Cerebral sinovenous thrombosis as a cause of subdural hemorrhage in the pediatric population: Is there a correlation?

PURPOSE: Cerebral sinovenous thrombosis is an increasingly recognized cause of stroke in children and neonates. Its true incidence appears to be underestimated. Despite being a rare event, certain studies have found a correlation between subdural hemorrhage and cerebral sinus thrombosis. The literature suggests that spontaneous cerebral sinovenous thrombosis in the pediatric population may lead to the occurrence of a subdural hemorrhage. In this report, we present a case of cerebral venous thrombosis associated with chronic subdural hematoma and review the literature to highlight the importance of these conditions. CASE REPORT: An 11-year-old boy was admitted in the neurosurgery department with headache and a neurological examination without changes. The imaging studies identified a heterogeneous subdural collection in the fronto-temporo-parietal region. The patient underwent surgical drainage of the subdural hematoma, and the procedure was performed without complications. The magnetic resonance and angiography showed an extensive thrombosis of the superior sagittal sinus, extending downward to the occipital sinus and partially to the right transverse sinus. CONCLUSIONS: Appropriate management in the diagnosis and an early treatment of dural sinus thrombosis associated with subdural hemorrhage can reduce the risk of recurrence and improve the clinical outcome.

[Comparison of methods of treatment of meningiomas invading the superior sagittal sinus]. / Sravnitel'naya otsenka metodov lecheniya meningiom, invaziruyushchikh verkhnii sagittal'nyi sinus.

There are various approaches to the treatment of patients with parasagittal meningiomas. OBJECTIVE: To optimize treatment strategy for meningiomas invading the superior sagittal sinus. MATERIAL AND METHODS: The study included 87 patients with benign parasagittal meningiomas between 2010 and 2012. Of these, 34 patients underwent surgery alone, 27 - radiotherapy, 26 - surgery and subsequent radiotherapy. Both groups were comparable in male-to-female ratio, age and localization of tumors in relation to superior sagittal sinus. The follow-up period was at least 5 years. We analyzed the effect of treatment on neurological status, Karnofsky score and tumor growth control. RESULTS: Mean volume of tumors was 43.3 cm3 in patients undergoing surgery and 6.7 cm3 in the radiotherapy group. In the combined treatment group, mean volume was 65.8 cm3 before surgery and 8.8 cm3 before irradiation. General cerebral symptoms (84%), epileptic seizures (37%) and movement disorders (31%) prevailed. Surgery provided the best results in patients with small meningiomas (<14 cm3) causing focal neurological symptoms. Isolated radiotherapy was the most effective in asymptomatic patients. Large tumors required surgery with adjuvant irradiation. CONCLUSION: Benign parasagittal meningiomas followed by focal neurological symptoms require surgical intervention regarding the best functional outcomes and tumor growth control. Radiotherapy without surgery is advisable for progressive asymptomatic tumors. Resection followed by irradiation is preferable if total resection without the risk of damage to veins and cortex is impossible.

A novel rat model for cerebral venous sinus thrombosis: verification of similarity to human disease via clinical analysis and experimental validation.

BACKGROUND: Cerebral venous sinus thrombosis (CVST) is a rare neurovascular disorder with highly variable manifestations and clinical courses. Animal models properly matched to the clinical form of CVST are necessary for elucidating the pathophysiology of the disease. In this study, we aimed to establish a rat model that accurately recapitulates the clinical features of CVST in human patients. METHODS: This study consisted of a clinical analysis and animal experiments. Clinical data for two centres obtained between January 2016 and May 2021 were collected and analysed retrospectively. In addition, a Sprague-Dawley rat model of CVST was established by inserting a water-swellable rubber device into the superior sagittal sinus, following which imaging, histological, haematological, and behavioural tests were used to investigate pathophysiological changes. Principal component analysis and hierarchical clustering heatmaps were used to evaluate the similarity between the animal models and human patients. RESULTS: The imaging results revealed the possibility of vasogenic oedema in animal models. Haematological analysis indicated an inflammatory and hypercoagulable state. These findings were mostly matched with the retrospective clinical data. Pathological and serological tests further revealed brain parenchymal damage related to CVST in animal models. CONCLUSIONS: We successfully established a stable and reproducible rat model of CVST. The high similarity between clinical patients and animal models was verified via cluster analysis. This model may be useful for the study of CVST pathophysiology and potential therapies.

[Surgical treatment of large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading].

OBJECTIVE: To investigate the surgical strategy for large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading. METHODS: The clinical data of 16 patients with large and giant recurrent meningioma in the middle and posterior third part of the superior sagittal sinus with extracranial invasion who underwent surgery in the Department of Neurosurgery of Peking University Third Hospital from May 2019 to May 2022 were retrospectively analyzed. All the patients underwent brain-enhanced magnetic resonance imaging (MRI), magnetic resonance venography (MRV), computed tomography angiography (CTA) and three-dimensional skull computed tomography (CT) before, to evaluate the extent of tumor invasion, the edema of brain tissue, the degree of skull damage, the blood supply of the tumor, and the degree of compression of the superior sagittal sinus, etc, and to formulate an individualized surgical plan. The neurological function of the patients was evaluated 1 week, 1 month, and 3 months after the operation, and the tumor condition was evaluated by brain-enhanced MRI 3 months, 6 months, and 1 year after the operation. RESULTS: The tumors in the 16 patients were all located in the middle and posterior 1/3 part of the superior sagittal sinus and invaded extracranially. Among them, 8 cases were operated for the second time, 6 cases for the third time, and 2 cases for the fourth time; In the last operation, the bone flap was used to repair the skull in 4 cases, and the titanium mesh was used in 12 cases; Tumor arterials of 3 cases were embolized under digital subtraction angiography (DSA). Tumors of 10 cases were resected at Simpson grade Ⅰ, and 6 cases at Simpson grade Ⅱ; 2 cases underwent decompressive craniectomy during operation, and 14 cases underwent cranioplasty at the same time; scalp incisions of 14 cases were directly sutured, and flap transposition was used in 14 cases. When evaluating nerve function after operation, the limb muscle strength was improved compared with that before operation, and the Karnofsky performance scale (KPS) score reached 100 points 3 months after operation. During the follow-up, 1 patient's tumor recurred after 1 year and received Gamma Knife treatment, and the rest of the patients had no recurrence during the follow-up period. CONCLUSION: Surgical treatment is the first choice for large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading. It is a safe and effective surgical method to take individualized surgical plan after detailed preoperative assessment of cerebral edema, tumor blood supply, venous sinus compression, and scalp invasion.

Diploic veins as collateral venous pathways in patients with dural venous sinus invasion by meningiomas.

BACKGROUND: Although it is known that diploic veins frequently communicate with the dural venous sinuses, the role of diploic veins in patients with venous sinus invasion from meningiomas remains unknown. METHODS: We retrospectively examined the medical records of 159 patients who underwent their first craniotomies for intracranial meningiomas. Contrast-enhanced magnetic resonance imaging was used to evaluate diploic vein routes, and digital subtraction angiography (DSA) was used to evaluate diploic vein blood flow. When high blood flow was visualized concurrently with the venous sinuses, the veins were classified as of the "early type." Diploic vein routes were classified into five routes. RESULTS: DSA was performed in 110 patients, with 14 showing superior sagittal sinus (SSS) invasion (SSS group) and 23 showing non-SSS venous sinus invasion (non-SSS group). The proportion of early type diploic veins was significantly higher in the SSS group (27.1%) than in other patients (patients without venous sinus invasion, 2.1%; non-SSS, 4.3%) (p < 0.01). In patients not in the SSS group, diploic veins were sacrificed during craniotomy in 76 patients, including four patients with veins of the early type. No patients demonstrated new neurological deficits postoperatively. In the SSS group, diploic veins were sacrificed in all patients, and early type diploic veins were cut in five patients. Two of these five patients showed postoperative neurological deficits. CONCLUSIONS: In the SSS group, diploic veins may function as collateral venous pathways, and attention is recommended for their interruption. In patients without SSS invasion, diploic veins, even of the early type, can be sacrificed.

Intracranial venous myxoma - An incidental finding.

Myxomas are the commonest type of benign cardiac tumors, however, myxomas of an extracardiac origin are rare. This case report presents the postmortem finding of a myxoma arising in the superior sagittal sinus of a 76-year-old woman in the absence of a cardiac primary tumor.

Microsurgical Resection of a Primary Intraosseous Meningioma Encasing the Superior Sagittal Sinus.

Primary intraosseous meningiomas (PIMs) are an infrequent variant of meningiomas characterized by hyperostosis and brain compression. En bloc surgical resection of giant PIMs involving critical structures such as venous sinuses or cranial nerves could be associated with significant morbidity. The objective of this report is to demonstrate the safety and feasibility of piecemeal resection of PIMs involving the superior sagittal sinus and frontal sinus. A 54-year-old female with a large 5 cm thick bifrontal primary intra-osseous meningioma encasing the anterior segment of the superior sagittal sinus and frontal sinus underwent a bifrontal craniotomy with piecemeal microsurgical resection of the lesion, complete frontal sinus exoneration, and a synthetic cranioplasty. Clinical outcome was measured by extent of resection, preservation of cortical draining veins and postoperative course. A Simpson grade I resection of the lesion was achieved following piecemeal resection of the giant PIM without clinical or radiographic evidence of venous infarct or injury. The postoperative course was uncomplicated, and the patient was discharged home 3 days after cranioplasty. A complete resection of a giant bifrontal PIM with superior sagittal sinus encasement and frontal sinus involvement can be achieved safely via a piecemeal approach without significant intra-operative morbidity.

Type III Intraosseous Meningioma Invading Superior Sagittal Sinus and Skull Periosteum.

Type III intraosseous meningioma is a very rare type of meningioma with extracranial extension. Herein, the author reported a case of type IIIC intraosseous meningioma with invasion of the superior sagittal sinus and skull periosteum. A 67-year-old woman was admitted to our hospital due to a mass on the left frontoparietal region for 4 years. Magnetic resonance imaging showed a skull tumor with invasion of the superior sagittal sinus. After partial resection of the tumor, pathological and immunohistochemical staining revealed that the epithelial meningioma derived from skull involved the skull periosteum. There was no enlargement of residual parasagittal tumor after 1 year of follow-up. The intraosseous meningioma in the present case was a rare benign tumor with good prognosis after surgery.

Skull fracture with effacement of the superior sagittal sinus following drone impact: a case report.

BACKGROUND: The popularity of unmanned aerial vehicles, or drones, raises safety concerns as they become increasingly common for commercial, personal, and recreational use. Collisions between drones and people may result in serious injuries. CASE REPORT: A 13-year-old male presented with a comminuted depressed skull fracture causing effacement of the superior sagittal sinus secondary to a racing drone impact. The patient experienced a brief loss of consciousness and reported lower extremity numbness and weakness after the accident. Imaging studies revealed bone fragments crossing the superior sagittal sinus with a short, focal segment of blood flow interruption. Neurosurgical intervention was deferred given the patient's improving neurological deficits, and the patient was treated conservatively. He was discharged home in stable condition. CONCLUSION: Drones may represent a hazard when operated inappropriately due to their capacity to fly at high speeds and altitudes. Impacts from drones can carry enough force to cause skull fractures and significant head injuries. The rising popularity of drones likely translates to an increased incidence of drone-related injuries. Thus, clinicians should be aware of this growing trend.

Superior Sagittal Sinus Thrombosis Related to the Use of Tamoxifen: A Case Report and Review of Literature.

Tamoxifen is a selective estrogen- receptor modulator commonly associated with an increased risk of thrombotic events, including cere- bral venous thrombosis. Ihe superior sagittal sinus appears to be the most affected site of cerebral venous thrombosis in patients with a history of malignancy. However, the underlying mechanism of tamoxifen- induced hypercoagulability and location of cerebral venous thrombosis are notwellunderstood. Here, we present a case of a 47-year-old female with a history of breast cancer, on tamoxifen for 10 months, found to have superior sagittal sinus thrombosis with additional thrombosis of the draining cortical veins. Furthermore, we review similar cases published in literature. We recommend that physicians should be aware ofthe potential of developing superior sagittal sinus thrombosis in patients who take tamoxifen and warn patients of this adverse event when prescribing the medication.

Endovascular treatment of a traumatic dural arteriovenous fistula of the superior sagittal sinus using dual lumen balloon microcatheter.

Dural arteriovenous fistula (DAVFs) induced by trauma in the superior sagittal sinus (SSS) are rare and difficult to treat because of their unique midline location, multiplicity of arterial feeders, and critical venous drainage. We report a case of an endovascular treatment using dual lumen balloon microcatheter on a patient with post-traumatic SSS DAVF. By the use of dual lumen Scepter balloon microcatheter, proximal Onyx reflux was prevented. In this case, complete embolization of the DAVFs was achieved and the outcome of the patient was fairly good.

LINAC radiosurgery in the management of parasagittal meningiomas.

BACKGROUND: At present, there is no general agreement for the best approach to parasagittal meningiomas. Invasion of the superior sagittal sinus is frequent and responsible for relatively high recurrence rates following conventional microsurgery. Radiosurgery has the potential to treat less accessible portions of these tumors, and its application in this pathology is increasing either as a primary or a complementary therapeutic tool. OBJECTIVE: To evaluate our results with LINAC radiosurgery for the treatment of parasagittal meningiomas. METHODS: The patient cohort consisted of 74 patients treated for parasagittal meningioma by LINAC radiosurgery at our institution's Radiosurgery Unit during a 15-year period. Women accounted for 61% of patients. Thirteen patients (18%) underwent radiosurgery as the primary treatment for their meningioma. RESULTS: The overall actuarial control rate was 90.6% at a mean follow-up of 49 months. In 17 patients (22.9%), there was no volumetric change. Fifty patients (67.5%) showed tumor shrinkage ranging from 15 to 80% of the original mass. In 7 patients, tumor recurrence was observed at an average time of 42.2 months after radiosurgery. All the patients with previously untreated tumors were controlled. Symptomatic transient peritumoral edema developed in 5 patients (6.7%) at a mean of 6.4 months after radiosurgery. Three patients complained of protracted headaches after treatment. CONCLUSIONS: LINAC radiosurgery was highly effective for the treatment of parasagittal meningiomas in this series. For small to medium-sized meningiomas with clear invasion of the sinusal lumen, radiosurgery is a reasonable option as a first-line treatment. Either alone or combined with conventional surgery, radiosurgery may improve the control rate for parasagittal meningiomas.

Report of a recurrent cerebral venous thrombosis in a young athlete.

BACKGROUND: Reports of occurrence of deep vein thrombosis during intensive sport are scarce. While a few cases have been described in the cerebral territory, these are only in the context of traumatism or anabolic agent consumption. Thus, causality with exercise remains uncertain and the mechanisms hypothetic. We present the case of a young athlete who experienced two episodes of severe cerebral venous thromboses (CVT), both during intensive training, in the absence of any other known thrombogenic factor. CASE PRESENTATION: A healthy 26-year-old man presented a thrombosis of the superior sagittal sinus during recent intensive training for a triathlon. Investigation at the time found no drug or anabolic steroid consumption, or any hematologic or coagulation disturbance. Anticoagulation therapy was initiated for 10 months with good outcome. One year later, soon after returning to intensive exercise, mainly running, the patient presented a thrombosis of the straight sinus complicated by bithalamic hyperintensities observed on T2 magnetic resonance imaging sequences. Anticoagulation treatment was reinitiated and led to repermeabilization of the cerebral vein and reversibility of thalamic abnormalities. Four months later, the patient was free of headache and had no cognitive impairment. He continues to practice intensive sport with vitamin K antagonist as preventive treatment. CONCLUSION: This is the first case report of recurrent CVT in a context of intensive sport, without any other thrombogenic features, suggesting a causal link. Intensive exercise should be considered as a potential promoting factor of CVT and investigated during routine examination.

Histopathological effects of different therapy strategies in experimental sinus thrombosis.

The optimal treatment for cerebral venous thrombosis is still under debate. The histological consequences of different treatments have not been systematically studied and may be of value in this debate. Thrombosis of the superior sagittal sinus was induced in rats by topical application of ferric chloride. Animals were treated 6 h after operation with subcutaneous injection of 450 IU/kg enoxaparin twice daily (n = 10), with 10 mg recombinant tissue plasminogen activator (rt-PA)/kg (n = 12), and with 6 mg abciximab/kg (n = 10). Eleven animals were treated with saline (controls), and four animals were sham-operated without thrombosis induction. Animals were killed on day 7. Coronal brain slices were stained with hematoxylin-eosin (HE) and against glial fibrillary acidic protein (GFAP), and factor VIII. Histology was quantified in parasagittal and temporal regions of interest. Compared with controls, counts of pyknotic neurons on HE stain were significantly lower in the enoxaparin group. Counts for GFAP-expressing astrocytes were highest in the enoxaparin (p < 0.001) and rt-PA (p < 0.05)-treated groups. Angiogenesis defined as factor VIII-expressing vessels was significantly (p < 0.01) higher in the enoxaparin and significantly lower (p < 0.01) in the rt-PA group compared with controls. In this animal model, we found histological differences related to the different treatments, which cannot be explained by recanalization and its speed alone.

The path of the superior sagittal sinus in unicoronal synostosis.

PURPOSE: This study investigates the anatomic relationship between the superior sagittal sinus (SSS) and the sagittal suture in infants with uncorrected unicoronal synostosis. The morphology of the SSS is also evaluated postoperatively to assess whether normalization of intracranial structures occurs following reconstruction. METHODS: The study sample consisted of 20 computed tomography scans (10 preoperative, 6 postoperative, and 4 unaffected controls) obtained between 2001 and 2013. The SSS and the sagittal suture were outlined using Analyze imaging software. These data were used to measure the maximum lateral discrepancy between the SSS and the sagittal suture preoperatively and to assess for postoperative changes in the morphology of the SSS. RESULTS: In children with uncorrected unicoronal synostosis, the SSS deviates to the side of the patent coronal suture posteriorly and tends to follow the path of the sagittal and metopic sutures. The lateral discrepancy between the SSS and the sagittal suture ranged from 5.0 to 11.8 mm, with a 99.9 % upper prediction bound of 14.4 mm. Postoperatively, the curvature of the SSS was statistically decreased following surgical intervention, though it remained significantly greater than in unaffected controls. CONCLUSIONS: The SSS follows a predictable course relative to surface landmarks in children with unicoronal synostosis. When creating burr holes for craniotomies, the SSS can be avoided in 99.9 % of cases by remaining at least 14.4 mm from the lateral edge of the sagittal suture. Postoperative changes in the path of the SSS provide indirect evidence for normalization of regional brain morphology following fronto-orbital advancement.

Microsurgical treatment for central gyrus region meningioma with epilepsy as primary symptom.

BACKGROUND: The objective of this article was to investigate the operation outcome, complications, and the patient's quality of life after surgical therapy for central gyrus region meningioma with epilepsy as the primary symptom. METHODS: All patients get at least 6 months of follow-up (range, 6-34 mo) after surgery. They underwent preoperative magnetic resonance imaging and video electroencephalography, and their clinical manifestations, imaging characteristics, microsurgical methods, and prognosis were retrospectively analyzed. RESULTS: The meningioma was located in the front and back of the central sulcus vein in 3 and 2 patients, respectively; in the compressed precentral gyrus and central sulcus vein in 3 patients; and in the precentral gyrus and postcentral gyrus each in 1 patient; beside the right sagittal sinus and invaded a thick draining vein on the brain surface in 1 patient and beside the right sagittal sinus and close to the precentral gyrus in 2 patients; invaded the superior sagittal sinus in 8 patients; crossed the cerebral falx and compressed cortex gyrus veins in 1 patient; invaded duramater and irritated skull hyperplasia in 3 patients; invaded duramater and its midline infiltrated into the superior sagittal sinus, was located behind the precentral gyrus, and enveloped the central sulcus vein. They were resected and classified by Simpson standards: 17 of the 26 patients had grade I, 6 patients had in grade II, and 3 patients had in grade III. CONCLUSIONS: Resection of central gyrus region meningioma by microsurgical technique avoids injury to the cerebral cortex, central sulcus vein, and other draining veins. Microsurgery improves the total resection rate, reduces recurrence rate, and lowers disability or death rate.

Surgical treatment of parasagittal and falcine meningiomas invading the superior sagittal sinus.

OBJECTIVE: We present our experience with surgery of parasagittal and falcine meningiomas invading the superior sagittal sinus with special consideration of the surgical complications and the incidence of tumour recurrence. MATERIALS AND METHODS: The analysis included 37 patients with parasagittal and falcine meningiomas invading the superior sagittal sinus. In 13 cases, the sinus was ligated and resected with tumour. In 14 cases, the sinus was entered with the goal of tumour resection and the sinus was reconstructed, while in 10 patients the sinus was not entered and the remaining residual tumour was observed for growth. RESULTS: Out of 13 patients after radical resection of the tumour and invaded part of sinus, 9 revealed haemodynamic complications: venous infarction (4), significant brain oedema (3) and hypoperfusion syndrome (2). 2 out of 14 patients after resection of the tumour from the lumen of the superior sagittal sinus with subsequent sinus repair developed venous infarction after surgery. Among 27 patients after radical tumour excision the remote follow-up revealed recurrence in 2 patients. There were no significant haemodynamic complications in none of 10 cases, in which the residual tumour was left after surgery in the superior sagittal sinus. In this group, 3 cases were subjected to early post-operative radiotherapy and local recurrence was observed in 4 patients. CONCLUSIONS: The aggressive surgical treatment of meningiomas infiltrating the superior sagittal sinus is associated with a high surgical risk. The incidence of recurrence of these tumours increases significantly in the case of non-radical excision of the tumour.

Cluster-like headache secondary to parasagittal hemangiopericytoma.

We describe an original case of cluster-like headache CLH) revealing a parasagittal tumor invading the superior sagittal sinus (SSS). Resection of the tumor (hemangiopericytoma) allowed the re-permeabilization of the SSS and was followed by the complete disappearance of CLH. Several mechanisms including obstruction of the SSS, hypervascularization with arterio-veinous shunt, and overflow in the cavernous sinus might explain the symptoms.

Intracerebral schwannoma mimicking parasagittal meningioma.

A 24-year-old female patient presented to the neurological department after a seizure that lasted for 10 minutes. Magnetic resonance imaging revealed a cystic and heterogeneously enhanced giant mass in the right frontal lobe mimicking parasagittal meningioma. Surgery via a single frontal craniotomy confirmed the tumor was attached to the falx cerebri and sagittal sinus. The histological diagnosis was schwannoma. Since total resection of the tumor, the patient was seizure free. Twelve months of follow-up revealed good outcome.

Primary Intracranial Ewing Sarcoma Invading the Superior Sagittal Sinus with EWSR1-FLI1 Gene Fusion and EWSR1 Gene Mutation: A Case Report and Literature Review.

BACKGROUND: Primary intracranial Ewing sarcoma (ES) is an extremely rare intracranial malignant tumor, mostly occurring in children and adolescents. Because of its rarity, the magnetic resonance imaging (MRI) features and treatment strategies of primary intracranial ES are still unclear. METHODS: The purpose of this study was therefore to report a case of primary intracranial ES, whose molecular features included both EWSR1-FLI1 (EWS RNA binding protein 1- Friend leukemia integration 1) gene fusion and EWSR1 gene mutation. It is worth noting that this is the first reported case of ES invading the superior sagittal sinus and mostly causing occlusion. At the same time, there were polymorphisms of four drug metabolism-related enzymes in the tumor. Subsequently, we conducted a literature review to characterize the clinical features, imaging findings, pathological features, treatments, and prognoses of primary intracranial ESs. RESULTS: A 21-year-old female was admitted to the hospital with headache with nausea and vomiting for 2 weeks. An MRI showed a 3.8 × 4.0 cm large heterogeneous mass in the bilateral parietal lobe with peritumoral edema. The tumor invaded the superior sagittal sinus and mostly caused occlusion of the middle segment of the superior sagittal sinus. The mass was successfully removed using a neuromicroscope. Postoperative pathology indicated a primary intracranial ES. High throughput sequencing (next generation sequencing) showed that there was EWSR1-FLI1 gene fusion and EWSR1 gene mutation in the tumor, with polymorphisms of four drug metabolism-related enzymes and low tumor mutational burden. Subsequently, the patient received intensity modulated radiation therapy. The patient has signed an informed consent form. CONCLUSIONS: The diagnosis of primary intracranial ES depended on histopathology, immunohistochemistry staining, and genetic testing. At present, total tumor resection combined with radiotherapy and chemotherapy is the most effective treatment. We report the first case of primary intracranial ES invading the superior sagittal sinus and causing middle segment occlusion, accompanied by EWSR1-FLI1 gene fusion and EWSR1 gene mutation.