Atypical and malignant solitary fibrous tumors in extrathoracic locations: evidence of their comparability to intra-thoracic tumors

Solitary fibrous tumor of the liver from development to resection

A 55-year-old man was annually followed up for a large hepatic cyst. In 2006, a 20-mm nodule was detected in contact with the cyst that gradually grew thereafter. By 2013, the mass had expanded to 90 mm, and a percutaneous biopsy revealed a solitary fibrous tumor (SFT). Surgical resection was subsequently performed, and the patient has since been doing well for 11 months, without recurrence. SFT of the liver is a rare neoplasm; only 44 cases have been reported to date. This is the first report to describe the long-term progression of hepatic SFT from the time of its development.

Intramedullary solitary fibrous tumor of cervicothoracic spinal cord

Solitary fibrous tumor is rare benign mesenchymal neoplasm. The spinal solitary fibrous tumor is extremely rare. The authors experienced a case of intramedullary solitary fibrous tumor of cervicothoracic spinal cord in a 48-year-old man with right lower extremity sensory disturbance. Spinal MRI showed intradural mass lesion in the level of C7-T1, the margin between the spinal cord and tumor was not clear on MRI. A Left unilateral laminectomy and mass removal was performed. Intra operative finding, the tumor boundary was unclear from spinal cord and it had intramedullary and extramedullary portion. After surgery, patient had good recovery and had uneventful prognosis. Follow up spinal MRI showed no recurrence of tumor.

Intraperitoneal solitary fibrous tumor

Solitary fibrous tumors of the pelvis are rare. We report the case of a 32-years-old patient who presented with abdominopelvic mass. The imaging studies showed a right adnexal mass of more than 10 cm. Exploratory laparotomy revealed a 20 cm mass at the Douglas pouch which was adhered to the posterior wall of the uterus. Complete resection of the mass was performed. Histological analysis showed a spindle cell undifferentiated tumor whose morphological and immunohistochemical profile are consistent with solitary fibrous tumor. It is important to know that although these tumors are rare, their evolution can be pejorative. Therefore, long-term followup should be recommended.

Nuclear relocation of STAT6 reliably predicts NAB2-STAT6 fusion for the diagnosis of solitary fibrous tumour

AIMS

Nuclear relocation of STAT6 has been shown in tumours with NAB2-STAT6 fusion, and has been proposed as an ancillary marker for the diagnosis of solitary fibrous tumours (SFTs). The aim of this study was to verify the utility of STAT6 immunohistology in diagnosing SFT.

METHODS AND RESULTS

A total of 689 formalin-fixed paraffin-embedded tumours comprising 35 pleural SFTs and 654 other mesenchymal tumours were investigated for STAT6 expression using immunohistochemistry. Nine dedifferentiated liposarcomas (DDLSs) and five SFTs were also examined for the presence of NAB2-STAT6 fusion at the protein level using the proximity ligation assay (PLA), and for copy number variants (CNVs) with the Illumina Infinium Human Methylation450 array. Thirty-four of 35 SFTs showed strong nuclear STAT6 expression. Furthermore, five of 68 DDLSs, two of 130 undifferentiated pleomorphic sarcomas and one of 63 cases of nodular fasciitis showed moderate to strong nuclear STAT6 expression. The PLA indicated the presence of NAB2-STAT6 fusion protein in SFTs, but signal was also detected in some DDLSs. Copy number analysis showed an overall low frequency of chromosomal imbalances in SFTs, but complex karyotypes in DDLSs, including amplification of STAT6 and MDM2 loci.

CONCLUSIONS

The detection of nuclear relocation of STAT6 with immunohistochemistry is a characteristic of SFTs, and may serve as a diagnostic marker that indicates NAB2-STAT6 fusion and helps to discriminate SFTs from histological mimics.

Recurrent solitary fibrous tumor in distal lower extremity: An extremely rare entity

Solitary fibrous tumor (SFT) represents a spectrum of mesenchymal tumors, encompassing tumors previously termed hemangiopericytoma, as having intermediate biological potential. Though they can occur at any site, lower distal extremity is a rare site and recurrence in it is extremely rare. Behavior of SFT is unpredictable. Histomorphology and clinical follow-up have poor correlation. The most important single indicator of clinical outcome is complete excision of the tumor at the time of primary presentation. Tumors with positive margins require close follow-up for several years owing to the potential for late local recurrence.

Concurrent Malignant Solitary Fibrous Tumor Arising from the Omentum and Grade 3 Endometrial Endometrioid Adenocarcinoma of the Uterus with p53 Immunoreactivity

A malignant solitary fibrous tumor arising from the omentum is extremely rare. To our knowledge, this is the first case of a malignant solitary fibrous omentum tumor coexisting with uterine corpus cancer. A 62-year-old woman presented to our hospital with vaginal discharge. Endometrioid adenocarcinoma was diagnosed by endometrial curettage. In addition, a solid tumor in front of the uterus was detected following computed tomography and/or magnetic resonance imaging, which was suspected to be a primary (or secondary) malignant tumor arising from the omentum. Hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and lymphadenectomy were performed. A malignant solitary fibrous tumor of the omentum and grade 3 endometrioid adenocarcinoma of the uterus were diagnosed by pathohistological analysis. Interestingly, the tumor cells were immunoreactive for p53. Adjuvant chemotherapy was administered for the uterine corpus cancer and the patient remains healthy 48 months after the surgery. These tumors may have become malignant due to the presence of p53 mutations.

STAT6 immunohistochemistry is helpful in the diagnosis of solitary fibrous tumors

Solitary fibrous tumor (SFT) is an uncommon fibroblastic neoplasm. Although histologic characteristics and frequent CD34 expression allow for an accurate diagnosis in the majority of SFT cases, a wide histologic spectrum and an occasional unexpected immunophenotype may pose diagnostic challenges. Molecular analyses have discovered that almost all SFTs harbor an NAB2-STAT6 fusion gene, which is considered specific to this tumor type. Recent studies have suggested that STAT6 immunohistochemistry is a reliable surrogate for detection of the fusion gene. Our aim was to validate these findings by examining a large number of SFT cases and a broad array of 30 different types of non-SFT tumors. A total of 49 SFTs with a range of histologic characteristics and 159 benign or malignant tumors that can mimic SFTs were retrieved and stained for STAT6. All 49 SFTs (100%) showed STAT6 expression that was restricted in the nucleus, mostly in a diffuse and strong manner, irrespective of the tumor sites and histologic patterns. The staining was uniform in most cases but was heterogenous in about 20% of the cases in which zonal staining attenuation was observed, likely reflecting variability in fixation or tissue ischemia. In contrast, only 4 non-SFT tumors (2.5%) exhibited weak nuclear STAT6 expression, whereas the remaining 155 cases showed no staining or often weak reactivity in both the cytoplasm and the nucleus. Therefore, nuclear STAT6 immunoreactivity is a highly sensitive and specific marker of SFTs and can be helpful when diagnosis is inconclusive by conventional methods.

Renal malignant solitary fibrous tumor with single lymph node involvement: report of unusual metastasis and review of the literature

Solitary fibrous tumors are rare mesenchymal spindle cell neoplasms that are usually found in the pleura. The kidneys are an uncommon site and only few cases of renal solitary fibrous tumor exhibit malignant behavior metastasizing to the liver, lung, and bone through the hematogenous pathway.

Solitary fibrous tumors in abdomen and pelvis: Imaging characteristics and radiologic-pathologic correlation

AIM: To describe the imaging features of solitary fibrous tumors (SFTs) in the abdomen and pelvis, and the clinical and pathologic correlations.

METHODS: Fifteen patients with pathologically confirmed SFTs in the abdomen and pelvis were retrospectively studied with imaging techniques by two radiologists in consensus. Patients underwent unenhanced and contrast-enhanced imaging, as follows: 3 with computed tomography (CT) and magnetic resonance imaging (MRI) examination, 8 with CT examination only, and 4 with MRI examination only. Image characteristics such as size, shape, margin, attenuation or intensity, and pattern of enhancement were analyzed and correlated with the microscopic findings identified from surgical specimens. In addition, patient demographics, presentation, and outcomes were recorded.

RESULTS: Of the 15 patients evaluated, local symptoms related to the mass were found in 11 cases at admission. The size of the mass ranged from 3.4 to 25.1 cm (mean, 11.5 cm). Nine cases were round or oval, 6 were lobulated, and 10 displaced adjacent organs. Unenhanced CT revealed a heterogeneous isodense mass in 7 cases, homogeneous isodense mass in 3 cases, and punctuated calcification in one case. On MRI, most of the lesions (6/7) were heterogeneous isointense and heterogeneous hyperintense on T1-weighted images and T2-weighted images, respectively. All tumors showed moderate to marked enhancement. Heterogeneous enhancement was revealed in 11 lesions, and 7 of these had cysts, necrosis, or hemorrhage. Early nonuniform enhancement with a radial area that proved to be a fibrous component was observed in 4 lesions, which showed progressive enhancement in the venous and delayed phase. No statistical difference in the imaging findings was observed between the histologically benign and malignant lesions. Three patients had local recurrence or metastasis at follow-up.

CONCLUSION: Abdominal and pelvic SFTs commonly appeared as large, solid, well-defined, hypervascular masses with variable degrees of necrosis or cystic change that often displaced adjacent structures.

Orbital solitary fibrous tumor: a case series with review of the literature

PURPOSE

To report the clinical features, patient demographics, management, and outcomes of a series of patients with orbital solitary fibrous tumors (OSFTs) and provide a review of the English literature describing this rare entity.

DESIGN

A review of patient demographics, clinical presentations, imaging, histopathology, surgical management, and outcomes were analyzed.

METHODS

A non-comparative retrospective chart review of the demographics, clinical presentations, imaging, histopathological features, management, and disease outcomes of patients presenting to a tertiary orbital center with a tissue diagnosis of OSFT between 2007-2012 was performed along with a review of the English-language literature.

RESULTS

Our study included four male patients, with a mean age of 48 years at referral. The most common presentations included a slowly growing mass, globe displacement, diplopia on extreme gazes, and/or facial disfiguration. All tumors were analyzed with histopathology and immunohistochemistry. Treatment involved the complete surgical excision of the lesion, obtaining clear margins. All patients remain alive and well with no evidence of recurrence after a minimum follow-up of 15 months (range 15 months-5 years).

CONCLUSION

SFTs should be considered when confronting a painless slowly growing orbital mass that induces globe displacement and/or facial deformity. Imaging will show a well-defined lesion that enhances with contrast. A careful initial surgical excision with clear margins is required for adequate local control of the tumor, avoiding recurrence and potential malignant transformation.

Clinicopathological findings in a case series of abdominopelvic solitary fibrous tumors

Solitary fibrous tumors (SFTs) represent a rare type of soft tissue tumor. Extrathoracic SFTs (ESFTs) in the soft tissues of the abdominopelvic cavity are extremely rare. Between January 2002 and January 2013, 10 patients were identified with abdominopelvic SFTs at the Northern Jiangsu People's Hospital. The clinicopathological data, treatment and follow-up results were retrospectively analyzed in this study. Patients included four females and six males, whose age ranged between 21 and 75 years (mean, 53.3 years). The maximum diameter of the tumors was 2.5-28 cm (mean, 12.7 cm). Two cases were diagnosed as malignant variants of ESFTs. R0 resection was performed in eight patients, while one patient underwent R1 resection, and one patient received palliative chemotherapy for an inoperable mass. Follow-up time ranged between 6 and 126 months (mean, 50 months). The patient with R1 resection suffered a local relapse, and the patient receiving palliative chemotherapy succumbed to the disease. The remaining eight patients remained free of disease. Abdominopelvic SFTs usually reveal an indolent process, although the majority of tumors in the present study were of giant size when diagnosed. The risk of local recurrence and metastasis correlates with tumor size and the histological status of surgical margins. The preferred treatment is complete resection followed by extended follow-up surveillance.

Solitary fibrous tumors/hemangiopericytomas with different variants of the NAB2-STAT6 gene fusion are characterized by specific histomorphology and distinct clinicopathological features

Recurrent somatic fusions of the two genes, NGFI-A-binding protein 2 (NAB2) and STAT6, located at chromosomal region 12q13, have been recently identified to be presumable tumor-initiating events in solitary fibrous tumors (SFT). Herein, we evaluated a cohort of 52 SFTs/hemangiopericytomas (HPCs) by whole-exome sequencing (one case) and multiplex RT-PCR (all 52 cases), and identified 12 different NAB2-STAT6 fusion variants in 48 cases (92%). All 52 cases showed strong and diffuse nuclear positivity for STAT6 by IHC. We categorized the fusion variants according to their potential functional effects within the predicted fusion protein and found strong correlations with relevant clinicopathological features. Tumors with the most common fusion variant, NAB2ex4-STAT6ex2/3, corresponded to classic pleuropulmonary SFTs with diffuse fibrosis and mostly benign behavior and occurred in older patients (median age, 69 years). In contrast, tumors with the second most common fusion variant, NAB2ex6-STAT6ex16/17, were found in much younger patients (median age, 47 years) and represented typical HPCs from deep soft tissue with a more aggressive phenotype and clinical behavior. In summary, these molecular genetic findings support the concept that classic pleuropulmonary SFT and deep-seated HPC are separate entities that share common features but correlate to different clinical outcome.

A huge malignant solitary fibrous tumor of kidney: case report and review of the literature

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1603694556107408.

Solitary fibrous tumor (SFT) is a spindle cell neoplasm that rarely occurs in the kidney. Malignant SFT of the kidney is particularly rare. Here, we report a 66-year old woman with a right flank mass that has been proved clinically and radiographically. Grossly, the largest diameter of the mass were measured up to 23 cm, was poorly circumscribed. Approximately 80% of the neoplasm consisted of hyperchromatic and pleomorphic spindled cells surrounding staghornlike blood vessels. Tumor cells frequently had mitoses and necrosis. However, the remainder of the mass was composed of haphazard, storiform or short fascicular arrangements of spindle cells in a loose myxoid to fibrous stroma. Immunohistochemically, we observed diffusely strong CD34 staining and an 85% Ki-67 proliferative index. The tumor partly showed negative CD34 and a 20% proliferative index. To our knowledge, this is the largest malignant renal SFT in the reported literatures and shows an obviously high proliferative index.

Malignant solitary fibrous tumor of the lumbar spinal root mimicking schwannoma: a case report

BACKGROUND CONTEXT

Malignant solitary fibrous tumors (SFTs) arising from the spinal cord are extremely rare and poorly understood mesenchymal neoplasms. To date, only one malignant SFT located in the spinal canal of the sacrum has been described, but none arising from the lumbar nerve root have been reported. Although most SFTs with benign histological features can be treated by complete surgical excision alone, malignant SFTs may require adjuvant therapy. However, systemic chemotherapy and radiotherapy have not been shown effective in patients with malignant SFTs.

PURPOSE

To describe a patient with a malignant SFT arising from the lumbar nerve root.

STUDY DESIGN

A case report and review of literature.

METHODS

We describe the clinical course of the patient and the radiological and pathological findings of the tumor. The effect of systemic chemotherapy was evaluated and the relevant literature was reviewed. This work has no disclosure of funding and was approved by the Institutional Review Board of Gifu University.

RESULTS

The tumor had been resected previously at another hospital, but it recurred and showed multiple metastatic lesions on both lungs within 3 months. Although the patient received systemic chemotherapy, both primary and metastatic lesions were found to be stable disease according to Response Evaluation Criteria in Solid Tumors. The patient died due to cachexia 6 months after her first visit.

CONCLUSION

This patient presented with a highly unusual tumor. Even if a tumor is a dumbbell-shaped mass, similar to a neural tumor, SFT should be considered in the differential diagnosis.

Intraorbital metastasis from solitary fibrous tumor

Solitary fibrous tumor (SFT) is a rare spindle cell tumor of mesenchymal origin that usually arises from pleura or pericardium but can also arise from many extraserosal sites. Although more than 50 cases of primary SFT of the orbit have been reported, there are no reports to date of a malignant nonophthalmic SFT metastasizing in the orbital soft tissues (although sphenoid wing bony involvement has been reported). The authors report here the first case of a patient with intraorbital metastasis of a CD34-positive malignant SFT. The patient was a 57-year-old man with a history of malignant pleural SFT and a prior kidney metastasis. He presented with the rapid appearance of proptosis and massive conjunctival chemosis preventing eyelid closure, and he was found to have a well-circumscribed metastasis to his lateral rectus muscle. Surgical excision cured his ocular symptoms, although he died 3 months later from brain and widespread metastases.

Primary solitary fibrous tumors of liver: a case report and literature review

A 42-year-old male presented right upper abdomen pain for more than 6 days, which misdiagnose calculus of intrahepatic duct and acute cholecystitis. An approximately 1.5 cm x 1.0 cm x 1.0 cm nodule was found and resected in left lateral lobe of hepatic. Pathological examination showed spindle cell and fibroblast -like cells within the collagenous stroma. Immunohistochemically, these spindle tumor cells showed diffuse Vim and Bcl-2 positive reactivity, but S-100 protein and HMB45 were negative. The post-operative course was uneventful. Solitary fibrous tumors of the liver, although rare, should be differentiated from mesenchymal lesions of the liver.

Loss of CD34 and high IGF2 are associated with malignant transformation in solitary fibrous tumors

The aim of this study was to characterize the subgroups of solitary fibrous tumor (SFT) and to investigate the expression of different biomarkers including CD34 and IGF2 in malignant transformation. Two hundred and ninety-four (294) SFTs from a single German consultation center of soft tissue tumors were categorized into the new proposal of SFT designation. We found the fibrous variant in 223 (75.9%), the cellular variant in 65 (22.1%), the fat forming variant in 4 (1.4%), and the giant cell-rich variant in 2 (0.6%) cases. Anatomical location, size, mitotic index, necrosis, cellularity, collagenous ropes, and growth pattern of the vessels were recorded. Criteria of malignancy were found in 68 (23%) tumors. Expression of IGF2, IGF1R, CD34, BCL2, CD99, SMA, S100, PanCK, and Ki67 was analyzed immunohistochemically. Low expression of CD34 and high expression of IGF2 were significantly associated with malignant transformation and the metastatic rate. Moreover the presence of necrosis showed the most significant p-value (p<0.004). Of all SFTs, the fibrous variant is the most common, followed by the cellular variant. The fat-forming and giant cell-rich variants are very rare. Low expression of CD34 and high expression of IGF2 are significantly associated with malignant transformation, and might be an interesting target of individualized therapy.

Large solitary fibrous tumour of the retroperitoneum: a case report and review of the literature

INTRODUCTION

This report describes an unusual case of a large solitary fibrous tumour (SFT) arising in the retroperitoneum.

CASE PRESENTATION

A 53-year-old woman presented at the Emergency Department with urinary retention and lumbar pain. The urological examination was negative, whereas a presacral retroperitoneal mass was disclosed on ultrasound. The laboratory studies, including tumour markers, were negative. On laparotomy, it was not possible to remove the mass completely due to the difficulty of dissecting it free of the sacrum. Grossly, the fragment had a yellowish-white surface, with areas of necrosis and haemorrhage. On immunohistochemistry, tumour cells were positive for CD34, CD99 and Bcl-2 and negative for CD45, synaptophysin, chromogranin, S100, neuron-specific enolase, CK AE1-AE3, CK7, Wilms' tumour 1, smooth muscle actin, factor VIII, myogenin, epithelial membrane antigen, thyroid transcription factor-1 and CD117, leading to a diagnosis of SFT. Molecular investigation ruled out synovial sarcoma.

CONCLUSION

Although SFT usually has a favourable prognosis, close follow-up is recommended due to the limited information on its long-term behaviour.

Solitary fibrous tumor of neck mimicking cold thyroid nodule in 99m tc thyroid scintigraphy

A 68-year-old man had a rapidly growing, painless neck mass, thought to be nodular goiter. Ultrasonography showed a giant, heterogeneous mass occupying the middle and superior poles and protruding outside of the left thyroid lobe. The results of the thyroid function tests were normal. Thyroid scintigraphy revealed a large hypoactive nodule in the left thyroid lobe. Complete surgical removal of tumor was performed and macroscopically demonstrated a well-demarked lesion outside the thyroid gland. Microscopically, the lesion was composed of fibroblast-like spindle cells in a patternless architecture and extensive stromal hyalinization. Immunohistochemistry showed positive reaction for CD34 in spindle cells and diffuse bcl-2 staining. The pathology was confirmed as solitary fibrous tumor. In the follow-up period after surgery, thyroid scintigraphy showed normal left thyroid lobe. Solitary fibrous tumor originated from or associated with thyroid gland is extremely rare. According to our knowledge, this is the first reported solitary fibrous tumor presenting like a cold thyroid nodule. This pathology must be considered for differential diagnosis of neck masses in the thyroid region.

Malignant solitary fibrous tumor of tandem lesions in the skull and spine

A Solitary Fibrous Tumor (Sft) Is A Rare Neoplasm Originated From The Pleura, But They Can Occur In A Variety Of Extrathoracic Regions. Although Many Cases Of Primary Sft Have Been Reported, There Are Extremely Rare Repots To Date Of A Malignant Sft In The Spine Or Skull. A 54-year-woman Visited Our Hospital Due To Low Back Pain And Both Leg Radiating Pain. Several Imaging Studies Including Magnetic Resonance Imaging And Computed Tomography Revealed Expansive Enhanced Lesions In The Occipital Bone, T8, S1-2, And Ilium, With Neural Tissue Compression. We Performed Surgical Resection Of The Tumor In Each Site, And Postoperative Radiosurgery And Chemotherapy Were Performed. However, After Six Months, Tumors Were Recurred And Metastasized In Multiple Regions Including Whole Spine And Lung. The Authors Report Here The First Case Of Patient With Malignant Sft Of Tandem Lesions In The Various Bony Structures, Including Skull, Thoracic Spine, And Sacral Spine, With A Rapid Recurrence And Metastasis. Although Malignant Sft Is Extremely Rare, It Should Be Considered In The Differential Diagnosis And Carful Follow-up Is Needed.

Prognosis of solitary fibrous tumors: a multicenter study

BACKGROUND

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors, and data regarding outcome and prognostic factors are scarce. We report the outcome and analysis of prognostic factors of a retrospective multicenter cohort study for patients treated for SFTs.

METHODS

Retrospective analysis was performed of patients treated for SFTs between 1995 and 2012. Clinical and histopathological features were analyzed for prognostic value. Endpoints were set at local recurrence, metastasis formation, or death. Survival was analyzed using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

A total of 81 patients underwent surgical resection of a SFT with curative intent. During follow-up, 21 patients developed distant metastases, while 18 patients developed local recurrence. The 5-year overall survival was 84 %. The local recurrence rate and the metastasis rate at 5 years were 29 and 34 %, respectively. Of all factors analyzed, positive resection margin significantly correlated with local recurrence [hazard ratio (HR) 4.8; 95 % confidence interval (95 % CI) 1.5-14.9]. Tumor size >10 cm (HR 4.4; 95 % CI 1.7-11.5) and high mitosis rate (HR 3.3; 95 % CI 1.06-10.3) significantly correlated with higher incidence of metastases. The combination of tumors >10 cm and high mitosis rate significantly correlated with higher incidence of metastases (HR 4.8; 95 % CI 1.4-16.2) and showed a trend toward worse overall survival (HR 5.7; 95 % CI 0.95-34.7).

CONCLUSIONS

A substantial portion of patients with a SFT developed local recurrence or metastases. Local recurrence is significantly higher in patients with positive resection margins; metastasis frequency is significantly higher in patients with tumors >10 cm and tumors with a high mitosis rate.

Extrathoracic location and "borderline" histology are associated with recurrence of solitary fibrous tumors after surgical resection

BACKGROUND

Most solitary fibrous tumors (SFTs) are cured by complete resection, but many recurrent and metastatic SFTs do not respond to treatment and are fatal. Malignant histology, defined by England's pathologic criteria, is strongly associated with recurrence, but some benign SFTs still behave aggressively. Several studies have suggested that extrathoracic SFTs have a worse prognosis. We reviewed thoracic and extrathoracic SFTs from our institution to determine if extrathoracic location is associated with recurrence, independent of malignant histology.

METHODS

With IRB approval, we retrieved patient pathology reports from the Johns Hopkins Surgical Pathology database between 1991 and 2011 and included 83 SFT patients in our analysis. Patient history and outcomes were obtained from the medical record and primary care physicians. Predictors of recurrence were analyzed by univariate and multivariate analysis and survival determined by the Kaplan-Meier method.

RESULTS

Of the 83 patients, 59 had extrathoracic SFTs in neurologic (n = 24), extremity or head/neck (n = 13), or visceral/intraabdominal (n = 22) sites. A total of 74 SFTs were classified benign and 9 as malignant. Of the 14 recurrences, 13 occurred in extrathoracic SFTs; only 7 were classified as malignant. Multivariate analysis confirmed that malignant histology had the strongest association with recurrence, but extrathoracic location also independently predicted recurrence. A total of 20 benign SFTs possessed 1 or more of England's criteria but to an insufficient degree for malignant classification. These "borderline" SFTs were more likely to recur than benign SFTs without these features.

CONCLUSIONS

Extrathoracic and "borderline" SFTs with any of England's criteria have a higher risk of recurrence.

Solitary fibrous tumor of the hypopharynx: case report and literature review

Solitary fibrous tumors are rare mesenchymal neoplasms that are increasingly being described in the head and neck. Clinical presentations may include compression by these tumors on vital surrounding structures. While malignant transformation is rare, treatment entails wide local excision. We present the case of a 74 year-old female with an increasingly enlarging symptomatic hypopharyngeal solitary fibrous tumor that was found on carotid duplex ultrasound. Transoral surgical excision resulted in relief of symptoms. Treatment options are discussed and a literature review of this uncommon disorder presented.

Correlation between clinical features, imaging and pathologic findings in recurrent solitary fibrous tumor of the orbit

PURPOSE

To correlate clinical features, imaging and pathologic findings in recurrent Solitary Fibrous Tumor of the orbit (SFT) in order to predict long-term behavior.

METHODS

Clinical features, imaging and pathologic findings of three patients with biopsy proven SFT are reported. Demographic and clinical features were recorded at presentation and at each consultation; imaging was performed as a diagnostic tool and for follow-up. A biopsy was performed at presentation and subsequently when symptoms worsened. Pathology specimens were reviewed retrospectively to corroborate diagnosis. Intraoperative and histopathologic features were recorded. A correlation was made between clinical, imaging and pathologic results to identify outcome predictors of recurrence, locally aggressive behavior and malignant transformation.

RESULTS

All cases presented recurrent tumors with locally aggressive behavior over time. All were women in the fifth decade of life. Tumors induced proptosis, swelling of the lids and eye displacement at presentation and were diagnosed as other types of collagen-rich tumors before CD34 immunohistochemistry was available. Mean follow-up was 26.6 years (range 12-37). Relevant findings for all cases included a heterogeneous, irregular tumor containing cystoid spaces filled with mucoid material diffusely enhancing with imaging techniques. Intraoperative findings included a gelatinous matrix within the center of the tumor mass, which was not present at primary resection. Histopathology could not detect specific cellular patterns or immunological markers related to these changes.

CONCLUSIONS

Recurrence and locally aggressive behavior was better predicted by imaging and surgical findings rather than histopathological characteristics. Cystoid degeneration in recurrent tumors may suggest malignant transformation over time.

[Solitary fibrous tumor of the orbit: Possibly recurrent in the long-run]

Solitary fibrous tumor (SFT) is a rare etiology of progressive unilateral exophthalmia. The tumor is of mesenchymal origin and it is usually well defined. But recurrences can occur despite of complete surgical resection. Metastases have been observed. Tumors of the SFT spectrum are considered as benign or low-grade malignant. Histological features do not currently allow any prognosis. The most important prognostic factor is complete surgical resection. Craniofacial approaches provide a good view of the tumor extensions and orbital contents. Recurrent tumors must be surgically removed when possible. Complementary treatments have not proved effective. A very long-term follow-up is mandatory.

Malignant solitary fibrous tumor involving the liver

Solitary fibrous tumors are predominantly benign and are most commonly found in the thoracic cavity and pleura; while reports exist in the literature of malignant solitary fibrous tumors and those located in extrathoracic organs, these cases are considered extremely rare. Herein, a case is reported of a malignant solitary fibrous tumor involving the liver that was diagnosed and treated in a 62-year-old woman. The patient presented with complaints of upper abdominal pain and unintentional weight loss. Computed tomography scan of the abdomen revealed a remarkably large mass, measuring 15 cm × 10 cm × 20 cm, which appeared to be unrelated to any particular organ. The intraoperative finding of a wide communication with the left liver suggested hepatic origin, and served as an indicator for tumor resection via left hemihepatectomy. The diagnosis of solitary fibrous tumor and its malignant nature was confirmed by histological and immunohistochemical examination of the resected tissues. Hepatic solitary fibrous tumor is very rare, and surgery remains the mainstay of treatment. Due to limited reports of such tumors in the literature, little can be said about the benefit of adjuvant therapy and prognosis for the rare cases with malignant histological findings.

Gene expression profiling of solitary fibrous tumors

Background

Solitary fibrous tumors (SFTs) are rare spindle-cell tumors. Their cell-of-origin and molecular basis are poorly known. They raise several clinical problems. Differential diagnosis may be difficult, prognosis is poorly apprehended by histoclinical features, and no effective therapy exists for advanced stages.

Methods

We profiled 16 SFT samples using whole-genome DNA microarrays and analyzed their expression profiles with publicly available profiles of 36 additional SFTs and 212 soft tissue sarcomas (STSs). Immunohistochemistry was applied to validate the expression of some discriminating genes.

Results

SFTs displayed whole-genome expression profiles more homogeneous and different from STSs, but closer to genetically-simple than genetically-complex STSs. The SFTs/STSs comparison identified a high percentage (∼30%) of genes as differentially expressed, most of them without any DNA copy number alteration. One of the genes most overexpressed in SFTs encoded the ALDH1 stem cell marker. Several upregulated genes and associated ontologies were also related to progenitor/stem cells. SFTs also overexpressed genes encoding therapeutic targets such as kinases (EGFR, ERBB2, FGFR1, JAK2), histone deacetylases, or retinoic acid receptors. Their overexpression was found in all SFTs, regardless the anatomical location. Finally, we identified a 31-gene signature associated with the mitotic count, containing many genes related to cell cycle/mitosis, including AURKA.

Conclusion

We established a robust repertoire of genes differentially expressed in SFTs. Certain overexpressed genes could provide new diagnostic (ALDH1A1), prognostic (AURKA) and/or therapeutic targets.

A case report of an intracaval extrathoracic solitary fibrous tumour

Solitary fibrous tumours are infrequent neoplasms based in the pleura that are predominantly benign with malignant pathology and behaviour described in 10-36% of cases. Extrathoracic solitary fibrous tumours (ESFTs) have been considered separately to their intrathoracic counterparts and comprise a third of all solitary fibrous tumours. The extrathoracic location was identified as an adverse prognostic factor for local recurrence but not for metastatic disease. So far, there have not been any reports of solitary fibrous tumours demonstrating caval infiltration. We present a case of a benign ESFT infiltrating into the perirenal inferior vena cava. Together with extrauterine leiomyomas, ESFTs should also be considered as a differential diagnosis for the rare benign lesions invading the inferior vena cava.

A case report of an intracaval extrathoracic solitary fibrous tumour

Solitary fibrous tumours are infrequent neoplasms based in the pleura that are predominantly benign with malignant pathology and behaviour described in 10-36% of cases. Extrathoracic solitary fibrous tumours (ESFTs) have been considered separately to their intrathoracic counterparts and comprise a third of all solitary fibrous tumours. The extrathoracic location was identified as an adverse prognostic factor for local recurrence but not for metastatic disease. So far, there have not been any reports of solitary fibrous tumours demonstrating caval infiltration. We present a case of a benign ESFT infiltrating into the perirenal inferior vena cava. Together with extrauterine leiomyomas, ESFTs should also be considered as a differential diagnosis for the rare benign lesions invading the inferior vena cava.

Meningeal hemangiopericytoma and solitary fibrous tumors carry the NAB2-STAT6 fusion and can be diagnosed by nuclear expression of STAT6 protein

Non-central nervous system hemangiopericytoma (HPC) and solitary fibrous tumor (SFT) are considered by pathologists as two variants of a single tumor entity now subsumed under the entity SFT. Recent detection of frequent NAB2-STAT6 fusions in both, HPC and SFT, provided additional support for this view. On the other hand, current neuropathological practice still distinguishes between HPC and SFT. The present study set out to identify genes involved in the formation of meningeal HPC. We performed exome sequencing and detected the NAB2-STAT6 fusion in DNA of 8/10 meningeal HPC thereby providing evidence of close relationship of these tumors with peripheral SFT. Due to the considerable effort required for exome sequencing, we sought to explore surrogate markers for the NAB2-STAT6 fusion protein. We adopted the Duolink proximity ligation assay and demonstrated the presence of NAB2-STAT6 fusion protein in 17/17 HPC and the absence in 15/15 meningiomas. More practical, presence of the NAB2-STAT6 fusion protein resulted in a strong nuclear signal in STAT6 immunohistochemistry. The nuclear reallocation of STAT6 was detected in 35/37 meningeal HPC and 25/25 meningeal SFT but not in 87 meningiomas representing the most important differential diagnosis. Tissues not harboring the NAB2-STAT6 fusion protein presented with nuclear expression of NAB2 and cytoplasmic expression of STAT6 proteins. In conclusion, we provide strong evidence for meningeal HPC and SFT to constitute variants of a single entity which is defined by NAB2-STAT6 fusion. In addition, we demonstrate that this fusion can be rapidly detected by STAT6 immunohistochemistry which shows a consistent nuclear reallocation. This immunohistochemical assay may prove valuable for the differentiation of HPC and SFT from other mesenchymal neoplasms.

Solitary fibrous tumours of the pleura: report of two cases and literature review

BACKGROUND

Solitary fibrous tumours of the pleura (SFTPs) are rare pleural mesenchymal neoplasms with distinct clinicopathological and immunohistochemical features, accounting for less than 5 % of all neoplasms involving the pleura.

METHODS

We present two cases of SFTP with a review of the current literature.

RESULTS

Clinical presentation varies according to size and intrathoracic localisation. The molecular pathology of SFTPs is largely unknown. Complete surgical resection is recommended with long-term clinic and radiographic follow-up due to its malignant potential.

CONCLUSIONS

This is a summary of available literature outlining current clinical practice in the diagnosis, management, and treatment of SFTPs in Ireland.

A solitary fibrous tumor with giant cells in the lacrimal gland: a case study

Orbital solitary fibrous tumor (SFT) has recently been proposed as the encompassing terminology for hemangiopericytoma, giant cell angiofibroma (GCAF), and fibrous histiocytoma of the orbit. The lacrimal gland is a very rare location for both SFT and GCAF. A 39-year-old man presented with a painless left upper eyelid mass. An orbital computed tomography scan identified a 1.1 cm-sized well-defined nodule located in the left lacrimal gland. He underwent a mass excision. Histopathologic examination showed a proliferation of relatively uniform spindle cells with a patternless or focally storiform pattern. Dilated vessels were prominent, but angiectoid spaces lined with giant cells were absent. Floret-type giant cells were mostly scattered in the periphery. The tumor was immunoreactive for CD34 and CD99, but negative for smooth muscle actin and S-100 protein. This is the first Korean case of SFT of the lacrimal gland with overlapping features of GCAF, suggesting a close relationship between the two entities.

Solitary fibrous tumor of the kidney: a case report

Solitary fibrous tumor is a spindle cell neoplasm mostly originating from pleura; however, it has also recently been reported to be extrapleural. A 57-year-old man presented with left lumbal pain. Ultrasonography and computed tomography showed a cystic lesion of 14 × 11 cm with solid areas and septations in middle and lower poles of the left kidney. Radical nephrectomy was performed. Immunohistochemical studies showed strong reactions with CD34 and CD99. A nuclear positivity with Ki-67 was observed in less than 1% of cells. Despite repeated stainings with vimentin, no clear tumor evaluation could be made due to artifacts. The tumor was negative with Bcl-2, desmin, HMB-45, S100, FVIII, and CD31. Histopathological and molecular studies made the diagnosis of a solitary fibrous tumor. The patient is now currently free of disease at the 26th month of followup.

Malignant solitary fibrous tumor of pleura accompanied with first symptoms of chest pain and hemoptysis: a case report

Solitary fibrous tumor of the pleura (SFTP) is a rare tumor especially presents malignant features. Such symptoms of hemoptysis and dyspnea were rarely seen and take 5% and 4% respectively in malignant SFTP. A 26-year-old Chinese man, presenting with hemoptysis in the emergency room, was hospitalized because of dyspnea. The X-ray examination revealed a tumor in the right chest cavity. The patient refused treatment, and the tumor grew rapidly, which complicated the symptoms of the patient. En-bloc excision of tumor plus the involved lung was performed. There was at least a 5000-ml mixture of blood and tumor tissue in the right chest cavity because of continuous bleeding, leading to a tumor capsule split. Histopathology and immunohistochemistry identified the tumor as malignant SFTP, but CD34 was negative. In this case, the tumor grew rapidly and aggressively in two months, indicating that close follow-up and active treatment are needed.

Soft tissue tumors of the anorectum: rare, complex and misunderstood

Anorectal soft tissue tumors are uncommon and often present both diagnostic and therapeutic challenges. Although many of these tumors are identified with imaging performed for unrelated reasons, most present with nonspecific symptoms that can lead to a delay in diagnosis. Historically, radical surgery (abdominoperineal resection) has been the mainstay of treatment for both benign and malignant anorectal soft tissue tumors. However, a lack of proven benefit in benign disease along with changes in technology has called this practice into question. In addition, the role of radiation and/or chemotherapy remains controversial. In this manuscript, we review the history and current status of anorectal soft tissue tumor management, with a particular focus on challenges in optimizing survival.

Intrathoracic thyroid solitary fibrous tumor presenting with respiratory failure

Solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm that arises primarily from the pleura, but recognized also in other tissues. SFT in the thyroid gland is extremely rare. Here we presented the second reported SFT arising in an intrathoracic goiter. The88-year-old woman was referred with a huge goiter involving upper mediastinum accompanied by airway obstruction and tracheostomy. The patient underwent a left subtotal thyroidectomy, which revealed a SFT. No recurrence was noted during 3 years of follow-up.

Hemangiopericytoma/solitary fibrous tumor of pectoralis major muscle mimicking a breast mass

INTRODUCTION

Hemangiopericytoma (HPC)/solitary fibrous tumor (SFT) is a very uncommon tumor of uncertain malignant behavior. In 1942, Stout and Murray first characterized these neoplasms as "vascular tumors arising from Zimmerman's pericytes" and till now hemangiopericytomas and solitary fibrous tumors of the soft tissues are regarded as features of the same entity in the soft tissue fascicle.

PRESENTATION OF CASE

We present a case of hemangiopericytoma/solitary fibrous tumor of the pectoralis major muscle in a 33-year-old female. She first noticed a painless mass in her right breast. Ultrasound of the breast revealed a large heterogeneously hypoechoic lesion within the pectoralis major muscle. Fine needle aspiration of the tumor did not produce any meaningful result. The lesion was completely removed by surgical resection. Histologically, the tumor had staghorn-like vasculature and immunohistochemistry for CD34 was positive, whereas desmin, smooth-muscle actin, S-100 protein, cytokeratins (AE1/AE3) and epithelial membrane antigen (EMA) were all negative. A diagnosis of hemangiopericytoma/solitary fibrous tumor was rendered.

DISCUSSION

Tumors comprising the HPC/SFT spectrum represent a small subset of soft tissue sarcomas and are found virtually at any site in the body. Wide surgical resection can achieve favorable long-term survival.

CONCLUSION

Due to the rarity and unpredictable biological potential of these tumors, long-term follow-up is mandatory even after radical resection, because recurrence or development of metastasis may be delayed many years.