Frozen Cytology of Meningeal Malignant Solitary Fibrous Tumor/Hemangiopericytoma

A 51-year-old woman presented with severe dizziness. The brain magnetic resonance image revealed a 5.5 cm multiloculated mass with a thick rim in the left temporal lobe. Cytological examination of frozen diagnosis of the mass showed hypercellular sheets of round and rhabdoid cells in a hemorrhagic background, and two mitotic figures were observed. Histologically, the excised dura-based mass consisted of predominantly round cells with small foci of rhabdoid tumor cells in a pseudoalveolar pattern in a hemorrhagic background, and the cells showed nuclear positivity for signal transducer and activator of transcription 6 as well as frequent mitosis. The mass was diagnosed as a grade 3 solitary fibrous tumor (SFT)/hemangiopericytoma (HPC). The cytological diagnosis of SFT/HPC is challenging because of the heterogeneous cytological findings, such as histological heterogeneity, and because there are no standardized cytological criteria for malignant SFT/HPC. Cytological findings, such as singly scattered small cells, hypercellularity, rare ropy collagen, and round and rhabdoid cells with pseudoalveolar pattern, may assist in the diagnosis of malignant SFT/HPC.

Varied presentation of sinonasal phosphaturic mesenchymal tumour: report of a case series with follow-up

PURPOSE

Phosphaturic mesenchymal tumour (PMT) of the paranasal sinuses is a rare tumour that is associated with oncogenous osteomalacia causing predominant musculoskeletal symptoms. We present a series of eight patients diagnosed to have PMT of the paranasal sinuses with varied presentation and highlight the appropriate evaluation required to arrive at the diagnosis.

METHODS

Retrospective review of eight patients diagnosed to have PMT-causing tumour-induced osteomalacia with follow-up data.

RESULTS

Eight patients, 4 males and 4 females, aged 36-67 years (mean = 44 years) presented with vague musculoskeletal symptoms (6 patients) or epistaxis (3 patients). Six patients were found to have hypophosphatemia, phosphaturia and raised FGF-23 levels preoperatively. All eight patients were found to have a tumour in the nose and/ paranasal sinuses with one patient having intracranial extension. All patients were treated with endoscopic excision of these tumours which resulted in resolution of symptoms and normalisation of biochemical abnormalities. In addition, one patient required a craniofacial resection. Histopathological features were consistent with PMT mixed connective tissue variant. Two atypical patients were seen. The longest follow-up was for 5 years and there was no evidence of recurrence during the follow-up period in any patient.

CONCLUSION

Diagnosis of PMT of the paranasal sinuses causing oncogenous osteomalacia requires a high index of suspicion when there are no ENT symptoms. Appropriate biochemical tests and histopathology lead to the correct diagnosis. Total endoscopic surgical excision leads to a good outcome.

SPINE METASTASIS OF INTRACRANIAL HEMANGIOPERICYTOMA: CASE REPORT OF TWO TREATMENTS

Objective:

To report the use of two techniques (radiosurgery and en bloc vertebrectomy) on the same patient for the treatment of two metastases in different sites of the spine arising from intracranial hemangiopericytoma. Intracranial hemangiopericytomas are rare, comprising approximately 2.4% of meningeal tumors and <1% of all tumors of the central nervous system. Metastases to the spine are even rarer: The largest case series reported in the literature has 5 and 7 cases.

Methods:

A 37-year-old man diagnosed with intracranial hemangiopericytoma was referred for a metastatic lesion in T12 and underwent en bloc resection using the Tomita technique.

Results:

The disease evolved with a metastasis to T2 treated by radiosurgery with 1600 cGy. The patient died 1,706 days after the en bloc resection of T12 and 1324 days after the radiosurgery of T2, and no recurrence occurred in these locations due to progression of the systemic diseases (liver and central nervous system).

Conclusion:

This is the first case reported in the literature in which two different techniques were used to treat metastatic lesions in the spine from an intracranial hemangiopericytoma and is unique for its use of two treatments in the same patient. Level of evidence: V, case report

Renal solitary fibrous tumor/hemangiopericytoma: computed tomography findings and clinicopathologic features

PURPOSE

To retrospectively characterize the clinical, pathological, and computed tomography (CT) findings of renal solitary fibrous tumor/hemangiopericytoma (rSFT/HPC).

METHODS

Twelve patients with rSFT/HPCs were enrolled. The CT findings and clinicopathological features were retrospectively reviewed.

RESULTS

This study included six male and six female patients (median age: 47; age range: 20-82 years). Eight benign (grade I) and four malignant (grade III) rSFT/HPCs were identified. Of the 12 lesions, 10 were in the renal sinus near the renal pelvis, while two replaced the whole kidney. Five lesions were well-defined, five were partially ill-defined, and two were ill-defined. Mild (5/12) and intermediate (1/12) hydronephrosis was observed. On the unenhanced CT images, ten tumors showed slightly higher density when compared to the normal renal parenchyma, and two masses were isodense to hypodense. After intravenous contrast medium injection, three enhancement patterns were observed, including "prolonged enhancement" (PE) (6/12), "gradual enhancement" (4/12), and "early washout" (2/12). A central fibrous scar was found in five patients. Compared to the grade I lesions, the grade III rSFT/HPC lesions tended to be larger (maximal diameter > 10 cm) and more heterogeneous with a higher incidence of the PE pattern.

CONCLUSIONS

We have shown that rSFT/HPCs usually arise from the renal sinus, and present as lobulated, slightly hyperdense, gradually enhancing soft tissue masses. CT findings, including large size, heterogeneity, and the PE pattern, may assist in the pre-operative identification of malignant grade III rSFT/HPCs.

Whole-tumor histogram analysis of apparent diffusion coefficient in differentiating intracranial solitary fibrous tumor/hemangiopericytoma from angiomatous meningioma

PURPOSE

To assess the role of histogram analysis of apparent diffusion coefficient (ADC) maps based on whole-tumor in differentiating intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) from angiomatous meningioma (AM).

MATERIALS AND METHODS

Pathologically confirmed intracranial SFT/HPC (n = 15) and AM (n = 20) were retrospectively collected and their clinical and conventional MRI features were analyzed. Diffusion-weighted (DW) images (b = 0 and 1000 s/mm²) were processed with the mono-exponential model. Regions of interest covering the whole tumor were drawn on all slices of the ADC maps to obtain histogram parameters, including mean ADC (ADCmean), median ADC (ADCmedian), maximum ADC (ADCmax), minimum ADC (ADCmin), skewness and kurtosis, as well as the 5th, 10th, 25th, 75th, 90th and 95th percentile ADC (ADC5, ADC10, ADC25, ADC75, ADC90 and ADC95). Differences of histogram parameters between SFT/HPC and AM were compared using Mann-Whitney U test. Receiver operating characteristic (ROC) curve was used to determine the diagnostic performance.

RESULTS

The ADCmin (P = 0.001) and ADC5 (P = 0.045) were significantly lower in SFT/HPCs than in AMs, while no significant difference was found in sex, age, conventional MRI features or any other histogram parameters between the two entities (P = 0.051-1.000). ADCmin showed the best diagnostic performance (area under curve [AUC], 0.86; sensitivity, 81.3%; specificity, 83.3%) in differentiating SFT/HPC from AM with optimal cutoff value being 569.00 × 10^-6  mm²/s, followed by ADC5 (AUC, 0.72; sensitivity, 68.8%; specificity, 75%) with optimal cutoff value being 781.97 × 10^-6  mm²/s.

CONCLUSION

SFT/HPC and AM share similar conventional MR appearances. Whole-tumor histogram analysis of ADC maps may be a useful tool for differential diagnosis, with ADCmin and ADC5 being potential parameters.

Rare Occurrence of an Intraocular Choroidal Solitary Fibrous Tumor/Hemangiopericytoma

Purpose

Tumors previously diagnosed as solitary fibrous tumors (SFT) and hemangiopericytomas (HPC) are characterized by the NAB2-STAT6 fusion gene, leading to nuclear STAT6 expression, and are now considered part of one SFT/HPC tumor entity by the 2016 World Health Organization Classification of Tumors of the Central Nervous System. We present the first primary choroidal SFT/HPC with the diagnosis confirmed by STAT6 expression.

Procedures

A 51-year-old man underwent enucleation for a choroidal mass, which revealed a spindle cell neoplasm involving the optic nerve, without extrascleral extension. Immunohistochemical stains for S-100, melan-A, tyrosinase, and HMB45 were all negative; however, detection of monosomy 3 by FISH favored a choroidal spindle cell melanoma. Four years later, he presented with hepatic metastases of a spindle cell tumor, and a year later with an epithelioid malignancy involving the calvarium.

Results

The calvarial tumor showed nuclear STAT6 immunoreactivity, supporting the diagnosis of SFT/HPC. Retrospectively, the choroidal and hepatic masses were also found to demonstrate nuclear STAT6 expression, supporting the diagnosis of a primary choroidal SFT/HPC with metachronous metastases to the liver and calvarium.

Conclusions

This case highlights the significance of considering SFT/HPC in the diagnosis of intraocular spindle cell tumors and the importance of STAT6 immunohistochemistry in the evaluation of such tumors.

Recurrent Sinonasal CD34-Negative Malignant Solitary Fibrous Tumor Diagnosed on STAT6 Immunohistochemistry and NAB2-STAT6 Fusion

A spectrum of mesenchymal neoplasms occur in the sinonasal region. One of these is solitary fibrous tumor (SFT), a translocation-associated neoplasm characterized by NAB2-STAT6 gene fusion. Sinonasal SFTs characteristically display CD34 immunopositivity, which aids in diagnosis. However, a small proportion of SFTs may be negative for CD34, making diagnosis difficult. The availability of STAT6 immunohistochemistry (IHC) has helped to overcome this. Malignant SFTs, characterized by increased cellularity and mitoses > 4 per ten high power fields, are extremely unusual in the sinonasal region, with only ten such cases reported to date. We report a case of a CD34-negative malignant SFT that was diagnosed using STAT6 IHC and confirmed by demonstrating NAB2 ex 4-STAT6 ex 2 fusion, and recurred 8 months after complete excision, to highlight the aggressive nature of this tumor.

Lipomatous hemangiopericytoma of the corpus spongiosum: a case report and review of the literature

BACKGROUND

Hemangiopericytoma (HPC) is an uncommon soft tissue tumor arising from pericytes. The urogenital system is rarely affected.

METHODS

The review of the literature used the PubMed database which was searched up to March 2015.

RESULTS

Herein, we report the first case of lipomatous HPC of the corpus spongiosum in a 37-year-old man in China. The lesion presented as a quickly growing mass. Contrast enhanced CT showed a heterogeneous fatty mass with a multifocal enhancing soft-tissue component. Microscopically, the neoplasm was composed of spindle cells, a mature fat component and collagenous stroma. The mitotic index was low at 1 to 3 mitoses per 10 high-power fields. Immunohistochemically, STAT6, Bcl-2, CD99 and CDK4 were positive; CD34 and SMA were negative. The mature adipocytes were positive for S-100. Ki-67 expression was found in approximately 5% of the tumor cells. Surprisingly, there was a diffuse and strong nuclear expression of MDM2, but, no amplification of MDM2 was demonstrated by FISH. An adequate excision of the tumor was performed.

CONCLUSION

No local recurrence or distant metastases occurred during the 18-month follow-up. In view of the unpredictable biological behavior of this tumor, a long follow-up period is mandatory.

Primary Intraparenchymal Central Nervous System Solitary Fibrous Tumor/Hemangiopericytoma Presenting with Intracerebral Hemorrhage: A Case Report

A 53-year old man who had a left hemiparesis from head injury of traffic accident 20 years ago visited an emergency room with suddenly developed semi-comatose mental status. Brain CT showed 8.6-cm sized solid and cystic mass on right temporal lobe that was associated with hemorrhage. Solid lesion showed a strong enhancement after an administration of contrast media. Because of severe mass effect, emergency operation was performed. The mass was an intraparenchymal lesion with yellowish cystic fluid and the firm reddish-brown solid lesion was hemorrhagic. The lesion was totally resected. Pathologically, anaplastic solitary fibrous tumor/hemangiopericytoma was diagnosed with 70/10 high power fields. Postoperative radiotherapy of 50 Gy was done. Postoperative 2 months later, the patient was recovered to alert mental state. We report this unusual case of non-dural based intraparenchymal solitary fibrous tumor/hemangiopericytoma with high mitotic index and acute massive hemorrhage. Rapid tumor growth of hypervascular tumor might have a chance of bleeding.

Activity of axitinib in progressive advanced solitary fibrous tumour: Results from an exploratory, investigator-driven phase 2 clinical study

BACKGROUND

To explore the activity of axitinib in advanced solitary fibrous tumour (SFT).

PATIENTS AND METHODS

In this investigator-driven phase II study on axitinib in advanced and progressive SFT, patients received axitinib, 5 mg bis in day (BID), until progression or limiting toxicity. Pathologic diagnosis was centrally reviewed, distinguishing malignant SFT (M-SFT) and high-grade/dedifferentiated SFT (HG/D-SFT) subtypes. The primary end-point was the overall response rate (ORR) by Choi criteria (Choi). Secondary end-points were response by Response Evaluation Criteria in Solid Tumours (RECIST), progression-free survival (PFS) and overall survival (OS).

RESULTS

From April 2015 and October 2017, 17 eligible patients entered the study (metastatic: 17; SFT subtype: 13 M-SFT, 4 HG/D-SFT; prior treatment: 9 antiangiogenics, 5 cytotoxics). All patients were evaluable for response. The best Choi response was seven partial response (PR) (ORR, 41.2%), six stable disease (SD) and four progressions. Choi-ORR was 54% (7/13) when only M-SFTs were considered. Four of seven responsive patients were pretreated with pazopanib. No responses were detected in HG/D-SFT. Best RECIST response was one PR (5.9%), 14 SD and two progressions. Toxicity was as expected. Median Choi-PFS was 5.1 (interquartile range [IQR]: 2.5-14.8) months. Median Choi-PFS was 14.8 (IQR: 5.1-18.0) and 2.8 (IQR: 2.0-5.9) months for patients responsive and non-responsive by Choi, respectively (p = 0.0416). At a 14.4-month median follow-up, median OS was 25.3 months.

CONCLUSION

This study showed that axitinib is active in progressive advanced SFT. One-half of patients carrying the malignant variant of the disease responded, with a >12-month median progression arrest. Responses were better detected with Choi and seen even in patients resistant to other antiangiogenics. Tolerability was good.

Solitary fibrous tumor of central nervous system masquerading as meninigioma: Report of a rare case

INTRODUCTION

Solitary fibrous tumor (SFT) is a rare neoplasm of mesenchymal origin that occurs most often in the visceral pleura. It rarely occurs in the central nervous system (CNS). If they occur intracranially, they are extra-axially located and develop from the meninges.

CASE REPORT

Herein, we present a case of SFT in a 45 years old female. MR imaging showed isointense to hypointense signal intensity, and marked enhancement. Microscopically, the tumors showed characteristic "patternless-pattern" architecture. Elongated tumor cells formed fascicles alternating with hypocellular densely collagenous stroma. Immunohistochemistry for STAT6, CD34, BCL2 and CD99 favours the definitive diagnosis of SFT.

CONCLUSION

In general, complete surgical resection may offer the best chance of a favourable clinical outcome. Their biological features remain largely unknown. Hence, the clinical management and prognosis is often challenging due to the lack of comprehensive data.

A Case Report of Meningeal Hemangiopericytoma: A 9-Year Journey from the Brain to the Spine

BACKGROUND

Hemangiopericytomas (HPCs) are rare and aggressive vascular mesenchymal tumors. Unlike meningiomas, which have a similar radiologic appearance, these tumors have a higher risk of local recurrence after resection, and distant metastasis can reach up to 23%. Metastases to the vertebral bones from an intracranial HPC are very rare, with so far only 9 cases reported in the literature.

CASE DESCRIPTION

We present the case of a 46-year-old man who was surgically treated for a presumed left parieto-occipital falx meningioma in 2008. He presented 9 years later with a thoracic vertebral mass that was causing relentless pain. Reexamination of the cranial pathology allowed correction of the diagnosis performed in 2008 to a meningeal HPC, and the spinal lesion was confirmed after surgery to be a metastatic tumor.

CONCLUSIONS

The literature lacks randomized controlled trials and large studies defining the natural history of HPC to draw clear recommendations for a precise management of the disease. However, en bloc resection followed by radiation therapy seems to provide the optimal treatment for a long disease-free survival.

Very rare localization of a retroperitoneal hemangiopericytoma revealed by lumbosciatalgia: A case report

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Hemangiopericytoma is a rare vascular tumor representing about 1% of all vascular tumors and approximatively 5% of all soft tissues sarcomas.

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Retroperitoneal hemangiopericytoma is a rare location.

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The radiologic feature suggests the diagnosis but the pathologic findings associated to immune histochemistery remain the only tool to confirm the diagnosis.

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Surgical excision is the most preferred treatment as it helps in relieving the symptoms as well as confirm the diagnosis.

Introduction: Hemangiopericytoma is a rare vascular tumor representing about 1% of all vascular tumors and approximatively 5% of all soft tissues sarcomas that arises from the pericytes of Zimmerman surrounding capillaries and postcapillaries vessels. Retroperitoneal hemangiopericytomas are rare among the localisations as it usually occurs in lower and upper extremities.

Presentation of case: We present a case of 31-year-old man with a well-defined retro peritoneal mass measuring about 105 × 73 × 83 mm at right lower quadrant of the abdomen anterior to right psoas muscle. Intraoperatively, an large mass measuring 10 × 8 cm was found arising from the retro peritoneum. A monobloc excision was performed. The postoperative course was uneventful. Histopathological examination with immune histochemistry revealed that tumoral cells were positive for desmin, CD34, smooth muscular antigen. Final diagnosis of hemangiopericytoma was made. On the last follow up at one year, he was symptom free.

Discussion: Hemangiopericytoma is a rare tumor. It takes origin from pericytes presenting as intervals along the walls of capillaries and post-capillary venules. Retroperitoneal hemangiopericytoma is a rare location. It is often discovered at late course, and can be revealed by various symptoms with the compression of the adjacent organs by the tumor Surgical resection should be considered in symptomatic cases or in case of diagnostic dilemma.

Conclusion: Retroperitoneal hemangiopericytoma can be benign but it should be treated the same way as aggressive tumors. It requires a careful and long term follow up.

Primary epidural hemangiopericytoma of the thoracic spine: Case report and literature review

Hemangiopericytoma (HPC) is a rare tumor originating from pericapillary cells. Rarely found in the central nervous system, it is extremely rare in the spinal canal. Because of the low incidence of this tumor, its radiographic features and clinical manifestations have not been extensively studied and reported, therefore, it is often misdiagnosed as a schwannoma or spinal meningioma. We describe an unexpected HPC in a 35-year-old woman who was admitted to the Peking Union Medical College Hospital with a severe backache, sensory abnormalities, and muscle weakness. Magnetic resonance imaging showed an enhancing lesion at T6-7 with severe compression of the spinal cord. Gross total resection was achieved, and subsequently, a marked neurologic improvement was observed. The diagnosis of primary extradural HPC in our patient was confirmed based on postoperative histopathology and immunohistochemistry. Neither recurrence nor metastasis of the tumor was found during the 14-month follow-up, which did not include radiotherapy. To describe the demography, radiologic features, treatment, and prognosis of spinal HPC, a comprehensive literature review was performed and 105 cases of primary spinal HPC from 1958 to 2017 were collected from 39 articles. Although rare, HPC should be considered in the differential diagnosis of intraspinal lesions. Immunohistologic examination is of decisive importance in making the diagnosis. Adequate surgical resection, when feasible, is the first choice of treatment for all cases of HPC; however, the outcomes of radiotherapy and chemotherapy have yet to be determined. Individualized treatment combined with long-term follow-up for each patient is recommended.

Metastatic craniocervical hemangiopericytoma presenting with hydrocephalus and papilledema - Case review

Hemangiopericytomas are rare mesenchymal tumors with propensity to recur locally and metastasize. We report the unique case of a fifty-five-year-old male with recurrence of a previously resected craniocervical hemangiopericytoma presenting with obstructive hydrocephalus secondary to new metastatic cerebellar deposits. Emergent surgical resection of the cerebellar hemangiopericytomas was performed prior to adjuvant radiotherapy. Hemangiopericytomas are rare but important differentials for craniocervical junction lesions. Gross total resection remains the cornerstone of management with post-operative radiotherapy and chemotherapy as potential adjuncts. Tumors located in deep regions pose complex management challenges as safe maximal excision may be limited by proximal eloquent structures.

The radiation therapy options of intracranial hemangiopericytoma: An overview and update on a rare vascular mesenchymal tumor

Hemangiopericytoma (HPC) is an extremely rare hypervascular tumor of mesenchymal lineage. It tends to recur and to develop distant metastases even many years after primary surgical resection. The management of recurrent and metastatic disease is not always so well defined. A complete surgical resection does not eliminate the high risk of local recurrences that occur in the central nervous system, often in the same surgical bed. However, treatment with adjuvant radiotherapy even in cases of complete resection remains controversial. Because of its rarity, there is no standard for treatment. We focused on radiotherapy treatment options, analyzing the literature and making a base on conduct further studies to establish the standard radiation dose to be used for locoregional control of such a complex and extremely rare disease and to help specialists to take the most appropriate therapeutic option.

Unusual occurrence of orbital hemangiopericytoma in the zygomatic bone of an adolescent: a case report

Background

Hemangiopericytoma and solitary fibrous tumor are considered related variants on the same spectrum and both may essentially be the same tumor. They are infrequently encountered in the orbital region while the zygomatic bone is an extremely rare location for these neoplasms to occur.

Case presentation

A 14-year-old boy presented with complaint of deformity of left infraorbital area and a firm, regular mass in the region. Orbital CT scan revealed a well-defined round isodense intraosseous lesion in the lowermost portion of the lateral orbital wall (zygomatic bone), expanding the bone and protruding anteriorly and medially. MRI showed the mass to be heterogenous and strongly enhancing with contrast medium. Inferior transconjunctival orbitotomy was performed and the mass was removed. The histopathologic examination and immunohistochemistry staining results (positive for CD34, CD31 and smooth muscle actin, but negative for CD99, S100, B-cell lymphoma 2 (bcl-2) and desmin) confirmed the diagnosis of hemangiopericytoma. The postoperative course was uneventful, with no evidence of recurrence after 5 years follow up.

Conclusions

This case represents the second hemangiopericytoma reported in the zygomatic bone. Although extremely rare, hemangiopericytoma/solitary fibrous tumor might be considered in the differential diagnosis of intraosseous lesions of the orbital and zygomatic region.

Metastatic cervical paravertebral solitary fibrous tumor detected by fluorodeoxyglucose positron emission tomography-computed tomography

Solitary fibrous tumors/hemangiopericytomas (SFT/HPC) are soft tissue tumors that can arise from the abdomen, pleura, head and neck, or extremities. We report an unusual case of recurrent hemangiopericytoma in a 67-year-old female presenting with a painless and palpable mass within her right posterior neck. Eight years after initial resection of the mass, a follow-up MRI showed multiple enlarging calvarial lesions. A whole body FDG-PET/CT revealed not only hypermetabolic calvarial lesions but also numerous hypermetabolic axillary node and osseous metastases. Though the majority of these soft tissue tumors exhibit benign behavior and carry a favorable prognosis, patients with these slow growing tumors are at risk for local recurrence and distant metastases which demonstrate substantial FDG avidity. Additional studies are needed to clarify the role of whole body FDG-PET/CT in the surveillance of SFT/HPC to detect recurrent or metastatic lesions.

Extrapleural solitary fibrous tumor: A distinct entity from pleural solitary fibrous tumor. An update on clinical, molecular and diagnostic features

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that was originally described to be localized in the pleura, but thereafter, this has been reported in several anatomic sites. Although the etiology of the neoplasm remains largely unknown, the pathogenesis seems to be related to an NAB2-STAT6 fusion gene due to paracentric inversion on chromosome 12q13. The diagnosis of extrapleural SFT is challenging, owing to its rarity, and requires an integrated approach that includes specific clinical, histological, immunohistochemical, and even molecular findings. Histologically, extrapleural SFT shares morphological features same as those of the pleural SFT because it is characterized by a patternless distribution of both oval- and spindle-shaped cells in a variable collagen stroma. In addition, morphological variants of mixoid, fat-forming, and giant cell-rich tumors are described. A correct diagnosis is mandatory for a proper therapy and management of the patients with extrapleural SFT, as extrapleural SFT is usually more aggressive than pleural form, particularly cases occurring in the mediastinum, retroperitoneum, pelvis, and meninges. Although SFT is usually considered as a clinically indolent neoplasm, the prognosis is substantially unpredictable and only partially related to morphological features. In this context, cellularity, neoplastic borders, cellular atypias, and mitotic activity can show a wide range of variability. We review extrapleural SFT by discussing diagnostic clues, differential diagnosis, recent molecular findings, and prognostic factors.

Efficacy and Safety of Pazopanib for Recurrent or Metastatic Solitary Fibrous Tumor

OBJECTIVE

To investigate the efficacy and safety of pazopanib for recurrent or metastatic solitary fibrous tumor (SFT) in first- and second-line settings.

METHODS

Patients histologically diagnosed with SFT at our hospital who received pazopanib monotherapy for inoperable disease between January 2013 and November 2016 were eligible. We retrospectively investigated treatment outcomes according to the treatment lines and assessed adverse events.

RESULTS

Nine patients were eligible. The median age was 67 years (range 42-81), and 6 patients (66.7%) were male. Four patients (50%) received pazopanib as second-line treatment. According to the RECIST and Choi criteria, the respective response rates were 0 and 50%, while the respective disease control rates were 88.9 and 75%. The median progression-free survival (PFS) was 6.2 months (95% confidence interval 3.2-8.8). Treatment line and high frequency of mitosis were not predictive of PFS (p = 0.67, 0.92). Two patients (22.2%) experienced elevated liver enzymes of grade 3 or higher.

CONCLUSION

Pazopanib is an effective treatment option for recurrent or metastatic SFT in first- and second-line settings. Liver injury is a major adverse event and adequate treatment withdrawal and dose reduction should be considered when necessary.

Surveillance for metastatic hemangiopericytoma-solitary fibrous tumors-systematic literature review on incidence, predictors and diagnosis of extra-cranial disease

BACKGROUND

Intracranial hemangiopericytomas (HPC) and solitary fibrous tumors (SFTs) (HPC-SFT) are rare vascular tumors that resemble meningioma on imaging and predominantly affect young adults. HPC-SFT have a high rate of local recurrence with well-known propensity for extracranial metastases. This provides clinical dilemmas frequently encountered in oncology: (i) How should these patients be monitored long term? (ii) Which primary tumors are more likely to metastasize?

OBJECTIVES

This systematic review aims to identify the incidence, common locations and time to presentation of extra-cranial metastases of HPC-SFT. We will assess the effect of primary tumor location, treatment, grade, patient age, gender and effect of local recurrence on rates of extra-cranial metastasis and discuss the ideal techniques by which patients with intracranial HPC-SFT should be monitored for extra-cranial metastases.

METHODS

Using PRISMA guidelines the authors searched Pubmed. Search terms included hemangiopericytoma, HPC, solitary fibrous tumor/ tumour, SFT, HPC-SFT, extra-cranial metastases, metastases, recurrence, monitoring, follow-up. Studies were identified up to 1st February 2018. Reference lists of identified articles were reviewed to detect other relevant citations. Data were extracted using a standard data collection form and results organized into (i) general study/patient characteristics, (ii) location of extra-cranial metastases, (iii) methods by which metastases were detected and followed up and (iv) characteristics of primary tumors.

RESULTS

Seventy-one studies were identified. Mean recorded follow up ranged from 4 to 312 months. Mean age at diagnosis was 42.0 years. The overall rate of extra-cranial metastasis was 28% (n = 251/904). The minimum time to extracranial metastases was 3 months and the maximum time was 372 months. In the 71 studies identified, where site of extra-cranial metastasis was specified, there were 347 metastases in 213 patients. The most common sites for metastases were bone (location not specified) (19.6%) followed by lung and pleura (18.4%), liver (17.6%), and vertebrae (14.1%). Extra-cranial metastatic disease is typically diagnosed following symptomatic presentation. There is little documentation of methods used to monitor patients with extra-cranial HPC-SFT and no clear surveillance paradigm observed. Higher primary tumor grade (WHO Grade III) was associated with a 1.88 (p = 0.016) increased risk of extra-cranial metastasis. Location and treatment of primary tumor, local recurrence, patient age and gender were not.

CONCLUSION

Patients with intracranial HPC-SFT require periodic, long term monitoring for extra-cranial metastases. Metastases occur in any age group and can occur early and late. They vary in location and are typically diagnosed following symptomatic presentation. There is no suggested imaging modality for surveillance. Higher grade primary tumors have a greater risk of metastasis. Regular clinical review is essential with early imaging for symptoms of recurrence/metastasis with imaging modality dependent on clinical concern. Quality evidence for an imaging surveillance protocol in this heterogeneous group of patients is lacking. A multicenter study on appropriate surveillance may be of benefit.

Solitary fibrous tumor of the ischioanal fossa-a multidisciplinary approach to management with radiologic-pathologic correlation

Solitary fibrous tumors are primary mesenchymal tumors, which may occur in any part of the body. Overall, these tumors are considered to have intermediate malignant potential with 5- and 10-year metastasis-free and overall disease-specific survival rates of 74% and 55%, and 89% and 73%, respectively (Demicco et al, 2012). Herein we present an unusual case of solitary fibrous tumors involving the ischioanal fossa in a 19-year-old woman with radiologic-pathologic correlation. This case was complicated by extensive tumor vascularity and was thus managed with preoperative embolization followed by en bloc surgical resection.

Intraoperative Transpedicular Onyx Injection to Reduce Vascularity of a Thoracic Hemangiopericytoma After Unsuccessful Preoperative Endovascular Embolization: a Technical Report

BACKGROUND AND IMPORTANCE

Hemangiopericytoma is a rare vascular tumor with central nervous system involvement representing only 1% of central nervous system tumors. They rarely affect the vertebral column. Complete surgical resection is the treatment of choice for hemangiopericytoma given their high rates of local recurrence. However, the high vascularity of such tumors with the risk of massive bleeding during surgery represents a significant challenge to surgeons. Therefore, preoperative endovascular embolization via the transarterial route has been advocated.

CLINICAL PRESENTATION

In the current study, we present a case of a T12 hemangiopericytoma that was managed by a 2-stage surgical resection, with the use of intraoperative transpedicular onyx injection to reduce intraoperative blood loss following an unsuccessful trial of preoperative endovascular embolization.

CONCLUSION

Preoperative endovascular embolization is not feasible in some cases due to the location of the segmental or radiculomedullary arteries in relation to tumor feeders and, rarely, small size of these arterial feeders. Percutaneous injection of onyx is an option. In this case report, we discuss direct intraoperative injection via a transpedicular route as a safe and effective method for decreasing the vascularity of some lesions and improving intraoperative blood loss.