Solitary fibrous tumour--everywhere, and a diagnosis in vogue

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

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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.

Solitary fibrous tumor of the parotid gland: Case report

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm that usually develops in the pleura and peritoneum. The head and neck region is involved in only 6% of the cases. Involvement of the parotid gland is a rare phenomenon, with only 24 cases reported in the literature. The aim of this study is to report an additional case of SFT affecting the parotid gland, and to review the literature on previously reported cases. The patient was a 42-year-old male with a 4-cm, fibro-elastic, movable, painless nodule in the inferior lobe of the parotid gland. The lesion was surgically excised and, following histopathological and immunohistochemical analysis, a diagnosis of SFT was rendered. The patient has been followed-up for ten months, with no signs of recurrence. Clinical, histopathological, immunohistochemical and treatment aspects of the tumor are discussed.

Key words:Solitary fibrous tumor, parotid gland, case report.

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.

Disseminated solitary fibrous tumour of the lung and pleura

Solitary fibrous tumours (SFTs) are a heterogeneous group of rare spindle-cell tumours. Classically they presented as a solitary pleural-based mass. Pulmonary parenchymal SFT is rare and multiple bilateral lesions are extremely rare. We present the clinical, imaging and histological features of SFT which are presented as multiple nodular lesions of the lung and pleura with probable distant metastasis.

Solitary fibrous tumor of the buccal vestibule: report of two cases

Solitary fibrous tumor (SFT) is a rare benign tumor that occurs most frequently in the pleura. It is considered rare in the maxillofacial area. Two new cases of SFT of the buccal vestibule are reported. The previously reported cases of oral SFT are reviewed. The tumors were composed of spindle-shaped cells that were arranged haphazardly and were positive for CD-34, BCL-2, CD-99 and vimentin. Although rare, SFT should be included in the differential diagnosis of oral soft tissue tumors. The clinical presentation and imaging can provide the clinician a better tool for preoperative diagnosis.

Pediatric Renal Solitary Fibrous Tumor

Solitary fibrous tumors (SFTs) are unusual spindle cell neoplasms initially described in the pleura but have since been discovered in many extrapleural locations. SFT of the kidney is extremely rare, the majority occurring in middle-aged adults. To date, only two pediatric cases of renal SFT have been reported. We report a case of large SFT in the kidney of a 3-year-old boy that was clinically and radiologically thought to be a nephroblastoma. This case is the first pediatric renal SFT to be reported with detailed histopathologic and cytogenetic analyses. SFT should be included in the differential diagnosis of pediatric renal tumors.

Response to chemotherapy of solitary fibrous tumour: a retrospective study

BACKGROUND

To report on anthracycline-based chemotherapy in a retrospective case-series analysis of solitary fibrous tumour (SFT) patients treated within the Italian Rare Cancer Network.

PATIENTS AND METHODS

We reviewed a set of SFT treated with chemotherapy since 2002, focusing on anthracycline, administered alone or in combination with ifosfamide. Responses to ifosfamide as a single agent were also evaluated. Pathologic diagnosis was centrally reviewed, distinguishing typical, malignant (MSFT) and dedifferentiated (DSFT) subtypes.

RESULTS

Among 42 SFT patients treated with chemotherapy, we selected 31 cases (mean age: 62 years; locally advanced/metastatic: 13/18; front-line/further line: 25/6; typical/MSFT/DSFT/not assessable: 1/17/12/1) who received anthracycline-based chemotherapy (anthracycline monotherapy: eight; anthracycline+ifosfamide: 23). 30 patients are evaluable for response. Best response by Response Evaluation Criteria in Solid Tumours (RECIST) was: partial response (PR): 6 (20%), stable disease (SD): eight (27%), progressive disease (PD): 16 (53%) cases. Responses were confirmed after 3 months. Median progression-free survival (PFS) was 4 (range 2-15) months, with 20% of patients being progression-free at 6 months. PR was found in 2/18 (11%) MSFT and 4/12 (30%) DSFT, with a median PFS of 3.5 and 5 months in MSFT and DSFT, respectively. 19 patients received high-dose prolonged-infusion ifosfamide (front-line/further line: 11/8; typical/MSFT/DSFT: 0/15/4) with two (10%) PR, five (26%) SD, 12 (63%) PD.

CONCLUSIONS

This retrospective series suggests that in SFT anthracyclines have a degree of antitumour activity in the range of soft tissue sarcoma chemotherapy. Ifosfamide monotherapy seemed to have lower activity. A higher response rate was observed in DSFT in comparison to MSFT. Studies on targeted therapies are ongoing.

Solitary fibrous tumor of all sites: outcome of late recurrences in 14 patients

BACKGROUND

We explore the pattern of late recurrence (LR) in solitary fibrous tumor (SFT), focusing on histopathologic characteristics, clinical presentation and patients (pts) outcome.

METHODS

Clinical records of all pts with confirmed pathologic diagnosis of SFT treated at our Institution from 2005 to 2011 were reviewed. We analysed the data of pts who relapsed ≥10 years after initial diagnosis.

RESULTS

A total of 14 pts were identified. The primary site of origin was pleura (5 pts), pelvis (4 pts), head and neck (3 pts) and retroperitoneum (2 pts). Primary tumor was a typical SFT in 5 and a malignant SFT in 7 out of 12 pts whose tumor tissue was available for revision. The median time to first recurrence was 12 years (range 10-23). The first relapse was local in 11 cases, distant in 3. Five pts later developed distant metastases. Four out of 5 cases of typical SFT developed distant metastases in spite of their initial benign aspect. No patient was disease-free at the time of the analyses.

CONCLUSION

Our series suggests that LR can occur in SFT and some cases can behave aggressively even in the absence of any primary morphologic evidence of malignancy. A prolonged follow-up may be advisable.

Malignant solitary fibrous tumor of the kidney: report of the first case managed with interferon

Solitary fibrous tumors of the kidney are extremely rare tumors with unpredictable behavior. We describe a case of a patient with a solitary fibrous tumor of kidney with malignant findings with distant metastasis and nephrectomy managed with subcutaneous interferon achieving 23 months of progression-free survival. To date there is no prospective evaluation of any specific modality of treatment, but the surgical management and long-term followup are the only ones so far recommended strategies in the management of these patients. Studies are awaited with more patients to evaluate the different strategies of systemic therapy reported so far to allow adding survival benefit.

Myxoid solitary fibrous tumor: a study of three cases

Limited myxoid areas are usually encountered in solitary fibrous tumor (SFT), but SFT with abundant myxoid stroma has only been reported occasionally. Myxoid SFT is defined as having myxoid changes in 50% or more of the tumor. We review the literature on myxoid SFT and add 3 new cases to those previously described. Microscopically, the lesions were composed of spindle cells arranged in a haphazard or storiform pattern in a cellular and hypocellular myxoid background with thin-walled "staghorn" branching vessels. Atypical features (necrosis, hypercellularity, or increased mitotic figures) were not identified. All cases were positive for CD34 and CD99 and had a benign course with a follow-up ranging from 15 to 70 months. Our review suggests that like classical SFT, myxoid SFT is associated with an indolent clinical course and favorable prognosis. Their recognition is crucial to distinguish a variety of myxoid spindle cell neoplasms with different prognoses and treatment options.

Sunitinib malate in solitary fibrous tumor (SFT)

BACKGROUND

To report on sunitinib activity in a retrospective series of 35 solitary fibrous tumor (SFT) treated at a single institution.

PATIENTS AND METHODS

From April 2008, 35 patients with progressive advanced SFT (male/female: 20/15; mean age: 58 years; meningeal/extrameningeal: 6/29; locally advanced/metastatic: 15/20; prior chemotherapy: 25) were treated, on an individual use basis, with continuous-dosing sunitinib 37.5 mg/day. Platelet-derived growth factor receptor beta (PDGFRB) and vascular endothelial growth factor receptor 2 (VEGFR2) status were assessed by immunohistochemistry and, in a subgroup of patients, by real time PCR.

RESULTS

Thirty-one patients were assessable for response by RECIST (one early death; three early interruptions). Best responses were 2 partial response (PR), 16 stable disease, 13 progressive disease. A <30% decrease in size was observed in three patients. Fourteen of 29 patients assessable by Choi criteria had a PR. Median progression-free survival by RECIST was 6 months (range 1-22). In two of six patients, resistance to sunitinib was overcome by increasing sunitinib to 50 mg/day. PDGFRB and/or VEGFR2 were positive in all cases and not predictive of response; a less aggressive morphology corresponded to an increased response rate (53% PR by Choi in the malignant SFT, 20% PR in the pleomorphic/dedifferentiated SFT).

CONCLUSIONS

Sunitinib is active in SFT. Response can be long-lasting.

Solitary fibrous tumors of the pleura

PURPOSE OF REVIEW

Solitary fibrous tumor of the pleura (SFTP) is a rare neoplasm of the pleura. Although an increasing number of case series have been reported in recent years, so far clinical behavior is still unpredictable. The following article presents a detailed review of the recent larger series of SFTP with particular attention to the clinical presentation, pathologic characteristics and surgical features in order to define more precisely the long-term outcome after treatment of this rare entity.

RECENT FINDINGS

Usually, after a complete surgical resection a very long survival could be expected in almost all cases. However, the preoperative detection and management of malignant SFTPs are still challenging issues.

SUMMARY

SFTP remains an enigmatic tumor. Clinical and radiological assessment is often unsatisfactory to obtain a definitive diagnosis. Benign SFTPs are almost always cured with complete surgical resection, and in cases of recurrence the re-do resection of benign recurrences is usually curative. Long-term survivals are also possible for malignant SFTPs, although a higher recurrence rate and higher tumor-related mortality can be expected in these cases. Histologic characteristics distinguishing benign from malignant variants are crucial in estimating the risk of recurrence and planning adjuvant therapies.

Slug, twist, and E-cadherin as immunohistochemical biomarkers in meningeal tumors

The overexpression of Twist and Slug and subsequent down-regulation of E-cadherin facilitate the acquirement of invasive growth properties in cancer cells. It is unclear which of these molecules are expressed in mesenchymal tumors in the central nervous system. Here, we investigated 10 cases each of hemangiopericytoma, solitary fibrous tumor, meningothelial, fibrous, angiomatous, and atypical meningiomas, and 5 cases of anaplastic meningioma for Slug, Twist, E-cadherin, and N-cadherin immunoexpression. Nuclear Slug expression was observed in 9/10 (90%) hemangiopericytomas and 5/10 (50%) solitary fibrous tumors, but not in any meningiomas, except for 1 case. Similarly, nuclear Twist expression was more extensive in hemangiopericytomas and solitary fibrous tumors than meningiomas. In contrast to Slug and Twist, the positive expression of E-cadherin was observed in 39/45 (87%) meningiomas, but not in any hemangiopericytomas or solitary fibrous tumors (P<0.0001). The fraction of tumor cells expressing E-cadherin in meningeal tumors was negatively correlated to those of Twist (P = 0.004) and Slug (P<0.0001). The overexpression of Slug and Twist with down-regulation of E-cadherin was characteristic findings in hemangiopericytomas and solitary fibrous tumors, but not in meningiomas. The immunohistochemical profiles of the two tumor groups may be useful as diagnostic markers in cases that present a differential diagnosis challenge.

Solitary fibrous tumor of the pleura: An analysis of forty patients

OBJECTIVE

To study the clinical characteristics, treatment and prognosis of patients with solitary fibrous tumor of the pleura (SFTP) in order to improve the diagnostic accuracy and treatment of SFTP.

METHODS

A retrospective analysis of clinical and imaging features, serum biochemical changes, pathological characteristics and treatment follow-up results was conducted for 40 SFTP patients from January 1998 to March 2010.

RESULTS

A chest CT diagnosis was conducted for 63.6% of the patients; the unenhanced and contrast-enhanced CT findings were significantly different among the cohort (P<0.01). Patients lacking a uniform MRI internal signal comprised 88.9% of the group, 66.7% showed T1 isointensity, 33.3% demonstrated T1 hypointensity, 44.4% showed T2 hypointensity and 44.4% had slight hypointensity. The follow-up time was between 2 and 116.9 months, with an average of 35 months; postoperative adjuvant therapy was not administered. Currently, all the studied patients are alive, with no metastasis or recurrence.

CONCLUSION

Chest CT is a valuable tool for diagnosis and surgical decisions, and the efficacy of MRI examination is comparable to chest CT. The majority of cases originated in the visceral pleural; for these, surgical resection is an effective treatment, and the prognosis is generally favorable.

Non-epithelial neoplasms of the prostate

Non-epithelial prostatic neoplasms are infrequent and cover a broad array of entities that include both benign and highly aggressive tumours. Because they are very infrequent, there is often limited understanding of them, and the recognition of these entities, when encountered, may pose a diagnostic challenge, owing to histological overlap between them or their rarity. Most lesions in this category are mesenchymal in origin, such as prostatic stromal tumours arising from specialized prostatic stroma, smooth muscle tumours, both benign and malignant, and solitary fibrous tumours. Less commonly occurring tumours include neural, germ cell and melanocytic tumours that may be derived from cells not normally present in the prostate. Some tumours have well-established extraprostatic counterparts and, when encountered, are more commonly extraprostatic/secondary in origin; these include gastrointestinal stromal tumours and most haematopoietic tumours. The majority of tumours are characterized by a spindle cell pattern with significant overlap in morphological features. In this setting, appropriate use of immunohistochemistry and molecular studies are often necessary for accurate diagnosis, prognosis, or prediction for therapy. This review addresses and updates the clinicopathological features of the entire spectrum of non-epithelial tumours with an approach to the histological diagnosis.

"Hitting all the right markers to save a life" Solitary fibrous tumors of the central nervous system: Case series and review of the literature

Background:

Solitary fibrous tumors (SFTs) of the central nervous system are uncommon. Their biological features remain largely unknown; hence, the clinical management and prognosis is often challenging due to the lack of comprehensive data. For this reason, we present two cases of large SFTs to illustrate a comprehensive review.

Methods:

This was a retrospective analysis of two patients: a 65-year-old male with a left parietooccipital lesion and a 70-year-old female with a right parietal convexity mass.

Results:

Gross total resection was performed in the male patient with no recurrence 30 months after resection. The second patient received stereotactic radiosurgery for what was initially thought to be a parafalcine meningioma; however, continued growth 1 year later prompted an open resection, with pathology indicative of an SFT. The tumor recurred the following year requiring repeat resection. Unfortunately, due to the aggressive nature of the lesion, the patient eventually succumbed to tumor burden a year later.

Conclusion:

Based on the literature review, the sometimes observed aggressive growth pattern, and also, the potential for malignant transformation, we recommend complete resection of SFTs with close sequential follow-up.

Resection of a giant, invasive malignant solitary fibrous tumor of pleura

Solitary fibrous tumor of pleura (SFTP) is a rare mesenchymal neoplasm that most commonly involves the pleura, is probably derived from fibroblasts, and has no relationship to malignant mesothelioma. Here, we report a case of complete resection of a giant malignant SFTP. A 61-year-old woman developed fever and left flank pain. Computed tomography revealed the tumor to be 13 cm in size and located in the left thoracic cavity, directly invading the left lower lobe of the lung. The patient underwent radical resection and left lower lobectomy. Immunohistochemical examination revealed a dense proliferation of spindle-shaped cells with ovoid nuclei and collagen fibers hyperplasia. The cells were positive for CD34 and vimentin, and were negative for cytokeratin AE1/AE3, calretinin, S-100 and smooth muscle α-actin. SFTPs have malignant potential, as 20-30 % of resected SFTPs reportedly contain malignant components. Careful long-term clinical follow-up is therefore required for all cases of SFTP.

Solitary fibrous tumor: an update on the spectrum of extrapleural manifestations

Solitary fibrous tumor (SFT) is a rare tumor initially believed to be a benign localized pleural tumor of mesothelial origin. Over the past few years, the literature on this tumor has grown tremendously. The tumor is now reported in diverse bodily locations, and recognized to have a wider range of clinical and radiological features. The most common extrapleural sites of the tumor are the orbits and the extremities. Tumors are often well-circumscribed masses, and vary in size from 1 cm to over 30 cm. The admixture of histological components in the tumor, namely, fibrous tissue, cellular components, and highly vascularized areas consisting of numerous closely packed small to medium-sized blood vessels, influence the imaging appearances of the tumor. On magnetic resonance imaging (MRI), the diagnosis of solitary fibrous tumor is suggested by a well-circumscribed mass that has smooth margins, and focal or diffuse hypointense signal on T2-weighted imaging due to fibrous content in the tumor. SFTs demonstrate strong focal or diffuse contrast enhancement due to the highly vascularized areas in the tumor.

Skull base metastases from a malignant solitary fibrous tumor of the liver. A case report and literature review

Solitary fibrous tumors (SFTs) of the liver are rarely described; only 38 cases have been reported in literature, most of which have shown benign clinical characteristics, and only 3 of these cases exhibited malignant variants. In this study, we present a 24-year-old woman with a 1-month history of a rapidly enlarging abdominal mass and a CT showing an exophytic heterogeneous liver mass with a firm parietal bone mass. The patient underwent a transcatheter arterial chemoembolization (TACE) before operation, and an extended right hepatectomy and craniectomy with a negative margin was performed under general anesthesia. The masses showed histological features of oval spindle cells haphazardly arranged in the classic short-storiform or so-called patternless pattern of solitary fibrous tumors. The tumor cells showed positive immunohistochemical reactions to CD34 and bcl-2. The tumor recurred in the residual liver 2 months after operation, metastatic osteoblastic lesions in the thoracic and lumbar vertebrae were identified 3 months after the operation, and lumbar vertebrae metastasis 7 months after operation paralyzed the patient. The patient underwent percutaneous ethanol injection therapy (PEI) and chemotherapy, but the patient died because of the uncontrolled tumor 16 months after the initial operation. To our knowledge, this is the first case of malignant solitary fibrous liver tumors with skeletal metastasis.

Solitary fibrous tumor arising in the mesentery: a case report

Background

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm usually found in the pleura, soft tissues and visceral organs. We describe one case arising in the mesentery, which is an exceptional localization.

Case presentation

A 71-year-old man was referred to our establishment for a painless hypogastric mass. Further investigation revealed a vascular tumor, which was resected en bloc. Pathological findings confirmed solitary fibrous tumor of the mesentery.

Conclusion

This is the second case of solitary fibrous tumor of the small intestine mesentery ever reported. It was managed by en bloc resection and close follow up considering the high risk of recurrence. Investigation should be made regarding the use of adjuvant systemic therapy to improve long-term survival for these patients.

Parotid gland solitary fibrous tumor: a case report and clinicopathologic review of 22 cases from the literature

Solitary fibrous tumors (SFTs) are rare tumors in the head and neck, and even more so in the parotid gland. The mass-like clinical presentation and histologic features result in frequent misclassification, resulting in inappropriate clinical management. There are only a few reported cases in the English literature. Twenty-one patients with parotid gland solitary fibrous tumor were compiled from the English literature (Medline 1960-2011) and integrated with this case report. The patients included 11 males and 11 females, aged 11-79 years (mean, 51.2 years), who presented with a parotid gland painless mass gradually increasing in size or with compression symptoms, with a mean duration of symptoms of 24.7 months. The mean tumor size was 4.5 cm. Grossly, all tumors were described as well-circumscribed to encapsulated, firm, homogenous white to tan masses. Seven patients had a preoperative fine needle aspiration performed, with the majority interpreted to represent pleomorphic adenoma or cementifying fibroma. Histologically, the tumors were well circumscribed, although many tumors showed focally entrapped normal salivary gland acini and ducts at the edge. The tumors were cellular, arranged in haphazard short interlacing fascicles of spindled to epithelioid cells. The spindled cells showed tapering cytoplasm with monotonous, round to oval nuclei with coarse nuclear chromatin distribution. Keloid-like to wiry collagen was present between the neoplastic cells. Mitoses were identified in most cases, while necrosis was absent. Isolated, patulous vessels were present, but a well developed "hemangiopericytoma-like" vascular pattern was not seen. Three tumors were classified as malignant, showing marked nuclear pleomorphism and increased mitoses. When immunohistochemistry was performed, all tumors showed strong and diffuse vimentin, with a majority showing CD34, bcl-2 and CD99 immunoreactivity; all cases tested were negative for S100 protein, cytokeratin, EMA, CAM5.2, smooth muscle actin, muscle specific actin, desmin, MYOD1, myogenin, CD117, GFAP, CD31, FVIII-RAg, collagen IV, p63, p53, calponin, caldesmon, CD56, NFP, and ALK-1. The principle differential diagnoses include pleomorphic adenoma, myoepithelioma, nodular fasciitis, schwannoma, fibromatosis coli, spindle cell "sarcomatoid" carcinoma, and spindle cell melanoma. All patients were managed with surgery, while two patients also received radiation therapy. Metastatic disease was identified in one patient immediately after excision. All patients with follow-up were alive without evidence of disease (n = 18), but the average follow-up is only 1.9 years. One patient is alive with disease at 12 months. Parotid gland SFT is a rare tumor, usually presenting in middle aged adults as a slowly growing mass. Characteristic histologic appearance with CD34 and bcl-2 immunoreactivity support the diagnosis. Surgery is the treatment of choice to yield a good outcome.

De novo malignant solitary fibrous tumor of the kidney

The kidney is a relatively infrequent site for solitary fibrous tumor (SFT). Among the previously reported cases, only two cases of malignant renal SFT developing via dedifferentiation from a pre-existing benign SFT have been reported. Here we reported a case of de novo malignant renal SFT clinically diagnosed as renal cell carcinoma in a 50-year-old woman. The tumor was circumscribed but unencapsulated and showed obvious hemorrhagic necrosis. Microscopically, the tumor was composed of patternless sheets of alternating hypercellular and hypocellular areas of spindle cells displaying mild to moderate nuclear atypia, frequent mitoses up to 8 per 10 high power fields, and a 20% Ki-67 proliferative index. Immunohistochemical studies revealed reactivity for CD34, CD99 and vimentin, with no staining for all other markers, confirming the diagnosis of SFT. No areas of dedifferentiation were seen after extensive sampling. Based on the pathologic and immunohistochemical features, a diagnosis of de novo malignant renal SFT was warranted. Our report expands the spectrum of malignant progression in renal SFTs. Even though this patient has been disease-free for 30 months, long-term follow-up is still mandatory.

Solitary fibrous tumor of the central nervous system: a 15-year literature survey of 220 cases (August 1996-July 2011)

We reviewed the world literature on solitary fibrous tumors of the central nervous system from August 1996 to July 2011, focusing on both clinicopathological features and diagnostic findings. The anatomical distribution of the 220 cases reported so far reveals that most are intracranial and just over one-fifth are intraspinal. In decreasing frequency, intracranial tumors involve the supratentorial and infratentorial compartments, the pontocerebellar angle, the sellar and parasellar regions, and the cranial nerves. Intraspinal tumors are mainly located in the thoracic and cervical segments. Although most solitary fibrous tumors of the central nervous system are dural based, a small subset presents as subpial, intraparenchymal, intraventricular, or as tumors involving the nerve rootlets with no dural connection. Preoperative imaging and intraoperative findings suggest meningioma, schwannoma or neurofibroma, hemangiopericytoma, or pituitary tumors. Immunohistochemistry is critical to establish a definitive histopathological diagnosis. Vimentin, CD34, BCL2, and CD99 are the most consistently positive markers. The usual histologic type generally behaves in a benign manner if complete removal is achieved. Recurrence is anticipated when resection is subtotal or when the tumor exhibits atypical histology. The proliferative index as assessed by MIB1 labeling is of prognostic significance. Occasionally, tumors featuring conventional morphology may recur, perhaps because of minimal residual disease left behind during surgical extirpation. Rare extracranial metastases and tumor-related deaths are on record. Surgery is the treatment of choice. Stereotactic and external beam radiation therapy may be indicated for postsurgical tumor remnants and for unresectable recurrences. Long-term active surveillance of the patients is mandatory.

Solitary Fibrous Tumor of the Central Nervous System

Solitary fibrous tumor (SFT) of the central nervous system was first described in 1996. A number of cases have been reported since. The authors present 5 new cases: 4 intracranial and 1 intraspinal. All patients were adults (age range, 47 to 75 years); 4 were male and 1 female; 4 cases were primary tumors; and 1 was a second tumor recurrence. All patients were surgically treated with gross total removal. All cases were histologically examined with immunohistochemical confirmation; 2 tumors exhibited diffuse classic histology, 1 tumor was a cellular variant, 1 tumor was myxoid, and 1 was predominantly classic with focal myxoid features and focally pleomorphic. The postoperative course was uneventful in all. The patient with the cellular variant experienced 2 local recurrences and eventually died of disease 10 years after the initial diagnosis. The patient with the myxoid variant—the tumor studied—which was the second recurrence of a previously misdiagnosed fibrous meningioma surgically treated 15 years earlier, had a recurrence after 2 years for the third time and eventually died of disease. Three patients are alive and well 11.6, 6, and 4 years after surgery. SFT is a rare tumor that needs to be differentiated from some mimickers, mainly fibrous meningioma, hemangiopericytoma, and with regard to the myxoid variant, also adult-onset myxochordoid meningioma and myxoid peripheral nerve sheath tumor. Immunohistochemistry is crucial for the correct diagnosis of SFT. The authors also performed a review of the literature and found a little more than 200 cases on record.

Somatic and visceral solitary fibrous tumors in the abdomen and pelvis: cross-sectional imaging spectrum

Solitary fibrous tumors (SFTs) are a unique group of mesenchymal neoplasms of fibroblastic or myofibroblastic origin. These tumors were originally described as "benign fibrous mesotheliomas" of the pleural cavity and were erroneously thought to be confined to the serosal surfaces (due to a putative mesothelial or submesothelial origin). It is now established that SFTs are ubiquitous neoplasms with both pleural and extrapleural distribution. Extrapleural SFTs commonly occur in middle-aged adults and manifest as asymptomatic, slow-growing, large tumors. Fewer than 5% of patients with SFTs present with symptomatic hypoglycemia. SFTs are histopathologically diverse with a variable admixture of fibroblasts or myofibroblasts, numerous thin-walled vessels, and dense fibrosis. Tumors previously categorized as hemangiopericytomas are now considered cellular variants of SFTs. At imaging, SFTs demonstrate remarkable heterogeneity, with variable degrees of enhancement, necrosis, or hemorrhage. Although most extrapleural SFTs have a benign clinical course, 10%-15% of these tumors demonstrate aggressive behavior in the form of recurrence or malignancy.

Solitary fibrous tumor of the cerebello-pontine angle

A case is presented of solitary fibrous tumor occurring in the cerebello-pontine angle. There have been only two other reported cases of a solitary fibrous tumors in this region. Imaging studies showed the tumor to be characteristic in shape and position of an acoustic tumor. However, at surgery the tumor was found to have a "rock hard" consistency. Solitary fibrous tumor differs from acoustic schwannoma and meningioma in its histopathological features and in this case, regrowth, after incomplete excision, was extremely rapid.

An intracranial malignant solitary fibrous tumor

Intracranial malignant solitary fibrous tumor (SFT) is very rare. It was identified in a 39-year-old female patient who underwent malignant transformation over 6 months. MRI revealed an 8 × 5 × 6 cm mass with heterogenous strong enhancement in the left occipital lobe. Histologic findings and immunophenotype (positive for CD34, bcl-2 and vimentin, and negative for epithelial membrane antigen or S100 protein) of the primary tumor were typical of SFT. However, there was a focal area (<10% of tumor volume) showing hypercellularity, nuclear pleomorphism and increased Ki-67 labeling index (LI) of 10% (average, 1%). At the second operation, the recurrent tumor revealed full-blown histologic features of malignant SFT, such as infiltrative brain invasion, marked nuclear pleomorphism, frequent mitotic figures (15/10 high power fields), and high Ki-67 LI (25%). The presence of atypical histologic finding or increased Ki-67 LI in the typical SFT, although it is focal, needs to be mentioned in the diagnosis and also may require more aggressive surgical management.

Malignant solitary fibrous tumor of retroperitoneum mimicking gastric submucosal tumor

Solitary fibrous tumors (SFTs) are an uncommon neoplasm characterized by the proliferation of spindle cells. The diagnostic criteria of malignant solitary fibrous tumors (MSFTs) include high cellularity, high mitotic activity (4>10 HPF), pleomorphism, hemorrhage and necrosis. This tumor frequently involves the pleura and MSFTs of retroperitoneum mimicking gastric submucosal tumor are very rare. We report a rare case of MSFT that presented as a gastric submucosal tumor. A gastroscopic examination showed a large bulging mucosa in the gastric body. Abdominal computed tomography revealed a well-defined heterogeneous enhancing mass between the left hepatic lobe and gastric body. Surgical resection was performed and histologic features were consistent with a MSFT.

Solitary Fibrous Tumor With Multiple Intracranial and Spinal Lesions: Case Report

BACKGROUND AND IMPORTANCE:

Solitary fibrous tumor (SFT) has been previously reported for its wide variety of presentations and atypical sites. We report a case of recurrent SFT with multiple intracranial and spinal lesions.

CLINICAL PRESENTATION:

A 45-year-old female with recurrent right frontoparietal SFT was found to have multiple intracranial and spinal lesions. Most of the lesions are asymptomatic. Each of the intracranial and spinal lesions has been confirmed histologically. In 1999 the patient was found to have a single right temporal SFT and had a gross total resection of the lesion. In 2005 the patient underwent a second gross total resection for the recurrence of the right temporal-parietal lesion, followed by radiation therapy. In 2009 she underwent a third and fourth gross total resection of the right frontoparietal lesion, and the L4-5 mass, as well as a cervical laminectomy for an extramedullary spinal lesion causing spinal compression.

CONCLUSION:

This is the first case report of recurrent SFT with multiple intracranial and spinal lesions. This case illustrates the nature of recurrence and multiplicity of SFT and raises the importance of a thorough investigation, especially in the entire neuroaxis, in patients with the diagnosis of SFT. This case also questions the justification of the name that was given to this tumor.