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

Solitärer fibröser Tumor der Zunge

Solitary fibrous tumors (SFT) are rare, mostly fibroblastic tumors usually situated in the pleura. Extrapleural manifestations have been described. However, the oral cavity is an uncommon localisation of this tumor. We report the very unusual case of an SFT affecting the tongue that could be removed completely because of its clear delineation. Intraoperative incisional biopsies were used to exclude malignancy. For definitive classification of the tumor, additional histopathologic examinations had to be carried out. Because SFT exhibit malignant behavior only in exceptional cases and their recurrence after complete removal has never been encountered, surgery can focus on the preservation of undisturbed function of the tongue.

Laryngeal solitary fibrous tumour

Solitary fibrous tumours (SFT) are rare neoplasms, with an uncommon laryngeal involvement. Only five cases of laryngeal localization have been described in literature. The following is a case of a 75-year-old man with a supraglottic neoplasm of the larynx; after the biopsy immunohistochemical study demonstrated a strong positivity for vimentin, CD34 and Bcl-2. The neoplasm was consequently classified as a SFT. CO(2) laser surgery of the supraglottic larynx, with a wide excision of the neoplasm, was performed. Twenty-four months on, the patient is alive, well and free of disease. Surgical resection is the treatment of choice for laryngeal SFT, but tumour-free resection margins must be achieved to prevent the possibility of local recurrence. Endoscopic resection by means of the CO(2) laser must be accurately planned with MRI or CT imaging to confirm of this kind of surgery.

Vaginal Solitary Fibrous Tumor

OBJECTIVE

Primary solitary fibrous tumors (SFTs) of the female genital tract are exceedingly rare. We report a spindle cell tumor of the vagina with features consistent with a SFT in a 52-year-old woman.

MATERIALS AND METHODS

The original tumor was studied with the appropriate panel of immunohistochemical stains. The first recurrence of the tumor was 10 months after its original incomplete excision, and a second recurrence occurred 29 months later. Both recurrences were analyzed using the same immunohistochemical panel.

RESULTS

After considering several related differential diagnoses, the diagnosis of SFT was made based on the morphological and immunophenotypic features.

CONCLUSION

To the best of our knowledge, this is the third case of vaginal SFT in the English literature, with 2 recurrences after incomplete excision.

Solitary fibrous tumours of the infratemporal fossa. Two case reports

INTRODUCTION

The solitary fibrous tumour is a rare neoplasm originally described as a pleural tumour. An increasing number of different locations are described in the literature. Among the extrapulmonary sites, head and neck can be involved and particularly the nose, the paranasal sinuses, the submandibular region, the parapharyngeal space and the infratemporal fossa.

MATERIAL

Two cases, one of a young woman and another of an elderly gentleman are reported, each presenting with a solitary fibrous tumour of the infratemporal fossa. In one case an antero-lateral, transcranio-facial and in the other, a transmandibular approach (without labiotomy) were utilized. In both cases complete excision of the lesion and good cosmetic results were achieved.

RESULTS

Both patients were free from the disease for 5 postoperatively.

CONCLUSIONS

To date, very few cases of solitary fibrous tumour of the craniofacial complex have been observed to enable an accurate prognosis. Thus, treatment and follow-up should be identical to fibrous tumours located in other areas.

Tumeur fibreuse solitaire de la vessie

INTRODUCTION

A solitary fibrous tumor is a rare circumscribed neoplasm that was long known in the pleura and has now described in many organs and soft tissues. Prognosis is favorable after complete excision.

CASE

We report a solitary tumor fibrous located in the bladder of a 38-year-old man with dysuria and a palpable abdominal mass.

DISCUSSION

Solitary fibrous tumors are reported very rarely in the urinary bladder. They may mimic other nonepithelial tumors in this site. Diagnosis based only on pathological features is difficult. When complete excision is possible, prognosis is generally good. Outcome is more serious in approximately 10-20% of cases, and strict follow-up is required.

Giant solitary fibrous tumour of the liver

Background

Solitary fibrous tumour (SFT) is an uncommon mesenchymal neoplasm that most frequently affects the pleura, although it has been reported with increasing frequency in various other sites such as in the peritoneum, pericardium and in non-serosal sites such as lung parenchyma, upper respiratory tract, orbit, thyroid, parotid gland, or thymus. Liver parenchyma is rarely affected. Clinically, SFTs cause symptoms after having reached a certain size or when vital structures are involved. In recent years, SFTs are more often identified and distinguished from other tumours with a similar appearance due to the availability of characteristic immunohistochemical markers.

Case presentation

In this manuscript we report the case of a large tumour of the liver, which was histologically diagnosed as a SFT, and showed involvement of a single hepatic segment. Because of the patient's presentation and clinical course, it may represent a radiation-induced lesion.

Conclusion

When a SFT has been diagnosed, surgery is the treatment of choice. The small number of patients with a SFT of the liver and its unknown natural behaviour creates the need to a careful registration and follow-up of all identified cases

Stereotactic radiosurgery as adjuvant treatment for residual solitary fibrous tumor

✓ This 50-year-old woman presented with headache and visual disturbance. Neuroimaging results demonstrated a well-demarcated tumor attached to the falx cerebri near the transverse sinus, and the lesion was subtotally removed. Based on histological and immunohistochemical evaluation, a solitary fibrous tumor (SFT) was diagnosed. During the next 32 months, the size of the residual tumor increased slightly at the transverse sinus. Stereotactic radiosurgery (SRS) was performed as an adjuvant treatment. Over the course of the next 4 years the tumor decreased in size. The authors suggest that SRS constitutes good adjuvant treatment for regrowing residual SFTs not amenable to reoperation.

Solitary Fibrous Tumor Arising from Cranial Nerve VI in the Prepontine Cistern: Case Report and Review of a Tumor Subpopulation Mimicking Schwannoma

OBJECTIVE:

The authors present a report of a solitary fibrous tumor (SFT) arising from the intradural component of the VIth cranial nerve as it travels through the prepontine cistern. SFTs of the central nervous system are extremely rare entities that clinically masquerade as dural-based lesions, such as meningiomas or hemangiopericytomas. Because of their infrequency and clinical similarity to other central nervous system (CNS) lesions, diagnosis is largely dependent on pathological features. In this study, the authors define a subpopulation of SFTs that seem to arise directly from nerve, rather than meninges, and clinically mimic the appearance of a schwannoma.

CLINICAL PRESENTATION:

The patient was a 29-year-old woman with a several-month history of progressive right arm and leg numbness and mild hemiparesis, with the development of diplopia 2 weeks before admission. Outside imaging revealed a 3.9-cm mass in the prepontine cistern with extension into Meckel's cave and the cavernous sinus, resulting in significant brainstem compression.

INTERVENTION:

The patient underwent preoperative angiography with embolization of feeding vessels off of the left meningohypophyseal trunk. The patient was then taken to the operating room by a combined neurosurgical and ear, nose, and throat team, where the patient underwent a retrolabyrinthine/subtemporal craniotomy for tumor resection. During resection of the prepontine component, the tumor was identified as originating from the left Cranial Nerve VI as it traversed through the prepontine cistern. Resection of the tumor component involving the cavernous sinus and Meckel's cave was deferred for follow-up treatment with intensity-modulated radiation therapy. Pathological examination revealed tissue consistent with the diagnosis of SFT.

CONCLUSION:

SFTs involving the CNS are rare entities that are almost always diagnosed after tissue is obtained because of their clinical and radiographic similarity to meningiomas. This patient had an SFT masquerading as a VIth cranial nerve schwannoma. Although the natural history of SFTs in the CNS is not completely understood, correct diagnosis is important, given the rate of recurrence found in the more common pleural-based SFT and examples of CNS SFTs with malignant features.

Spindle cell predominant trichodiscoma: a fibrofolliculoma/trichodiscoma variant considered formerly to be a neurofollicular hamartoma: a clinicopathological and immunohistochemical analysis of 17 cases

Seventeen solitary nasal tumors that fulfilled all diagnostic criteria of so-called neurofollicular hamartoma, apart from distinct S100-positivity, were compared histopathologically and immunohistochemically with seven typical trichodiscomas from a similar clinical setting. Both the S100-negative neurofollicular hamartoma-like tumors and the trichodiscomas expressed an identical CD13-positive/CD34-positive fibrocytic immunophenotype without co-expression of neural/perineural (S100, neurofilament, epithelial membrane antigen), myogenic (desmin, calponin, muscle-specific actin, and alpha-smooth muscle actin), or melanocytic (S100, HMB45, NKI/C3, MelanA) epitopes. Histopathologically, there was striking morphologic overlap between trichodiscoma and S100-negative neurofollicular hamartoma-like tumor, apart from a highly characteristic fascicularly organized cellular fibrocytic stroma in the latter. We conclude that fibrofolliculoma/trichodiscoma and neurofollicular hamartoma-like tumor are morphologic variants of a single hamartomatous entity in which neurofollicular hamartoma-like tumor occupies the cellular pole of the morphologic spectrum. The entity formerly known as neurofollicular hamartoma appears to be nothing but a particularly cellular trichodiscoma with a distinctively organized stroma composed of CD34-positive fibrocytes. We therefore propose the new term spindle cell predominant trichodiscoma (SCPT) for this particular variant of the morphologic fibrofolliculoma/trichodiscoma spectrum.

Solitary Fibrous Tumor of the Floor of the Mouth: Case Report and Review of the Literature

Solitary fibrous tumor is an uncommon spindle cell neoplasm that is believed to be of mesenchymal origin. Rarely does it originate in the oral cavity, and only 1 case of this lesion in the floor of the mouth has been previously reported. We describe a new case of solitary fibrous tumor arising from the soft tissues of the floor of the mouth.

Solitary fibrous tumor of the retropharynx causing obstructive sleep apnea

Solitary fibrous tumors (SFTs) are rare, usually benign, spindle cell neoplasms that most often originate near mesothelium-lined surfaces of the pleural or peritoneal cavity. SFTs reported in the head and neck occur most commonly in the oral cavity, sinonasal tract, and orbit. We report a case of SFT of the retropharynx causing severe obstructive sleep apnea. The diagnostic and management strategies of SFTs are discussed.

Intraparenchymal solitary fibrous tumor of the lung: an uncommon cause of a pulmonary nodule

Solitary fibrous tumor of the lung is a rare mesenchymal tumor entity that has been characterized histologically. Its CT features have not been described before in the radiologic literature. We present the clinical, radiologic, and imaging features of a solitary fibrous tumor of the lung. The lesion we describe demonstrated slow growth and well defined margins. Specifically, we demonstrate its avid heterogeneous enhancement following intravenous contrast administration. Although rare, the diagnosis should be considered in asymptomatic slow growing pulmonary nodules with similar features.

Malignant Solitary Fibrous Tumor of the Kidney: Report of a Case and Comprehensive Review of the Literature

Renal solitary fibrous tumors (SFTs) have been reported infrequently. We report a 76-year-old man with a left renal mass that had previously been shown radiographically to be stable, but was now growing. Grossly, the mass measured 12 cm, was poorly circumscribed, and invaded beyond the renal capsule. Approximately 10% of the neoplasm consisted of haphazardly arranged spindle cells admixed with dense collagenous bands, which is typical of benign SFT. However, the remainder of the mass was composed of pleomorphic, spindled sarcoma cells with frequent mitoses and foci of necrosis. Immunohistochemically, we observed CD34 labeling in the benign SFT component with loss of expression in the sarcomatous component, focal labeling for Bcl-2 protein in both areas, and absence of labeling for cytokeratin, renal cell carcinoma marker, S100 protein, CD117, and muscle markers in both areas. To our knowledge, this is the first reported case of malignant renal SFT, likely representing transformation from a histologically documented benign SFT component.

[Solitary fibrous tumor of the pancreas. A case report]

Solitary fibrous tumour (SFT), a rare mesenchymal neoplasm usually arising from the pleura, may also occur in many other extra pleural sites. It has exceptionally been described in the pancreas. This report describes the case of a benign SFT of the pancreas occurring in a 41-year-old man who presented with a solid epigastric mass. Pathological and immunohistochemical findings are presented. Imaging features on ultrasonography, CT, MRI, and arteriography are widely detailed. Surgical resection of the tumour was performed, and the patient died from postoperative complications.

Solitary fibrous tumour and haemangiopericytoma: evolution of a concept

Haemangiopericytoma (HPC) was described in 1942 by Stout and Murray as a distinctive soft tissue neoplasm, presumably of pericytic origin, exhibiting a characteristic well-developed "staghorn" branching vascular pattern. Over the years, it appeared that this growth pattern was a non-specific one, shared by numerous, unrelated benign and malignant lesions, and that HPC was better considered as a diagnosis of exclusion. Three categories of lesion may now be individualized within the heterogeneous group of HPC-like neoplasms. The first category corresponds to those non-HPC neoplasms that occasionally display HPC-like features (e.g. synovial sarcoma). Lesions belonging to the second category show clear evidence of myoid/pericytic differentiation and correspond to true HPCs. They generally show a benign clinical course, and include glomangiopericytoma/myopericytoma, infantile myofibromatosis (previously called infantile HPC), and a subset of sinonasal HPCs. The third category is the solitary fibrous tumour (SFT) lesional group, which includes fibrous-to-cellular SFTs, and related lesions such as giant cell angiofibromas and lipomatous HPCs. In practice, any HPC-like lesion can be allocated to one of these categories, leaving the ill-defined "haemangiopericytoma" category empty.

Solitary fibrous tumour of the oral cavity with histological features of aggressiveness

We operated on a 65-year-old woman and removed a solitary fibrous tumour from her oral mucosa. Microscopically we found marked atypia, abundant necrosis, increased number of mitotic figures (>4 in 10 high-power fields) and hypercellularity. The tumour cells were strongly stained for CD34. There has been no recurrence after 18 months.

Recurrent solitary fibrous tumour in the cerebellopontine angle

Solitary fibrous tumours (SFT) of the central nervous system are rare. They resemble meningioma in clinical presentation, imaging features and appearance at surgery. Schwannoma, hemangiopericytoma and other spindle cell mesenchymal neoplasms should also be considered in the differential diagnosis. Although the histogenesis of this tumour is still debated, strong CD34 reactivity of the tumour cells suggests that SFT is mesenchymal. We present the clinical, radiological, and pathological features of an SFT located in the cerebellopontine angle (CPA). A 55-year-old female presented with 6 months of headache. The MRI scan showed a contrast enhancing ovoid mass in the left CPA. At craniotomy, the tumour was completely resected. Histolopathological diagnosis was of meningioma. Three years later, the symptoms recurred and an MRI scan demonstrated tumour recurrence. A repeat craniotomy was performed and the lesion was again completely excised. Tumour morphology on histopathology and immunoreactivity for CD34 of the tumour cells supported the diagnosis of SFT. Review of the original tumour also disclosed immunoreactivity for CD34. Ki67 labeling indices were less than 1% in both tumours.

A Highly Vascular Intracranial Solitary Fibrous Tumor Treated with Radiotherapy and Toremifene: Case Report

OBJECTIVE AND IMPORTANCE:

A case of an unusual intracranial solitary fibrous tumor with features of high vascularity and resultant difficulty at resection is presented. The use of surgery, radiotherapy, and toremifene has been successful with no recurrence after 18 months.

CLINICAL PRESENTATION:

A 33-year-old male patient presented with a 1-year history of loss of vision on the left side and a 3-month history of headache and lethargy. Magnetic resonance imaging showed a lobulated mass (7.6 × 4.5 cm) in the left temporal fossa and left parasellar, sellar, and suprasellar regions, with a “dural tail” more typical of meningioma. Vascular supply was from both the internal carotid arteries and the left middle meningeal artery, precluding embolization.

INTERVENTION:

At the time of the craniotomy, a highly vascular tumor was found. Intraoperative hemorrhage limited resection to 20% of the tumor. The histological diagnosis was of a solitary fibrous tumor with an unusually angiomatoid architecture. After the operation, radiotherapy and toremifene were administered. A dramatic reduction in the size of the tumor was seen with no recurrence to date.

CONCLUSION:

The use of surgery, radiotherapy, and toremifene in treatment of a vascular intracranial solitary fibrous tumor has been successful and warrants further research.

Ultrastructural spectrum of solitary fibrous tumor: a unique perivascular tumor with alternative lines of differentiation

Eight tumors diagnosed as solitary fibrous tumor (SFT) of the oral cavity were studied. Histologic spectrum was entirely comparable with the extrapleural SFT of other sites. One tumor had glomus tumor-like foci. Immunohistochemical results confirmed most of the previous observations, indicating characteristic expression of vimentin, CD34, bcl-2, and CD99. Factor XIIIa and alpha-smooth muscle actin were less commonly reactive and a very few cells were faintly positive for factor VIII-related antigen and Ulex europaeus agglutinin 1. All were essentially negative for S-100 protein, desmin, CD31, and CD68. In stark contrast to the conclusive immunoprofile, ultrastructural investigation of six tumors demonstrated considerable cellular heterogeneity. Other than fibroblasts, perivascular undifferentiated cells and pericytes predominated, but endothelial cells were regularly present. There was a distinctive proliferation of pericytic cells in four tumors, one of which had glomoid foci of myopericytes. The extreme increase in number of Weibel-Palade bodies occurred in voluminous capillary endothelium. Occasional single and clustered cells with consistent features of endothelium showed intracytoplasmic lumen formation. Such composite cells constituted an integral segment of richly vascularized SFT. Myofibroblastic form smooth muscle differentiation was present in only a minority of cells. From phenotypic analysis by electron microscopy, SFT may originate from a unique, perivascular multipotent mesenchyme sharing with its lineage with pericytes, fibroblasts, and infrequently, endothelium. Consequently, morphological features of SFT may become diversely varied by whether predominantly constituent cells are undifferentiated, pericytic or fibroblastic in nature.

Determination of stromal signatures in breast carcinoma

Many soft tissue tumors recapitulate features of normal connective tissue. We hypothesize that different types of fibroblastic tumors are representative of different populations of fibroblastic cells or different activation states of these cells. We examined two tumors with fibroblastic features, solitary fibrous tumor (SFT) and desmoid-type fibromatosis (DTF), by DNA microarray analysis and found that they have very different expression profiles, including significant differences in their patterns of expression of extracellular matrix genes and growth factors. Using immunohistochemistry and in situ hybridization on a tissue microarray, we found that genes specific for these two tumors have mutually specific expression in the stroma of nonneoplastic tissues. We defined a set of 786 gene spots whose pattern of expression distinguishes SFT from DTF. In an analysis of DNA microarray gene expression data from 295 previously published breast carcinomas, we found that expression of this gene set defined two groups of breast carcinomas with significant differences in overall survival. One of the groups had a favorable outcome and was defined by the expression of DTF genes. The other group of tumors had a poor prognosis and showed variable expression of genes enriched for SFT type. Our findings suggest that the host stromal response varies significantly among carcinomas and that gene expression patterns characteristic of soft tissue tumors can be used to discover new markers for normal connective tissue cells.

Low-grade sarcomas with CD34-positive fibroblasts and low-grade myofibroblastic sarcomas

A subset of low-grade fibrosarcomas is composed of CD34-positive spindle cells. These include dermatofibrosarcoma, its morphologic variants, and its associated fibrosarcoma, solitary fibrous tumor, hemangiopericytoma and their malignant counterparts, and some cases of myxoinflammatory fibroblastic sarcoma. Dermatofibrosarcoma and related lesions are characterized by a t(17;22)(q22;q13) rearrangement resulting in fusion of the genes COL1A (17q21-22) and PDGFB1 (22q13). Solitary fibrous tumor displays varying cellularity and fibrosis and a peripheral hemangiopericytomatous pattern; most tumors formerly called hemangiopericytoma are now subsumed into the category of solitary fibrous tumor, although a few strictly defined examples are recognized; however, these are probably not composed of pericytes. Myofibroblastic malignancies are best identified by electron microscopy, with which varying degrees of differentiation, including the presence of fibronexus junctions, can be identified. Low-grade sarcomas showing myofibroblastic differentiation include myofibrosarcomas and inflammatory myofibroblastic tumors. Myofibrosarcomas are spindle cell neoplasms that occur in children or adults in the head and neck, trunk, and extremities as infiltrative neoplasms and that display a fascicular or fasciitis-like pattern with focal nuclear atypia and variable expression of myoid antigens. These sarcomas are prone to recurrence and a small number metastasize. Inflammatory myofibroblastic tumor (synonymous with inflammatory fibrosarcoma) is a neoplasm arising predominantly in childhood, and frequently in intraabdominal locations. It has spindle cells in fascicular, fasciitis-like and sclerosing patterns, with heavy chronic inflammation including abundant plasma cells. Many IMT have clonal chromosomal abnormalities involving 2p22-24, and fusion of the ALK gene with tropomyosin 3 (TPM3-ALK) or tropomyosin 4 (TPM4-ALK) is found in a subset.

Solitary fibrous tumors of the pleura: clinical, radiological, surgical and pathological evaluation

AIMS

To report a clinicopathological series of cases of solitary fibrous tumor of the pleura from Taiwan.

METHODS

Clinical data was collected from a review of medical records and telephone interviewing for follow-up.

RESULTS

Eight patients, three men and five women aging from 34 to 71 years, underwent tumor resection and were followed in a period from 7 months to 13.5 years. Six patients underwent standard thoracotomy and two had VATS for tumor excision. Tumors were pathologically benign in seven patients and malignant in one. Patients were all alive with no evidence of tumor recurrence at the time of this report.

CONCLUSIONS

One should always consider SFTPs as potentially malignant tumors. Complete resection remains the mainstay of cure. Standard thoracotomy should always be considered when a high suspicion of malignancy is raised, whereas VATS may be a preferred approach for smaller tumors.

Tumor fibroso solitario de la próstata

We report a new case of a solitary fibrous tumor. It is a tumor which involve to genitourinary system unusual time, and it is exceptional in the prostate. Our patient began with bladder compression symptoms. Radiological studies showed polilobed mass that moved out the bladder although the could not show the pelvic organ was involved. The definitive diagnosis was made by histology and inmunohistochemestry of the surgical piece.

Solitary fibrous tumor in the occipitocervical region: a case report

STUDY DESIGN

Case report of a solitary fibrous tumor in the occipitocervical region.

OBJECTIVE

To describe a rare clinical entity and successful management in a patient with solitary fibrous tumor in the occipitocervical region.

SUMMARY OF BACKGROUND DATA

Solitary fibrous tumor is a rare spindle cell neoplasm of adults that arises most commonly in the pleura. Recently, this tumor has been reported in a number of other sites. However, its occurrence in the occipitocervical region is rare.

METHODS

The patient presented with a painless mass in the left posterior neck. Resection of the tumor was performed.

RESULTS

Histopathological study revealed features of a solitary fibrous tumor. Clinical follow-up review for 2.5 years shows no evidence of recurrence or metastasis.

CONCLUSION

A case of extrapleural solitary fibrous tumor in the occipitocervical region was reported. Solitary fibrous tumor should be considered in the differential diagnosis in a tumoral mass of this region.

Solitary fibrous tumor of the spinal cord: A clinicopathologic study of two cases

Two cases of solitary fibrous tumor of the spinal cord are described. The patients were two men, 36 and 47 years old. Clinically, they sought medical care because of progressive paresthesias or urinary incontinence caused by a nodular, fairly circumscribed intraspinal tumor of the cervical and thoracic spinal cord, respectively. Preoperative magnetic resonance images suggested meningioma. In both cases, laminectomy with tumor resection was carried out. Microscopically, the tumors featured short spindle cells haphazardly enmeshed in a collagenized ground substance. No atypia, necrosis, or significant mitotic activity was recognized. Tumor cells were positive for CD34, bcl2, vimentin, and, in one case, CD99. Both patients recovered from symptoms and are alive and well 12 and 18 months, respectively, after surgical resection. The differential diagnosis includes meningioma, schwannoma, and hemangiopericytoma, all of which may occur in the spinal canal. A careful morphologic approach and the judicious use of immunohistochemistry may assist in distinguishing among these conditions, although some irreducible difficulties may be posed by hemangiopericytoma. Although solitary fibrous tumor of the spinal cord presents with fairly comparable clinical, instrumental, and pathologic patterns, we believe that compilation of more cases is needed to segregate it as a distinct clinicopathologic entity.

Intra-abdominal synovial sarcoma: a clinicopathological study

AIMS

To evaluate a series of synovial sarcomas arising in the abdomen, pelvic cavity, or retroperitoneum. Synovial sarcoma is rare within the abdomen. In this location, it can be confused with other biphasic tumours and with other spindle and round cell sarcomas.

METHODS AND RESULTS

Cases were retrieved from archives. There were 11 intra-abdominal tumours among 300 synovial sarcomas in two referral practices (3.7%). Three were pelvic (two midline, one sidewall) and eight were retroperitoneal. They occurred in six males and five females aged from 25 to 75 years (mean 49 years, median 46 years), and ranged in diameter from 65 to 470 mm (mean 210 mm, median 150 mm). Six examples were biphasic, five were monophasic and seven had poorly differentiated areas. Monophasic tumours displayed at least one epithelial marker. One biphasic tumour had a SYT-SSX2 fusion gene. Seven sarcomas were high-grade and four of intermediate grade malignancy. Follow-up data were available in 10 patients. In all but one case, tumour recurred or metastasized within the abdomen. The pelvic sarcomas also metastasized outside the abdomen. Eight of 10 patients (80%) died of disease with survival from 4 to 36 months (mean 17 months, median 18 months). Two patients were alive with disease at 43 and 48 months.

CONCLUSIONS

Synovial sarcomas rarely arise within the abdomen and pelvis. They occur mainly in middle age, attain a large size, are difficult to excise and recur locally. Pelvic tumours metastasize distantly. Retroperitoneal tumours remain confined to the abdomen and, unlike synovial sarcomas elsewhere, do not metastasize remotely, although mortality is high.

Solitary fibrous tumor of the mammary gland: a potential pitfall in breast pathology

We report three cases of solitary fibrous tumor of the breast. The patients were adult to elderly women and complained of a slowly but relentless growing lump. The tumors were fairly circumscribed and cured by means of lumpectomy or, in one case, simple mastectomy. Histologically, they featured the customary "patternless pattern" of short spindle cells haphazardly arranged in fascicles within a collagenized or myxoid ground substance. In two cases, a prominent hemangiopericytic arrangement of tumor cells around a rich vascular framework could be noticed. Cellular areas were often present and showed nuclear overlapping, clumping of chromatin, and a brisk mitotic activity. No atypical mitosis was recognized. Tumor cells were immunoreactive for CD34, bcl2, and vimentin only. On follow-up there was no evidence of either local recurrence or distant metastases. Solitary fibrous tumors of the breast may represent a significant diagnostic problem because of the close mimicry to numerous benign and malignant mammary lesions composed of spindle cells; diagnostic clues may be further obscured in cellular and actively proliferating tumors. A brief overview of mammary solitary fibrous tumor taxonomy along with the principal differential diagnoses within the breast is presented.

A paediatric case of a solitary fibrous tumour of the parotid gland

Solitary fibrous tumours are rare and they were first described in the pleura of the lungs. However this rare tumour is being increasingly recognised in the oro-facial region and other extra-pleural sites among adults. We present a paediatric case of a solitary fibrous tumour of the parotid gland in an 11-year-old girl who was also diagnosed as having type I neurofibromatosis.

Intramedullary and extramedullary solitary fibrous tumor of the cervical spine

✓ Solitary fibrous tumor is a spindle cell tumor deriving from mesenchymal cells that arises most commonly in the pleura. Only very recently has this tumor been reported in the spine. A solitary fibrous tumor strongly resembles other spindle cell neoplasms of the spine and may be an unrecognized entity if not routinely considered in the differential diagnosis of spinal neoplasms. The authors report an unusual intra- and extramedullary location for a solitary fibrous tumor of the cervical spine. Findings in this case and a comprehensive review of the literature indicate that solitary fibrous tumors can originate from various spinal anatomical substrates and mimic both intra- and extramedullary tumor types.

Solitary Fibrous Tumor of the Liver with Presenting Symptoms of Hypoglycemic Coma

We report a patient with solitary fibrous tumor of the liver, a rare fibrous neoplasm which to our knowledge has been reported in only 21 patients in the English literature. Most frequently, solitary fibrous tumors arise in the thoracic cavity, particularly in the pleura. Hypoglycemia has rarely been associated with these mesenchymal tumors. The presentation of this patient with hypoglycemic coma without preceding symptomatology, to our knowledge, has never been reported.

Solitary Fibrous Tumor of the Spinal Nerve Rootlet: Report of a Case Mimicking Schwannoma

We report a case of solitary fibrous tumor involving the spinal nerve root at the L1-L2 level in a 67-year-old man. The patient presented with lumbar pain and weakness in his right lower extremity. Histologically, the tumor was composed of a proliferation of monomorphous spindle cells in an abundant collagenous stroma; neither necrosis nor mitoses were evident. These cells were strongly immunoreactive with CD34, Bcl-2, CD99, and vimentin, but were negative with S100 protein, smooth muscle actin, and epithelial membrane antigen. Such an immunohistochemical profile was consistent with a solitary fibrous tumor of the spinal nerve rootlet and ruled out the main differential diagnoses, schwannoma and meningioma. The present case suggests that solitary fibrous tumor should be considered in differentiating spindle cell lesions of the spinal cord and nerve rootlet.

Solitary fibrous tumor of the orbit: a clinicopathologic study of six cases with review of the literature

Solitary fibrous tumor of the orbit is a rare spindle cell neoplasm. There are 42 cases of solitary fibrous tumor of the orbit available in the literature. We present six more cases of orbital solitary fibrous tumors, which presented to our institute between 1999 and 2001. We highlight the need for clinical recognition of these tumors as a distinct entity and inclusion of this tumor in the etiological differential diagnosis of well-circumscribed orbital lesions presenting as unilateral proptosis in both children and in adults. The diagnosis may be suspected based on radiological features supported by histopathologic and immunohistochemical study. The strong CD34 immunoreactivity of this tumor supports its diagnosis. Complete surgical resection is the most important prognostic factor of this tumor.

Solitary fibrous tumor of the pleura

Solitary fibrous tumors of the pleura are an uncommon but increasingly recognized neoplasm derived from mesenchymal cells located in the submesothelial lining of the pleural space. They may be differentiated from mesotheliomas and other pleural tumors due to unique immunohistochemical characteristics. The vast majority of these tumors are benign, and complete surgical resection remains the mainstay of therapy for both the benign and malignant variants. In this review, the clinical presentation, radiologic features, histologic findings, and treatment options for this tumor are described.

Solitary fibrous tumor with malignant potential arising in sublingual gland

A rare case is described of a solitary fibrous tumor (SFT) with malignant potential arising in the sublingual gland. A 59-year-old man presented with a 4-month history of a slowly enlarging painless mass in the center of the floor of the mouth. The tumor was a well-demarcated, firm mass with a multicystic lesion. The tumor exhibited highly cellular areas of spindle cells with patternless architecture alternating with hypocellular areas. The tumor cells were positive for CD34 and bcl-2 as well as vimentin, and negative for epithelial, myogenic, neurogenic and histiocytic markers. The tumor cells formed multiple satellite nodules around dilated ducts in the multicystic lesion, indicating infiltrative growth. In addition, areas exhibiting higher cellularity with increased mitoses were noticed in the satellite nodules, although cellular atypia was not obvious. These findings led to a final diagnosis of SFT with malignant potential. There has been no recurrence or metastasis for 27 months after the surgery. Solitary fibrous tumor of the salivary gland must be differentiated from various spindle cell neoplasms including myogenic, peripheral nerve sheath, fibroblastic and fibro-histiocytic spindle cell neoplasms, hemangiopericytoma and myoepithelioma. In addition to characteristic morphological features, an immunohistochemical positivity for CD34 and bcl-2 may aid in the diagnosis of SFT.

Solitary fibrous tumour of the tongue: a case report with immunohistochemical studies

The solitary fibrous tumour (SFT), also known as a localized fibrous mesothelioma, is a neoplasm characterized by the proliferation of capillaries surrounded by masses of round or spindle-shaped cells. SFT has been discovered in many locations, however, it is extremely rare for SFT to be found in the intraoral region. We report here case of SFT arising from the tongue of a 75-year-old woman. To our knowledge, this is the second case reported of SFT originating from the tongue.

Immunohistochemical localization of endothelial cell markers in solitary fibrous tumor

Solitary fibrous tumor (SFT) is an uncommon tumor first reported in the pleura, but recently described in other tissues. CD34, which is expressed in hematopoietic stem cells, endothelial progenitor cells and vascular endothelial cells, is observed in most SFT and some investigators believe that its expression is a definitive marker of this tumor. In the present study, the expression of vascular endothelial cell markers, such as vascular endothelial growth factor receptor (VEGFR)-1 (flt-1), VEGFR-2 (flk-1/KDR), Tie-2 and c-Met, was examined in SFT to clarify the relationship between SFT and endothelial cells. By immunohistochemical staining of tumor cells from 26 patients, VEGFR-1 was detected in 24 (92%), VEGFR-2 in five (19%), Tie-2 in 14 (54%), and c-Met, a specific receptor of hepatocyte growth factor (HGF) in 23 patients (88%). Furthermore, VEGFR-3 (flt-4) immunoreactivity was detected in eight of 26 patients (31%). In contrast, VEGF, VEGF-C and HGF, which are ligands for the receptors, were not localized in the SFT cells. These findings indicate that most SFT may closely relate to vascular or lymphatic endothelial cells and the endothelial growth factors may contribute to the growth of SFT in a paracrine manner.

Steroid hormone receptor in pleural solitary fibrous tumours and CD34+ progenitor stromal cells

Solitary fibrous tumours (SFT), originally described in the pleura, were subsequently recognized in numerous extrapleural sites. This suggests that a common stem cell, present in various organs and tissues, may be at the origin of SFT and that specific factors may be involved in the proliferation of such cells. Recently it has been described that steroid hormone receptors, progesterone receptors in particular, are expressed by extrapleural SFT. In addition, progesterone may participate as growth factor in many CD34(+) stromal neoplasms, which express low levels of the hormone receptors. The present study analysed the expression of androgen (AR), oestrogen (ER) and progesterone (PR) receptors in a series of 32 pleural SFT, 10 mesotheliomas and in reactive tissue of chronic pleuritis. ER and AR were never expressed by SFT or by chronic pleuritis, whereas PR were demonstrated in 2/16 "large" (>8 cm) and in 6/16 "small" (< or =8 cm) pleural SFT (all expressing CD34, bcl-2 and CD99). PR(+) SFT had a significantly higher proliferative activity (p = 0.04) (Ki-67 mean value 6.5%) and lower p27(kip1) (mean value 51.5%) expression than the PR(-) cases (Ki-67 mean value 3.81% and p27(kip1) mean value 57.86%). One of the cases expressing a high level of PR (80%) recurred 1 year after first surgery and the recurrence was PR(+) as well, but with a lower percentage of nuclear receptor expression (12%). In addition, in chronically inflamed subserosal tissue, a subpopulation of CD34(+) endothelial and interstitial dendritic cells was identified, which also expressed PR. These findings suggest that the CD34(+) submesothelial interstitial dendritic cells, activated during reactive processes, may be the stem cells that give rise to SFT, and that progesterone might participate in the growth of SFT through modulation of its specific receptors.

A case of solitary fibrous tumor of the parotid gland: review of the literatures

We report a rare case of solitary fibrous tumor of the parotid gland. A 47-year-old woman presented with a 3-year-history of left-sided subauricular swelling. Computed tomographic scans and magnetic resonance images revealed a well-defined and dumbbell-shaped mass, measuring about 30 mm in its greatest dimension, in the left parotid gland. Because the tumor occupied both superficial and deep lobes of the gland, she underwent total parotidectomy with preservation of the facial nerve. The microscopic finding showed short-spindle and ovoid cells arranged in a haphazard pattern with interspersed thin collagen fibrils. Immunohistochemically, the tumor cells were strongly positive for CD34, bcl-2 and vimentin, whereas stains for S-100, cytokeratin, smooth muscle actin, collagen type IV and CD117 (KIT) were negative. On the basis of these findings, the tumor was diagnosed as solitary fibrous tumor. Her post-operative course was uneventful, and she is currently free from disease 14 months after surgery. Diagnosis, clinical behavior and treatment of solitary fibrous tumor are reviewed from perusal of the literature.