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Perivascular wall tumors (PWTs) are common well-known canine mesenchymal tumors. The term PWT has not yet been applied to cats; only 2 cases of feline soft tissue hemangiopericytomas (HEPs) are available. In human medicine, sinonasal HEP-like tumor/glomangiopericytoma (SHPCL/GP) and intranasal solitary fibrous tumor (SFT) are well-known mesenchymal tumors with staghorn vasculature and low malignant potential; however, these entities have not been described in small animals. We describe here the pathologic and immunohistochemical features of 2 cases of feline intranasal mesenchymal tumors consistent with PWTs and resembling human SHPCL/GP (case 1), and human intranasal SFT (case 2). Both cats developed intranasal, unilateral, polypoid, expansile neoplasms with a mostly patternless growth of spindle cells, minimal stroma, and prominent staghorn vessels. The stroma was PAS negative, which excludes a glomus tumor. Immunohistochemistry identified diffuse vimentin and PDGFRβ expression. Case 1 was α-SMA positive (as is human SHPCL/GP); case 2 was negative (as is human intranasal SFT). Both tumors were incompletely excised, leading to recurrence in case 1. Case 2 was lost to follow up. To our knowledge, intranasal PWTs have not been reported previously in cats. The frequency of the lesions is not known, but awareness of these entities may assist in their recognition and better characterization in the future.

In the 2016 WHO classification of tumors of the central nervous system, hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) were integrated into a new entity (SFT/HPC). Metastases to bone, liver, lung, and abdominal cavity are of concern. Only 37 cases of patients with liver metastases due to intracranial SFTs/HPCs have been reported. Herein, we present our experience in the management of patients with liver metastases from intracranial SFTs/HCPs. All consecutive patients who were treated for liver metastases from intracranial SFTs/HPCs from January 2014 to December 2020 were enrolled. Overall, three patients were treated for liver metastasis from SFTs/HPCs with curative intent. Two patients with bilobar metastases at presentation required surgical resection, transarterial embolization, stereotactic radiofrequency ablation (SRFA) and systemic therapy. One patient with a singular right liver lobe metastasis was treated with SRFA alone. This patient shows no evidence of liver metastases 39 months following diagnosis. Of the two patients with bilobar disease, one died 89 months following diagnosis, while one is still alive 73 months following diagnosis. Long-term survival can be achieved using a multimodal treatment concept, including surgery, loco-regional and systemic therapies. Referral to a specialized tertiary cancer center and comprehensive long-term follow-up examinations are essential.

As a recommended second-line option for advanced soft tissue sarcoma, trabectedin can provide the necessary balance between long-term tumor control and preserved quality of life. Three case studies illustrate the long-lasting responses that patients can achieve with second-line trabectedin. A female patient with metastatic leiomyosarcoma maintained disease control for 2 years with trabectedin (× 41 cycles) with excellent tolerability and no relevant adverse events. At the time of writing, a male patient with a metastatic solitary fibrous tumor was asymptomatic after 30 cycles of trabectedin and treatment was ongoing. A young male patient with a recurrent, nonresectable, retroperitoneal myxoid/round cell liposarcoma was able to continue his sporting activities (triathlons) over 2 years with trabectedin (× 14 cycles) plus watchful waiting.

Background: We report a case of a 23-year-old man with a solitary fibrous tumor of the great omentum who presented clinically as a case of dull abdominal pain. Case Presentation: Solitary fibrous tumor normally occurs in the visceral pleura. Extrathoracic solitary fibrous tumor is rare, especially those from the great omentum, with approximately 31 cases reported in the literature. Conclusion: After reviewing and summarizing the imaging findings of 31 cases of solitary fibrous tumor of the greater omentum, we considered that the characteristic findings can provide a reliable basis for preoperative diagnosis.

Purpose This study aimed to evaluate the role of postoperative radiotherapy (PORT) in intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC).Materials and Methods A 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.Results The 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).Conclusion This 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.

We present a retrospective study of 65 cases of solitary fibrous tumors (SFTs) of several localizations including the most common site of origin in the pleura and lungs. SFTs are mesenchymal fibroblastic tumors with an unpredictable biological potential ranging from benign to malignant. We investigated morphologic characteristics, proliferation activity evaluated by immunohistochemical expression of Ki-67 antigen, and the existence of NAB2-STAT6 fusion gene together with Ki-67, TPX2, and TERT mRNA expression levels. The aim was to define relationships between proliferation activity and biological potential and progression of the disease. We measured Ki-67, TPX2, and TERT mRNA levels using quantitative real-time reverse transcription PCR (RQ-RT-PCR). We observed a significant association between increased Ki-67 and TERT mRNA levels and the SFTs with malignant potential. Also, we investigated the effect of TERT promoter mutation on telomerase activation and patient outcome in our SFT cohort. We verified that TERT promoter mutation was frequent (36.6%) and present in a majority of malignant SFTs and SFTs with uncertain biological behavior. TERT promoter mutation alone predicted the disease recurrence.

This case report represents a solitary fibrous tumor, which is a very rare neoplasm in the parotid gland.80-year-old Caucasian female patient with palpable, immobile, painless, slow growing, semi-rigid-elastic neoplasm in the left parotid gland, that was existing for four months. There were no signs of inflammation and facial paralysis. The tumor was initially interpreted as a salivary gland neoplasm of uncertain origin. Fine needle aspiration was performed 2 times; however, the precise diagnosis was challenging. The tumor was excised, regional lymphadenectomy was performed. Morphological and immunophenotypical findings were consistent with solitary fibrous tumor of parotid gland. Currently, the patient is under regular follow-up period at 9 months with no evidence of metastasis or recurrence.Although very rare, solitary fibrous tumor (SFT) should be suspected in cases of slow growing, solid, well-defined nodules of the parotid gland. The SFT of the parotid gland are usually benign tumors, however there is a low risk of recurrency and malignant behavior with metastatic potential. Complete resection of the tumor should be performed since it is crucial for management without any recurrence.

Pulmonary sclerosing pneumocytoma (PSP) is a tumor of pneumocytic origin that is classified as a benign neoplasm. To date, aggressive behavior of this tumor has rarely been reported. Here, we describe a case of a 56-year-old woman with a huge, 19-cm PSP that resulted in mediastinal shift and showed microscopic endobronchial invasion and necrosis. The differential diagnosis included malignant mesenchymal tumors, such as solitary fibrous tumor; however, PSP was confirmed based on the characteristic thyroid transcription factor 1 positivity and membranous expression of Ki-67 on immunohistochemical staining of tumor cells.

Solitary fibrous tumor (SFT) is a spindle cell neoplasm that occurs commonly in the pleural space. One-third of SFTs arising from an extrathoracic organ are found in the head and neck region, and they arise rarely in the sinonasal tract. Most of these tumors are benign, but malignant tumors are identified in some cases. Here we report a rare sinonasal SFT arising from the frontal recess. A 32-year-old male patient with chief complaint of headache and left facial pain visited the outpatient clinic. He had suffered from paranasal pain and nasal obstruction for several months, and symptoms became more severe in the previous three months. The mass rapidly increased in size and was protruding from the left nostril when he visited the hospital. After computed tomography and magnetic resonance imaging scans, transnasal endoscopic resection of the tumor was performed, and gross total tumor removal was successfully achieved. We believe this case will be helpful for providing information regarding management of such uncommon huge sinonasal tumors originating from the frontal recess.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare neoplasm arising from spindle cells and most commonly arising from pleura. Spinal SFT/HPC is a rare entity; hence, it is not on the top of the differential diagnosis list when a clinician faces a spinal lesion. In the review of the literature, there exist less than 50 case reports of intradural extramedullary SFT/HPC. Here, we present a 54-year-old female patient who underwent subtotal surgical excision of an intradural extramedullary spinal mass pathologically reported to be SFT/HPC and had symptomatic recurrence in the 3rd year of follow-up. Surgical intervention was unachievable and the patient was given 45 Gy to the surgical cavity followed by a 5.4 Gy boost to visible tumor with external radiotherapy. Patient reported significant relief of her symptoms. We aim to contribute to the formation of a treatment algorithm for this rare entity.

BACKGROUND Tumor-to-tumor (TMT) metastasis is a rare phenomenon in which a primary malignancy undergoes metastasis to an additional synchronous or metachronous primary tumor. CASE REPORT This is a case report of a tumor-to-tumor metastasis from a poorly differentiated adenocarcinoma of the esophagus to a solitary fibrous tumor (SFT) of the right posterior neck, in a 70-year-old-male with a solitary right vertebral artery. After appropriate work-up and involvement of the necessary specialties, the patient underwent a complex surgical resection with negative margins. CONCLUSION We present the unique case of a patient with TMT from esophageal adenocarcinoma to an SFT in the posterior neck, not previously reported in the literature. This rare condition with unique oncologic implications highlights the need for a multidisciplinary approach, in this case involving thoracic surgery, head-and-neck surgery, medical oncology, radiation oncology, pathology, and neurosurgical sub-specialty services.

A 70-year-old woman was referred to our hospital for asymptomatic pancreatic tumors. She had a history of hemagiopericytoma (HPC) about 20 years ago, and no apparent recurrence has been observed. Contrast-enhanced computed tomography revealed two hypervascular tumors in the head and uncinate process of the pancreas, and no obvious neoplastic lesions were found in other organs. Endoscopic ultrasound guided fine-needle aspiration cytology was performed and histopathology showed that spindle-shaped tumor cells were arranged in a hemangiopericytoma-like pattern and positive for STAT6, which was a characteristic feature of solitary fibrous tumors (SFTs). Immunohistochemical staining for surgical pathology specimens from past HPC showed positive expression of STAT6, which was Grade 2 central nervous system solitary fibrous tumor/hemagiopericytoma (CNS SFT/HPC) according to the current WHO classification. From these findings, the pancreatic tumors were preoperatively diagnosed as pancreatic metastases of CNS SFT/HPC. She underwent pancreaticoduodenectomy. Histopathological examination of the surgically resected specimen proved that the both pancreatic tumors were SFT/HPC. Thus, pancreatic tumors were finally diagnosed as asynchronous pancreatic metastases from CNS SFT/HPC. Although extremely rare, metastatic pancreatic tumors derived from SFT/HPC should be considered as a differential diagnosis for hypervascular pancreatic tumors, especially when having a past history of brain tumors.

Fibrous Solitary Tumors are infrequent neoplasms originating from mesenchymal tissues, most commonly arising from the visceral pleura and frequently exhibiting a benign behavior. Extra-pleural localization is unusual and the site of origin of these tumors from the parenchyma of the parotid gland is considered extremely rare. We report the case of a 66-years old woman with non-painful slow-growing left latero-cervical mass, who underwent a gadolinium-enhanced Magnetic Resonance Imaging showing a mass originating from the deep lobe of the parotid gland extending into the retro-pharyngeal space. After a total parotidectomy with tumor excision, a diagnosis of histologically proven fibrous solitary tumor of the parotid gland was made. Two years later, CT scan showed post-operative recurrence and further satellite localization in the neck, distant from the initial mass. We performed a literature review of the published similar cases, in order to clinicopathological and imaging features of this rare entity.

Purpose Non-squamous cell carcinoma (non-SCC) accounts for about 5% of laryngeal malignancies. Survival data are limited, and consensus on management principles is lacking. The present study reviews our experience in the surgical treatment of non-metastatic non-SCC of the larynx and compares oncological and functional outcomes in a cohort of patients affected by traditional SCC. Methods We collected data on 592 patients affected by laryngeal neoplasms. Univariate and multivariable survival analyses were performed using Cox proportional-hazards models; survival estimates were reported by hazard ratios (HR) with 95% confidence intervals (CI), and survival curves were established with the Kaplan–Meier method. Results We identified 326 patients affected by untreated SCC, while 21 had non-SCC histotypes. The non-SCC cohort was composed of 5 soft tissue sarcomas, 8 chondrosarcomas, 2 adenoid cystic carcinomas, 2 neuroendocrine carcinomas, 2 solitary fibrous tumors, 1 Kaposi’s sarcoma, and 1 malignant peripheral nerve sheath tumor. Overall survival and disease-specific survival were not significantly different according to histology (p = 0.6 and p = 0.349, respectively). The non-SCC group showed an increased risk of recurrence (HR 5.87; CI95 2.15–16.06; p p = 0.31) was found at multivariable analysis between the two groups in total laryngectomy-free survival with an organ preservation rate over 5 years of 81% for the non-SCC histologies. Conclusion Non-SCC is a broad spectrum pathology, but generalized laryngeal surgical management principles are still feasible and it is possible to identify patients amenable to conservative surgical treatment without affecting survival.

Pazopanib, a multi-targeted tyrosine kinase inhibitor, is associated with cardiovascular adverse events, such as hypertension, cardiac dysfunction, and thromboembolism. However, symptomatic pazopanib-related bradycardia is uncommon. We herein report a case of symptomatic bradycardia of 35 beats per minute in a patient with solitary fibrous tumor/hemangiopericytoma (SFT/HPC) treated with pazopanib for 1 month. His heart rate recovered to a normal range soon after pazopanib cessation. He restarted pazopanib at a reduced dose, which was continued without SFT/HPC progression or bradycardia recurrence. This case highlights the possibility of bradycardia induced by pazopanib and the importance of monitoring the patient's heart rate.

Background Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) are rare tumors of mesenchymal origin. Here, the authors present a rare case of anaplastic HPC in the jugular foramen (JF). The authors also conduct a systematic review of the literature to examine the current fund of knowledge on JF HPC/SFTs. Methods A systematic MEDLINE search was conducted using key words “hemangiopericytoma” OR “solitary fibrous tumor” AND “jugular foramen” OR “extracranial” OR “skull base.” Clinicopathologic characteristics and outcomes of the present case were reviewed and compared with those in the literature. Results A 41-year-old male, who had undergone stereotactic radiation therapy 6 years ago for a presumed glomus jugulare tumor, presented to our institution with worsening dysphagia, hoarseness, persistent tongue weakness, and radiographic evidence of tumor progression. The patient underwent uncomplicated gross total resection with sacrifice of the infiltrated hypoglossal nerve. Histopathologic evaluation revealed anaplastic HPC/SFT (World Health Organization grade III). Review of the literature yielded 9 additional cases of JF HPC/SFT in 5 males (56%) and 4 females (44%), with a mean age of 49.6 years old. Patients commonly presented with pain (37.5%) and lower cranial nerve deficits (100%). Preoperative diagnoses included glomus jugulare (n = 2) or JF schwannomas (n = 3). All patients underwent microsurgical resection of the lesion, except for 1 who refused all treatment after diagnostic biopsy. Conclusion The authors present the only reported case of anaplastic HPC of the JF. The illustrative case and those found on systematic review of the literature highlight the importance of tissue diagnosis and appropriate management.

The clinical evolution of solitary fibrous tumors (SFTs) is often uncertain and several risk stratification systems (RSS) have been proposed. The Demicco et al. RSS is the most frequently implemented. In this study we aim to validate two alternative RSS (Sugita et al. and G-Score) using results for the Demicco RSS from a previous study of 97 SFTs. In addition, we aim to determine whether reclassified cases had any distinctive molecular features. As the Sugita et al. system substitutes mitotic count with Ki-67 index we also investigated whether Ki-67 results for tissue microarrays are comparable to those obtained using whole tissue sections. In the present study we detected that many cases classified by Demicco RSS as low-risk were reclassified as intermediate risk using the new system (G-score RSS). Kaplan-Meier survival plots for G-Score RSS showed that the low-risk and intermediate-risk SFTs had a similar evolution that contrasted with the more aggressive high-risk group. Moreover, the similar evolution in both low and intermediate-risk groups occurred despite the G-score system being stricter in classifying low-risk tumors. We observed that Sugita RSS does not provide any better risk stratification in comparison with the Demicco RSS, and testing both RSS in our series produced similar Kaplan-Meier survival data. We found some discordant results when comparing whole sections and the corresponding tissue microarrays samples, finding the hotspot areas easier to locate in whole sections. Forty-one SFTs with initial low-risk assigned by the Demicco RSS were reclassified as intermediate-risk by G-score finding both TP53 and HTER mutations in four cases, only HTER mutation in 11 cases, and only TP53 mutation in 2 cases. All six cases of SFT classified as high-risk by both the Demicco and G-score RSS suffered recurrence/metastasis, and half showed both TP53 and HTER mutations. Five SFTs were categorized as low-risk by both Demicco and G-score, of which 4 cases revealed HTER mutation. Regarding the outcome of these 5 patients, two were lost to follow-up, and one of the remaining three patients suffered recurrence. We believe that although the presence of both TP53 and HTER mutations may confer or be related to poor evolution, the isolated presence of HTER mutation alone would not necessarily be related to poor outcome. The G-score RSS more accurately identified low-risk patients than the other two risk models evaluated in the present series. Late recurrence/metastasis may occasionally be observed even in low-risk SFTs categorized by stricter classification systems such as the G-score RSS. These findings support the possibility that additional, as yet unknown factors may influence the clinical evolution of SFTs. In conclusion, given the possibility of late recurrence, long-term follow-up is recommended for all SFT patients, even in cases classified as low risk by the stricter G-score system. An integration of clinical, radiological, pathological, and molecular findings may improve SFT risk stratification and better predict patient outcome.

Introduction: Meningeal solitary fibrous tumors (SFT), like all SFT, are defined by NAB2-STAT6 fusion and share clinicopathologic similarities with meningiomas, the most frequent meningeal tumors. Our aim is to establish the molecular identity of meningeal SFT and seek molecular prognostic factors. Methods: RNA sequencing and whole exome sequencing (WES) were performed in STAT6-positive SFT and grade 2–3 meningiomas, and data concerning other soft tissues tumors was obtained from the local database. Uniform manifold approximation and projection (UMAP), individual gene expression and Gene Set Enrichment Analysis (GSEA) were performed. Results: RNA clustering shows that SFT share a common molecular signature, different from any other type of tumoral tissue. Meningeal SFT aggregate with other SFT, with no clinical or histological subgroup. Comparison of genes expressions suggests significant over-expressions of ZIC2, ZIC3, ZIC5, GABBR2, TP53 in CNS-SFT. The pathogenic TP53 c.743G > T variant, previously undescribed in SFT, was found in one sample of meningeal SFT during malignant progression. Conclusions: Meningeal SFT are molecular counterparts of extra-meningeal SFT, completely separate from meningiomas. They might develop from the same tissues and benefit from the same treatments as SFT.

An intracranial collision tumor is a rare lesion composed of two histologically different neoplasms in the same anatomic location. Even more rare is the collision tumor of a solitary fibrous tumor/hemangiopericytoma (SFT/HPC) and meningioma. The patient was a 46-year-old woman who had a 40 × 35 × 30-mm mass in the vermis of the cerebellum. Histologically, the mass consisted of two different components. One component showed the morphology of meningioma (World Health Organization (WHO) grade I), and the other component exhibited small round cell proliferation with hypercellular density, which was revealed to be SFT/HPC (WHO grade III) based on STAT6 immunohistochemistry. STAT6 showed completely different immunohistochemistry results in these two components (nuclear-negative in meningioma and nuclear-positive in SFT/HPC). Since these two neoplasms are associated with different prognoses, they should be distinguished from each other. When meningioma and an SFT/HPC-like lesion are identified morphologically, it is important to recognize the presence of such a collision tumor composed of meningioma and SFT/HPC, and identify the SFT/HPC component by employing STAT6 immunohistochemistry.

Here, we report a case of an orbital solitary fibrous tumor (SFT) with multiple local recurrences, even after orbital exenteration, and lung metastases after 41 years. The report discusses the clinical and histopathological findings of this case. A 34-year-old female patient with an orbital SFT was treated with orbital exenteration after local resection failed to prevent a recurrence. Ten years later, the patient underwent radiation therapy, followed by two rounds of gamma knife treatment, leading to remission. Forty-one years after the first treatment, the patient, at the age of 75 years, was found to have lung metastases along with orbital recurrence for the eighth time. The patient underwent radiation therapy but died from radiation pneumonitis. Our case emphasizes the need for long-term follow-up of patients with orbital tumors, even after orbital exenteration, to monitor for metastasis.

Salivary gland neoplasms are uncommon, and most exhibit epithelial differentiation. Mesenchymal neoplasms of the salivary gland are rare, and the incidence ranges from 1.9% to 5%. The aim of this study is to identify the types and clinical-pathological features of mesenchymal salivary neoplasm and review their differential diagnosis. A retrospective search for mesenchymal neoplasms of salivary glands from our institution's pathology archives from the 2004–2021 period and consultation files of one of the authors (AER) was performed. The clinical data were obtained from available medical records, and the histological slides and ancillary studies were retrieved and reviewed. We identified a total of 68 cases that form the study cohort. Thirty-five patients were male, and thirty-three patients were female, with a mean age of 48 years (range, 7 months–79 years), and the male to female ratio was 1:.94. Sixty-three (92.6%) of sixty-eight tumors were benign and included: 38 (56%) lipomas, 9 (13%) hemangiomas, 7 (10.3%) schwannomas, 3 (4.4%) neurofibromas, 3 (4.4%) lymphangioma, 2 (3%) solitary fibrous tumors, 1 (1.5%) myofibroma. Five of sixty-eight (7.4%) were malignant and included: 3 (4.4%) Adamantinoma-like Ewing sarcomas, 1 (1.5%) malignant peripheral nerve sheath tumor (MPNST), and 1 (1.5%) malignant solitary fibrous tumor. The involved sites included: parotid (55), submandibular gland (5), parapharyngeal space (5), buccal mucosa minor salivary gland (2), and sublingual gland (1). Sixty-seven patients underwent surgical resection. One patient with lymphangioma manifested a recurrence/persistence a week post-surgery. One patient with a parotid hemangioma developed post-operative numbness, and another patient developed chronic postauricular pain after surgery. Two patients with MPNST and one patient with adamantinoma-like Ewing sarcoma underwent neoadjuvant chemoradiation and were disease-free after treatment. The remaining 37 patients with available follow-up ranging from 7 days to 96 months (mean, 18 months) had a favorable outcome and were disease-free after treatment. Mesenchymal neoplasms of salivary gland are rare; most are benign and demonstrate adipocytic, endothelial, and schwannian differentiation; awareness of their development is important for adequate diagnosis. The mainstay of treatment is surgical excision, with the extent determined by tumor type. Adjuvant therapy is reserved for high-grade sarcomas and may be given in a neoadjuvant or adjuvant setting.

Angiomatoid fibrous histiocytoma (AFH) is an uncommon soft tissue neoplasm that can exhibit diverse morphological features, including myxoid change. Rarely, the tumor occurs intracranially and poses considerable diagnostic challenges to neuropathologists. This is compounded by a recently coined entity, referred to as intracranial myxoid mesenchymal tumor (IMMT). These tumors show significant overlaps with intracranial myxoid AFH from clinicopathological and molecular genetic viewpoints. We described an unusual intracranial tumor in a 30-year-old man. The tumor exhibited "classic" histological features of myxoid AFH and EWSR1:CREM fusion, a relatively novel variant of EWSR1:CREB family fusion, first identified in IMMT. We also performed a comprehensive literature review comparing the clinicopathological features of intracranial AFHs and IMMTs. Peritumoral lymphoplasmacytic cuffing appears to be the only morphological finding that is consistently absent in reported cases of IMMT while being present in most intracranial AFHs. Otherwise, both tumors showed considerable overlaps in clinical, histological, and immunohistochemical features and have a common molecular genetic signature of EWSR1:CREB family fusion, including EWSR1:CREM fusion. Our case appeared to be the first described EWSR1:CREM-fused intracranial tumor to show prominent peritumoral lymphoplasmacytic cuffing and myxoid change in addition to most of the other "classic" morphologic features of AFH. As such, while the current literature appears to be lacking when it comes to defining intracranial myxoid AFH and IMMT as separate nosological entities, they likely represent a morphological spectrum of a common entity characterized by EWSR1 rearrangement, akin to solitary fibrous tumors and hemangiopericytomas with the signal transducer and activator of transcription 6 gene (STAT6) rearrangement.

Background Recent comprehensive studies have revealed several molecular alterations that are frequently found in meningiomas. However, effective treatment reagents targeting specific molecular alterations have not yet been identified because of the limited number of representative research models of meningiomas. Methods We performed organoid cultures using meningioma cells and meningioma tumor tissues. Using immunohistochemistry and molecular analyses consisting of whole-exome sequencing, RNA-seq, and DNA methylation analyses, we compared the histological findings and molecular profiling of organoid models with those of parental tumors. Further, using these organoid models together with a public database of meningiomas, we explored molecular alterations, which are a potent treatment target for meningioma. Results We established 18 organoid models comprising of two malignant meningioma cells (HKBMM and IOMM-Lee), 10 benign meningiomas, four malignant meningiomas, and two solitary fibrous tumors (SFTs). The organoids exhibited consistent histological features and molecular profiles with those of the parental tumors. Using a public database, we identified that upregulated forkhead box M1 (FOXM1) was correlated with increased tumor proliferation. Overexpression of FOXM1 in benign meningioma organoids increased organoid proliferation; depletion of FOXM1 in malignant organoids decreased proliferation. Additionally, thiostrepton, a FOXM1 inhibitor combined with radiation therapy, significantly inhibited the proliferation of malignant meningioma organoid models. Conclusions An organoid model for meningioma enabled us to elucidate the tumor biology of meningioma along with potent treatment targets for meningioma.

Introduction Solitary fibrous tumor (SFT), a fibroblastic neoplasm characterized by a specific genetic alteration (NAB2-STAT6 fusion) and relatively specific immunohistochemical profile (STAT6/CD34 positivity), is seldom the subject of cytopathology data. We report our experience with scrape smears and fine-needle aspiration (FNA) biopsies of SFT in a large patient cohort. Materials and methods A search was made of our cytopathology and surgical pathology databases for cases diagnosed as solitary fibrous tumor (SFT). FNA biopsy smears, imprint smears, and cell blocks were performed and examined using standard technique. Results Thirty-four cases from 30 patients (M:F = 1.1:1; age range: 24-86 years, x = 58 years) met inclusion criteria for this study. All patients had prior or subsequent tissue confirmation of SFT. Twenty-seven (79%) specimens were FNAs, and 7 (21%) were scrape smears. Most cases (29, 85%) represented primary tumors, 4 (12%) were metastatic deposits, and 1 (3.5%) was a locally recurrent neoplasm. Sites included: pleura/lung 9 (26%), head/neck 8 (24%), lower extremity 7 (21%), trunk 4 (12%), intra-abdominal 3 (9%), upper extremity 2 (7%), and mediastinum 1 (4%). Mean tumor size was 7.2 cm (range: 1.5-19 cm). Three (9%) cases were diagnosed specifically as SFT. Remaining diagnoses were spindle cell neoplasm/proliferation 14 (41%), nondiagnostic 5 (15%), specific type of sarcoma 3 (9%), malignant round cell tumor 2 (6%), sarcoma 2 (6%), malignant tumor 2 (6%) and single cases of melanoma, pleomorphic adenoma, and mesenchymal tumor. Immunohistochemical (IHC) testing was performed in 7 of 27 (26%) cell blocks. Conclusion SFT FNA cytopathology is morphologically ambiguous, overlapping with a broad array of other spindle cell proliferations. A specific diagnosis is only possible with added staining of STAT6 coupled with a set of other IHC markers.

Purpose. To retrospectively describe the clinical characteristics, management, and outcomes of four cases of orbital solitary fibrous tumor (SFT). In one patient, we present an ultrasonic aspirator system for tumor removal. Methods. Four patients with orbital SFT were selected: one patient with orbital SFT, another patient with frontal and ethmoidal SFT and orbital affectation with high rates of recurrence, the third patient with frontal lobe SFT and orbital invasion with multiple recurrences, and the fourth case with a history of craniopharyngioma surgery and SFT located on the orbital apex. Results. All cases showed proptosis, eye movement restriction, and, in three cases, visual acuity alteration. Different treatments were applied: in three cases, excision was performed, one of them with an ultrasonic aspirator system, and in the remaining case, an exenteration was done (in two cases, radiosurgery treatment was also applied). The immunohistochemical study revealed SFT, similar to hemangiopericytomas (HPCs). No recurrence has been observed after surgical treatment. Conclusion. The SFT is a spectrum of different tumors with similar histopathological characteristics. The use of immunohistochemical markers is very helpful in the diagnosis. The main problem of orbital involvement is the risk of damaging important structures adjacent to the tumor during the surgical removal. The ultrasonic aspirator system allows elimination of the tumor without damaging other orbital structures.

Objectives Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) were considered two distinct entities, but a common gene fusion, NAB2-STAT6, has been identified in both. Although rare, HPCs and SFTs do metastasize, some many years later after resection. Given the extended disease-free interval, it can be difficult to determine with certainty if an HPC or SFT at a new anatomic location represents a second primary or metastatic disease. Methods RNA was extracted from formalin-fixed, paraffin-embedded tissue of two patients with multiple SFT/HPC samples. The fusion gene was amplified by reverse transcription polymerase chain reaction (RT-PCR) and a custom-designed Archer FusionPlex panel (94 target genes) and the Illumina NextSeq 550. Results We identified two patients with multiple resections for HPC/SFT during 26 years at our institution. The first patient had a history of HPC and almost 10 years later she was diagnosed with malignant SFT. The HPC and the SFT shared the same fusion breakpoint. The second patient had multiple lesions in the brain and bone/soft tissue over a 27-year span following a diagnosis of meningeal SFT. Three lesions from this patient shared the same fusion breakpoint. Conclusions Our study demonstrated the same fusion breakpoints in primary and metastatic SFTs/HPCs at different time points using both RT-PCR and the Archer fusion panel.

Huge primary epidural solitary fibrous tumors in the sacrum are a rare clinical entity. The purpose of this article is to present our experience in treating such large and complex neoplasms in a 31-year-old woman. The patient complained of constant nocturnal bilateral hip and lower back pain and unilateral radicular symptoms (numbness, paresthesias) in the left S1/S2 dermatomal distribution. Diagnostic imaging, biopsy, preoperative endovascular embolization, two-staged tumor resection, and lumbosacroiliac fusion were performed. The treatment resolved the patient's neurological symptoms and resulted in overall good postoperative functionality. The patient has been in remission for more than five years despite her refusal of adjuvant radiotherapy.

Mesenchymal tumors of the mediastinum are a heterogenous group of rare tumors with divergent lineages. Mediastinal mesenchymal tumors are diagnostically challenging due to their diversity and morphologic overlap with nonmesenchymal lesions arising in the mediastinum. Accurate histologic diagnosis is critical for appropriate patient management and prognostication. Many mediastinal mesenchymal tumors affect distinct age groups or occur at specific mediastinal compartments. Neurogenic tumors, liposarcoma, solitary fibrous tumor, and synovial sarcoma are common mesenchymal tumors in the mediastinum. Herein, we provide an update on the diagnostic approach to mediastinal mesenchymal tumors and a review of the histologic features and differential diagnosis of common benign and malignant mesenchymal tumors of the mediastinum.

Solitary fibrous tumor and desmoplastic small round cell tumor are primary peritoneal malignant tumors. Despite their morphological differences, these diseases are united by low morbidity, the lack of pathogenic symptoms, similar radiological signs, and scant knowledge of prognostic factors. Considering the low morbidity, reliable differential diagnostic signs have not been established at present, which greatly complicates the timely formulation of the diagnosis. On the contrary, cases of choosing the wrong treatment tactics and the lack of a unified management algorithm are increasingly being identified. Radiation and instrumental diagnostic methods such as computed tomography, magnetic resonance imaging, laparoscopy are crucial in determining the extent of the tumor, it is necessary to take into account the biological characteristics of the tumor (morphological type), which affect the nature of tumor growth. With a solitary fibrous tumor and a desmoplastic small-round cell tumor, the computed tomography picture is characterized by the presence of isolated nodular formations in any part of the abdominal cavity, which can also be accompanied by a large omentum, ascites, an increase in retroperitoneal lymph nodes, and distant metastasis to the lungs and bones is possible. In general, the main task of diagnosing a primary peritoneal neoplasm is to take sufficient quality biological material, with the leading role in the diagnosis being given to histological and immunohistochemical studies. On the other hand, the independent experience of many clinics does not exceed single surveillance. This information does not allow doctors to confidently navigate the problem; accordingly, there is a need for multicenter and, possibly, prospective, randomized scientific research in order to develop a unified algorithm for managing patients with primary peritoneal tumors. The approaches to the treatment of these tumors are currently not standardized and not well studied due to the rarity of the pathology. According to the available information, the treatment of desmoplastic small round cell tumors is based on multimodal therapy, including systemic chemotherapy and surgery, and possibly radiation therapy. Traditional treatment algorithms for this pathology include the surgical stage and systemic or intracavitary chemotherapy, while the treatment sequence may be different and depends primarily on the prevalence of the disease. For solitary fibrous tumor, surgical treatment, by contrast, is the method of choice. Thus, when choosing a treatment strategy for a primary peritoneal tumor, it is first of all necessary to take into account the morphological type of the tumor and rely on known data on the benefits of a particular method. In this article, we tried to present modern information on the diagnosis and treatment of rare forms of primary peritoneal tumors.

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm mostly originates from pleura, but rarely from other parts of the body including pericardium. We report a case of a 44-year-old woman with dyspnea and intermittent edema in whom a large intrapericardial mass was discovered by echocardiography. Computed tomography (CT) revealed a focal pericardial calcification in right AV grove with pressure on right ventricle and right atrial, with no connection to cardiac chambers. Histopathological findings after complete resection of the mass revealed fibroconnective tissue with heavy calcification and no evidence of inflammation or malignancy. We reviewed the literature on pericardial solitary fibrous tumors up to 2020.

Solitary fibrous tumor is a very rare mesenchymal tumor that occurs mostly in the pleura, and there are few reported cases of a presence in the central nervous system, particularly in the cerebellum. In 2016, the WHO classified solitary fibrous tumors into grade I. In this article, we present a case of malignant solitary fibrous tumor recurring 8 years after surgery in a 63-year-old male. Magnetic resonance imaging showed low to intermediate mixed signal intensity on T1W1. Immunohistochemical staining positivity for Vimentin, CD99, CD34 and Bcl-2, it is consistent with the immunohistochemical characteristics of solitary fibrous tumor. We resected the patient's tumor, and the patient was followed up for 3 months with no signs of recurrence. Solitary fibrous tumors are very rare in the central nervous system. Immunohistochemical staining positivity for CD34 and Bcl-2 is strongly expressed in most solitary fibrous tumor. Surgical resection is the preferred treatment. Due to the small number of cases, the biological behavior and prognosis of this tumor need to be further explored.

OBJECTIVES Recurrence rates of solitary fibrous tumours of the pleura (SFTP) after surgical resection vary widely in the published literature. Our objective was to systematically review the existing literature to determine an accurate estimate of SFTP recurrence rates after surgical resection and to determine risk factors associated with recurrence. METHODS PubMed, EMBASE and the Cochrane library were systematically searched for randomized controlled trials and observational studies (prospective or retrospective) through 20 June 2020 that reported the recurrence rates after surgical resection. The outcome of interest was recurrence. RESULTS Of the 23 included studies comparing 1262 patients, the overall recurrence of SFTP in patients who underwent surgical resection was 9% [95% confidence interval (CI) 7–12%; I2 = 52%]. In addition, pooled benign and malignant recurrence rates were 3% (95% CI 2–5%; I2 = 8%) and 22% (95% CI 15–32%; I2 = 52%), respectively. A benign SFTP was associated with a significantly lower recurrence rate than a malignant SFTP [odds ratio (OR) 0.11; 95% CI 0.06–0.20; I2 = 0%]. There was no significant difference in the recurrence rates between lesions originating from parietal versus visceral pleura (OR 1.30; 95% CI 0.28–6.02; I2 = 59%). Female sex was associated with increased recurrence (OR 5.29; 95% CI 1.66–16.92; I2 = 0%). CONCLUSIONS Collectively, this systematic review demonstrated a 9% SFTP post-resection recurrence rate. Furthermore, the recurrence rates for benign and malignant SFTP were 3% and 22%, respectively. Histological malignancy and female sex were associated with higher risk.

Objective To evaluate preliminary results of a 3D‐printed modular prosthesis for spinal reconstruction after multilevel thoracolumbar total en bloc spondylectomy (TES). Methods Patients with thoracolumbar spinal tumors treated surgically between January 2016 and April 2019 were included in this retrospective study. A total of 17 male and 10 female patients with a mean age of 42 (range, 15–72) years comprised the sample. The pathological diagnoses included six chondrosarcomas (one of them was mesenchymal chondrosarcoma), six giant cell tumors, three malignant peripheral nerve sheath tumors, two osteosarcomas, two undifferentiated high‐grade pleomorphic sarcomas (UPS), two solitary fibrous tumors, one Ewing's sarcoma, one liposarcoma, and four metastatic tumors. Tumors involved 2 levels in 14 patients, 3 levels in seven patients, 4 levels in four patients, 5 levels in one patient, and 6 levels in one patient. A 3D‐printed modular prosthesis was used for anterior column reconstruction after TES. All analyses were performed using SPSS version 18.0 (SPSS, Inc., Chicago, IL). Descriptive statistics were used to analyze the demographic data and clinical outcomes. Data forms included mean, standard deviation and range. Results Under general anesthesia, all patients received TES with an average operative time of 639 (range, 210–1650) min, and the mean blood loss during operation was 4.1 (range, 0.8–13.3) L. Twenty‐two patients have been transferred to ICU for a mean time of 3.2 (range, 0–6) d. All patients had follow‐up procedures except for one, who died of perioperative complications. Mean time of follow‐up was 22 (range, 12–41) months. Local recurrence (19.2%) occurred in two patients with intralesional margin and three patients with marginal margin, respectively. At the end of follow‐up, three patients died of disease, eight patients were alive with disease, and 15 patients had no evidence of disease. Average lengths of resected vertebrae and modular prostheses were 71.4 ± 26.5 mm (range, 40–142 mm) and 68.4 ± 23.9 mm (range, 40–132 mm), respectively. In 26 patients with minimum follow‐up of more than 1 year, no evidence of internal fixation failure or dislocation of vertebral prosthesis was found. Asymptomatic prosthetic subsidence into adjacent vertebral bodies occurred in 10 patients with a mean length of 1.8 ± 1.0 mm (range, 1–4 mm). The subsidence was seen at proximal end in two patients, distal end in four patients, and both ends in four patients. Eighteen major complications and 14 minor complications were found in 15 patients. All patients fully recovered at 3 or 6 months after operation. At the latest follow‐up, in 23 alive patients, 19 can walk independently and two can achieve outdoor activities by walking aid. Conclusion For spinal reconstruction after multilevel thoracolumbar TES, 3D‐printed modular vertebral prosthesis is suitable for different length of anterior column reconstruction with less mechanical complications, and can provide a stable environment to maintain or rehabilitate patients' neurological function in short‐term follow‐up., 3D‐printed modular vertebral prosthesis for spinal reconstruction after multilevel thoracolumbar TES is suitable for different lengths of anterior column reconstruction with less mechanical complications, and can provide a stable environment to maintain or rehabilitate patients' neurological function in short‐term follow‐up.

Objectives The aim of this study was to evaluate the histomorphologic presentation and the expression of stem cell–related markers in a series of oral solitary fibrous tumors (SFTs). Study Design Histopathological variables and the expression of the standard stem cell markers CD34 and CD99, used for SFT diagnosis, as well as STAT6 were evaluated in 13 oral SFTs. The expression of the cancer stem cell markers CD44, ALDH1, Bmi-1, and Nanog and the tumor suppressor gene p16Ink4a were also investigated. Results The majority of oral SFTs were circumscribed and characterized by a proliferation of spindle cells arranged in a hyalinized stroma. Only 2 oral SFTs showed >4 mitoses/10 high-power fields. Hypercellularity as well as nuclear and cellular pleomorphism were classified as low and moderate in most of the oral SFTs. All oral SFTs were positive for CD34, STAT6, CD44, ALDH1, Bmi-1, and p16Ink4a. CD99 and Nanog expression was observed in 11 and 10 oral SFT cases, respectively. Conclusion We suggest that STAT6 and ALDH1 have relevant diagnostic value. The expression of CD44, ALDH1, Bmi-1, and Nanog, which is observed in cancer stem cells, may confer advantages to oral SFT cells.

To investigate an additional value of [68Ga]Ga-DOTA-TOC PET/CT for characterizing suspected pancreatic neuroendocrine neoplasms (NENs) in a large study cohort. This retrospective study included 167 patients who underwent [68Ga]Ga-DOTA-TOC PET/CT for suspected pancreatic NENs detected by contrast-enhanced CT (n = 153) and/or MRI (n = 85). Two board-certified radiologists independently reviewed CT and/or MRI as well as [68Ga]Ga-DOTA-TOC PET/CT and scored the probability of NEN on a 5-point scale. Radiologists’ diagnostic performances with and without [68Ga]Ga-DOTA-TOC PET/CT were compared using pathologic findings as the standard of reference. All 167 patients were pathologically diagnosed with NENs (n = 131) or non-NENs (n = 36) by surgery (n = 93) or biopsy (n = 74). The non-NEN group included focal pancreatitis (n = 7), gastrointestinal stromal tumor (n = 6), serous cystadenoma (n = 5), metastatic renal cell carcinoma (n = 4), intrapancreatic accessory spleen (n = 4), ductal adenocarcinoma (n = 3), solid pseudopapillary neoplasm (n = 2), intraductal papillary mucinous carcinoma (n = 1), adenosquamous carcinoma (n = 1), schwannoma (n = 1), paraganglioma (n = 1), and solitary fibrous tumor (n = 1). Radiologists’ diagnostic performance significantly improved after the addition of [68Ga]Ga-DOTA-TOC PET/CT (AUC of CT: 0.737 vs. 0.886 for reviewer 1 [p = 0.0004]; 0.709 vs. 0.859 for reviewer 2 [p = 0.0002], AUC of MRI: 0.748 vs. 0.872 for reviewer 1 [p = 0.023]; 0.670 vs. 0.854 for reviewer 2 [p = 0.001]). [68Ga]Ga-DOTA-TOC PET/CT significantly improved sensitivity (CT: 87.4% vs. 96.6% for reviewer 1 [p = 0.001]; 74.8% vs. 92.5% for reviewer 2 [p = 0.0001], MRI: 86.9% vs. 98.4% for reviewer 1 [p = 0.016]; 70.5% vs. 91.8% for reviewer 2 [p = 0.002]). [68Ga]Ga-DOTA-TOC PET/CT provided an additional value over conventional CT or MRI for the characterization of suspected pancreatic NENs. • [ 68 Ga]Ga-DOTA-TOC PET/CT could provide additional value over conventional CT and/or MRI for the exact characterization of suspected pancreatic NENs by increasing AUC values and sensitivity. • Diagnostic improvement was significant, especially in NENs showing an atypical enhancement pattern. • The inter-observer agreement was improved when [ 68 Ga]Ga-DOTA-TOC PET/CT was added to CT and/or MRI.

Solitary fibrous tumor (SFT) is a relatively rare primary tumor of the pleura, originating from the mesenchymal cells. The tumor has a non-specific clinical, laboratory, and radiological features. Patients may be asymptomatic or have non-specific clinical features including chest pain, dyspnea, cough, and paraneoplastic symptoms. Complete surgical resection is indicated in all cases to avoid recurrence of the tumor. We described a 49-yearold woman who presented with unexplained right chest pain and repeated attacks of hypoglycemia, associated with pleural SFT. Keywords: Pleura; thoracic oncology; solitary fibrous tumor; paraneoplastic hypoglycemia; Doege-Potter syndrome

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors most commonly arising from the pleura in the thoracic cavity. The impact of tumor size on risk of recurrence in thoracic SFTs is not well understood. A single institution review was performed on all resected thoracic SFTs (1992–2019) with giant SFT defined as ≥ 15 cm. Clinical information, pathologic characteristics, and long-term survival data were collected, and predictors of recurrence and survival were evaluated with regression and Kaplan–Meier analysis. There were 38 thoracic SFTs resected from patients, with the majority of tumors (n = 23, 60.5%) originating from visceral pleura. There were nine (23.7%) giant SFTs with a mean size 20.4 cm (range 17–30 cm). Mean follow-up time was 81.0 months (range 1–261 months), during which 4 of 38 (10.5%) patients experienced a recurrence within the thorax (range 51–178 months). The presence of tumor necrosis (p = 0.021) and ≥ 4 mitoses per high-powered field (p = 0.010) were associated with SFT recurrence on univariate regression. Overall 5-year, 10-year, and 20-year survival was 78.2%, 72.6%, and 42.4%, respectively, and SFT-related mortality occurred in three patients at 83, 180, and 208 months postoperatively. There were no recurrences or SFT-related mortality among patients with giant SFT. This study represents one of the largest contemporary single institution reviews of long-term outcomes of giant thoracic SFT. Our data suggest that size is not a risk factor for recurrence in thoracic SFTs and long-term survival is excellent for giant SFTs.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor primarily found in the pleura, with occasional presentations in extra-pleural locations. SFTs are typically diagnosed based on compressive symptoms due to their large size. Most SFTs are benign with a low recurrence rate, with an overall good prognosis with an overall 5-year survival of over 90%. Approximately 12-22% of SFTs are malignant and are associated with a higher recurrence rate of up to 78%. Given the low incidence and sparse case series literature, no adjuvant therapies have demonstrated a survival benefit. We present the first case of abdominal malignant SFTs with peritoneal dissemination, describing the presentation, histopathology, treatment planning and surveillance.

Meningeal solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) were categorized as the same entity in the World Health Organization (WHO) 2016 classification of tumors of the central nervous system (CNS). Although NAB2-STAT6 fusion protein can be used to distinguish most of SFT/HPC from the other sarcomas, additional biomarkers were requested to separate meningeal SFT/HPC from meningioma and the molecular pathological difference between meningeal SFT/HPC and extra-CNS SFT/HPC still remains unclear. In this study, we evaluated the expression of TTF-1 in 67 meningeal SFT/HPC, 62 extra-CNS SFT/HPC and 201 meningiomas samples with immunohistochemistry (IHC) assays. The results showed that TTF-1 was detected in 23 of 67 (34.3%) meningeal SFT/HPC, 3 retroperitoneum SFT/HPC and none of meningiomas. Meanwhile, the copy number variation and mRNA expression of TTF-1 were measured by real-time quantitative PCR (qPCR) in meningeal SFT/HPC. These results demonstrated that TTF-1 protein expression level was significantly correlated with its transcription level, but independently related to the gene copy number variant. In conclusion, our study suggested that a large proportion of meningeal SFT/HPC was positive to TTF-1, while very few extra CNS SFT/HPC cases and no meningiomas were stained. So TTF-1 has value as an auxiliary diagnostic marker for meningeal SFT/HPC.

Objective 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 20 years and to make a review of the literature on this topic. Methods Retrospective review that includes patients diagnosed with intracranial solitary fibrous tumor/hemangiopericytoma (TFS/HPC) that have undergone surgery from 1997 to 2017. It includes patients that had nuclear expression of STAT6 (detected by immunohistochemistry) and grade II/III histopathological diagnosis (defined by the World Health Organization in 2016). We collected demographic data, tumor characteristics, treatment and survival of these patients. Results A total of 19 patients fulfilled inclusion criteria. The median follow up was 96 months (12–230). The mortality rate was 21% (n = 4). The median follow up survival was 19.16 years. 57.9% of patients presented at least 1 tumor recurrence (n = 11) (recurrences of 6%, 67% y 90% at 1, 5 and 10 years). Five patients presented extracranial metastasis. Patients with tumors Conclusions A series of patients undergoing TFS / 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.

Background Solitary fibrous tumors (SFTs) occurring in the parapharyngeal space are rare, and their final diagnosis depends on pathological and immunohistochemical analyses. Once the tumor is diagnosed, complete resection and regular postoperative follow-up are required. Case summary A 40-year-old male patient with a right parotid gland mass discovered 8 years ago was admitted to hospital. The mass showed no tenderness or local skin redness. Imaging was carried out as the patient had stable vital signs and showed that the mass was a dumbbell-shaped tumor comprising a superficial tumor approximately 5 cm long and 3 cm wide in size that compressed the right parotid gland and a deep tumor located in the right parapharyngeal space approximately 4.5 cm long and 2.5 cm wide in size. Both tumors were connected in the middle. Prior to surgery, the tumors were considered to be parapharyngeal schwannomas. During surgical dissection, the tumors were found to be smooth and tough, without obvious adhesion to the surrounding tissues. The tumors were revealed to be a SFT following postoperative pathological analysis. Conclusion SFTs in the parapharyngeal space are rarely reported, and complete resection of such tumor is recommended. Adjuvant chemoradiotherapy is used in patients with extensive tumor invasion to lower the recurrence rate. Postoperative long-term follow-up is required.

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.

Background Hemangiopericytomas (HPC) are vascular tumors and can be found at any place where vessels are present. These were previously known as ‘extrapleural Solitary Fibrous Tumour’. These tumors may reoccur and metastasize after surgical excision. We present herein a HPC of the greater omentum, diagnosed as left inguinal hernia preoperatively. Case presentation A 61-year-old male, presented with a huge painless mass in his left inguinoscrotal region secondary to weigh-lifting associated with malaise and vague abdominal pain. A well-defined, non-tender, and firm mass was found at the left lower abdomen extending to the left inguinoscrotal region. Based on the examination, a diagnosis of indirect inguinal hernia was made. Abdominal ultrasound showed a heterogeneous, hyporeflective, and vascularized mass. Contrast-enhanced computed tomography scan identified a localized, extraperitoneal, heterogeneously hypodense, well-defined, and lobulated mass, with marked contrast enhancement. On exploration, an encapsulated large mass originating from the omentum with enormously dilated blood vessels was excised. On histopathology, a neoplastic lesion, composed of spindle-shaped cells and moderate cytoplasm was identified. The blood vessels appeared thin-walled with a staghorn appearance in hemangiopericytic pattern. Omental sections showed fibro adipose tissue with dilated lymphatics and thick-walled blood vessels. Features were consistent with a malignant HPC of 20 × 14 × 10 cm. Conclusion We present an unusual presentation of primary omental malignant HPC as an inguinal hernia, treated by complete surgical resection. These tumors are rare therefore, timely diagnosis is important for proper evaluation, diagnosis, and treatment. It also requires long-term follow up for better survival., Highlights • Hemangiopericytoma (HPC), previously known as ‘extrapleural Solitary Fibrous Tumor’, is a vascular tumor. • A well-defined, non-tender, and firm mass was found at the left lower abdomen extending to the left inguinoscrotal region. • Based on the examination, a diagnosis of indirect inguinal hernia was made. • CT scan showed a contrast enhancing, localized, extraperitoneal, heterogeneously hypodense, and lobulated mass. • On exploration, an encapsulated large mass originating from the omentum with enormously dilated blood vessels was excised. • On histopathology, features were consistent with a malignant HPC of 20 × 14 × 10 cm.

In 2016, the World Health Organization (WHO) central nervous system (CNS) classification scheme incorporated molecular parameters in addition to traditional microscopic features for the first time. Molecular markers add a level of objectivity that was previously missing for tumor categories heavily dependent on microscopic observation for pathologic diagnosis. This article provides a brief discussion of the major 2016 updates to the WHO CNS classification scheme and reviews typical MR imaging findings of adult primary CNS neoplasms, including diffuse infiltrating gliomas, ependymal tumors, neuronal/glioneuronal tumors, pineal gland tumors, meningiomas, nerve sheath tumors, solitary fibrous tumors, and lymphoma.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor with an intermediate tendency to metastasize. Meningeal hemangiopericytoma (HPC), arising in the meningeal membranes, also is considered an SFT. Although SFT is assumed to show an unpredictable behavior, the authors defined some factors associated with its aggressive behavior. This retrospective study was based on the medical records of 81 SFT patients treated surgically, with the median follow-up period of 59 months. The patients were assigned to three histopathologic groups based on the 2016 WHO classification: group 1 (SFT, 29 patients), group 2 (cellular SFT/hemangiopericytoma [HPC], 27 patients), and group 3 (malignant SFT/anaplastic HPC, 25 patients). The SFT histopathologic classification was associated with distant metastasis (DM) (p = 0.007). The multivariate analysis showed that cellular SFT had an independent impact on DM (odds ratio [OR] = 25.42; p = 0.006). Tumor diameter larger than 7.25 cm was correlated with DM (p = 0.010) and the patient’s disease-specific death (DSD) (p = 0.007). A 1-cm increase in tumor diameter enhanced the likelihood of metastasis by 1.26 (OR = 1.26; 95% confidence interval [CI], 1.05–1.53). Tumors originating from the central nervous system (CNS) showed a greater tendency toward local recurrence (LR) (p = 0.039) and DM (p = 0.05). Radiotherapy had no association with LR, DM, or DSD. The 10-year disease-specific survival rate was 82.7%. Tumor size and histopathologic diagnosis are the predictors of SFT’s aggressive behavior. Cellular SFTs behave as aggressively as the malignant form of the tumor. A SFT grading based on SFT cellularity would contribute to anticipation of its aggressive behavior.

BACKGROUND Malignant solitary fibrous tumors (SFTs) account for 15%-20% of all SFTs, and malignant SFTs arising from the greater omentum are extremely rare. Most malignant SFTs of the greater omentum are diagnosed via pathological examinations after surgery. In this study, we report a case of malignant omental SFT and review the published literature on this rare malignancy. CASE SUMMARY A 64-year-old female presented with an abdominal mass, and underwent exploratory surgery, during which a huge tumor originating from the greater omentum and intraperitoneal implants were identified and resected. The results of the pathological examination, immunohistochemistry staining, and gene sequencing led to the diagnosis of malignant SFT of the greater omentum. The patient died one and a half years later due to tumor recurrence and metastasis. CONCLUSION This is the first report of the application of gene sequencing in the diagnosis of malignant SFTs of the greater omentum.

Purpose To highlight the increasing importance of gene fusions in the diagnosis, prognosis, and therapy of ocular adnexal tumors. Design Perspective. Methods A focused review of gene fusions, their pathogenic mechanism, and gene fusion detection methods in lacrimal gland and primary orbital and ocular adnexal soft tissue tumors; reappraisal of diagnostic, prognostic, and therapeutic approach to ocular adnexal tumors in light of emerging molecular genetic data. Results The widespread implementation of fluorescence in situ hybridization and next-generation sequencing methods in pathology practice has led to identification of recurrent gene rearrangements and fusions in a variety of tumors. As a result, molecular genetic methods have become the gold standard for diagnosis of tumors with overlapping histology and immunophenotype, such as small round blue cell tumors. Identification of canonic gene fusions has led to development of sensitive and specific immunohistochemical markers, such as STAT6 in solitary fibrous tumor. In addition to diagnostic accuracy, gene fusions have prognostic implications, such as unfavorable prognosis of PAX3-FOXO1 fusion in alveolar rhabdomyosarcoma. Finally, recognition of gene fusions as a driving mechanism in neoplasia has led to development of U.S. Food and Drug Administration–approved targeted therapies, such as TRK inhibitors for NTRK fusion-positive cancers. Conclusion The discovery of recurrent gene fusions in various tumors, including those involving ocular adnexa, has led to a deeper insight into the molecular mechanisms of these neoplasms, revolutionizing our approach to their diagnosis, prognostication, and therapy.