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.

Value of SSTR2A and Claudin - 1 in Differentiating Meningioma from Schwannoma and Hemangiopericytoma

BACKGROUND:

The distinction between meningioma, schwannoma and solitary fibrous tumour/ hemangiopericytoma can be challenging in some cases. This study evaluates the expression of Somatostatin receptor 2A (SSTR2A) and Claudin-1 in these different tumours.

MATERIAL AND METHODS:

Thirty-five cases of meningioma, 10 cases of intracranial schwannoma and 10 cases of hemangiopericytoma were assessed. The immunohistochemical expression of SSTR2A and Claudin-1 was evaluated and scored according to the percentage of immunostained tumour cells (0: 1+, 2+ and 3). The intensity of staining was classified as weak, moderate and strong.

RESULTS:

Positivity for SSTR2A and Claudin-1 was encountered in 89% and 49% of meningiomas respectively. None of the schwannomas or hemangiopericytomas was positive for any of both markers. All grade I and II meningiomas were positive for SSTR2A, and only 20% of grade III showed positive staining (p < 0.05). Claudin-1 positivity was detected in 50%, 43% and 60% of grade I, II and III meningioma respectively, with significantly higher intensity in grade III (p < 0.05).

CONCLUSION:

SSTR2A is highly sensitive and specific for meningioma. Claudin-1 is highly specific for meningioma, with low sensitivity. The adjunctive use of both markers can be very helpful in the diagnosis of meningioma and its distinction from schwannoma and hemangiopericytoma.

Subcutaneous glucagon infusion and continuous glucose monitoring enable effective management of hypoglycemia in a patient with IGF-2-producing hemangiopericytoma

Background

Ectopic insulin-like growth factor (IGF)-2 production is a rare complication of an array of epithelial and mesenchymal tumors, and can clinically manifest as life-threatening hypoglycemia.

Case presentation

A 49-year-old woman with 13-year history of metastatic hemangiopericytoma, previously treated with multiple rounds of chemotherapy and palliative radiation, presented to the emergency department after a hypoglycemic seizure. On arrival, glucose was 18 mg/dL (1.0 mmol/L) and required continuous dextrose infusion for maintenance within normal limits. Insulin was <2.0 μU/mL, C-peptide 0.1 ng/mL, and beta-hydroxybutyrate <0.2 mmol/L. Random cortisol was 21 μg/dL; sulfonylurea screen, and insulin antibodies were negative. IGF-2 level was 1320 ng/mL; IGF-1 was within normal limits and IGF binding protein (BP)-3 suppressed. Dexamethasone, started at 6 mg twice daily, allowed discontinuation of the glucose infusion. Given concern for nocturnal hypoglycemia, and patient interest in steroid-sparing anti-hypoglycemic regimen, she was also started on overnight continuous subcutaneous glucagon infusion via insulin pump. She was discharged with instructions to maintain a diet high in complex carbohydrates during the day, while utilizing glucagon pump at night. She was also started on continuous glucose monitoring system (CGMS) with an alarm to warn of hypoglycemia. Glucagon infusion rate was later titrated based on CGMS readings. Abdominal CT revealed increasing size of a right upper quadrant mass not previously subjected to radiotherapy. After radiation to this area, hypoglycemia improved, allowing further glucagon titration. In parallel, IGF-2 level declined to 380 ng/mL.

Conclusions

Ectopic IGF-2 production is a rare but often fatal complication of many cancers, and should be considered on the differential diagnosis in patients with malignancy and unexplained hypoglycemia. Once hypoglycemia is diagnosed, patients often have end-stage disease. While treatment of the causative tumor is the only definitive intervention, anti-hypoglycemia therapy is a life-saving, temporizing measure. In this case, the patient attained euglycemia and survived 3 months after presentation before ultimately succumbing to other malignancy-related complications. Given efficacy in management of hypoglycemia while awaiting definitive tumor-directed therapy, we submit nighttime subcutaneous glucagon infusion and CGMS are valuable additions to the physician’s armamentarium in managing this condition.

Navigation-assisted endoscopic endonasal surgery of a glomangiopericytoma with intraorbital extension: A case report and literature review

A glomangiopericytoma, or sinonasal type hemangiopericytoma, is a rare lesion which accounts for <0.5% of all sinonasal tumors. The mainstay treatment is wide excision. Instead of traditional open surgical approaches, such as midfacial degloving or lateral rhinotomy, we offer a case of 21-year-old male with diagnosis of glomangiopericytoma with skull base and intraorbital invasion and received navigation-assisted endoscopic excision of a glomangiopericytoma.

[Solitary Fibrous Tumor of the Kidney]

A 59-year-old woman was referred to our hospital with the finding of an incidentaloma in her right kidney. Computed tomographyand magnetic resonance imaging showed a solid tumor, approximately8 cm in diameter, at the lower pole of the right kidney. Partial nephrectomy was performed without a renal vessel clamp. Histopathologically, fibroblast-like spindle cells were proliferating with rich collagenous fibers, and tumor cells were infiltrated into the renal parenchyma. The tumor cells were stained positive with CD34, CD99, and bcl-2. The tumor was diagnosed as solitaryfibrous tumor originating from the kidney based on these histopathological findings. The patient was followed 3 years after surgery with neither recurrence nor metastasis.

A Case of Glomangiopericytoma at the Nasal Septum

Glomangiopericytoma (GPC) is a rare sinonasal perivascular tumor that accounts for < 0.5-1% of all sinonasal tumors. GPC is categorized as a low-grade neoplasm with borderline malignancy and a tendency of local recurrence. GPC is a rare mesenchymal neoplasm characterized by the perivascular proliferation of tumor cells, and it requires being distinguished from solitary fibrous tumors. Here, we report a case of GPC in a 68-year-old male patient who presented at the emergency room of our hospital with a complaint of sudden epistaxis. A small, reddish, protruding tumor was observed on the right nasal septum. A biopsy revealed a possible perivascular tumor such as a GPC or solitary fibrous tumor. Thus, we performed complete resection with endoscopic surgery. The size of the resected tumor was 12 × 5 mm, and it showed a uniform proliferation of oval-to-short spindle-shaped cells with slightly branching vascular structures. The tumor cells showed minimal cytologic atypia and there were an average of 3 mitoses in 10 high power fields. Necrosis was not observed. The tumor cells showed strong and diffuse nuclear immunostaining with beta catenin and were negative with STAT6, CD34 and bcl-2. The MIB-1 labeling index was approximately 5%. Genetic testing revealed CTNNB1 mutation (p.S33C). Thus, a diagnosis of low grade GPC was made on the biopsy and the patient could be successfully treated with endoscopic resection.

Multiple Lipomatous Hemangiopericytomas in the Foot and Ankle

Since its first description, the diagnosis and terminology of hemangiopericytoma have been in controversy. We report perhaps the first case of multiple lipomatous hemangiopericytoma occurring in the foot and ankle region.

Urgent surgical management of congenital intracranial hemangiopericytoma in a preterm neonate

Hemangiopericytoma is a rare mesenchymal tumor originating from capillary pericytes, known as Zimmermann pericytes. The adult form is not uncommon and generally malignant but tumor is found rarely in children. Here we describe an intracranial hemangiopericytoma in a preterm newborn whose had the tumor resected successfully shortly after birth.

Long-Term Outcome and Prognostic Factors After Repeated Surgeries for Intracranial Hemangiopericytomas

OBJECTIVE

The goals of the present study were to identify predictors of better survival and to propose appropriate management strategies for recurrent hemangiopericytomas (HPC) and anaplastic hemangiopericytomas (AHPC).

METHODS

Between 2008 and 2016, 191 patients underwent surgeries for HPC and/or AHPC at our institute, and during follow-up the tumors recurred in 57 patients, including 31 males (54.4%).

RESULTS

At the first recurrence, 30 patients (52.6%) underwent surgery, 25 patients (43.9%) declined surgery, and 2 patients (3.5%) received Gamma Knife treatment. The 1-year, 3-year, and 5-year actuarial rates of second progression-free survival in the HPC group were 73.3%, 46.7%, and 24.9%, respectively; the rates in the AHPC group were 66.7%, 66.7%, and 0%, respectively. The actuarial 1-year, 3-year, and 5-year overall survival rates of HPC after the first recurrence were 87.4%, 69.2%, and 39.5%, respectively; in the AHPC group, the rates were 85.2%, 45.9%, and 24.5%, respectively. Each 1-month increase in the time interval from first surgery to first recurrence (first recurrence-free survival) (hazard ratio, 0.972; 95% confidence interval, 0.952-0.993; P = 0.010) was strongly associated with better overall survival. Patients who received surgery with or without radiation at their first recurrence survived longer than patients who did not (estimated median survival time, 53.0 months vs. 35.7 months; P = 0.028).

CONCLUSIONS

Treatment is imperative for the first recurrence of HPC or AHPC. More attention should be paid to patients with shorter first recurrence-free survival. Surgery is the first choice for their first recurrence and radiotherapy should be administered if there is no history of radiotherapy.

Rho kinase proteins display aberrant upregulation in vascular tumors and contribute to vascular tumor growth

BACKGROUND

The serine/threonine protein kinases ROCK1 and 2 are key RhoA-mediated regulators of cell shape and cytoskeletal dynamics. These proteins perform multiple functions in vascular endothelial cell physiology and are attractive targets for cancer therapy based on their roles as oncogenes and metastatic promoters. Given their critical functions in both of these processes, we hypothesized that molecular targeting of ROCK proteins would be exceedingly effective against vascular tumors such as hemangiomas and angiosarcomas, which are neoplasms composed of aberrant endothelial cells.

METHODS

In this study, we compared ROCK1 and 2 protein expression in a large panel of benign and malignant vascular tumors to that of normal vasculature. We then utilized shRNA technology to knockdown the expression of ROCK1 and 2 in SVR tumor-forming vascular cells, and evaluated tumor size and proliferation rate in a xenograft model. Finally, we employed proteomics and metabolomics to assess how knockdown of the ROCK paralogs induced alterations in protein expression/phosphorylation and metabolite concentrations in the xenograft tumors.

RESULTS

Our findings revealed that ROCK1 was overexpressed in malignant vascular tumors such as hemangioendotheliomas and angiosarcomas, and ROCK2 was overexpressed in both benign and malignant vascular tumors including hemangiomas, hemangioendotheliomas, hemangiopericytomas, and angiosarcomas. shRNA-mediated knockdown of ROCK2, but not ROCK1, in xenograft vascular tumors significantly reduced tumor size and proliferative index compared to control tumors. Proteomics and metabolomics analysis of the xenograft tumors revealed both overlapping as well as unique roles for the ROCK paralogs in regulating signal transduction and metabolite concentrations.

CONCLUSIONS

Collectively, these data indicate that ROCK proteins are overexpressed in diverse vascular tumors and suggest that specific targeting of ROCK2 proteins may show efficacy against malignant vascular tumors.

[Solitary fibrous tumor/hemangiopericytoma of central nervous system: a clinicopathologic analysis of 71 cases]

Objective: As solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) share the same molecular genetics features, the 2016 WHO classification of central nervous system (CNS) tumors had created the combined term SFT/HPC and assigns three grades. This study aims to investigate the clinicopathologic characteristics, diagnosis, differential diagnosis and prognosis of CNS SFT/HPC. Methods: Seventy-one cases of CNS SFT and HPC were retrospectively reclassified and studied. Histopathological, immunohistochemical and imaging features were analyzed. The follow-up data were analyzed. Results: There were 37 male and 34 female patients. The median age was 48 years (range, 3-77 years). Twelve cases (17%) were WHO grade Ⅰ, 26 (37%) were WHO grade Ⅱ and 33 (46%) were WHO grade Ⅲ. Microscopically the tumor could show traditional SFT phenotype, HPC phenotype or mixed phenotype. Immunochemically, 97%(69/71) were positive for STAT6, with 96%(66/69)showing diffuse strong staining. Approximately 90% were diffusely positive for bcl-2, CD99 and vimentin. The expression rate of CD34 decreased with increasing tumor grade, and the mean expression rate was 78%. SSTR2a was variably expressed in 10% (7/71) of cases including one case showing strong cytoplasmic staining. A few cases expressed EMA, CD57 and S-100 focally. The Ki-67 index ranged from 1% to 50%. Thirty four patients were followed up for 8-130 months; 12 patients(35%)had recurrences, and two (6%) had liver metastases. Conclusions: CNS SFT/HPC is relatively uncommon. There was significant morphological overlap or transition between different grades. STAT6 is a specific marker for the diagnosis of this tumor. Surgical resection is the preferred treatment. WHO grade Ⅱ and Ⅲ SFT/HPC show rates of local recurrence and systemic metastasis, with liver being the most common site of extracranial metastasis.

STAT6 Reliably Distinguishes Solitary Fibrous Tumors from Myofibromas

Solitary fibrous tumors (SFT) and myofibromas (MF) historically have belonged to the same morphologic spectrum and have been lumped together under the nonspecific umbrella term, "hemangiopericytoma" along with other pericytic/myoid tumors. While current evidence shows clear distinction between the two entities, they frequently remain in the same histopathologic differential diagnosis. This diagnostic dilemma especially is common for smaller incisional biopsies from the oral cavity. STAT6 immunohistochemistry (IHC) recently was established as a reliable method to detect solitary fibrous tumor; however, the literature is sparse regarding STAT6 reactivity in MFs. The authors report ten new cases of oral solitary fibrous tumor, discuss histopathologic similarities and differences between the two tumors, and list respective STAT6 IHC expressivity. After IRB approval, 10 cases diagnosed as SFT and 24 cases of MF were collected from the University of Florida Oral and Maxillofacial Pathology Biopsy Service between the years 1994 and 2016. The original hematoxylin and eosin slides and related IHC were reviewed. IHC with STAT6 antibody was performed on all 34 samples, and the findings were analyzed. All cases were from the oral cavity or perioral regions. 10/10 SFTs expressed STAT6 nuclear reactivity, while no cases of MF showed nuclear expression of STAT6. STAT6 is a dependable marker to differentiate SFTs from MFs.

Soft Tissue Tumors Rarely Presenting Primary in Bone; Diagnostic Pitfalls

Primary bone sarcomas represent extremely rare entities. The use of now abolished labels, such as malignant fibrous histiocytoma and hemangiopericytoma, has significantly hampered the chance of identifying specific entities. It is now accepted that a broad variety of mesenchymal malignancies most often arising on the soft tissue may actually present as primary bone lesions. A more accurate morphologic partition is justified based on availability of distinct therapeutic options. An integrated diagnostic approach represents the only way to achieve a correct classification. In consideration of the significant complexity, primary bone sarcomas should ideally be handled in the context of expert centers.

Metastatic intraocular hemangiopericytoma in a dog

A 10-year-old Labrador Retriever who had been undergoing therapy for a recurrent hemangiopericytoma of the right flank presented to the Kansas State University Ophthalmology service for evaluation of a painful left eye. Examination revealed secondary glaucoma and irreversible blindness of the affected eye and multifocal chorioretinal lesions in the fellow eye. Therapeutic and diagnostic enucleation of the left eye was performed and histopathologic examination demonstrated the presence of a presumed metastatic spindle cell sarcoma. Further immunohistochemical staining confirmed the intraocular neoplasia to be metastatic spread from the previously removed flank mass. Rapid progression in size and number of chorioretinal lesions in the right eye was noted in the post-operative period until the patient was euthanized one month after surgery. This case report is the first to document intraocular metastasis of hemangiopericytoma in a veterinary patient.

Extraparenchymal Lesions in Adults

This article reviews the most frequent extra-axial tumors of the central nervous system, from the most common meningioma to some uncommon conditions, like Rosai-Dorfman disease, focusing on imaging techniques, pearls, and pitfalls as well as a more practical approach.

Intraspinal dissemination of intracranial hemangiopericytoma: Case report and literature review

BACKGROUND

The authors report the case of a 53-year-old woman suffering from thoracic myelopathy caused by intraspinal dissemination of hemangiopericytoma. In literature, hemangiopericytoma is commonly found as an intracranial lesion, and often hematogenously metastasizes to the bone or liver; however, intradural spinal dissemination is extremely rare.

CASE DESCRIPTION

The patient presented with gait disturbance due to thoracic myelopathy 6 years after surgical treatment for intracranial hemangiopericytoma. Magnetic resonance imaging demonstrated intradural disseminated lesions compressing the spinal cord. Although the patient underwent resection of the intradural spinal tumor, the lesion was tightly adherent to the dorsal surface of the spinal cord. Therefore, it resulted in subtotal removal. Immediately after the surgery, symptoms related to the thoracic myelopathy resolved. The patient was free from disease progression for 14 months after whole spine radiotherapy.

CONCLUSION

Recognition of this type of progression is important in the clinical management of intracranial hemangiopericytoma because intradural spinal dissemination dramatically degrades neurological functions.

Hypervascular Lesions of the Cerebellopontine Angle: The Relevance of Angiography as a Diagnostic and Therapeutic Tool and the Role of Stereotactic Radiosurgery in Management. A Comprehensive Review

BACKGROUND

The cerebellopontine angle (CPA) is a narrowed skull base area containing important cranial nerves and vessels and bordering with eloquent areas of the posterior fossa. Tumors of the CPA are a heterogeneous group and can have extradural, intradural/extra-axial, or intra-axial origins. Their vascular supply changes depending on their anatomic origin. Symptomatic, large CPA tumors require surgical resection in order to prevent irreversible, severe neurological damages. However, its tight and strategical location make surgery in the CPA very challenging and require appropriate pre-surgical planning. Pre-surgical diagnosis is of great importance as it allows us to choose the optimal management for the particular patient. This is of further significance when encountering high-risk lesions such as hypervascular tumors. Neurosurgeons should utilize every available pre-surgical diagnostic modalities as well as neo-adjuvant treatments in order to reduce such risks.

METHODS

We review all reported cases of hypervascular lesions of the CPA and discuss the roles of angiography and stereotactic radiosurgery in their management.

RESULTS

Three lesions of the CPA can be considered as truly hypervascular: hemangioblastomas, hemangiopericytomas and paragangliomas. All lesions share many radiological features. However, each lesion has a different anatomical origin and hence, has a characteristic vascular supply. Pre-surgical angiography can be utilized as a diagnostic tool to narrow down the differential diagnosis of a vascular CPA lesion, based on the predominant supplying vessel. In addition, pre-surgical embolization at time of angiography will narrow the associated surgical risks.

CONCLUSIONS

Angiography is a crucial diagnostic and therapeutic tool, helping both in narrowing the presurgical differential diagnosis and in controlling intraoperative bleeding. Because of the high surgical risks associated with resection of vascular tumors in the CPA, noninvasive treatments, such as stereotactic radiosurgery, also may have a crucial role.

Liver metastasis of meningeal hemangiopericytoma: a study of 5 cases

Mesenchymal tumors in the liver, whether primary or metastatic, are rare. Meningeal hemangiopericytoma (HPC) is characteristically associated with delayed metastasis and the liver is one of the most common sites. Despite its consistent histological features, a pathological diagnosis of HPC in the liver is sometimes not straightforward due to its rarity and usually remote medical history of the primary meningeal tumor. In this report, the clinicopathological features of 5 cases of metastatic HPC to the liver were reviewed and described.

Metastatic extrapleural malignant solitary fibrous tumor presenting with hypoglycemia (Doege-Potter syndrome)

We report a rare case of metastatic malignant solitary fibrous tumor (SFT) that presented with hypoglycemia because of insulin growth factor-2 production. Initial workup included computed tomography imaging that revealed a large, partially necrotic liver mass, a hypervascular pancreatic head lesion, and 2 renal lesions. Following hepatic resection, pancreatic head resection and nephrectomy, all these lesions demonstrated pathological findings that were consistent with SFT. The patient also had a history of an intracranial mass that had been previously resected and treated with gamma knife therapy at an outside institution, which was found to also be SFT. Six months after initial pancreatic head resection, the patient developed a new lesion involving the pancreatic tail that was found to represent recurrent metastatic SFT. This case emphasizes the highly aggressive nature of extrapleural SFT, while rare, and the role of imaging in follow-up for disease recurrence.

Metastatic Intracranial Hemangiopericytoma to the Spinal Column: A Case Report

Intracranial hemangiopericytoma (HPC) is a rare brain tumor with aggressive biologic behavior associated with high recurrence rate and often with extracranial metastasis. The most common sites of extracranial metastasis of the intracranial HPC are the long bones, lung, liver and abdominal cavity in the order of frequencies. Extracranial metastases usually occur long after the initial diagnosis of the primary tumor. Metastatic intracranial HPC to the vertebra has been rarely reported. We present a case of intracranial HPC metastasized to the L2 vertebral body 13 years after multiple surgical resections and radiotherapy of the primary intracranial HPC.

Gamma knife radiosurgery for residual or recurrent intracranial hemangiopericytomas

Residual or recurrent hemangiopericytoma (HPC) has been treated with radiosurgery; however, its long-term outcome is not well known. This study is to investigate the long-term outcome of gamma knife radiosurgery (GKS) for residual or recurrent HPCs. We conducted a retrospective analysis of 18 patients who underwent gamma knife radiosurgery for residual or recurrent HPCs. Of the 18 patients, 10 patients had high-grade HPCs (27 tumors) and 8 had low-grade HPCs (13 tumors). Median overall survival (OS) after the first GKS was 134.7months and actuarial survival rate at 1, 5, and 10years was 85.6%, 85.6%, and 37.4%, respectively. At the last follow-up, local tumor control was achieved in 32 (80.0%) of the 40 GKS-treated tumors. New lesions developed out of initial GKS target in 8 patients (44.4%). They were also treated with additional GKS. The actuarial local control rate of 40 tumors at 1-, 3-, and 5-years was 89.3%, 60.9%, and 37.5%, respectively. The median local recurrence-free interval of 40 tumors after initial GKS for each lesion was 86.1months for low-grade and 40.5months for high-grade tumors (p=0.010). Extracranial metastases developed in 7 (38.9%) patients with high-grade pathology and became a cause of death in 3 patients. Intracranial tumor control can be achieved over the long term, though additional GKS is frequently necessary. Extracranial metastasis is common in HPC of high-grade pathology. Close surveillance and aggressive treatment is recommended not only for intracranial tumor but also for possible extracranial metastases.

Is a Solitary Fibrous Tumor in the External Auditory Canal Benign?

A solitary fibrous tumor (SFT) is an extremely rare, distinct otological soft-tissue tumor. Only two such tumors in the external auditory canal have been reported. A SFT related to hemangiopericytomas (HPC), which commonly arise in the central nervous system. HPCs act malignant in many cases, while SFTs at other sites are mainly benign. A 25-year-old female presented with highly vascular tumor at the right external auditory meatus and bleeding from the mass when a crust was removed from its surface. After excisional biopsy followed by pre-operative embolization, this tumor confirmed with SFT. The recurrence rate of SFT is very low after complete resection, with a slightly increased risk of recurrence with extrathoracic tumors. We describe the third case of SFT in the external auditory canal and review the literature.

Solitary fibrous tumour presenting with a single bone metastasis: report of six cases and literature review

Background

Solitary fibrous tumour (SFT) is a rare soft tissue sarcoma with a low metastatic potential. A higher metastatic rate is observed in the high-grade/dedifferentiated variant. The most common expected site of distant spread are the lungs and the liver. Bone involvement is generally viewed as a late stage of disease spread. We report on a retrospective series of SFT patients relapsing with a single distant bone recurrence as first metastatic event, without evidence of other organ involvement.

Case presentation

All patients affected by a single distant bone metastasis from SFT as first distant event, without any evidence of other site of metastasis, observed at our Institution, were considered. Bone involvement from SFT was pathologically assessed in all cases and confirmed by expert pathologists. A total of six patients were retrospectively identified. Primary tumour arose from the meninges in four patients, from soft tissues in two. Bone metastases were located to the vertebrae, the hip, the acetabulum and the rib. In all cases, bone relapse was the first event, with one patient presenting a local relapse. Median time from the primary tumour and the evidence of bone relapse was 40 months (range 0–58). In 2/6 patients bone metastasis was treated with radiotherapy (RT), in 2/6 with surgery, in 2/6 with surgery plus RT. At a median follow-up of 55 months (range 23–88), 5/6 patients are alive (2/5 without disease, 3/5 with multicentric metastatic disease) and one is dead of disease. 2/6 patients did not relapse after the treatment of the bone metastasis.

Conclusions

This small series in a relatively rare histology suggests that isolated, possibly late, bone metastases are a plausible scenario, in particular in meningeal SFT. Notably, new bone lesions in a patient with a history of SFT should be always investigated. Exclusive local treatments may be an option, though collection of such series would be needed to define the best treatment strategy.