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

The Peculiar Case of a Large Right Lower Quadrant Solitary Fibrous Tumor With Vasculature Arising from the Splenic Artery and Vein

We present the interesting case of a patient with peritoneal solitary fibrous tumor (SFT). The patient initially presented with right lower quadrant pain. Computed tomography findings revealed the presence of a large mass near the cecum, with both arterial and venous blood supply arising directly from the splenic artery and vein. The patient ultimately underwent surgical excision of the mass, and pathological examination was consistent with benign SFT. Not only is the location of our patient's tumor exceedingly rare, but also, to our knowledge, it is the first reported case of SFT with such a unique vascular supply.

Risk assessment in solitary fibrous tumors: validation and refinement of a risk stratification model

Solitary fibrous tumors are an uncommon sarcoma type characterized by NAB2-STAT6 gene fusion. While solitary fibrous tumors metastasize in 5-25% of cases, it has historically been challenging to determine which specific tumor and patient characteristics predict aggressive behavior. We previously reported on a novel risk stratification scheme for solitary fibrous tumors incorporating patient age, tumor size, and mitotic activity to predict risk of metastasis. Herein we validate this risk stratification scheme in an independent, lower-risk population of 79 patients with primary non-meningeal solitary fibrous tumors, and propose incorporating tumor necrosis as a fourth variable to further improve the risk score. Fifty-seven percent of cases were considered low risk, 29% intermediate risk, and 14% high risk for metastasis. Of 50 patients with sufficient clinical follow-up data, no metastases developed in the low-risk patients (n=23), while there was a 7% 10-year metastatic risk in the intermediate risk group (n=17), and a 49% 5-year metastatic risk for the high-risk patients (n=10). When tumor necrosis was added as a fourth variable to the model, predictive power was enhanced. Under the revised stratification, the proportion of tumors identified as low risk increased to 66%, with no metastasis at 10 years, intermediate risk cases comprised 24% with 10% risk of metastasis at 10 years, and high risk comprised 10% of cases with 73% risk of metastasis at 5 years. In Kaplan-Meier analysis, this fourth-variable stratification provided significant discrimination between the risk groups (P=0.0005). These findings confirmed the clinical utility of our previously published risk stratification model and support the inclusion of necrosis as a fourth variable in the model.

Sinonasal and rhinopharyngeal solitary fibrous tumour: a case report and review of the literature

Solitary fibrous tumours are rare neoplasms that arise mostly from the pleura. Much more rarely they can also be found in extrapleural sites, including the head and neck. We report a rare case of a sinonasal and rhinopharyngeal solitary fibrous tumour. The tumour, measuring 67 x 28 x 55 mm, was first embolised and then successfully removed through endonasal endoscopic surgery. Histopathologic analysis confirmed the nature of the lesion, which was positive for CD34 and vimentin. A post-operative CT scan and endoscopic follow-up demonstrated total resection and absence of recurrence after 13 months.

A malignant solitary fibrous tumour arising from the first lumbar vertebra and mimicking an osteosarcoma: a case report

Background

A solitary fibrous tumour (SFT) is an unusual neoplasm typically found in soft tissues. Although SFTs can arise in the bones, they very rarely arise in the vertebral arch. Here, we describe a case of a SFT that arose in the vertebral arch of the first lumbar (L1) spinal vertebrae and mimicked osteosarcoma.

Case presentation

A 49-year-old woman presented with a 2-month history of lower back pain and a lumbar region mass. Magnetic resonance imaging demonstrated a heterogeneously enhanced mass in the L1 vertebral arch. The patient received neoadjuvant chemotherapy, followed by a surgical procedure comprising an anterior spinal fusion and en bloc resection. Histologically, our initial diagnosis was osteosarcoma. The postoperative course was uneventful, and the patient received adjuvant chemotherapy. However, the tumour metastasised to the lung 5 years after the first surgery, and a second surgery was performed for lung tumour resection. The histology of the metastatic lung tumour appeared similar to that of the malignant SFT, and the specimen from the first surgery was re-examined. Immunohistochemically, the tumour was positive for STAT6. Reverse transcription-polymerase chain reaction revealed a NAB2-STAT6 fusion gene, thus confirming our final diagnosis of malignant SFT. The patient died of disease progression 8 years after the first surgery; however, there was no evidence of local recurrence.

Conclusions

Malignant SFT in the vertebral arch is extremely rare and very difficult to distinguish histologically an osteoid from lace-like collagen. STAT6 immunostaining is useful for distinguishing malignant SFTs from other neoplasms. Although it is difficult to completely resect a SFT arising from the spine, we demonstrated the feasibility of an en bloc resection of spinal tumours arising from posterior elements, without local recurrence.

Pancreatic metastasis from an osseous solitary fibrous tumour

A 73-year-old man presented with a right-sided chest wall mass that showed an epitheloid neoplasm with mild cytologic atypia on core needle biopsy. He underwent surgical resection, and final pathology revealed solitary fibrous tumour/hemangiopericytoma with negative margins. Three years after surgical resection, the patient presented with fatigue, abdominal pain, weight loss and mildly elevated liver function tests. Further workup revealed a 1.2 cm hypervascular mass in the neck of the pancreas. This case report summarises the surgical treatment and outcomes for a patient who presented with this rare tumour.

Pancreatic solitary fibrous tumor in a toddler managed by pancreaticoduodenectomy: a case report and review of the literature

Solitary fibrous tumor (SFT) of the pancreas is rare, with 15 adult cases reported in the English literature. We described a 14-month-old boy who presented with obstructive jaundice. Dominantly elevated serum CA19-9 was detected. Imaging studies revealed a well-circumscribed, solid mass in the pancreatic head. A pancreaticoduodenectomy (child procedure) was performed using Shen’s anastomosis technique. After resection of the tumor, liver function and serum tumor markers normalized and clinical signs receded. The boy was disease free after a follow-up of 12 months. Histological examination showed the tumor consisted of “patternless pattern” arranged spindle tumor cells and keloid-like hyalinized collagen. Immunohistochemical staining was positive for CD34 and vimentin. Mutation analysis of CTNNB1 was negative. To the best of our knowledge, our patient was the first case of pancreatic SFT in a pediatric population. SFT should be considered in differential diagnosis when confronted with a pancreatic tumor in children. Complete resection should be meticulously pursued.

[Parauterine solitary fibrous tumor: about a case]

Les tumeurs fibreuses solitaires du tractus génital féminin sont extrêmement rares. Nous rapportons le cas d’une patiente âgée de 78 ans qui a présenté une masse pelvienne. L’exploration chirurgicale a montré une tumeur parautérine. L’examen anatomopathologique a conclu à une tumeur fibreuse solitaire avec des signes de malignité. Les suites ont été marquées par le décès de la patiente. Il est important de connaître ces tumeurs dont l’évolution peut être péjorative. Un suivi au long cours doit être recommandé pour les tumeurs résécables.

Malignant solitary fibrous tumor in retroperitoneum: A case report and literature review

RATIONALE

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor occurs in various sites. Malignant SFT in retroperitoneum is extremely rare.

PATIENT CONCERNS

We report a case of malignant retroperitoneal SFT in a 59-year-old man presented with right flank pain for 1 month.

DIAGNOSES, INTERVENTIONS AND OUTCOMES

A laparotomy and resection of the tumor were performed, the histopathologic and immunohistochemical findings were consistent with malignant retroperitoneal SFT. No adjuvant treatment was performed, and the patient had no signs of recurrence or metastasis at the 12 months follow-up.

LESSONS

Complete surgical excision is the basic treatment principle for malignant retroperitoneal SFT. The histologic features and the Ki-67 label index are helpful for the diagnosis of malignant SFT.

Solitary Fibrous Tumors: 2016 Imaging Update

Optimal management of solitary fibrous tumor requires a multidisciplinary approach with proper histopathological mapping and use of various imaging modalities for exact delineation of primary tumor and metastatic disease if present. In this article, the authors present a comprehensive review of the spectrum of imaging findings of solitary fibrous tumors involving various organ systems and discuss the role of molecular targeted therapies in the management of metastatic disease.

A Rare Case of An Atypical Solitary Fibrous Tumour of Orbit

Solitary fibrous tumours are of mesenchymal origin and comprise of uncommon spindle cell neoplasias. Most commonly the lesions arise from pleura but other rarer sites include lungs, peritoneum, pericardium, nasal cavities, thyroid, parotid gland and orbit. We report the case of a 41-year-old male patient who presented to us with a painless, progressive growth of a mass in the superior part of left orbit with proptosis and inferotemporal displacement of the left eye. Computed Tomography (CT) scan revealed homogeneous enhancing lesion in the superior compartment of left orbit in the extraconal region, extending intraconally and distorting the globe. Upon imaging, the differential diagnosis were lacrimal gland tumour, atypical cavernous haemangioma and nerve sheath tumour. Surgical treatment included complete excision of the mass with the intraoperative finding of mass extending upto the superior oblique tendon, a part of which was excised. Histopathological examination revealed CD34 positive, Bcl-2 and MIC-2 positive tumour with the diagnosis of a solitary fibrous tumour with atypical features but no malignant features. After a follow-up of 18 months, no recurrence was detected.

Malignant solitary fibrous tumor of thoracic spine with distant metastases: Second reported case and review of the literature

Solitary fibrous tumor (SFT) usually originates from the pleura because of abnormal proliferation of fibroblast cells. It is extremely rare for the tumor to originate from the spine. Here, we report the second case of malignant SFT of thoracic spine with distant metastases in a 35-years-old female.

Integrally calcified solitary fibrous tumor in the retroperitoneum: a case report and review of the literature

Solitary fibrous tumor (SFT) is a rare stromal neoplasm and usually occurs in the thoracic cavity. We here report a case of retroperitoneal SFT with prominent calcification. A 64-year-old man presented with an incidentally detected retroperitoneal mass in the right upper abdomen. Imaging tests indicated an integrally calcified mass. The lesion was observed for 2 years and laparoscopically resected according to the patient's wish. Microscopically, the mass was mostly occupied by calcification and proliferous spindle cells were scattered with positive CD34 expression. We diagnosed morphologically benign SFT and the patient remained disease-free 1 year after the excision. There has been no report of such integrally calcified SFT. Retroperitoneal SFT is difficult to make a preoperative diagnosis, and careful follow-up after the excision is recommended because morphological malignancy does not always correspond to clinical malignancy.

TERT promoter mutations and prognosis in solitary fibrous tumor

Solitary fibrous tumor is a mesenchymal neoplasm exhibiting a broad spectrum of biological behavior and harboring the NAB2-STAT6 fusion. Clinicopathologic parameters are currently used in risk-prediction models for solitary fibrous tumor, but the molecular determinants of malignancy in solitary fibrous tumors remain unknown. We proposed that the activation of telomere maintenance pathways confers a perpetual malignant phenotype to these tumors. Therefore, we investigated telomerase reverse transcriptase (TERT) reactivation induced by promoter mutations as a potential molecular mechanism for aggressive clinical behavior in solitary fibrous tumor. The retrospective study included tumor samples from 94 patients with solitary fibrous tumor (31 thoracic and 63 extra-thoracic). Follow-up information was available for 68 patients (median, 46 months). TERT promoter mutation analysis was performed by PCR and Sanger sequencing, and TERT mRNA expression was assessed by real-time quantitative reverse transcription PCR. Patients were stratified into clinicopathologic subgroups (high-risk (n=20), moderate-risk (n=28), and low-risk (n=46)) according to the risk-stratification model proposed by Demicco et al. TERT promoter mutations were identified in 26 of 94 (28%) solitary fibrous tumors: -124C>T in 23 tumors (88%), -124C>A in 1 tumor (4%), and -146C>T in 2 tumors (8%). Real-time quantitative reverse transcription PCR revealed that TERT mRNA expression was higher in all solitary fibrous tumors with the mutant TERT promoter than those with the wild-type TERT promoter. TERT promoter mutations were strongly associated with high-risk clinicopathologic characteristics and outcome. An adverse event (relapse, death) occurred in 16 of 68 (24%) patients, 12 with solitary fibrous tumors with TERT promoter mutations and 4 with the wild-type TERT promoter. TERT promoter mutations were strongly associated with older age (P=0.006), larger tumor size (P=0.000002), higher risk classifications (P=2.9 × 10^-9), and a worse event-free survival (P=0.0082). Thus, TERT promoter mutations in solitary fibrous tumor influence gene expression and are associated with adverse patient outcome. Integrating TERT promoter mutational status with existing multivariable risk-prediction models might improve risk prediction in patients with solitary fibrous tumor.

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.

Solitary fibrous tumor of the greater omentum, mimicking gastrointestinal stromal tumor of the small intestine: a case report

Solitary fibrous tumor (SFT) is one of the mesenchymal tumors, which rarely arises in the abdominal space. We report a very rare case of abdominal SFT, mimicking another mesenchymal tumor. A 52-year-old Japanese man was referred to our hospital for further evaluation and treatment of gallbladder polyp. Contrast-enhanced computed tomography (CT) showed an enhanced nodule within the gallbladder, and incidentally, also showed a well-circumscribed mass adjacent to the small intestine. The mass was depicted as slightly high density in plain CT, and with contrast-enhancement, the mass was partially stained in early phase and the stained area spread heterogeneously in delayed phase. Magnetic resonance imaging showed that the abdominal mass was depicted as slightly high intensity on T2-weighted imaging and low intensity on T1-weighted imaging. With double-balloon endoscopy and capsule endoscopy, we did not find any tumor inside the small intestine. These visual findings lead us to diagnose it as gastrointestinal stromal tumor of the small intestine with extraluminal growth. We planned to resect both the gallbladder polyp and the intraperitoneal tumor at the same time for pathologic diagnosis and treatment. When the operation was performed, we found a milk-white lobulated tumor on the greater omentum and the tumor was entirely resected. Microscopically, the gallbladder polyp was diagnosed as tubular adenoma, and the omental tumor was diagnosed as SFT. It is important to bear in mind that omental SFTs sometimes mimic other mesenchymal tumors and should be included in the differential diagnosis of abdominal tumor not revealed by endoscopy.

Two Cases of Solitary Fibrous Tumor Involving Urinary Bladder and a Review of the Literature

Solitary fibrous tumor (SFT) is a rare neoplasia of mesenchymal origin, initially described in visceral pleura and lately discovered to have ubiquitous distribution. SFT of the urogenital tract is uncommon and appears to have similar morphologic features and biologic behaviors as SFTs found elsewhere. We present two new cases of SFT of the bladder and review 22 similar cases published in the literature. Due to the general indolent behavior of these lesions, a complete but organ sparing surgical excision should be considered when technically feasible. Therefore, proper identification and characterization of SFT through morphological and immunohistochemical criteria on biopsy specimens are mandatory in the differential diagnosis from other more aggressive spindle-cell tumors, thus avoiding unnecessary radical surgery.

Recurrent solitary fibrous tumor of lumbar spine with vertebral body involvement: imaging features and differential diagnosis with report of a case

Solitary fibrous tumors (SFTs) of the spine are exceedingly rare tumors of mesenchymal origin. Most spinal SFTs arise from the thoracic spine, followed by cervical spine, and last lumbar spine with only 6 cases reported in literature. SFTs represent a wide range of neoplasms, ranging from benign to malignant. These tumors can develop a late recurrence, even after a decade or more of initial presentation, requiring long-term follow-up. We present a case of recurrent SFT of the lumbar spine with vertebral body involvement, presenting more than a decade after initial resection. It was initially misdiagnosed as a paraganglioma. To the best of our knowledge, there have been only 3 previous cases reporting SFT with vertebral body involvement.

Solitary Fibrous Tumor of the Sigmoid Colon Masquerading as an Adnexal Neoplasm

Solitary fibrous tumor is a rare, benign spindle cell neoplasm that was first described in the thoracic pleura. This tumor is now known to occur at many extrapleural sites. There are established criteria for the diagnosis of malignant solitary fibrous tumor including ≥4 mitotic figures per 10 high-power fields, increased cellularity, cytologic atypia, infiltrative margins, and/or necrosis. Although all solitary fibrous tumors have the potential to recur or metastasize, those with malignant histologic features tend to behave more aggressively. We report a case of solitary fibrous tumor, with malignant histologic features, in a 21-year-old woman which arose from the serosal surface of the sigmoid colon.

Practical Issues for Retroperitoneal Sarcoma

Background

Retroperitoneal sarcoma is rare. Using initial specimens on biopsy, a definitive diagnosis of histological subtypes is ideal but not always achievable.

Methods

A retrospective institutional review was performed for all cases of adult retroperitoneal sarcoma from 1996 to 2015. A review of the literature was also performed related to the distribution of retroperitoneal sarcoma subtypes. A meta-analysis was performed.

Results

Liposarcoma is the most common subtype (45%), followed by leiomyosarcoma (21%), not otherwise specified (8%), and undifferentiated pleomorphic sarcoma (6%) by literature review. Data from Moffitt Cancer Center demonstrate the same general distribution for subtypes of retroperitoneal sarcoma. A pathology-based algorithm for the diagnosis of retroperitoneal sarcoma is illustrated, and common pitfalls in the pathology of retroperitoneal sarcoma are discussed.

Conclusions

An informative diagnosis of retroperitoneal sarcoma via specimens on biopsy is achievable and meaningful to guide effective therapy. A practical and multidisciplinary algorithm focused on the histopathology is helpful for the management of retroperitoneal sarcoma.

Solitary fibrous tumour of gluteus: a case report about an uncommon localization of a rare neoplasm

Solitary fibrous tumour (SFT) is a rare benign tumour that occurs most frequently in the pleura. It is considered rare in soft tissues. We report a case of a middle-aged woman that presented a solitary fibrous tumor of gluteus. The tumour was composed of mesenchymal spindle-shaped cells positive for CD34 and bcl-2. Although rare, SFT should be included in the differential diagnosis of mesenchymal soft tissue tumours. The clinical presentation and imaging can be helpful for a better pre-operative diagnosis.

A recurrent solitary fibrous tumor of the thigh with malignant transformation: A case report

INTRODUCTION

We describe an unusual case of a uniformly high-grade malignant solitary fibrous tumor (SFT) of the thigh with recurrence after wide resection in a 31-year-old man.

PRESENTATION OF CASE

Our current case showed a long-term benign course before the operation, although the subcutaneous tumor was larger than 10cm at presentation. The SFT was diagnosed by needle biopsy, and wide resection was performed. Histological findings showed proliferation of capillaries surrounded by masses of spindle-shaped cells without any cytologic atypia, and the percentage of MIB-1-positive nuclei was 2.1%. However, a rapidly enlarging recurrent tumor was observed 11 months after the operation. A second wide resection for the recurrent tumor was performed. Histologically, the tumor cells uniformly displayed significant cytologic atypia and pleomorphism, and had 40-50 mitoses per 10 high-power fields. The proportion of MIB-1-positive nuclei was 48%. Consequently, the tumor was diagnosed as a SFT with malignant transformation.

DISCUSSION

The malignant transformation described in past studies showed high-grade areas within benign, low-grade, or intermediate-grade SFTs. Therefore, in contrast to our case, uniformly high-grade malignant histological findings at recurrence were not described.

CONCLUSION

Even if a tumor is non-malignant during the clinical course, as confirmed by tissue biopsy, the possibility of tumor progression to high-grade sarcoma at recurrence should be considered, and the treatment strategy should be determined carefully.

Solitary fibrous tumor of the orbit

Solitary fibrous tumor (SFT) is a rare spindle-cell neoplasm originating from the mesenchyme. It was originally thought to occur exclusively in the intrathoracic region but has been recently described in extrapleural sites including the orbit. SFT of the orbit is a rare lesion, which can be misdiagnosed as hemangiopericytoma, fibrous histiocytoma, meningioma, or neurofibroma. Immunohistochemistry plays an important role. We report an orbital SFT in a 39-year-old female presented with painless, progressive proptosis, and diminished vision in the right eye for the duration of 6 months. Magnetic resonance imaging demonstrated well-defined enhancing mass lesion. The patient underwent complete tumor removal through a right fronto-orbital approach, and a pathological diagnosis of the solitary fibrous tumor was made. Postoperatively, the patient was symptom-free. Clinical and pathological findings including immunohistochemistry are presented along with a brief discussion of literature.

Resectable extra-pleural and extra-meningeal solitary fibrous tumours: A multi-centre prognostic study

BACKGROUND

Extra-pleural and extra-meningeal solitary fibrous tumour (SFT) is a rare sarcoma histotype curable with surgery in the majority of patients. The behaviour of these tumours ranges from indolent/very low grade to malignant/high grade but it is still not possible to accurately predict prognosis after surgery. We have investigated a multi-centre series to stratify the risk of recurrence to patients with SFTs.

METHODS

We retrospectively analysed the data from 243 patients who underwent surgery (2002-2011) at four sarcoma referral centres.

RESULTS

Upon univariate analysis, hypercellularity, atypia, necrosis, high mitotic rate (ie >4 mitoses/10 HPF) were associated with both disease-free and overall survival. Surgical margins were a significant prognostic factor for disease-free (P = 0.007) but not for overall survival. Unexpectedly, larger tumour size was associated with a better prognosis (P = 0.038) and fewer recurrences (P = 0.024). Upon multivariable analysis, high mitotic rate (hazard ratio, HR = 2.85, P = 0.002), cellular atypia (HR = 1.62, P = 0.015) and hypercellularity (HR = 1.82, P = 0.031) were significantly associated with recurrences. A SFT recurrence score has been provided to stratify risk of recurrence.

CONCLUSION

This study provides a prognostic model to stratify risk of recurrence in patients with resectable SFTs. This allows clinician to decide on an optimal follow-up strategy and to select patients that may benefit from adjuvant treatments.

The Current Status of Solitary Fibrous Tumor: Diagnostic Features, Variants, and Genetics

Solitary fibrous tumor (SFT) is a fibroblastic mesenchymal tumor originally described in the pleura but now shown at almost every anatomic site. Histopathologically, SFT is characteristically a circumscribed neoplasm composed of variably cellular and patternless distributions of bland spindle and ovoid cells within prominent collagenous stroma and shows diffuse expression of CD34, but it has a broad spectrum of both morphology and of biologic behavior. Many different names (particularly hemangiopericytoma) were previously used in the course of our understanding of this neoplasm but are now subsumed under the term "SFT," and the putative cell of origin was debated. However, it is now recognized that SFT is a translocation-associated neoplasm, consistently associated with NAB2-STAT6 gene fusions arising from recurrent intrachromosomal rearrangements on chromosome 12q, and this translocation is a likely major contributor to its pathogenesis. While most SFT with classical morphologic features behave in an indolent manner and those with overtly malignant histologic features tend to be aggressive neoplasms that behave as high-grade sarcomas, the behavior of SFT is unpredictable, and it is important to be aware of the propensity for aggressive behavior in a minority of histologically classical SFT and to ensure adequate clinical follow-up. Surgical excision remains the treatment gold standard; while radiotherapy and conventional chemotherapeutic agents have only shown limited efficacy, further understanding of the molecular events underlying tumorigenesis may allow the development of novel targeted treatments. We review SFT, discussing the morphologic spectrum and variants, including malignant and dedifferentiated subtypes, clinicopathological aspects, recent molecular genetic findings, and the differential diagnosis.

Transsphincteric tumor resection in case of a pararectal solitary fibrous tumor

Transsphincteric resection of rectal tumors was first described about 120 years ago. Nowadays, this approach faded into obscurity due to standardized guidelines and practice in surgical oncology including lymphadenectomy, mesorectal excision and radical dissection of veins. However, transsphincteric resection seems reasonable in some cases, especially if an abdominal approach can be avoided. In the following, we will present and describe the technique of the transsphincteric approach with its variations in rectal surgery in the case of a rare pararectal tumor.

Primary hepatic solitary fibrous tumor with histologically benign and malignant areas

Extrapleural solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm, presenting most commonly in the intrathoracic sites but which has been reported at numerous extrathoracic locations. The majority of intra-thoracic SFTs are benign, but 10%-15% behave aggressively. We report a case of primary hepatic SFT with histologically benign and malignant areas. A 65-year-old man underwent an abdominal CT scan following a cerebrovascular accident, which demonstrated a sharply demarcated large liver mass with a heterogenous enhancing area and occupying most of the left lobe of the liver. Histological examination following a hemihepatectomy showed an SFT with morphological patterns ranging from benign to malignant areas, including pleomorphism, increased cellularity, herringbone pattern, necrosis and a raised mitotic count. On review of the literature, only an occasional case report with malignant areas in a hepatic SFT was identified. This case highlights that SFT should be included in the differential diagnosis of a hepatic spindle cell lesion, and that on rare occasions, malignant areas can occur in this already uncommon neoplasm.

Solitary Fibrous Tumor of the Lower Leg: A Rare and Difficult Diagnosis

Solitary fibrous tumor (SFT) is a rare neoplasm that commonly originates in the pleura. Extrapleural locations are rare and for this reason sometimes difficult to diagnose. Malignant forms with local recurrence or distant metastases have been reported, also as a consequence of inappropriate treatment. In this article, we report the case of an SFT of the lower leg in a 37-year-old man. Leg SFT is a rare occurrence, and differential diagnosis may be difficult because they can mimic a variety of benign and malignant mesenchymal tumors; immunohistochemical analysis for CD34, CD99, vimentin, and Bcl-2 is necessary. Misdiagnosis carries a significant risk of inadequate removal with subsequent increased risk of recurrence and distant metastases.

Clinical Characteristics and Outcomes for Solitary Fibrous Tumor (SFT): A Single Center Experience

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm of fibrous origin. The 2013 WHO classification of soft tissue tumors defines malignant forms as hypercellular, mitotically active (>4 mitosis/10 high-power fields), with cytological atypia, tumor necrosis, and/or infiltrative margins. With an IRB-approved protocol, we investigated patient records and clinicopathologic data from our Sarcoma Database to describe the clinical characteristics of both benign and malignant SFT. All pathology specimens were reviewed by two pathologists. Descriptive statistics and univariate/multivariate survival analysis were performed. Patient records and Social Security Death Index were used to evaluate vital status. Of 82 patients, 47 (57%) were women and 73 (89%) were Caucasian. Median age was 62 years (range, 20 to 89). Thirty-two (39%) patients succumbed to the disease. Primary tumor site was lung/pleura in 28 (34%), abdomen/pelvis in 23 (28%), extremity in 13 (16%), and head/neck in 9 (11%) patients. Pathology was described as benign in 42 (51%) and malignant in 40 (49%) patients. Compared to benign SFT, malignant histology is associated with larger tumor size, higher mitotic counts, metastatic disease at diagnosis, and greater use of chemotherapy and radiation therapy. Gender, age, and tumor site were not significantly different between benign and malignant subtypes. By univariate analysis, only benign vs. malignant variant and complete resection positively impacted overall survival (P = 0.02 and P<0.0001, respectively). In the multivariable analysis of overall survival, receiving chemotherapy or not receiving surgery were two variables significantly associated with higher failure rate in overall survival: patients with chemotherapy vs. no chemotherapy (P = 0.003, HR = 4.55, with 95% CI: 1.68–12.34) and patients without surgery vs. with surgery (P = 0.005, HR = 25.49, with 95% CI: 2.62–247.57). Clear survival differences exist between benign and malignant SFT. While surgery appears to be the best treatment option for benign and malignant SFT, better systemic therapies are needed to improve outcomes of patients with metastatic, malignant SFT.

An update on primary hepatic solitary fibrous tumor: An examination of the clinical and pathological features of four case studies and a literature review

BACKGROUND

Primary hepatic solitary fibrous tumor is a rare neoplasm that originates in the submesothelial tissue of the liver and is frequently misdiagnosed because of its rarity and unfamiliar characteristics.

AIM

To analyze, summarize and update the clinical and pathological features of primary hepatic solitary fibrous tumor.

METHODS

We systematically extract the clinical data of 4 cases from the relevant medical records, analyze the macroscopic, histological and immunohistochemical features and review the 59 previously reported cases in the English literatures.

RESULTS

The patients' mean age 50.75 years (range, 49-52 years), and the gender ratio was 1:1. The tumors ranged in size from 2.3 to 12.0cm (average diameter, 7.85cm). The tumors were composed of spindle cells with oval, fusiform or banded nuclei that were arranged in bundled, storiform or peculiar random patterns. Mitosis and hemangiopericytoma-like vessels were occasionally observed. Immunohistochemically, three cases were positive for Signal transduction and activator of transcription 6, cluster of differentiation 34, B-cell lymphoma-2 and vimentin but were negative for nervous, muscular and hepatocellular markers. Hepatic lobectomy was performed in all cases, and one patient received adjuvant chemotherapy simultaneously. One patient suffered two recurrences without metastasis, and the remaining patients experienced favorable outcomes.

CONCLUSIONS

A consensus on the essential and definite diagnostic criteria for primary hepatic solitary fibrous tumor must be reached in a timely manner. Signal transduction and activator of transcription 6 is a highly sensitive and specific immunohistochemical marker for primary hepatic solitary fibrous tumor.

Retroperitoneal solitary fibrous tumor: surgery as first line therapy

BACKGROUND

Solitary fibrous tumors (SFT) of the retroperitoneum are rare spindle cell neoplasms, with a paucity of data on treatment outcomes. We hypothesized that surgical excision offered acceptable outcomes in SFTs.

METHODS

The National Cancer Database (NCDB) was used to identify patients with SFT from 2004 to 2011. Primary outcome measures were 30 day mortality and overall survival. Descriptive analyses were performed. Furthermore, a systematic review of published literature was conducted after creating a pre-specified search strategy.

RESULTS

Of 51 patients in the NCDB, 58.8 % (n = 30) were males, with a median age 60 years (IQR 49-72 years). Median tumor size was 16 cm (IQR 11-21 cm). Surgical resection was performed in 92.2 % (n = 47) with 63.8 % (n = 30) having a margin negative resection. Peri-operative mortality was 2.1 % (n = 1). Of survival outcomes available for 18 patients, the median OS was 51.1 months. From the systematic review, we identified 8 studies, with 24 patients. Median age and tumor size was similar to the NCDB [47.5 years (IQR 39-66.5 years), 12 cm (IQR 7-17 cm)]. Majority [91.7 % (n = 22)] underwent surgical excision alone while one received adjuvant chemotherapy and none received radiation. After median follow up of 54 months (IQR 28-144 months), 79.2 % (n = 19) were alive without disease. Three patients (12.5 %) died of disease, one was alive with disease and one was lost to follow up. Recurrence was reported in 16.7 % (n = 4) of patients.

CONCLUSION

Complete surgical excision is a viable treatment modality for retroperitoneal SFT leading to long term survival. Low recurrence rates would argue against the need for routine adjuvant radiation or chemotherapy.

Malignant Solitary Fibrous Tumor of the Pancreas

Solitary fibrous tumor (SFT) arising in the pancreas is exceedingly rare, with only 11 cases reported in the English literature. All cases described thus far have exhibited benign histology. We report the first case of malignant SFT of the pancreas. The patient was a 52-year-old woman who presented with obstructive jaundice and a 15-cm pancreatic head mass. The mass showed areas with typical histologic features for SFT including small fibroblastlike cells arranged in the well-characterized "patternless pattern" of architecture, hemangiopericytomalike vessels, areas with dense collagen and infrequent mitoses (0-2 per 10 high-power fields [HPFs]). In addition, multiple areas with an overtly sarcomatous morphology were present, containing large spindle and epithelioid cells with nuclear pleomorphism, marked cellularity, up to17 mitoses per 10 HPFs, and necrosis. Immunohistochemical stains were positive for CD34 and B-cell CLL/lymphoma 2 (Bcl-2) in both benign and malignant components and showed strong, diffuse p53 and p16 staining in the malignant component. At last follow-up (40 months), the patient was alive and well without evidence of disease. However, given that the presence of a malignant component in extrapancreatic SFT has been associated with recurrence/metastasis and death, complete surgical resection and close long-term follow-up is required.

A Solitary Fibrous Tumor (Cellular Form) of the Ankle

A solitary fibrous tumor (SFT) is a rare type of mesenchymal tumor composed of uniform spindle cells that is classically described as a patternless feature. SFT normally originates from the pleura, with an SFT originating from skin rarely reported. We report what we believe to be the first case of an SFT arising from the ankle. Our case was confirmed histopathologically with immunohistochemical staining.

Head and neck solitary fibrous tumors: a rare and challenging entity

The objective of this study is to analyze the outcome of treatment for solitary fibrous tumors (SFTs) in the head and neck area. SFTs present as slow-growing masses, often with local compressive symptoms that are difficult to distinguish from other soft-tissue tumors. SFTs are commonly treated using local excision without adjuvant therapy. To date, only heterogeneous small series have been published, documenting the treatment results and outcome with these tumors. Retrospective study of patients with histopathologically confirmed SFT treated at two tertiary referral hospitals between 2004 and 2014. Eight men and four women with histologically confirmed SFT were identified in the records. Their age range was 37-82 years (mean 57.8 years). The mean follow-up period for eight patients was 6.75 years (range 1-24 years). Four patients were lost to follow-up. Sublocalizations were neck (n = 3), orbit (n = 2), paranasal sinus (n = 2), cheek (n = 2), hard palate (n = 1), parotid gland (n = 1), and tongue (n = 1). The first-line treatment for all of the tumors identified was surgical excision. In four cases, the surgical margins were narrow or unclear due to piecemeal resection in the paranasal sinus and orbit (n = 3) or a tumor location deep in the parapharyngeal space (n = 1). Recurrences developed in two of these cases (in the orbit and parapharyngeal space), and the other two patients were lost to follow-up. Radiotherapy and chemotherapy were not administered as first-line treatments. Overall, the local recurrence rate (n = 2/8) was 25 %. The disease-specific survival rate was 100 %. These results are consistent with the literature data and show that safe surgical excision, without opening of the tumor capsule, reduces the risk of local recurrence and leads to a favorable outcome. Tumors in the head and neck often represent a surgical challenge, and wide surgical margins are rarely possible due to the complex three-dimensional anatomic compartments in the region. Head and neck surgeons should therefore be aware that there is an increased risk of recurrence in these patients; tightly scheduled follow-up visits are mandatory for at least 10 years, if not longer. Radiotherapy only appears to be an option in patients with unresectable tumors or when wide surgical excision would cause severe functional morbidity.

Malignant solitary fibrous tumor of the thyroid: a case-report and review of the literature

Solitary fibrous tumor (SFT) is an uncommon spindle-cell neoplasm that most often involves the pleura, rarely occurring in extra-thoracic locations. Twenty-six cases of SFT arising in the thyroid gland have been described. We report a case of a 60-year-old woman presenting an 8-month history of enlargement of the neck associated with dysphagia. The patient underwent a right hemithyroidectomy and SFT of the thyroid was diagnosed. Immunohistochemistry showed positivity for CD34 marker, and the high number of mitoses and the presence of cellular atypia suggested that the tumor was malignant. To our knowledge, this is the second case of malignant SFT of the thyroid gland ever reported. Due to the rarity of these tumors, the indication of adjuvant therapy and prognosis are uncertain. Long-term follow-up after surgical resection seems to be advisable.

Solitary fibrous tumor of the nasal cavity and paranasal sinuses: A case report

Solitary Fibrous Tumors (SFT) are rare neoplasms first described in 1931 by Klemperer and Rabin. SFT's have mesenchymal rather than mesothelial origin. They arise mostly from serous membranes, although they also originate in other regions such as: the urogenital system, mediastinal space, lungs, vulva, orbit, thyroid, nasopharyngeal region, larynx, salivary glands. SFT of the nasal cavity and paranasal sinuses are extremely rare. To the year 2014 only 33 cases were reported in English literature.

PATIENTS AND METHODS

We present a case of 58-year-old man with solitary fibrous tumor localized in the right nasal cavity. The patient presented with an 18-month history of epistaxis and right epiphora. He also reported unilateral right-sided nasal obstruction over the last 6 months.

RESULTS

CT disclosed a large, homogeneous mass in the nasal cavity infiltrating and destroying nasal septum, turbinates, occupying right maxillary sinus, right ethmoid, extending to the right frontal sinus and right orbit. The infiltration of the right oculus was suspected. Biopsy revealed fibrocytes and histiocytes proliferation with rich vascularization. There was no evidence of histological malignancy. Pathology results were significant for SFT.

CONCLUSION

The tumor was excised by means of right lateral rhinotomy. Neither the extension to the right maxillary sinus nor the orbital floor infiltration was seen intraoperatively despite the fact, that it was observed in computed tomography before the surgery. The patient had a 5.5-year follow up after surgery, radiological examination showed no recurrence.

Ocular adnexal (orbital) solitary fibrous tumor: nuclear STAT6 expression and literature review

PURPOSE

To report the clinico-pathological features of solitary fibrous tumor occurring in the ocular adnexa (OA) in a single center. To assess the presence of NAB2-STAT6 genes fusion in OA solitary fibrous tumor detected by nuclear overexpression of STAT6.

METHODS

Retrospective study including orbital and OA solitary fibrous tumors treated between 2006 and 2014 in our center. The clinical, radiological, and histopathological findings were evaluated. STAT6 expression was assessed by immunohistochemistry.

RESULTS

Five patients were identified and presented with a chronic OA mass. The tumors were radiologically well delimited, highly vascularized and without bone erosion. All the patients underwent complete surgical excision. Pathological examination confirmed solitary fibrous tumor in all cases. All tumors demonstrated a nuclear expression of STAT6. There were no recurrences, with a mean follow-up of 5 years after surgery. Our review demonstrated that proptosis was the most common presentation occurring in 60 % of the cases. In the ocular adnexa, adverse histological criteria were found in 19.7 % of the tumors, and recurrences were observed in 48 % of these cases. Thirty-six percent of patients presented at least one local recurrence, and metastastic spread was found in 2.4 % of the cases. Tumor-related death was described in two cases.

CONCLUSION

Ocular adnexal SFT are rare and usually present as a chronic orbital mass with proptosis. In the OA, solitary fibrous tumor demonstrates STAT6 nuclear expression, as documented in other locations. Recurrences are unusual and metastasis exceptional. Initial surgical resection should be complete in order to avoid recurrence.

A rare mesenchymal neoplasm at unusual location: Solitary fibrous tumor of vulva

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We report a rare case of solitary fibrous tumor of vulva.

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The lesion is usually benign.

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Needs workup for malignant features and other close differentials.

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Early aggressive resection ensuring clear margins is recommended.

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Tendency for recurrence warrants long term follow-up.