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

A not so solitary fibrous tumor of the liver

Solitary fibrous tumor (SFT) is a rare neoplasm. Liver parenchyma is a rare location of SFT and, in this case, it usually follows a benign course. We report here the case of a 54-year-old man who presented a large SFT tumor of the right hepatic lobe. The tumor was surgically resected. Local recurrence occurred 6 years later as a 15 cm diameter liver tumor. Histological examination of the resected lesion showed features of an aggressive form of SFT. Two years later, the patient presented with complaints of neck pain and ensuing examinations revealed a tumor of the cranial base. A new surgical resection was performed and histological examination confirmed a metastasis of the SFT. Few weeks later, the patient presented an irreducible psoitis due to an iliac bone metastasis. He died within 1 month.

Sunitinib malate and figitumumab in solitary fibrous tumor: patterns and molecular bases of tumor response

Antiangiogenic treatment activity has been reported in solitary fibrous tumor (SFT), a rare and little chemosensitive sarcoma. We explored the activity of sunitinib malate (SM) in SFT and studied receptor tyrosine kinase (RTK) activation profile. Eleven patients with progressive metastatic SFT resistant to chemotherapy were treated with continuous-dosing 37.5 mg/d SM on a named-use basis. One of them also received the insulin-like growth factor I receptor (IGFIR) inhibitor figitumumab after developing secondary resistance to SM. Besides, biochemical, molecular, and fluorescence in situ hybridization analyses were done in eight naïve SFTs whose cryopreserved material was available to clarify RTK upstream and downstream signaling. In two cases treated with SM and belonging to the naïve series, both pretreatment and posttreatment samples were available. Ten patients were evaluable for response to SM. The best response according to the Choi criteria was six partial response (all with Response Evaluation Criteria in Solid Tumors stable disease), one stable disease, and three progressive disease. Responses lasted >6 months in five patients. The eight naïve samples showed high expression/phosphorylation of PDGFRB, epidermal growth factor receptor, and IGFIR/IR, in the presence of their cognate ligands. Downstream pathways revealed expression/activation of Akt, extracellular signal-regulated kinase 1-2 and, closely related to SFT subtypes, of S6 and 4E-BP1. In two patients, whose pretreatment and posttreatment clinical and molecular status were available, biochemical data confirmed the activity of SM, although they also suggested a possible time-dependent shift of dominant RTK from PDGFRB to IGFIR/insulin receptor. A Response Evaluation Criteria in Solid Tumors partial response to figitumumab corroborated these findings. SM has antitumor activity in SFT, possibly through a PDGFRB-mediated mechanism, but treatments with IGFIR/insulin receptor and possibly epidermal growth factor receptor inhibitors are worth testing.

[Primary malignant solitary fibrous tumor/hemangiopericytoma of the parotid gland]

Solitary fibrous tumor (SFT) was first described in the pleura by Lietaud in 1767; later in 1870, Wagner described the localized nature of this type of tumor and Klemperer and Rabin classified pleural tumors into two types: diffuse mesotheliomas and localized mesotheliomas. Recent years have seen the redefinition of this neoplasm, due to better technology; it is now proven that this neoplasm may have multiple different extrapleural origins including the head and neck regions. This diversity of locations is related to the particular mesenchymal histogenesis of SFT which allows its development from very unusual sites such as the salivary glands (SGs). In this particular site, this neoplasm is very infrequent and most of reported cases refer to benign disease, with just one case informed so far of primary malignant SFT.

Solitary fibrous tumor of the adrenal gland with unusual immunophenotype: a potential diagnostic problem and a brief review of endocrine organ solitary fibrous tumor

Solitary fibrous tumor was initially thought to be a pleura-based tumor. However, over the last two decades, its involvement in a variety of extrapleural sites gained recognition. Nonetheless, a primary involvement of the endocrine organs is rare, and in this report, we detail an instance where the tumor affected the adrenal gland of a 71-year-old Arab man. On histology, besides the typical morphologic features seen in solitary fibrous tumor, the neoplasm also exhibited unusual features on immunohistochemistry such as positive staining for cytokeratin AE1/3 and calponin in conjunction with diffuse expression for S-100. The genetic tests for t(X:18) as seen in synovial sarcoma were negative, and the overall histological appearance favored a diagnosis of solitary fibrous tumor. To the best of our knowledge, this report represents the fifth case of a solitary fibrous tumor primarily occurring in the adrenal gland. The differential diagnoses of this neoplasm in our case and a brief summary of solitary fibrous tumor primarily involving the various endocrine organs are presented.

Malignant solitary fibrous tumor: cytopathologic findings and differential diagnosis

BACKGROUND

Malignant solitary fibrous tumors (SFTs) are extremely uncommon and poorly understood mesenchymal neoplasms. There are only rare published accounts of the cytopathologic features of these tumors, prompting the current study.

DESIGN

All cases of malignant SFT with preoperative fine-needle aspirations (FNAs) from 1999 to 2008 were retrieved from the archives of 3 large teaching hospitals. FNA smears and cell block material including immunoperoxidase stains were reviewed, and the cytologic characteristics were described.

RESULTS

Thirteen cases of malignant SFT were identified in 11 patients. Mean age was 58 years, with a men:women ratio of 1:2.6. The tumors were generally large, with a mean size of 13.4 cm. Cytomorphologic features included mostly hypercellular smears with tissue fragments of monotonous, plump spindled cells with blunt-ended and indented nuclei and fragile, wispy cytoplasm. Also seen were bare nuclei, occasional mitoses, and rare necrosis. Some cases showed a predominance of epithelioid cells, whereas others displayed a loose myxomatous matrix. There was a general lack of single cells. None of the cases was diagnosed accurately as malignant SFT on FNA, and only 6 cases were called malignant or suspicious for malignancy.

CONCLUSIONS

The FNA diagnosis of malignant SFT is extremely difficult and needs histologic material for accurate interpretation. Predominant FNA diagnoses were SFT or spindle cell neoplasm. Malignant SFT must be included in the differential diagnosis of a spindle cell neoplasm of any anatomic site, particularly if it displays features not typical of benign SFT. Immunoperoxidase staining has some utility, mainly in ruling out other neoplasms in the differential diagnosis.

[Solitary fibrous tumour of the smooth palate]

The solid fibrous solitary tumour of the oral cavity is an extremely rare entity. It is also of complicated diagnosis because of its extensive morphologic diversity (especially when there is a small amount of biopsied tissue) and because of its similarity to many mesenchymal injuries, mostly with hemangiopericytoma. The prognosis is reserved because of the few cases reported, mainly depending on tumour location and size.

[Solitary fibrous tumor of the pelvis: a rare extrathoracic manifestation]

Solitary fibrous tumors (SFT) are rare spindle cell neoplasms. To date only very few cases of pelvic SFT have been reported in the literature. SFT are characterized by unique microscopic and immunohistochemical findings. Complete local resection is the treatment of choice. Recurrence and metastasis may be related to infrequent malignant histological features, but histology is not always a reliable predictor for prognosis. Therefore long-term follow-up is necessary.We report about a male patient with a malignant pelvic SFT. After complete resection the tumor recurred after a short period of 6 months posterior to the original location in the pelvis. The differential diagnoses and the therapy options are discussed with a review of the present literature.

Expanding the spectrum of malignant progression in solitary fibrous tumors: a study of 8 cases with a discrete anaplastic component--is this dedifferentiated SFT?

Dedifferentiation is a well recognized, if sometimes controversial, form of tumor progression in certain types of soft tissue and bone sarcoma, and confers a worse prognosis when compared with the low-grade counterpart. To date, dedifferentiation has not been described in solitary fibrous tumor (SFT). Among 948 cases of both intrathoracic and extrathoracic SFTs in our files accessioned between 1988 and 2008, we identified 8 cases of conventional SFT with a discrete anaplastic component, which we believe represents dedifferentiation. These occurred in 3 men and 5 women, 40 to 76 years old (median 60 y), and measured 3.4 to 20.0 cm (median 8.5 cm). Two cases were intrathoracic, 2 were located in the deep soft tissue of thigh, and single cases were located in the omentum, scalp, retroperitoneum, and abdominal wall. In addition to typical features of benign-appearing SFT there was an abrupt transition to nondistinctive high-grade sarcoma in all cases. The latter included epithelioid, round cell, and/or spindle cell components with increased mitotic activity, necrosis, and cystic degeneration. By immunohistochemistry, 7 of 8 cases were CD34 positive in the usual SFT areas, whereas 5 showed loss of CD34 in the poorly differentiated component. Six of 7 cases stained for p53 and p16 showed either negative or scattered positive cells in well-differentiated SFT areas, in contrast to positive or stronger and more diffuse staining in the high-grade component. Follow-up information available in 7 patients ranged from 1 to 58 months (mean 24 mo). Three patients with the largest tumors (9.0, 17.0, and 20.0 cm) died of disease, whereas 3 patients whose tumors measured 8.0 cm or less were treated by surgical excision only, and show no evidence of disease but with only limited follow-up. One patient with an 11.5 cm intrathoracic tumor is alive with disease at 58 months after recurrence and metastasis. We describe, apparently for the first time, what seems, at least in our view, to be dedifferentiation in primary SFT. Our results demonstrate that dedifferentiation in SFT, comparable with that in other low grade/intermediate soft-tissue tumors, poses a higher risk of tumor recurrence and/or metastasis, most notably in large and deep-seated tumors. Similar to other dedifferentiated sarcomas, abrupt transition between low grade and high-grade areas is typically observed with loss of CD34 positivity. The p53 and p16 overexpression in the high-grade component is common as in other dedifferentiated lesions, perhaps pertaining to the underlying molecular mechanism.

New insights into the hemangiopericytoma/solitary fibrous tumor spectrum of tumors

PURPOSE OF REVIEW

This review provides an overview of the hemangiopericytoma/solitary fibrous tumor (HPC/SFT) spectrum of tumors, focusing on the histopathologic characteristics, clinical features, diagnosis, and treatment of HPC/SFT.

RECENT FINDINGS

Due to the relatively insensitive nature of HPC/SFT to radiotherapy and cytotoxic chemotherapy, new therapies are needed for treatment of advanced disease. Inhibition of angiogenic pathways may provide a novel therapeutic mechanism for targeting this malignancy. Combination therapy with temozolomide and bevacizumab has recently emerged as a potentially promising regimen for HPC/SFT.

SUMMARY

With many novel targeted therapies currently in development for soft tissue sarcomas, a better understanding of the molecular pathogenesis and aberrations of HPC/SFT is needed to determine optimal therapeutic agents. Identifying appropriate targets and designing rational prospective clinical trials will not only improve treatment of HPC/SFT but will also lead to a new paradigm of personalized, targeted therapy.

Extrapleural solitary fibrous tumor: a clinicopathologic study of 19 cases

This study reports a series of 19 extrapleural solitary fibrous tumors. The patients included 6 men and 13 women with age ranging from 27 to 86 years. Three patients showed local recurrence. In 2 tumors, a diagnosis of malignancy was made. All of the tumors were strongly positive for CD34, and 3 of them expressed high levels of progesterone receptor. Solitary fibrous tumors are fairly rare, occurring in many parts of the body, and their behavior is unpredictable.

Solitary fibrous tumors of the pleura: results of surgical treatment and long-term prognosis

OBJECTIVE

We sought to define the long-term outcome of surgically treated solitary fibrous tumors of the pleura.

METHODS

We performed a retrospective review from December 1972 through December 2002.

RESULTS

There were 84 patients (39 men and 45 women) with a median age of 57 years (range, 34-83 years). Forty-six patients were symptomatic. Surgical resection included pulmonary wedge excision in 62 patients, lobectomy in 4 patients, segmentectomy in 2 patients, chest wall resection in 3 patients, isolated pleural resection in 7 patients, and chest wall resection with pulmonary wedge excision, lobectomy, or pneumonectomy in 3, 2, and 1 patients, respectively. Tumors were polypoid in 57 patients, sessile in 20 patients, and intrapulmonary in 7 patients. Histopathology was benign in 73 and malignant in 11 patients. Nine (82%) patient with malignant tumors and 37 (54%) patients with benign tumors were symptomatic (P = .11). The median tumor diameters for malignant and benign tumors were 12.0 and 4.5 cm, respectively (P = .001). Operative mortality and morbidity occurred in 3 (3.6%) and 7 (8.1%) patients, respectively. Median follow-up in survivors was 146 months (range, 23-387 months). Median survival for patients with benign and malignant tumors was 284 and 55 months, respectively, and 5-year survival was 88.9% and 45.5%, respectively (P = .0005). Eight (9.5%) patients had recurrent solitary fibrous tumors of the pleura. Recurrences were malignant in 6 and benign in 2 patients. Localized chest recurrences occurred in 3 patients, all of whom had reresection, with 2 patients again having recurrence.

CONCLUSION

Resection of benign solitary fibrous tumors of the pleura carries an excellent prognosis. Larger tumors are more likely to be malignant. Both benign and malignant tumors can recur. Although prolonged survival after resection of malignant tumors is possible, recurrence is common.

Solitary Fibrous Tumor of the Liver: Retrospective Study of Reported Cases

A solitary fibrous liver tumor is a rare disease that is difficult to diagnose. Radiological findings are not specific and cannot confirm benignity or malignancy. Immunohistologically, CD 34, Vimentin, and Desmin should be used as markers to precisely diagnose solitary fibrous tumors. In most cases, there is low cellularity with no cellular atypia or necrosis, making this a benign lesion. Occasionally, a large size, high mitotic rate, cellular pleomorphism and atypia, and necrosis are interpreted as features suggestive of an increase malignant potential. The outcome of solitary fibrous tumor mostly is related to resectability, although correlated with neither pathological grade nor tumor size. Thus, total surgical resection of the neoplasm is most commonly proposed. Physicians should be alerted that solitary fibrous tumor of the liver can be malignant and can metastasize.

Solitary fibrous tumor of the oral cavity: clinicopathologic and immunohistochemical study of 21 cases

We describe clinical, morphologic, and immunohistochemical features of 21 cases of solitary fibrous tumor presenting in the oral cavity. There were 9 male and 12 female patients with a median age of 51 years (range 37-83). The most common locations included the buccal mucosa (the most common site), lip, maxillary or mandibular vestibule and tongue. Histopathologic examination showed well-circumscribed tumors with two well-defined patterns: the classic pattern with densely cellular areas alternating with hypocellular areas in a variably collagenous, vascular stroma and a more uniformly sclerotic pattern with only subtle classic areas. The spindle-shaped neoplastic cells consistently showed immunoreactivity for antibodies directed against CD34. Five of nineteen cases (26%) were reactive for CD99 and 19 of 19 for Bcl-2. Follow-up information was available in 17 cases and averaged 54 months, with no evidence of recurrence or metastasis in any of these patients. Awareness that solitary fibrous tumor may present in the oral cavity is important so that confusion with other spindle cell neoplasms can be avoided. We also briefly describe the differential diagnosis and compare this series, the largest single series of intraoral SFT, to cases previously reported in the literature.

Inaccuracy of fine-needle biopsy in the diagnosis of solitary fibrous tumour of the liver

Solitary fibrous tumour (SFT) is an uncommon neoplasm of mesenchymal origin that primarily affects the pleura and mediastinum. SFTs may occur elsewhere in the body including the liver, peritoneum, orbit and other soft tissues. Recent advances in immunohistochemical analysis have allowed greater identification of SFTs. Nevertheless, radiologically it remains difficult to distinguish SFTs of the liver from other solitary tumours as they have many common features. We report a case of SFT of the liver and highlight the potential inaccuracy of percutaneous biopsy in the diagnosis of large solitary liver tumours.

Solitary fibrous tumour of the liver: a rare imaging diagnosis using MRI and diffusion-weighted imaging

Solitary fibrous tumour of the liver is an extremely rare neoplasm, the reported imaging features of which are largely non-specific. We present a case in which dynamic contrast-enhanced CT, MRI and diffusion-weighted MRI findings suggested a diagnosis of solitary fibrous tumour of the liver that was subsequently confirmed by immunohistochemical evaluation.

An aggressive solitary fibrous tumor with evidence of malignancy: a rare case report

Solitary fibrous tumor (SFT) is rare mesenchymal neoplasm that has been originally and most often documented in the pleura. Recently, the ubiquitous nature of the SFT has been recognized with reports of involvement of numerous sites all over the body, i.e, upper respiratory tract, breast, somatic tissue, mediastinum, head, and neck, etc. The diagnosis of SFT still remains an enigma in our field. Furthermore, malignant SFT is extremely rare and only two cases have been reported in the oral cavity till date. Here, we present a rare case report of an aggressive solitary fibrous tumor which presented as a palatal mass and extended throughout the middle cranial fossa and exhibited features of malignancy.

[Malignant solitary fibrous tumor of the abdominal wall in a man]

We report the first case of malignant solitary fibrous tumor of the abdominal wall in a man. Immunohistochemical staining for CD34 and bcl-2 were positive. Surprisingly, estrogen and progesterone receptors were focally positive. Expression of steroid hormone receptor in solitary fibrous tumor was rarely reported in the literature. In a few series, these receptors were identified as a risk factor of recurrences after surgical excision. Six months after complete surgical resection of the mass, our patient has been quite well without any evidence of recurrence.

[Solitary fibrous tumor of the retroperitoneum]

Solitary fibrous tumour is unusual, arising most commonly in the pleura and can also occur in a large number of other sites. We report the case of a 34-year-old man with a retroperitoneal solitary-fibrous tumour, revealed by abdominal pain and hypoglycaemia. We describe the histopathological and immunohistochemical features. Solitary-fibrous tumour should be included in the differential diagnosis of spindle cell tumours in this location. Despite complete local excision, local recurrence and metastasis are seen. The behaviour of theses tumours is unpredictable and patients with solitary fibrous tumour require careful and long-term follow-up.

Solitary fibrous tumor of the larynx

BACKGROUND

True mesenchymal, non-cartilaginous neoplasms of the larynx are rare. Extrapleural solitary fibrous tumor (SFT) is a localized neoplasm characterized by proliferation of thin-walled vessels and collagen-producing cells and is considered within the "hemangiopericytoma-solitary fibrous tumor" spectrum. SFT primary in the larynx is exceptional.

DESIGN

Case report set in a comparison with other cases reported in the English literature (MEDLINE 1966 to 2007).

RESULTS

A 49-year old white male presented with difficulty breathing, progressive over the past 2 years. He denied dysphagia and weight loss. Past medical history was significant for asthma. He denied cigarette smoking or alcohol abuse. There were no cervical deformities on physical exam. Fiberoptic laryngoscopy was performed upon stabilization of respiratory function. A smooth, round, submucosal mass measuring 2.3 cm in greatest diameter arising from the inferior surface of left true vocal cord was causing near total obstruction of the endolaryngeal space. The mass was excised. The surface mucosa was intact and unremarkable. A cellular, spindle cell neoplasm was arranged in loose fascicles, associated with heavy collagen fiber deposition. The collagen was wiry and heavy. Cells were bland with cytoplasmic extensions. The nuclei were vesicular to hyperchromatic and elongated with inconspicuous nucleoli. Vessels were prominent and delicate, with patulous spaces. Mitotic figures were easily identified, but atypical forms were not present. The cells were strongly and diffusely immunoreactive with CD34 and bcl-2, while non-reactive with cytokeratin, EMA, actin, ALK-1, S100, desmin, and CD117. These findings confirmed a diagnosis of extraplural solitary fibrous tumor. Without further disease, the patient is alive without evidence of disease, 12 months after surgery.

CONCLUSIONS

The characteristic histologic pattern of solitary fibrous tumor can be noted in extrapulmonary locations. Development in the larynx is uncommon, but the tumor presents as a polypoid mass with characteristic histologic and immunophenotypic features. Conservative local excision is the treatment of choice to yield an excellent prognosis.

Solitary fibrous tumor of the orbit: CT and MR imaging findings

BACKGROUND AND PURPOSE

Solitary fibrous tumor (SFT) is a rare spindle-cell neoplasm originating from mesenchymal fibroblast-like cells. The purpose of this study was to describe the CT and MR imaging features of SFTs in the orbit.

MATERIALS AND METHODS

We retrospectively reviewed CT and MR images in 6 patients (2 men and 4 women), aged 18 to 51 years, with SFT proved on histologic examination located in and around the orbit. All patients underwent CT (including dual-phase CT in 3), and MR imaging was obtained in 3. We evaluated the imaging findings with emphasis on the location, size, margin, internal architecture, and pattern of enhancement of the lesion.

RESULTS

All 6 lesions were found as a solitary, well-defined mass, ranging in size from 18 to 30 mm (mean, 24 mm). Three were located in the postseptal orbit, 2 in the lacrimal sac, and 1 on the lower eyelid. Compared with the cerebral cortex, all 3 lesions examined by MR imaging showed homogeneous isointense signal intensity on T1-weighted images and heterogeneous mixed isointense and hyperintense signal intensity on T2-weighted images. On visual inspection, all 6 lesions showed marked homogeneous (n = 4) or heterogeneous (n = 2) enhancement on postcontrast CT and MR images. In 3 patients examined with dual-phase CT, all lesions demonstrated rapid enhancement with early washout of contrast material.

CONCLUSION

SFT might be included in the differential diagnosis of soft tissue masses in the orbit, if one sees a markedly enhancing mass showing the similar characteristics to those of the internal carotid artery on postcontrast CT or MR images.

Lack of a common or characteristic cytogenetic anomaly in solitary fibrous tumor

Solitary fibrous tumor is a mesenchymal tumor that was initially described as a pleural-based lesion, but later was discovered in many other locations. The light-microscopic appearance of solitary fibrous tumor may overlap with other diagnostic entities; however, consistent tumor cell CD34 immunoreactivity is useful in establishing the diagnosis. Limited data suggest that solitary fibrous tumors are karyotypically diverse, and no common or characteristic anomaly has yet emerged for this entity. Cytogenetic analysis of two solitary fibrous tumors, one peritoneal and the other arising in the liver, revealed predominantly structural abnormalities in the former and numerical imbalances in the latter. Clonal karyotypic abnormalities were lacking in three additional solitary fibrous tumors.

Deep "benign" fibrous histiocytoma: clinicopathologic analysis of 69 cases of a rare tumor indicating occasional metastatic potential

Benign fibrous histiocytoma (FH) is one of the most common mesenchymal neoplasms of the skin. Several histologic variants of cutaneous FH have been described, some of which also have distinct clinical features including a propensity for local recurrence. Deep benign FH is an uncommon and poorly recognized clinical subtype that arises in subcutaneous or deep soft tissue. Only a single small series of these neoplasms has been published, and their clinical behavior is not well characterized. In this study, we report the clinicopathologic features of 69 deep FH retrieved from our consultation files. The patients included 41 males and 28 females, ranging in age from 6 to 84 years (median, 37 y). The most common anatomic location was the extremities (58%); the remainder arose on the head and neck (22%), trunk (11%), and in the deep soft tissue of the retroperitoneum, mediastinum, or pelvis (9%). All lesions arising in nonvisceral soft tissue were subcutaneous. The tumors ranged from 0.5 to 25 cm in size (median, 3.0 cm) and were well circumscribed grossly and microscopically. All tumors were composed of bland ovoid to spindle cells arranged in a storiform pattern with admixed lymphocytes. Multinucleate giant cells, osteoclastic giant cells, and/or foam cells were present in 59% of cases, whereas the other 41% were cytologically monomorphic, often resembling cellular FH. Other common findings included a hemangiopericytomalike vascular pattern (42%) and stromal hyalinization (39%). Four cases were classified as atypical deep FH due to the presence of scattered markedly pleomorphic spindle cells within an otherwise histologically typical lesion. The median mitotic rate was 3/10 HPF; 10 cases (14%) had >10 mitoses/10 HPF. Necrosis (2 cases) and lymphovascular invasion (1 case) were rare. Immunohistochemistry revealed expression of CD34 in 20/50 cases (40%), smooth muscle actin in 15/40 (38%), and focal desmin in 1/12 (8%). Of the 37 patients for whom clinical follow-up was available (median, 40 mo), 8 (22%) had a local recurrence; in all 8 cases, the tumor had been marginally or incompletely excised. Metastases occurred in 2 patients (5%), both of whom ultimately died of disease; however, this number is likely exaggerated due to consultation bias. The metastasizing tumors were large (6 and 9 cm) and 1 had tumor necrosis but they were otherwise histologically identical to the nonmetastasizing lesions. In summary, deep FH has many histologic features in common with cutaneous cellular FH; however, it usually has a more diffusely storiform pattern than the latter, is well circumscribed, and may have striking hemangiopericytomalike vessels. Similar to the cellular, aneurysmal, and atypical variants of FH, deep FH recurs in approximately 20% of cases and may rarely metastasize.

Solitary fibrous tumour of prostate: evaluation and management of a rare tumour

Solitary fibrous tumours, which are commonly described as arising from the pleura, are rarely seen in the lower urinary tract. Although malignant changes have been reported, these tumours are usually benign. This case report discusses the radiological features, management strategy and histopathology of a solitary fibrous tumour arising from the prostate.

Solitary fibrous tumor of the oral cavity: the need for an extensive sampling for a correct diagnosis

BACKGROUND

Solitary fibrous tumor (SFT) is an uncommon but well-characterized soft tissue tumor that was first described as a pleural lesion and now is considered ubiquitous, having been detected at many extra-pleural sites (abdominal cavity, orbit, upper respiratory tract, and oral cavity). Histologically, SFT may show wide morphological variability of both its cellular and stromal components, which may lead to incorrect diagnosis especially when dealing with small incisional biopsies.

MATERIALS

We report on the clinical, morphological and immunohistochemical features of eight SFT occurring in the oral cavity.

RESULTS

Microscopically all eight tumors showed widely variable morphological features in terms of cellular density and stromal architecture, thus simulating benign fibrous histiocytoma, schwannoma, hemangiopericytoma or low-grade sarcoma in distinct areas of the same lesion. Among these eight cases, five had been diagnosed as SFT, two as benign fibrous histiocytoma and one as low-grade sarcoma.

CONCLUSIONS

In consideration of the heterogeneous morphological appearance of SFT, inaccurate sampling of the mass may lead to misdiagnosis and inappropriate treatment. Therefore, an accurate histological examination of multiple tissue sections is advised, along with the use of appropriate immunostains.

[Neurogenic spindle-cell tumors of the mediastinum: two cases]

INTRODUCTION

Neurogenic tumors can develop from neural cells in any location. They are commonly found, however, in the mediastinum, most often in its posterior compartment. Neurogenic tumors can be benign or malignant. In the anterior compartment, they must be distinguished from their differential diagnoses.

CASES

We report one case of a malignant peripheral nerve sheath tumor in the posterior mediastinum of a 29-year-old man and another of a schwannoma of the anterior mediastinum, in an 82-year-old woman.

DISCUSSION

Neurogenic tumors of spindle-shaped cells in the mediastinum are generally benign, but can be malignant. Often asymptomatic, they are usually detected on standard pulmonary radiography, but computerized tomography is necessary, supplemented by magnetic resonance imaging, especially for posterior mediastinal tumors, to provide additional information and to assess its possible extension to adjacent structures. Radiographic, clinical, and especially histopathological features are essential for diagnosis.

Intracranial solitary fibrous tumors: imaging findings in 6 consecutive patients

BACKGROUND AND PURPOSE

Intracranial solitary fibrous tumors (ISFTs) are rare mesenchymal neoplasms originating in the meninges. The aim of this study was to describe the CT, MR imaging, and angiographic features of the solitary fibrous tumor and to identify imaging characteristics.

MATERIALS AND METHODS

We retrospectively reviewed CT, MR, and angiographic findings in 6 cases of ISFT. We evaluated the size, shape, and location of the tumor; the internal content and margin of the lesion; the pattern of enhancement; and the change of the adjacent structures. Density on noncontrast CT scans, signal intensity on MR images, and angiographic features were also documented.

RESULTS

Each lesion appeared as a discrete extra-axial mass (size, 3-7 cm; mean, 5 cm). Five lesions were entirely solid, and 1 had peritumoral cyst. All 5 of the noncontrast CT scans showed hyperattenuated masses, and the tumors exhibited marked heterogeneous enhancement. No lesion contained calcification, and 2 cases showed bone invasions. On the MR images, 4 lesions showed mixed signal intensity on T2-weighted imaging. All of the lesions revealed marked heterogeneous enhancement. All of the tumors had thickening of the meninges adjacent to the tumor. Angiography showed delayed tumor blushing in all, and 3 of them had dysplastic dilation of the tumor vessels.

CONCLUSION

Although there are no pathognomonic imaging findings, some imaging features, such as the "black-and-white mixed" pattern on T2-weighted images and marked heterogeneous enhancement, might be helpful in the diagnosis of intracranial solitary fibrous tumor.

Solitary Fibrous Tumor on Needle Biopsy and Transurethral Resection of the Prostate

One of the least commonly encountered spindle cell tumors seen on prostatic needle biopsy or transurethral resection (TUR) of the prostate is solitary fibrous tumor (SFT). We studied 13 cases of SFTs identified on either prostate needle biopsy (n=9) or TUR of the prostate (n=4). Mean patient age at diagnosis was 63 years (range: 46 to 75 y; median: 65 y). Twelve men presented with urinary tract symptoms and 1 patient was biopsied during work-up of bone metastases. Ten cases were SFTs originating in the prostate, 2 cases arose between the prostate and rectum extending into the prostate (n=2), and 1 case was a pelvic mass without infiltration of the prostate. In 9 cases, a complete tumor resection was attempted by cystoprostatectomy (n=2), radical prostatectomy (n=4), pelvic exenteration (n=2), or pelvic tumor resection (n=1). Enucleation (n=1) and TUR (n=1) were performed in 2 other cases. Tumor sizes ranged from 8.5 to 15 cm in 7 radically resected cases. Mitotic rates were 3 to 5 per 10 high power fields in 5 cases, with the remaining cases having either rare (n=4) or no mitoses (n=4). Seven cases demonstrated areas of necrosis. Based on a combination of increased cellularity, mitotic activity, necrosis, nuclear pleomorphism, and infiltrativeness, 4 prostatic SFTs were malignant, 4 were benign, and 2 were borderline. Of the 3 non-prostatic SFTs, 1 was malignant and 2 were borderline. All tumors but 1 were immunoreactive for CD34 (n=12). Material for additional immunohistochemistry was available for the majority of cases with positive stains for Bcl-2 (11/11), CD99 (7/10), beta-catenin (5/10), and c-kit (0/11). Three SFTs demonstrated >or=10% p53 immunoreactivity including 1 tumor with 50% positivity; and 3 cases had Ki-67 rates of >or=20%. Although all SFTs were initially clinically considered to be of prostatic origin, some of the cases arose in the pelvis with secondary involvement of the prostate. Approximately 50% of prostatic SFTs were malignant. Even in the prostatic and nonprostatic SFTs with no overt malignant features, sometimes it was necessary to remove the prostate and in some instances the adjacent organs because of the large size of the tumors. SFTs must be differentiated from other spindle cell neoplasms of the prostate especially from gastrointestinal stromal tumors that may arise from the rectal wall with invasion of the prostate or from the region between the rectum and the prostate.

Pulmonary lipomatous hemangiopericytoma: report of a rare tumor and comparison with solitary fibrous tumor

Lipomatous hemangiopericytoma is a rare mesenchymal tumor showing areas of lipid-containing cells admixed with a spindle-cell component. Like other hemangiopericytomas, it shows a similar vascular pattern to solitary fibrous tumor and, partly for this reason, it and other hemangiopericytomas have been subsumed into solitary fibrous tumor. The present study provides a comprehensive documentation of a single case of pulmonary lipomatous hemangiopericytoma of the lung, the first to be described at this site, and compares it with solitary fibrous tumor, in terms of clinical, histological, immunohistochemical, ultrastructural, and cytogenetic findings. Apart from the lipid-laden-cell component, pulmonary lipomatous hemangiopericytoma and solitary fibrous tumor were similar histologically. Bcl-2 was positive in both. CD34 was minimally expressed in pulmonary lipomatous hemangiopericytoma, which possessed some non-descriptive intercellular junctions, a feature shared by solitary fibrous tumor, which was CD34 positive. However, one of the latter was rich in gap junctions, a feature consistent with strong connexin (Cx) 43 staining and the existence, hitherto unappreciated, of a CD34/Cx43-positive tumor cell network. In pulmonary lipomatous hemangiopericytoma, chromosomal deletions of 43-44, X, -Y were found. In solitary fibrous tumor, 46, XY, del(13)(q?) abnormalities and abnormalities involving chromosome 10 were frequently observed. These similarities and differences are discussed in the context of the currently favored diagnostic fusion of hemangiopericytoma and solitary fibrous tumor.

Giant Pelvic Solitary Fibrous Tumor Obstructing Intestinal and Urinary Tract: A Case Report and Literature Review

We are reporting a giant pelvic neoplasm, a rare solitary fibrous tumor that presented with a large bowel obstruction and bilateral ureteral obstruction because of its size and location. Preoperative diagnosis required complex pathological studies to exclude a high-grade sarcoma suspected clinically. Complete resection was required for resolution of obstructive symptoms. Prognosis for solitary fibrous tumors is usually good after complete resection. Recurrence and metastasis may be related to rare aggressive histological features, including nuclear atypia, hypercellularity, greater than four mitoses/10 high power fields, and necrosis. Because histology is not always a reliable predictor of prognosis, careful long-term follow-up is necessary for this tumor. Solitary fibrous tumors (SFTs) are rare spindle cell neoplasms most likely arising from mesenchymal cells. SFTs were originally described in the pleura, the most common site for this tumor; however, extrathoracic SFTs are seemingly diagnosed with increased frequency. We report a case of a giant pelvic SFT that required complicated clinical management.

SOLITARY FIBROUS TUMORS OF THE CENTRAL NERVOUS SYSTEM

OBJECTIVE

This is a retrospective study of 18 patients harboring a solitary fibrous tumor of the central nervous system. Therapeutic management and outcome were analyzed.

METHODS

Between 1999 and 2004, 18 patients harboring central nervous system solitary fibrous tumors were surgically treated at our two institutions. There were nine men and nine women. The patient ages ranged from 33 to 75 years, with a median age of 56.1 years. The locations were spinal in six cases (33.3%), the posterior fossa in six cases (33.3%), supratentorial in four cases (22.2%), and orbital in two cases (11.2%).

RESULTS

The median follow-up period was 45.3 months. Gross total resection was achieved in 10 cases (55.6%); tumor recurrence or progression occurred in nine cases (50%). Incomplete surgical resection was significantly associated with recurrence (P = 0.018). On univariate analysis, extent of surgery was also associated with a longer progression-free survival (P = 0.05). No statistically significant correlation can be found between histological features and recurrence.

CONCLUSION

Prognosis of solitary fibrous tumors of the central nervous system remains unclear; consequently, careful and close monitoring of patients and long-term follow-up are mandatory. Radical surgical excision seems to be a significant and reliable prognosis factor, although pathological prognostic features must be defined. In other respects, the role of postoperative radiotherapy in atypical or incompletely resected solitary fibrous tumors of the central nervous system remains to be determined and, therefore, warrants larger series with longer follow-up periods.

Advanced malignant solitary fibrous tumor in pelvis responding to radiation therapy

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm that is benign in most cases. Although SFT was first recognized to arise only in the pleura, recent reports indicate that SFT can involve a wide range of anatomical sites. To date, 17 cases of pelvic SFT have been reported. Herein is reported a case of a 74-year-old woman with a giant malignant SFT in the pelvis. Along with massive invasion to adjacent organs and multiple lung metastases detected on radiography, biopsy from the tumor through the vaginal wall showed malignant looking spindle-cell neoplasm with increased cellularity, areas of necrosis, and high mitotic activity (5/10 high-power fields). Immunohistochemically, the tumor cells were diffusely and strongly positive for CD34, CD99, and bcl-2. Based on pathological features and clinical presentation, diagnosis of malignant SFT was made. The patient received systemic and the intra-arterial chemotherapy followed by whole pelvic radiation therapy (50 Gy). Initial chemotherapies failed to control the tumor. Afterwards, improvement was observed radiologically and pathologically in the 12 months' follow up after the radiation therapy. This is the first report related to therapeutic remarks on advanced malignant SFT.