Solitary Fibrous Tumor/hemangiopericytoma Research Articles

Establishment and characterization of a patient-derived solitary fibrous tumor/hemangiopericytoma cell line model.

Solitary fibrous tumor/Hemangiopericytoma (SFT/HPC) is a rare subtype of soft tissue sarcoma harboring NAB2-STAT6 gene fusions. Mechanistic studies and therapeutic development on SFT/HPC are impeded by scarcity and lack of system models. In this study, we established and characterized a novel SFT/HPC patient-derived cell line (PDC), SFT-S1, and screened for potential drug candidates that could be repurposed for the treatment of SFT/HPC. Immunohistochemistry profiles of the PDC was consistent with the patient's tumor sample (CD99+/CD34+/desmin-). RNA sequencing, followed by Sanger sequencing confirmed the pathognomonic NAB2exon3-STAT6exon18 fusion in both the PDC and the original tumor. Transcriptomic data showed strong enrichment for oncogenic pathways (epithelial-mesenchymal transition, FGF, EGR1 and TGFβ signaling pathways) in the tumor. Whole genome sequencing identified potentially pathogenic somatic variants such as MAGEA10 and ABCA2. Among a panel of 14 targeted agents screened, dasatinib was identified to be the most potent small molecule inhibitor against the PDC (IC50, 473 nM), followed by osimertinib (IC50, 730 nM) and sunitinib (IC50, 1765 nM). Methylation profiling of the tumor suggests that this specific variant of SFT/HPC could lead to genome-wide hypomethylation. In conclusion, we established a novel PDC model of SFT/HPC with comprehensive characterization of its genomic, epigenomic and transcriptomic landscape, which can facilitate future preclinical studies of SFT/HPC, such as in vitro drug screening and in vivo drug testing.

SIGNIFICANTLY STRONG EXPRESSION OF STAT6 AND SSTR2A IN DIFFERENTIATE THE SOLITARY FIBROUS TUMOR / HEMANGIOPERICYTOMA (SFT/HPC) AND MENINGIOMA

Background: Solitary fibrous tumor / hemangiopericytoma (SFT / HPC) and fibroblastic types of meningioma have similarities that is difficult to distinguish based on histology. Immunohistochemistry of STAT6 and SSTR2A are definitive biomarkers in both tumors. Inversion-mediated fusions between two genes, NAB2 and STAT6, were detected in SFT / HPC that inducES proliferation in cells. The somatostatin receptor (SSTR) 2 is located on chromosome 17q25.1 which is expressed diffusely in meningiomas.
 Objective: This study aimed to determine the expression of STAT6 and SSTR2A in SFT/HPC and meningiomas.
 Methods: An analytical observational study with consecutive sampling on 64 samples diagnosed with SFT/HPC and meningioma. Samples divided into 3 groups, group 1 consisted of grade I meningoma, group 2 consisted of grade II and III meningioma and group 3 consisted of solitary fibrous tumor/Hemangiopericytoma (SFT/HPC).
 Results: Based on the Mann Withney comparative test, STAT6 expressions showed significant differences in group 1 and 3, as well as group 2 and 3 (P < 0.05). SSTR2A expressions in group 1 and 3, as well as group 2 and 3 also showed significant differences (P < 0.05).
 Conclusion: Immunohistochemistry of STAT6 and SSTR2A is strongly expressed in SFT/HPC and meningioma.
 Keywords: Meningeal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC), Meningioma, STAT6, SSTR2A.

Risk Stratification for Management of Solitary Fibrous Tumor/Hemangiopericytoma of the Central Nervous System.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) of the central nervous system (CNS) is a rare meningeal tumor. Given the absence of prospective or randomized data, there are no standard indications for radiotherapy. Recently, the NRG Oncology and EORTC cooperative groups successfully accrued and completed the first prospective trials evaluating risk-adapted adjuvant radiotherapy strategies for meningiomas. Using a similar framework, we sought to develop prognostic risk categories that may predict the survival benefit associated with radiotherapy, using two large national datasets. We queried the National Cancer Database (NCDB) and the Surveillance, Epidemiology, and End Results (SEER) databases for all newly diagnosed cases of SFT/HPC within the CNS. Risk categories were created, as follows: low risk-grade 1, with any extent of resection (EOR) and grade 2, with gross-total resection; intermediate risk-grade 2, with biopsy/subtotal resection; high risk-grade 3 with any EOR. The Kaplan-Meier method and Cox proportional hazards regressions were used to determine the association of risk categories with overall and cause-specific survival. We then determined the association of radiotherapy with overall survival in the NCDB, stratified by risk group. We identified 866 and 683 patients from the NCDB and SEER databases who were evaluated, respectively. In the NCDB, the 75% survival times for low- (n = 312), intermediate- (n = 239), and high-risk (n = 315) patients were not reached, 86 months (HR 1.60 (95% CI 1.01-2.55)), and 55 months (HR 2.56 (95% CI 1.68-3.89)), respectively. Our risk categories were validated for overall and cause-specific survival in the SEER dataset. Radiotherapy was associated with improved survival in the high- (HR 0.46 (0.29-0.74)) and intermediate-risk groups (HR 0.52 (0.27-0.99)) but not in the low-risk group (HR 1.26 (0.60-2.65)). The association of radiotherapy with overall survival remained significant in the multivariable analysis for the high-risk group (HR 0.55 (0.34-0.89)) but not for the intermediate-risk group (HR 0.74 (0.38-1.47)). Similar results were observed in a time-dependent landmark sensitivity analysis. Risk stratification based on grade and EOR is prognostic of overall and cause-specific survival for SFT/HPCs of the CNS and performs better than any individual clinical factor. These risk categories appear to predict the survival benefit from radiotherapy, which is limited to the high-risk group and, potentially, the intermediate-risk group. These data may serve as the basis for a prospective study evaluating the management of meningeal SFT/HPCs.

Biphenotypic sinonasal sarcoma—A recently described entity with many mimics: A case report

Biphenotypic sinonasal sarcoma (BSNS) is a recently described, low-grade, slow-growing sarcoma with neural and myogenic features with exclusive location in sinonasal track and characteristic PAX3- MAML3 gene fusion. Differentiating this tumor from its commoner mimics needs knowledge of this entity to avoid over treatment. This tumor has unique morphology, clinical course, and genetics. We report this in a 47-year-old female who was diagnosed with such a rare, solitary fibrous tumor-hemangiopericytoma (HPC-SFT) on limited initial biopsy. On subsequent excision, typical morphology and immunohistochemistry helped to clinch the diagnosis.

A Single-Center Retrospective Analysis of Intracranial and Spinal Solitary Fibrous Tumor/Hemangiopericytoma Clinical Outcomes: Sex Association With Aggressiveness

Solitary fibrous tumor/hemangiopericytoma (SFT/HPCT) is a rare tumor characterized by high recurrence rate and metastatic potential, even after surgical resection. We report on the clinical outcomes and risk factors for metastasis and progression-free survival (PFS) of patients diagnosed with SFT/HPCT. We retrospectively identified patients with intracranial or spinal SFT/HPCT who underwent surgical resection and/or radiation therapy at our institution between 1995 and 2021. Baseline demographics, tumor characteristics, and outcome data were collected, and factors associated with PFS and metastasis were analyzed. Thirty-four subjects (mean age, 46.4 years; 44% female) with a histopathologically proven diagnosis of SFT/HPCT were included; the median follow-up was 89.7 months. Twenty-two tumors were supratentorial (67%), 6 (18%) were infratentorial, and 5 (15%) were spinal. Eleven patients had documented occurrence of metastasis (32%). Detailed preoperative and postoperative data were available for 25 patients (74%) who received treatment at our institution after their initial diagnosis. Of those, 20 (80%) underwent gross total resection (GTR), and 12 (48%) received either adjuvant or salvage radiotherapy. Univariate analyses revealed that males had a shorter mean PFS compared with females (25 months vs. 78 months; P= 0.01), and that patients who underwent GTR had a longer mean PFS compared with those who underwent subtotal resection (54 months vs. 23 months; P= 0.02). Male sex was the sole risk factor for metastasis (odds ratio, 6.75; 95% confidence interval, 1.19-38.02). Our data demonstrate a strong association between male sex and the outcomes of shorter PFS and higher risk for metastases. Further research is warranted to understand the clinical characteristics and outcomes of this rare tumor.

Intracranial solitary fibrous tumor/hemangiopericytoma: Role and choice of postoperative radiotherapy techniques

BackgroundIntracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a novel rare disease after the 2016 WHO reclassification. Surgery is the main treatment. Postoperative adjuvant radiotherapy is often used, but the effects of different radiotherapy techniques are still unclear. The purpose of this study was to analyze the effects of postoperative radiotherapy (PORT) and different radiotherapy methods on the efficacy of patients with intracranial SFT/HPC.Materials and methodsWe retrospectively analyzed 42 patients with intracranial SFT/HPC who underwent surgical treatment from 2008 to 2022, 20 of whom were treated with postoperative intensity-modulated radiotherapy (IMRT) and 22 with postoperative stereotactic radiosurgery (SRS). The Kaplan–Meier method was used to analyze the disease-free survival (DFS) of all the 42 patients receiving postoperative radiotherapy and the time to progression (TTP) of 22 of these patients experiencing recurrence. A multivariate Cox proportional hazards model was used to detect prognostic factors of survival.ResultsIn the analysis of PORT patients, the median DFS was 8.33 years for PORT IMRT patients and 3.04 years for PORT SRS patients. The 10-year DFS incidence was 46.0% in the PORT IMRT group and 27.5% in the SRS group. Among the 22 patients who relapsed, the median TTP of other patients was 1.25 years, of which 3 received radiotherapy alone and 1 received symptomatic treatment, while the median TTP of surgical and surgical combined with radiotheray patients were 1.83 and 2.49 years, respectively (p=0.035).ConclusionPORT IMRT could prolong DFS compared with PORT SRS. It indicated that PORT IMRT radiotherapy technology was a feasible option for SFT/HPC. Moreover, TTP results of relapsed patients showed that, surgery and surgery combined with radiotherapy treatments have no significant difference on TTP in relapsed patients, but both of them were better than other treatments.

Intracranial Solitary Fibrous Tumor/Hemangiopericytoma Treated with Microsurgical Resection: Retrospective Cohort Analysis of a Single-Center Experience.

ObjectiveTo provide benchmarks for further studies of solitary fibrous tumor/hemangiopericytoma (SFT/HPC) of the central nervous system (CNS), we investigated the association of baseline demographic, clinico-pathologic, and treatment factors with outcomes in those treated at our center.MethodsWe conducted a retrospective, cohort analysis of patients treated for SFT/HPC at the University of Washington 1990–2020. Kaplan-Meier and univariable Cox analyses assessed relationships between baseline variables and local or global CNS recurrence, extraneural recurrence, progression-free survival (PFS) and overall survival (OS).ResultsAmong 34 eligible patients, median duration of follow-up was 79 months (range 13–318 months). Local and global CNS recurrence occurred at a median of 81 m (95% CI 48–151) and 81 m (95% CI 47–112), respectively. Extraneural metastases occurred at a median 248 m (95% CI 180-Not Reached) and only in grade 3 tumors. Median PFS and OS were 76 months (95% CI: 47–109 months) and 210 months (95% CI 131–306 months), respectively. Univariable Cox analyses showed that age at diagnosis was associated with local (p = 0.01) and global CNS relapse (p = 0.01), and PFS (p = 0.03). Gross total resection was associated with decreased local or global CNS relapse (p = 0.02) and improved PFS (p = 0.03); peri-operative radiation was associated with decreased local CNS relapse (p = 0.02).ConclusionFollowing microsurgical resection of SFT/HPC, CNS relapse is common and associated with age, extent of resection, and adjuvant radiation. Extraneural relapse occurs in some patients. Delayed time-to-initial relapse justifies prolonged surveillance, but optimal approaches have not been defined.

Differentiation of intracranial solitary fibrous tumor/hemangiopericytoma from atypical meningioma using apparent diffusion coefficient histogram analysis

This study aimed to investigate the value of apparent diffusion coefficient (ADC) histogram analysis in differentiating intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) from atypical meningioma (ATM). Retrospective analyzed the clinical, magnetic resonance imaging, and pathological data of 20 and 25 patients with SFT/HPC and ATM, respectively. Histogram analysis was performed on the axial ADC images using MaZda software, and nine histogram parameters were obtained, including mean, variance, skewness, kurtosis, and the 1st (ADC1), 10th (ADC10), 50th (ADC50), 90th (ADC90), and 99th (ADC99) percentile ADC. Differences in ADC histogram parameters between SFT/HPC and ATM were compared by an independent t test or Mann-Whitney U test, while the statistically significant histogram parameters were further analyzed by drawing receiver operating characteristic (ROC) curves to evaluate the differential diagnostic performance. Among the nine ADC histogram parameters we extracted, the mean, ADC1, ADC10, ADC50, and ADC90 in the SFT/HPC group were greater than those of ATM, and significant differences were observed (all P < 0.05). ROC analysis showed that the ADC1 generated the highest area under the curve (AUC) value of 0.920 in distinguishing the two tumors, when using 91.00 as the optimal threshold. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value in distinguishing between SFT/HPC and ATM were 84.00%, 85.00%, 84.44%, 87.50%, and 81.00%, respectively. ADC histogram analysis can be a reliable tool to differentiate between SFT/HPC and ATM, with the ADC1 being the most promising potential parameter.

Dorsal spine intradural extramedullary hemangiopericytoma: a case report

Introduction: Hemangiopericytomas are rare CNS Neoplasms constituting &lt;1% of CNS tumours. They are more commonly seen in cranium than in spine where they present as Intradural extramedullary in location. They rarely metastasize to Lung and Bone.World Health Organization Classification of Tumors of the Central Nervous System (CNS WHO) assigned the combined term solitary fibrous tumor/ hemangiopericytoma (SFT/HPC) to such lesions in 2016 due to their same genetic makeup. Case report: Our case is about a 61-year-old diabetic male who presented with insidious onset, gradually progressive thoracic backache and asymmetric weakness with tightness and numbness of both lower limbs for last 6 months with no sphincter incontinence and bed bound for last 15 days. Clinically he had asymmetric spastic paraparesis of lower limb. His MRI Dorsal spine showed a 1.5 ґ 2 cm heterogeneously contrast enhancing Intradural lesion at D6-D7 compressing the cord from dorsolaterally with extensive cord edema from C5 to L2. Preoperative diagnosis of Meningioma/ Metastasis was made and patient underwentD5-D7 laminectomy and tumour excision. Intraoperative findings, there was no dural attachment, there were multiple tortuous blood vessels overlying greyish pink, fleshy, suckable, highly vascular, capsulated tumor posterolateral to cord. The superior aspect of tumor was adherent to cord with no clear interface. Tumor was seen separate from Left D7 nerve root. Post operatively patient improved symptomatically and neurologically. His HPE was suggestive of Hemangiopericytoma WHO Grade II (IHC markers CD34 and CD 31 was positive and KI 67% index of 10-15%). Patient has been on follow up and planned for metastatic workup. Conclusion: Spinal Hemangiopericytoma are rare disease with nonspecific radiological features making preoperative diagnosis difficult. Differential diagnosis of hemangiopericytoma should be kept in case of atypical and high - grade radiological features. Gross total resection without compromising the neurological status should be the goal to prevent local recurrence. Proper consensus regarding the follow up and adjuvant therapies of spinal Hemangiopericytoma are still lacking.

Postoperative progression of intracranial grade II-III solitary fibrous tumor/hemangiopericytoma: predictive value of preoperative magnetic resonance imaging semantic features.

Preoperative prediction of postoperative tumor progression of intracranial grade II-III hemangiopericytoma is the basis for clinical treatment decisions. To use preoperative magnetic resonance imaging (MRI) semantic features for predicting postoperative tumor progression in patients with intracranial grade II-III solitary fibrous tumor/hemangiopericytoma (SFT/HPC). We retrospectively analyzed the preoperative MRI data of 42 patients with intracranial grade II-III SFT/HPC, as confirmed by surgical resection and pathology in our hospital from October 2010 to October 2017, who were followed up for evaluation of recurrence, metastasis, or death. We applied strict inclusion and exclusion criteria and finally included 37 patients. The follow-up time was in the range of 8-120 months (mean = 57.1 months). Single-factor survival analysis revealed that tumor grade (log-rank, P = 0.024), broad-based tumor attachment to the dura mater (log-rank, P = 0.009), a blurred tumor-brain interface (log-rank, P = 0.008), skull invasion (log-rank, P = 0.002), and the absence of postoperative radiotherapy (log-rank, P = 0.006) predicted postoperative intracranial SFT/HPC progression. Multivariate survival analysis revealed that tumor grade (P = 0.009; hazard ratio [HR] = 11.42; 95% confidence interval [CI] = 1.832-71.150), skull invasion (P = 0.014; HR = 5.72; 95% CI = 1.421-22.984), and the absence of postoperative radiotherapy (P = 0.001; HR = 0.05; 95% CI = 0.008-0.315) were independent predictors of postoperative intracranial SFT/HPC progression. Broad-based tumor attachment to the dura mater, skull invasion, and blurring of the tumor-brain interface can predict postoperative intracranial SFT/HPC progression.

Tumor volume and the dural tail sign enable the differentiation of intracranial solitary fibrous tumor/hemangiopericytoma from high-grade meningioma

ObjectivesIntracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare mesenchymal neoplasm with imaging features mimicking high-grade meningioma (HGM) and can easily be misdiagnosed. We sought to determine the value of routine preoperative data in differentiating these tumors. Patients and methodsPatients with confirmed SFT/HPC or HGM between January 2012 and June 2020 were identified. A total of 28 preoperative variables (including age, sex, tumor location, tumor volume, 10 traditional MRI features, and 14 peripheral blood indices) were collected for each patient. The top features were selected sequentially based on the least absolute shrinkage and selection operator (LASSO) and support vector machines-recursive feature elimination (SVM-RFE) methods. Differentiation and calibration of the classifiers were assessed by receiver operating characteristic (ROC) curves and calibration curves, respectively. Nomograms were constructed based on multivariate analysis. ResultsA total of 127 patients, including 29 with SFT/HPC and 98 with HGM, were analyzed. Three features were first selected using the LASSO and SVM-RFE methods, and corresponding models were developed. Although the area under the curve (AUC) of model 1 was the highest, a comprehensive analysis suggested the superiority of model 2, which consisted only of the features tumor volume (TV) and dural tail sign (DTS) (AUC: 0.942, sensitivity: 93.10%, p-value of H-L test: 0.734, Brier score: 0.07). A risk score formula and a nomogram were constructed. ConclusionsTV can be used to effectively identify SFT/HPC and HGM, whereas adding DTS can improve the overall prediction accuracy. As these two variables are routinely available and are easy for clinicians to master, they can provide a powerful reference for clinical decision-making.

The Role of Postoperative Radiotherapy in Intracranial Solitary Fibrous Tumor/Hemangiopericytoma: A Multi-institutional Retrospective Study (KROG 18-11).

PurposeThis study aimed to evaluate the role of postoperative radiotherapy (PORT) in intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC).Materials and MethodsA total of 133 patients with histologically confirmed HPC were included from eight institutions. Gross total resection (GTR) and subtotal resection (STR) were performed in 86 and 47 patients, respectively. PORT was performed in 85 patients (64%). The prognostic effects of sex, age, performance, World Health Organization (WHO) grade, location, size, Ki-67, surgical extent, and PORT on local control (LC), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival (OS) were estimated by univariate and multivariate analyses.ResultsThe 10-year PFS, and OS rates were 45%, and 71%, respectively. The multivariate analysis suggested that PORT significantly improved LC (p < 0.001) and PFS (p < 0.001). The PFS benefit of PORT was maintained in the subgroup of GTR (p=0.001), WHO grade II (p=0.001), or STR (p < 0.001). In the favorable subgroup of GTR and WHO grade II, PORT was also significantly related to better PFS (p=0.028). WHO grade III was significantly associated with poor DMFS (p=0.029). In the PORT subgroup, the 0–0.5 cm margin of the target volume showed an inferior LC to a large margin with 1.0–2.0 cm (p=0.021). Time-dependent Cox proportion analysis showed that distant failures were significantly associated with poor OS (p=0.003).ConclusionThis multicenter study supports the role of PORT in disease control of intracranial SFT/HPC, irrespective of the surgical extent and grade. For LC, PORT should enclose the tumor bed with sufficient margin.

Analysis of the inflammatory tumor microenvironment in meningeal neoplasms.

Properties of the inflammatory tumor microenvironment are associated with disease subtype, grade, and prognosis in various cancer entities. As immune-modulatory therapies are currently being explored in patients with meningeal neoplasms, we investigated their inflammatory microenvironment (meningiomas and solitary fibrous tumor/hemangiopericytoma (SFT/HPC)). 74 meningeal tumor specimens: (10/74 (13.5%) atypical meningioma; 8/74 (10.8%) anaplastic meningioma; 8/74 (10.8%) chordoid meningioma; 9/74 (12.2%) fibroblastic meningioma; 10/74 (13.5%) transitional meningioma; 3/74 (4.1%) rhabdoid meningioma; 7/74 (9.5%) meningothelial meningioma; SFT/HPC (19/74 (25.7%) were retrieved from the Neuro-Biobank, Medical University of Vienna, Austria. Tumor-infiltrating lymphocyte (TIL) infiltration could be observed in the majority of the investigated specimens (CD3+: 66/74 (89.2%); CD8+: 47/74 (63.5%); CD45RO+: 29/73 (39.2%); FOXP3+ 19/74 (25.7%); PD1+: 3/74 (4.1%). No difference in TIL infiltration was observed between SFT/HPC and meningioma cases. Higher density of FOXP3+ TILs was observed with increasing WHO grade in meningioma specimens (p = 0.005). Membranous programmed cell death ligand 1 (PD-L1) expression was observed in 4/74 (5.4%) specimens, with 3/74 (4.1%) presenting with 1% and 1/74 (1.4%) with 3% PD-L1 expressing tumor cells. Lymphatic vessels as identified by podoplanin immunohistochemistry were observed in 10/74 (13.5%) specimens and were significantly associated with presence of membranous PD-L1 expression on tumor cells (p = 0.003). Infiltration by various TIL subtypes can be observed in the majority of meningeal neoplasms, with enrichment of FOXP3-positive regulatory T-cells in higher-grade meningioma. PD-L1 expression on tumor cells was only infrequently found. A better understanding of the pathobiological role of the immune system in meningeal neoplasms may facilitate development of immunomodulatory treatment approaches in meningeal tumors.

Intracranial anaplastic solitary fibrous tumor/hemangiopericytoma: immunohistochemical markers for definitive diagnosis.

Intracranial anaplastic hemangiopericytoma (AHPC) is a rare and malignant subset of solitary fibrous tumor/hemangiopericytoma (SFT/HPC) as per the WHO 2016 Classification of Tumors of the Central Nervous System. AHPC portends a poor prognosis and is associated with higher rates of recurrence/metastasis in comparison with SFT/HPC. Accordingly, it is critical to continue to define the clinical course of patients with AHPC and in so doing further refine clinicopathologic/immunohistochemical (IHC) criteria needed for definitive diagnosis. Herein, we describe clinical/histological characteristics of six patients with AHPC. In addition, we reviewed and analyzed the expression of various IHC markers reported within the literature (i.e., a total of 354 intracranial SFT/HPCs and 460 meningiomas). Histologically, tumors from our six patients were characterized by a staghorn-like vascular pattern, mitotic cells, and strong nuclear atypia. Immunohistochemically, all tumors displayed positive nuclear staining for STAT6; other markers, including CD34 and Bcl-2, were expressed only in three patients. Analysis of IHC expression patterns for SFT/HPC and meningioma within the literature revealed that nuclear expression of STAT6 had the highest specificity (100%) for SFT/HPC, followed by ALDH1 (97.2%) and CD34 (93.6%). Of note, SSTR2A (95.2%) and EMA (85%) displayed a high specificity for meningioma. Anaplastic SFT/HPC is a tumor with poor prognosis that is associated with higher rates of recurrence and metastasis in comparison with SFT/HPC. Given that anaplastic SFT/HPC requires more aggressive treatment than meningioma despite of a similar presentation on imaging, it is crucial to be able to distinguish between these tumors.

Results in the treatment of intracranial hemangiopericytomas. Case series.

Intracranial hemangiopericytoma (HPC) is a rare central nervous system tumor characterized by its low incidence, high rate of local recurrence and risk of metastasis. The main objectives of this paper are two: to show the results in the treatment of HPC in our institution in the last 20years and to make a review of the literature on this topic. Retrospective review that includes patients diagnosed with intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) that have undergone surgery from 1997 to 2017. It includes patients that had nuclear expression of STAT-6 (detected by immunohistochemistry) and gradeII/III histopathological diagnosis (defined by the World Health Organization in 2016). We collected demographic data, tumor characteristics, treatment and survival of these patients. A total of 19 patients fulfilled inclusion criteria. The median follow up was 96 months (12-230). The mortality rate was 21% (n=4). 57.9% of patients presented at least one tumor recurrence (n=11) (recurrences of 6%, 67% y 90% at 1, 5 and 10years). Five patients presented extracranial metastasis. Patients with tumors <6cm had greater survival (P<.05). A series of patients undergoing SFT/HPC were presented according to the new WHO criteria. Size is a predictor of survival. Currently there are no validated criteria for surgical resection in this pathology. A classification with surgical guidance would be useful.

Primary Solitary Fibrous Extradural Tumor of Thoracic Spine: A Case Report

Background Data: Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare central nervous system (CNS) tumor. Its incidence in the spine is even rarer. It is diagnosed histopathologically as preoperative imaging reveals no pathognomonic features. It is most common in the thoracic spine and may have a poor prognosis despite surgery and adjuvant therapy. We present a case of thoracic extradural spinal primary SFT to be added to the list of the few reported cases. Purpose: To report a rare tumor of extradural SFT in the thoracic spine. Study Design: A case report. Patient and Methods: We report one of a middle-aged female who presented with sensory and motor weakness for 2 months. With relevant work-up and an MRI imaging, an extradural lesion was noted in the spine. The patient underwent an en bloc resection of the lesion with a smooth postoperative course and the specimen was analyzed for histopathology. Result: The histopathological analysis of the specimen showed features suggestive of a SFT; immunohistochemistry (IHC) was correlated with the histopathological diagnosis. At the 3-month follow-up, the patient had improvement in the power of the lower limbs and spasticity from grade 7/11 to grade 10/11 according to thoracic myelopathy JOA score. Conclusion: SFTs are rare tumors whose clinical course is unpredictable. They commonly occur in intradural extramedullary and rarely extradural sites. The goal of treatment is complete excision. (2020ESJ212) Abstract Background Data: Solitary fibrous tumor/ Solitary fibrous tumor/ Haemangiopericytoma (SFT/HPC) is a rare tumour of CNS. Its incidence in spine is even rarer. It is a mainly a histopathalogical diagnosis as preoperative imaging has no pathognomic features. Most common in the dorsal spine and has poor prognosis despite surgery and adjuvant therapy despite its pathological behavior. It has been cited most commonly only as case reports. Purpose: To add to literature of a rare tumor of the CNS especially in the spine. Study Design: Case Report Patient and methods: We are adding one such case of a dorsal extradural spinal primary SFT to the list of few cases that have already been reported. We present One such case in a middle age female who presented with sensory motor weakness for a period of 2 months. With relevant work up and an MRI imaging in which an extradural lesion was noted in the spine. Patient underwent an enbloc resection of the lesion and the specimen was analyzed for histopathology. Result:The histopathological analysis of the specimen showed features suggestive of solitary fibrous tumor with IHC studies correlating with the histopathological diagnosis. On 3-month post operative follow-up the patient she had improvement in the power of the lower limbs and spasticity. Conclusion: SFTs are rare tumours whose clinical course is unpredictable. They commonly occur in intradural extramedullary sites. Spinal involvement is a reported rare occurrence. The lack of large case series is attributed to its poor understanding. The goal of treatment is complete excision. Key: SFT, Spine, Rare, Extradural

How to differentiate spinal cord hemangiopericytoma from common spinal cord tumor?

IntroductionTumors of the spinal cord are rare and some can be confused with each other. We report a rare spinal cord solitary fibrous tumor/hemangiopericytoma (SFT/HPC), and propose keys to differentiate spinal cord tumors from each other. Case reportA 67-year-old man presented weakness with recent diffuse sensory disorders in the right lower limb. Spinal MRI revealed a T8-T9 intradural extramedullary mass with spinal cord compression. Gross total resection of a poorly vascularized intradural tumor was achieved. It was an encapsulated extramedullary tumor, which was difficult to separate from the spinal cord due to the presence of pial adhesions. Definitive diagnosis was grade 1 SFT/HPC of the spinal cord. One-year follow-up MRI revealed complete excision without any evidence of residual tumor. ConclusionSFT/HPC is a very rare spinal tumor that can be extramedullary, intramedullary or both. It may perfectly mimic meningioma. The maximal resection is the best treatment, but can be challenging because of the tumor's firm consistency and pial adherences to the spinal cord. Outcome is good in case of gross total resection, but there is a risk of very late recurrence, requiring long-term follow-up.

Solitary fibrous tumor/hemangiopericytoma of the penis.

Solitary fibrous tumor/hemangiopericytoma (SFT-HMP) is a rare spindle-cell mesenchymal tumor, thought to be of myofibroblastic origin. Penile SFT-HMP was mentioned in the literature in two separate case reports which were published in 2015 and 2017. We present the first case of SFT-HMP which is localized on corpus cavernosum of the penis. A 55-year-old man presented to our clinic with a small and gradually growing lesion on his penis for the past year, which recently caused difficulties during sexual intercourse. On physical examination; a well-shaped, nodular non-fluctuant, solid, painless mass, measuring 4×4 cm was palpated. Magnetic resonance imaging showed 5×5 cm mass located on the right corpus cavernosa. Under spinal anesthesia, surgical excision was performed. Pathologically, the tumor had an irregular architecture patterns and was characterized by hypercellular areas separated by thin-walled, branching vessels, lined with a single layer of flattened endothelial cells. SFT-HMP rarely occurs in genital tract and penile presentation is among the rarest. It should be classified and considered under penile masses, especially if the mass is well circumscribed, painless and slowly growing in nature. After differential diagnosis, surgical excision is mandatory.

Differentiating intracranial solitary fibrous tumor/hemangiopericytoma from meningioma using diffusion-weighted imaging and susceptibility-weighted imaging.

Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) and meningioma are difficult to distinguish owing to their overlapping imaging manifestation on routine magnetic resonance imaging. The purpose of this study was to assess whether SFT/HPC can be differentiated from meningioma with diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI). We retrospectively reviewed DWI, SWI, conventreional MR, and CT imaging features of 16 patients with SFT/HPC and 96 patients with meningioma. The apparent diffusion coefficient (ADC) value, normalized ADC (nADC) value, and degree of intratumoral susceptibility signal intensity (ITSS) were compared between SFT/HPCs and meningiomas using two-sample t tests, and among SFT/HPCs, low-grade and high-grade meningioma were tested using one-way analysis of variance (ANOVA). Receiver operating characteristic (ROC) curve and logistic regression analyses were performed to determine the differentiation capacity. The ADC value, nADC value, and the degree of ITSS in SFT/HPC were significantly higher than those in low-grade and high-grade meningiomas (all p < 0.05). The threshold value of > 1.15 for nADC provided 75.00% sensitivity and 60.42% specificity for differentiating SFT/HPC from meningioma. Compared with nADC, the degree of ITSS had a moderate sensitivity (62.50%) and a higher specificity (85.42%) using the threshold value of > 1.00. Furthermore, combining DWI and SWI can achieve a relatively high differentiation capacity with a sensitivity of 81.25% and specificity of 78.12%. The nADC ratios and ITSS are useful for differentiating SFT/HPC from meningioma. Combining ITSS and nADC value appears to be a promising option for differential diagnosis.

Clinical and Radiographic Features for Differentiating Solitary Fibrous Tumor/Hemangiopericytoma From Meningioma

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) and meningioma exhibit similar radiographic features; however, they differ in their prognoses. Preoperative differentiation between them is important for determining the treatment and follow-up plan. The aim of this study was to determine the factors that can be used to differentiate SFT/HPC from meningioma and World Health Organization (WHO) grade I from grade II meningioma. The analysis included 84 cases: 5 of SFT/HPC, 72 of WHO grade I meningioma, and 7 of WHO grade II meningioma. Clinical characteristics and conventional magnetic resonance imaging, perfusion magnetic resonance imaging, and magnetic resonance spectroscopy (MRS) LCModel parameters were evaluated via multivariate logistic regression analysis to identify the factors that distinguish SFT/HPC from meningioma. Patients with SFT/HPC were mostly men and were younger than those with meningioma. The percentage of T2-weighted images in meningioma was greater than thatin SFT/HPC. There were significant differences betweenSFT/HPC and meningioma in levels of glutamate, phosphocholine, myo-inositol, or glycerophosphocholine+ phosphocholine derived from long echo-time MRS, and myo-inositol derived from short echo-time MRS. Stepwise logistic regression analysis revealed that the age of <45 years and myo-inositol in short echo-time MRS of ≧6.347 were associated with a diagnosis of SFT/HPC with high sensitivity and specificity. However, no factors were found that differentiated WHO grade I meningioma from WHO grade II meningioma. Age and myo-inositol level calculated from MRS are useful factors for distinguishing SFT/HPC from meningioma preoperatively.