary synovial sarcoma according to the histology and SYT-SSX gene analysis.

Synovial cell sarcoma: a rare laryngeal tumor

Synovial cell sarcoma is a soft tissue tumor that occurs predominately in the lower limbs near the joints. Lesions of the head and neck are extremely rare. The larynx is the least frequent site with only about 20 cases reported in the literature. Treatment of these tumors is controversial and should follow the guidelines for other tumor sites. We report the case of a 37-year-old man with primary laryngeal synovial cell sarcoma, who was surgically managed by a narrow field laryngectomy.