A case report of sinonasal glomangiopericytoma: An important reminder to always collect specimen.

OBJECTIVES: To present a case report of sinonasal glomangiopericytoma (GPC) in a female patient in her thirties and to highlight the importance of collecting pathology specimens even in routine sinus surgery cases. METHODS: A case report detailing the diagnosis of GPC in a female in her thirties, including her initial presentation, treatment, and follow-up, along with a brief review of the literature. RESULTS: Pathology of the collected specimen revealed sinonasal GPC along with chronic rhinosinusitis. Immunohistochemistry was positive for SMA, beta-catenin, and cyclin D1; and negative for STAT6, ERG, pankeratin, SOX10, and S100. CONCLUSION: This diagnosis expands the knowledge around the demographic profile of GPC patients. GPC should be included in the differential diagnosis of sinonasal masses, even in younger patients. The case highlights the importance of collecting the entire pathology specimen in all cases, even of ones that seem routine and benign.

Pediatric upper lip myopericytoma: a case report and comprehensive review.

BACKGROUND: Myopericytoma is a rare spindle cell tumor of mesenchymal origin, typically benign, characterized by concentric proliferation of tumor cells around blood vessels within subcutaneous tissue. It primarily occurs in middle-aged adults and is often located in distal extremities, although cases have been reported in proximal extremities and head-neck regions. However, occurrences within the oral cavity are exceedingly rare. To date, literature reviews have identified only two cases in children under 10 years old and reported only five cases of myopericytoma occurring in the lip region. We provide a comprehensive review and analysis of all documented cases to better understand this condition. CASE PRESENTATION: A 7-year-old girl presented to oral and maxillofacial surgery with the discovery of a painless mass on the inner aspect of the upper lip. The diagnosis of myopericytoma was confirmed by histological examination (HE staining), alcian blue staining, and immunohistochemistry. CONCLUSIONS: Following surgical excision, there were no signs of recurrence at a 3-month follow-up. The pathological diagnosis of myopericytoma is quite challenging, and immunohistochemical testing is necessary.

Efficacy and toxicity of photon, proton, and carbon ion radiotherapy in the treatment of intracranial solitary fibrous tumor/hemangiopericytoma.

BACKGROUND: Solitary fibrous tumors (SFT) of the central nervous system are rare and treatment options are not well established. The aim of this study was to evaluate the clinical outcomes of radiotherapy (RT) and re-radiotherapy (re-RT) for de novo intracranial SFT and recurrent intracranial SFT. METHODS: This retrospective study analyzed efficacy and toxicity of different RT modalities in patients who received radiotherapy (RT) for intracranial SFT at Heidelberg University Hospital between 2000 and 2020 following initial surgery after de novo diagnosis ("primary group"). We further analyzed the patients of this cohort who suffered from tumor recurrence and received re-RT at our institution ("re-irradiation (re-RT) group"). Median follow-up period was 54.0 months (0-282) in the primary group and 20.5 months (0-72) in the re-RT group. RT modalities included 3D-conformal RT (3D-CRT), intensity-modulated RT (IMRT), stereotactic radiosurgery (SRS), proton RT, and carbon-ion RT (C12-RT). Response rates were analyzed according to RECIST 1.1 criteria. RESULTS: While the primary group consisted of 34 patients (f: 16; m:18), the re-RT group included 12 patients (f: 9; m: 3). Overall response rate (ORR) for the primary group was 38.3% (N = 11), with 32.4% (N = 11) complete remissions (CR) and 5.9% (N = 2) partial remissions (PR). Stable disease (SD) was confirmed in 5.9% (N = 2), while 41.2% (N = 14) experienced progressive disease (PD). 14% (N = 5) were lost to follow up. The re-RT group had 25.0% CR and 17.0% PR with 58.0% PD. The 1-, 3-, and 5-year progression-free survival rates were 100%, 96%, and 86%, respectively, in the primary group, and 81%, 14%, and 14%, respectively, in the re-RT group. Particle irradiation (N = 11) was associated with a lower likelihood of developing a recurrence in the primary setting than photon therapy (N = 18) (OR = 0.038; p = 0.002), as well as doses ≥ 60.0 Gy (N = 15) versus < 60.0 Gy (N = 14) (OR = 0.145; p = 0.027). Risk for tumor recurrence was higher for women than for men (OR = 8.07; p = 0.014) with men having a median PFS of 136.3 months, compared to women with 66.2 months. CONCLUSION: The data suggests RT as an effective treatment option for intracranial SFT, with high LPFS and PFS rates. Radiation doses ≥ 60 Gy could be associated with lower tumor recurrence. Particle therapy may be associated with a lower risk of recurrence in the primary setting, likely due to the feasibility of higher RT-dose application.

Conditional survival analysis and dynamic survival prediction for intracranial solitary-fibrous tumor/hemangiopericytoma.

BACKGROUND: As the form of World Health Organization Central Nervous System (WHO CNS) tumor classifications is updated, there is a lack of research on outcomes for intracranial combined solitary-fibrous tumor and hemangiopericytoma (SFT/HPC). This study aimed to explore conditional survival (CS) pattern and develop a survival prediction tool for intracranial SFT/HPC patients. METHODS: Data of intracranial SFT/HPC patients was gathered from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. The patients were split into training and validation groups at a 7:3 ratio for our analysis. CS is defined as the likelihood of surviving for a specified period of time (y years), given that the patient has survived x years after initial diagnosis. Then, we used this definition of CS to analyze the intracranial SFT/HPC patients. The least absolute shrinkage and selection operator (LASSO) regression and best subset regression (BSR) were employed to identify predictive factors. The Multivariate Cox regression analysis was applied to establish a novel CS-based nomogram, and a risk stratification system was developed using this model. RESULTS: From the SEER database, 401 patients who were diagnosed with intracranial SFT/HPC between 2000 and 2019 were identified. Among them, 280 were included in the training group and 121 were included in the internal validation group for analysis. Our study revealed that in intracranial SFT/HPC, 5-year survival rates saw significant improvement ranging from 78% at initial diagnosis to rates of 83%, 87%, 90%, and 95% with each successive year after surviving for 1-4 years. The LASSO regression and BSR identified patient age, tumor behavior, surgery and radiotherapy as predictors of CS-based nomogram development. A risk stratification system was also successfully constructed to facilitate the identification of high-risk patients. CONCLUSION: The CS pattern of intracranial SFT/HPC patients was outlined, revealing a notable improvement in 5-year survival rates after an added period of survival. Our newly-established CS-based nomogram and risk stratification system can provide a real-time dynamic survival estimation and facilitate the identification of high-risk patients, allowing clinicians to better guide treatment decision for these patients.

Clinical outcomes of solitary fibrous tumors and hemangiopericytomas and risk factors related to recurrence and survival based on the 2021 WHO classification of central nervous system tumors.

OBJECTIVE: The authors aimed to explore the clinical outcomes and risk factors related to recurrence of and survival from solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) that were reclassified according to the 2021 WHO classification of central nervous system (CNS) tumors. METHODS: The authors retrospectively collected and analyzed the clinical and pathological data of SFTs and HPCs recorded from January 2007 to December 2021. Two neuropathologists reassessed pathological slides and regraded specimens on the basis of the 2021 WHO classification. The prognostic factors related to progression-free survival (PFS) and overall survival (OS) were statistically assessed with univariate and multivariate Cox regression analyses. RESULTS: A total of 146 patients (74 men and 72 women, mean ± SD [range] age 46.1 ± 14.3 [3-78] years) were reviewed, and 86, 35, and 25 patients were reclassified as having grade 1, 2, and 3 SFTs on the basis of the 2021 WHO classification, respectively. The median PFS and OS of the patients with WHO grade 1 SFT were 105 months and 199 months after initial diagnosis; for patients with WHO grade 2 SFT, 77 months and 145 months; and for patients with WHO grade 3 SFT, 44 months and 112 months, respectively. Of the entire cohort, 61 patients experienced local recurrence and 31 died, of whom 27 (87.1%) died of SFT and relevant complications. Ten patients had extracranial metastasis. In multivariate Cox regression analysis, subtotal resection (STR) (HR 4.648, 95% CI 2.601-8.304, p < 0.001), tumor located in the parasagittal or parafalx region (HR 2.105, 95% CI 1.099-4.033, p = 0.025), tumor in the vertebrae (HR 3.352, 95% CI 1.228-9.148, p = 0.018), WHO grade 2 SFT (HR 2.579, 95% CI 1.343-4.953, p = 0.004), and WHO grade 3 SFT (HR 5.814, 95% CI 2.887-11.712, p < 0.001) were significantly associated with shortened PFS, whereas STR (HR 3.217, 95% CI 1.435-7.210, p = 0.005) and WHO grade 3 SFT (HR 3.433, 95% CI 1.324-8.901, p = 0.011) were significantly associated with shortened OS. In univariate analyses, patients who received adjuvant radiotherapy (RT) after STR had longer PFS than patients who did not receive RT. CONCLUSIONS: The 2021 WHO classification of CNS tumors better predicted malignancy with different pathological grades, and in particular WHO grade 3 SFT had worse prognosis. Gross-total resection (GTR) can significantly prolong PFS and OS and should serve as the most important treatment method. Adjuvant RT was helpful for patients who underwent STR but not for patients who underwent GTR.

Intracranial Solitary Fibrous Tumor Mimicking Meningioma.

Solitary fibrous tumor (SFT) is a clinically rare tumor derived from mesenchymal spindle cells. Central nervous system SFT represents only 0.09% of tumors occurring on the meninges, while intracranial solitary fibrous tumors (ISFT) are even more rare. Due to the similar genetic characteristics it shares with hemangiopericytoma, in 2016, the World Health Organization (WHO) classified it as a single disease called solitary fibrous tumor (SFT)/hemangiopericytoma. We reported a case of a 60-year-old female with an intracranial solitary fibrous tumor (ISFT). The patient's magnetic resonance imaging showed a mass adhering extensively to the dura mater, with adjacent thickening of the meninges and evidence of a meningeal tail sign. These radiologic findings suggested a meningioma. The tumor was surgically removed and sent for pathologic examination, which confirmed that the tumor was consistent with a solitary fibrous tumor(WHO III). Due to its rarity and similarities with meningioma, ISFT is often misdiagnosed as other types of brain tumors. ISFT is poorly understood and poses a diagnostic challenge. Our case report presents several features suggestive of meningioma, but histopathological examination after surgery confirmed the diagnosis of SFT. Knowledge of these tumors is crucial for neurosurgeons to include them in preoperative differential diagnosis.

Infantile (congenital) anaplastic intracranial solitary fibrous tumor/hemangiopericytoma-A case report with brief literature review.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare primary central nervous system (CNS) tumor, included in the World Health Organization (WHO) 2016 classification. Very few cases have been described in the literature so far, especially the infantile type. It is a mesenchymal tumor of the fibroblastic type, characterized by the fusion of NAB 2 and STAT 6 genes. A 10-month-old boy presented to our neurosurgery department with complaints of increasing head circumference since 1 month of age. The magnetic resonance imaging (MRI) showed a space-occupying lesion measuring 8.2 cm × 7 cm × 6.9 cm in the fronto-temporo-parietal region with a clinical diagnosis of glioma/atypical teratoid rhabdoid tumor (ATRT). The microscopy revealed a spindle cell tumor arranged in a patternless pattern with variable cellularity, increased mitosis, and areas of coagulative necrosis. The immunohistochemistry showed vimentin, CD 34, STAT6, CD99 positivity whereas Glial fibrillary acidic protein, Epithelial membrane antigen, and S-100 negativity. Hence, a diagnosis of anaplastic SFT/HPC (grade-III) was rendered. The patient improved after gross total resection (GTR). The primary intracranial congenital SFT/HPC are extremely rare, often a clinico-radiologically misdiagnosed entity. Thus, the immunohistochemistry/molecular study in addition to histology is mandatory for accurate diagnosis.

Impact of extent of resection and postoperative radiotherapy on survival outcomes in intracranial solitary fibrous tumors: a systematic review and meta-analysis.

The knowledge of optimal treatments for patients with intracranial solitary fibrous tumor (SFT) is limited, with inconclusive results from previous studies. In this study, we conducted a meta-analysis of relevant studies to identify the prognostic impact of the extent of resection (EOR) and postoperative radiotherapy (PORT) on survival outcomes of patients with intracranial SFT. We searched the Medline, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) to identify relevant studies published till April 2022. Progression-free survival (PFS) and overall survival (OS) were the outcomes of interest. Differences between two cohorts (gross total resection [GTR] vs. subtotal resection [STR] and PORT vs. surgery only) were estimated by calculating hazard ratios. Twenty-seven studies were selected for the meta-analysis, including data of 1348 patients (GTR, n = 819 vs. STR, n = 381 and PORT, n = 723 vs. surgery only, n = 578). Pooled hazard ratios of PFS (1, 3, 5, and 10 years) and OS (3, 5, and 10 years) revealed that the GTR cohort showed sustained superiority over the STR cohort. In addition, the PORT cohort was superior to the surgery-only cohort with respect to all PFS periods. Although the 10-year OS between the two cohorts was not statistically different, PORT showed significantly better 3- and 5-year OS than surgery only. The study findings suggest that GTR and PORT provide significant benefits for PFS and OS. Aggressive surgical resection of tumors to achieve GTR followed by PORT should be implemented as optimal treatments for all patients with intracranial SFT when feasible.

Treatment and Management of a Sinonasal Hemangiopericytoma.

Sinonasal Hemangiopericytoma (HPC) is a rare vascular tumor originated from Zimmermann's pericyte with not well valuable course. The diagnosis needs a careful ENT endoscopic examination, radiological study and histopathological analysis with immunohistochemistry for confirmation of diagnosis. We describe a case of a male patient, 67 years old, with history of repeated monolateral right epistaxis. Endoscopic and radiological examination showed an ethmoid-sphenoidal lesion which occupied the entire nasal fossa extending towards the choana, with blood supply coming from the posterior ethmoidal artery. The patient performed an extemporaneous biopsy with subsequent en-bloc removal in operating room, without prior embolization, with the Centripetal Endoscopic Sinus Surgery technique (CESS). The histopathologic analysis led to the diagnosis of sinus HPC. The patient performed close endoscopic follow-ups every 2 months, without performing radio or chemotherapy, and with no evidence of recurrence after 3 years of follow-up. Analyzing the recent literature, a more indolent course with low recurrence rates after total endoscopic surgery remotion was described. Preoperative embolization can be useful in determinate cases, but cause to different complications, it should not be ordinarily performed.

Uterine hemangiopericytoma with cardiac involvement and pulmonary metastasis: A case report and literature review.

Uterine hemangiopericytoma is extremely rare. This article describes a case of uterine hemangiopericytoma. The tumor involved the parauterine vein; extended into the inferior vena cava, right cardiac cavity, and pulmonary artery; and metastasized to the lungs. It was irregular in shape and exhibited the string-of-beads sign on echocardiography, and it was tightly attached to the right ventricular surface and pulmonary artery wall. The patient underwent tumor resection without adjuvant treatment. A pelvic nodule was found 3 months postoperatively and was considered a recurrent lesion.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Radiological Differentiation Between Intracranial Meningioma and Solitary Fibrous Tumor/Hemangiopericytoma: A Systematic Literature Review.

BACKGROUND: Intracranial solitary fibrous tumor (SFT) is characterized by aggressive local behavior and high post-resection recurrence rates. It is difficult to distinguish between SFT and meningiomas, which are typically benign. The goal of this study was to systematically review radiological features that differentiate meningioma and SFT. METHODS: We performed a systematic review in accordance with PRISMA guidelines to identify studies that used imaging techniques to identify radiological differentiators of SFT and meningioma. RESULTS: Eighteen studies with 1565 patients (SFT: 662; meningiomas: 903) were included. The most commonly used imaging modality was diffusion weighted imaging, which was reported in 11 studies. Eight studies used a combination of diffusion weighted imaging and T1- and T2-weighted sequences to distinguish between SFT and meningioma. Compared to all grades/subtypes of meningioma, SFT is associated with higher apparent diffusion coefficient, presence of narrow-based dural attachments, lack of dural tail, less peritumoral brain edema, extensive serpentine flow voids, and younger age at initial diagnosis. Tumor volume was a poor differentiator of SFT and meningioma, and overall, there were less consensus findings in studies exclusively comparing angiomatous meningiomas and SFT. CONCLUSIONS: Clinicians can differentiate SFT from meningiomas on preoperative imaging by looking for higher apparent diffusion coefficient, lack of dural tail/narrow-based dural attachment, less peritumoral brain edema, and vascular flow voids on neuroimaging, in addition to younger age at diagnosis. Distinguishing between angiomatous meningioma and SFT is much more challenging, as both are highly vascular pathologies. Tumor volume has limited utility in differentiating between SFT and various grades/subtypes of meningioma.

Non-islet cell tumor-induced hypoglycemia in the setting of metastatic intracranial hemangiopericytoma: case report and review of the literature.

Intracranial hemangiopericytoma, particularly in the setting of extracranial metastatic disease, can cause severe hypoglycemia; but there is limited description of this phenomenon in the neurosurgical literature. We report the case of a male patient with recurrent meningeal hemangiopericytoma that had metastasized to multiple extracranial locations, who presented with severe, symptomatic hypoglycemia and abnormal levels of insulin, pro-insulin, insulin-like growth factors I and II, and C-peptide. This case highlights the association between hemangiopericytoma and abnormal levels of peptide hormones involved in glucose homeostasis, which may serve as a warning sign for hemangiopericytoma and/or metastatic disease.

Intracranial hemangiopericytoma after radiation treatment: first case in the literature.

BACKGROUND: Radiation exposure is a known risk factor for meningioma but there are no data regarding hemangiopericytoma and radiation exposure. CASE DESCRIPTION: We report a 29-year-old pineoblastoma patient diagnosed with a hemangiopericytoma at a different location, after a successful surgical excision and adjuvant radiotherapy for the original tumor 4-year prior. CONCLUSION: Hemangiopericytoma emergence can be seen after radiotherapy.

Malignant Progression of a Superior Cerebellar Tentorium Solitary Fibrous Tumor in the Pineal Region with Intracranial Metastases: A Case Report and a Literature Review.

BACKGROUND: Pineal region solitary fibrous tumors (SFT) incorporate a histologic spectrum of rarely metastasizing mesenchymal neoplasms that include tumors formerly classified as hemangiopericytoma. CASE REPORT: Here, we describe a rare case of SFT of the pineal region in a 25-year-old man with a literature review. After the first surgery, the tumor reappeared as a local low-grade recurrence, followed by metastasis to the right parietal lobe, and then hyperacute intraparenchymal hematoma at the metastatic site, and later presentation of widespread intracranial intra-axial and extra-axial metastases during the follow-up period. Systemic metastases were not detected. The histopathological evaluation of the resected tissues confirmed the malignant progression of the tumor. CONCLUSION: The diagnosis of SFT of the pineal region through clinical and imaging features can be considerably challenging. Large size, intratumoral cystic areas, and intense contrast enhancement are the main conventional imaging characteristics of the tumor. Surgery is the first preferential treatment. All recurrent or metastatic cases were grade II or grade III tumors. Adjuvant radiotherapy should be added to surgical treatment in high-grade tumors. Gamma knife radiosurgery is a treatment option for intracranial metastases.

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

BACKGROUND: Preoperative prediction of postoperative tumor progression of intracranial grade II-III hemangiopericytoma is the basis for clinical treatment decisions. PURPOSE: 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). MATERIAL AND METHODS: 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). RESULTS: 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. CONCLUSION: Broad-based tumor attachment to the dura mater, skull invasion, and blurring of the tumor-brain interface can predict postoperative intracranial SFT/HPC progression.

The Natural History of Parapharyngeal Solitary Fibrous Tumor/Hemangiopericytoma: A Case Report.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is extremely rare, and most of them are immediately treated for radical resection. However, the information concerning its natural history remains unclear. In this report, we presented a patient with parapharyngeal SFT/HPC, who was not immediately treated with surgical resection at first diagnosis. After approximately 3 years, the tumor volume doubling time (TVDT) and specific growth rate (SGR) could be measured through 3 serial magnetic resonance imagings. The TVDTs in the early and late pretreatment stages were 350 and 180 days, respectively, while the SGRs were 0.002 and 0.003, respectively. The growth rate of this disease entity is generally slow and may accelerate in the disease process.

Rare magnetic resonance imaging findings of intracranial solitary fibrous tumor: A case report.

RATIONALE: Solitary fibrous tumor (SFT) is a rare mesenchymal spindle cell tumor. SFT in the central nervous system (CNS) is rare. This case reports rare magnetic resonance imaging (MRI) findings of intracranial SFT (ISFT). PATIENT CONCERNS: We report a 47-year-old female patient who was found to have weakness in her right limb with walking instability 2 months before the visit. DIAGNOSES: Based on imaging, the provisional diagnosis was meningioma. Postsurgical histopathological diagnosis confirmed World Health Organization (WHO) grade I SFT/hemangiopericytoma (HPC). INTERVENTIONS: The lesion was totally excised. The patient improved remarkably after the operation, without any signs of associated limb movement disorder. OUTCOMES: No local recurrence or metastases were observed in the follow-up 3 months after the surgery. LESSONS: Intracranial SFT is a rare mesenchymal tumor. Due to different tumor components, imaging manifestations are diverse and lack of characteristics, so preoperative diagnosis is challenging. Our case provides a rare ISFT with significantly decreased signal intensity in T2 weighted images (T2WI), which is an important supplement to the rare imaging findings of intracranial SFT.

Liver Metastasis From Intracranial Hemangiopericytoma 8 Years After Initial Resection: Case Report.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare intracranial tumor that arises from pericytes surrounding the blood vessels. Solitary fibrous tumor/hemangiopericytoma accounts for less than 1% of primary brain tumors and is classified as grades I, II, or III based on mitotic count. These tumors often masquerade as meningiomas. Histologically, SFT/HPC is vascular with high cellularity and often surrounded by connective tissue. Immunohistochemistry is positive for stat 6, vimentin, and CD34. Although aggressive surgical resection is the mainstay of treatment, close long-term follow-up is necessary as recurrence or extra cranial metastasis can present several years after resection.

Hemangiopericytoma/solitary fibrous tumor of the cranial base: a case series and literature review.

BACKGROUND: Hemangiopericytomas (HPCs) are uncommon soft tissue tumors. HPCs that grow in the cranial base are rare. Therefore, skull-base surgeons tend to overlook this disease. This study aimed to increase the awareness of HPCs by summarizing case data from our institution and related publications. We also aimed to contribute to the number of reported cases for future systematic reviews of HPCs. METHODS: This study included all patients who underwent surgery for HPC/solitary fibrous tumor (SFT) between August 2015 and August 2019. All surgeries were performed at Xiangya Hospital Central South University. We analyzed clinical characteristics, surgical highlights, treatment modalities, and outcomes. RESULTS: We included six patients, aged 32-64 years. Lesions were located in the parapharyngeal space in three patients, pterygopalatine fossa in two, and saddle area in one. All patients underwent nasal endoscopic endonasal surgery. In five patients, tumors involved the internal carotid artery (ICA). The exposure and protection of the ICA during surgery are challenging but critical to complete tumor removal. The 3-year overall survival(OS) rate was 66.7%. CONCLUSIONS: HPC/SFTs are rare tumors of the cranial base that are prone to recurrence. Cranial base HPC/SFTs are often closely associated with the ICA. To our knowledge, this case series reports the largest number of cases of HPCs associated with the ICA. We believe that there is a strong relationship between patient prognosis and whether the tumor encircles the ICA and whether the tumor is completely resected. To confirm this suggestion, more cases are needed for further analysis.