bcl-2 expression in pleural and extrapleural solitary fibrous tumours

Mesenchymal tumours of the pleura: review and update

Primary mesenchymal tumours of the pleura are uncommon and can be diagnostically challenging due to their overlapping histopathologic and immunophenotypic features. Herein we discuss selected mesenchymal tumours of the pleura, including solitary fibrous tumour, calcifying fibrous tumour, desmoid fibromatosis, synovial sarcoma, schwannoma, malignant peripheral nerve sheath tumour, inflammatory myofibroblastic tumour, follicular dendritic cell sarcoma, epithelioid hemangioendothelioma, and desmoplastic small round cell tumour. We review their clinicopathologic characteristics, along with an update on the relevant immunohistochemical and molecular features.

Laryngeal solitary fibrous tumour: diagnostic challenge in a rare presentation

Solitary fibrous tumours (SFT) are rare spindle cell mesenchymal neoplasms, most commonly appearing as well-circumscribed localised lesions arising from the abdominal or pelvic peritoneum. Their presence in the head and neck region is very rare; even more so in the post-cricoid region, with only one case described in the literature to date. The clinical behaviour of SFT may vary from benign to malignant, but only 10-15% of SFT demonstrate local recurrence or distant metastasis. The usual presenting symptoms of dysphagia and weight loss are very vague to give a definite diagnosis, and examination, even under general anaesthesia, combined with biopsies can sometimes be misleading, as in our case. Here, we describe a very challenging case of supraglottic SFT originating from the post-cricoid area. Our 73-year-old patient presented with dysphagia and upon examination a large supraglottic mass was revealed. Biopsies from the mass pointed to malignancy and the patient underwent total laryngectomy. The laryngeal specimen contradicted the biopsy and revealed a rare solitary fibrous tumour with benign features and thus adjuvant treatment was not necessary. Ever since the patient has been attending regular follow-up sessions and remains disease-free 18 months after surgery.

Spindle Cell Tumors of the Pleura and the Peritoneum: Pathologic Diagnosis and Updates

A diverse group of both benign and malignant spindle cell tumors can involve the pleura or the peritoneum. Due to their rarity and overlapping morphologic features, these tumors can pose considerable diagnostic difficulty in surgical pathology. As these tumors differ in their prognosis and clinical management, their correct pathologic diagnosis is critical. In addition to histologic assessment, select immunohistochemical and molecular tools can aid the distinction among these tumors. In this review, we consider some of the major histologic differential diagnosis of spindle cell tumors involving these serosal membranes. This list of tumors includes: solitary fibrous tumor, inflammatory myofibroblastic tumor, desmoid fibromatosis, synovial sarcoma, sarcomatoid carcinoma, spindle cell melanoma, dedifferentiated liposarcoma, epithelioid hemangioendothelioma, and sarcomatoid mesothelioma. We describe their salient clinicopathologic and genetic findings, with a review on some of the recent discoveries on their molecular pathogenesis.

Implications of Adverse Biological Factors and Management of Solitary Fibrous Tumors of the Pleura

Solitary fibrous tumors arise in many locations throughout the body and are genetically and histologically considered a single disease. Solitary fibrous tumors of the pleura (SFTP) are the most common tumor of this disease. Most of the SFTPs are treated with surgery alone, and chemotherapy and radiotherapy do not seem to play a role in treatment. Tumor size and unfavorable histology are risk factors for malignant potential. Incomplete resection is an important risk factor for recurrence.

A Rare Case of a Solitary Fibrous Tumor of the Spermatic Cord

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors, originally identified in the pleura. Even though they have subsequently been described in several extrapleural sites, the incidence of SFTs in the spermatic cord is particularly rare. Here, we report a case of a 27-year-old male that presented with a 3-year history of left scrotal swelling. Computed tomography (CT) and ultrasound demonstrated multiple solid, hypoechoic well-circumscribed masses that were separate from the testis. Surgical excision of the mass led to pathologic diagnosis of a solitary fibrous tumor involving the spermatic cord. Solitary fibrous tumors, although rare, are an important differential diagnosis for urogenital tumors.

Orbital solitary fibrous tumors: a multi-centered histopathological and immunohistochemical analysis with radiological description

BACKGROUND

Solitary fibrous tumors (SFT), formerly called hemangiopericytoma, are rare tumors derived from mesenchymal cells originally described in the pleura, but these tumors may affect extraserosal tissues including the lacrimal gland and orbit.

OBJECTIVE

Conduct a multi-centered clinical, radiological and histopathological analysis of 17 orbital SFT cases.

DESIGN

A retrospective case series.

SETTING

Three eye centers in two countries.

PATIENTS AND METHODS

The data collected from the charts of 17 adult patients presenting with tissue diagnosis of orbital hemangiopericytoma or SFT from January 2003 to December 2018 included demographics, clinical imaging and histopathological information including immunohistochemical (IHC) characteristics.

MAIN OUTCOME MEASURES

The demographic characteristics, clinical presentation, and histopathological patterns or variants of SFT were analyzed.

SAMPLE SIZE

17 adult patients.

RESULTS

Mean age was 45 years (range 23-80 years). Male to female ratio was 3:1. The right eye was affected in 12 (70.5%) patients. Commonest presentation was proptosis in 13/17 (76% of patients). Other symptoms were impaired motility (29%) and ptosis (11%). Lesions mostly affected the medial orbit (35%), then orbital apex in 11%. The histopathological classic pattern-less variant was the commonest. One case with aggressive behavior, multiple recurrences and atypical features was encountered. Immunohistochemical (IHC) markers used included CD34 expression in all cases, Bcl-2 expression in 10/11, CD99 in 9/9 and Vimentin in 4/4. STAT6 was used in 2 cases.

CONCLUSIONS

SFTs are rare tumors affecting the orbit in both genders equally in their mid-forties, but showed male predominance in our analysis with a predominant classic histopathological pattern. Tissue diagnosis is essential and requires IHC studies for confirmation.

LIMITATIONS

Sample size is relatively small owing to the rarity of this tumor in the orbit.

CONFLICT OF INTEREST

None.

Cervical, Intradural Extramedullary Solitary Fibrous Tumor of the Spinal Cord: A Case Report and Review of the Literature

Solitary fibrous tumors (SFTs) are rare, spindle cell neoplasms of the mesenchymal origin. Lesions localized to the spine are exceptionally uncommon, only described in the literature in case reports and small case series. While these lesions are typically benign, there are a few reports in which they recur or present as malignancies. The patient presented in the case herein was a 72-year-old male, who presented with a 1-year history of lower extremity weakness, pain, and numbness and was found to have a cervical, intradural extramedullary tumor. In addition to the case report, the authors perform a thorough review of all previously published cases of spinal SFT.

Solitary fibrous tumor of the scrotum: a case report and review of the literature

BACKGROUND

Solitary fibrous tumor (SFT) is a rare soft tissue tumor originally reported in the pleura. Although it has been reported in various extra-pleural sites, the occurrence of SFT in the scrotum is extremely rare. Herein, we present a 48-year-old man who had scrotal SFT. There are very few reported cases of genitourinary SFTs, this is only the fifth report of SFT of the scrotum in the English medical literature.

CASE PRESENTATION

In this study, we report on a 48-year-old man who presented with a 5 × 8 cm scrotal mass between his testes. Physical examination revealed a 4.7 × 8.5 cm lobulated tumor mass located between his testicles. Surgical excision of the tumor with scrotal approach was done and pathology reported a SFT. The patient was alive without tumor recurrence or distant metastasis during ongoing follow-up for 9 months post-operatively..

CONCLUSION

Scrotal SFTs are very rare and only five cases have been reported in English literature to date. Treatment often involves surgical resection, and a definite diagnosis is made with the help of immunohistochemistry. The current general consensus for the management of SFTs is long-term follow-up after surgical excision of the tumor.

Solitary fibrous pleural tumor. A rare and challenging case

INTRODUCTION

Solitary fibrous tumor of the pleura (SFTP) is a rare tumor originating from mesenchymal tissue underlying the mesothelial pleural layer with only a limited number of reported cases. Benign and malignant SFTP usually appear as a well-defined, homogeneous, and rounded mass on imaging. Complete en bloc is usually the treatment of choice.

CASE PRESENTATION

44 years old gentleman presented with the unintentional weight loss and chest discomfort for 6 months. A CT scan of chest showed a 30 × 20 × 20 cm heterogeneously enhancing soft tissue mass involving the entire right hemithorax. PET scan showed a localized disease. Therefore, a complete right upper lobectomy and complete removal of mass was done, that resulted in complete expansion of the middle and lower lobe. The patient remains stable till date. Biopsy revealed a fibrous pleural tumor.

CONCLUSION

Complete surgical resection of the tumor is usually sufficient, but there are reported cases with recurrence. Wedge resection for complete excision can be carried out for tumors arising from visceral pleura. Extra pleural excision can be done without chest wall resection in tumors arising from the parietal pleura.

Orbital solitary fibrous tumor: A painless mass after a dacryochystorhinostomy

The solitary fibrous tumor (STF) is a rare spindle cell tumor that most often occurs in the pleura, mediastinum and other serosal sites, but it can be found anywhere. The authors present a case report of a 35-year-old male who was submitted to an eventless left external dacryocystorhinostomy (DCR) due to epiphora. During the surgery no tumors or anomalous tissues were visualized. Five months later the patient presented a painless mass at the lower medial quadrant of the left orbit, near the lacrimal fossa. A computed tomography, a magnetic resonance imaging and an orbital ultrasound were performed. A round, very vascularized and highly contrast enhanced mass was found. An anterior orbitotomy was done. Histological aspects and immunohistochemical markers were consistent with STF. The tumor was not visualized during the DCR. The authors think that the growth of the tumor and the weakening of the tissues in the medial canthus after the DCR allowed the tumor to move anteriorly within the orbit.

The Diagnosis of Pleural Tumors Other Than Mesothelioma

CONTEXT

- Pleural pathology has been dominated by discussions relating to the diagnosis, prognosis, etiology, and management of malignant mesothelioma. However, there exists a diverse group of other neoplasms that involve the pleura; the most common by far is metastatic carcinoma, usually of pulmonary origin. Other metastatic tumors of varied histogenesis do occur but are less common. Primary pleural neoplasms other than diffuse malignant mesothelioma are either uncommon or rare and have received less attention.

OBJECTIVE

- To provide a review of those diverse tumors that can involve the pleura other than mesothelioma in order to facilitate their accurate diagnosis.

DATA SOURCES

- Review of relevant literature published via PubMed and other search engines.

CONCLUSIONS

- A wide variety of tumors can involve the pleura. In most cases, the approach of considering the morphologic features with appropriate immunohistochemistry, in the correct clinical context, allows for a confident diagnosis. For a number of those soft tissue tumors that are well recognized in the pleura, such as solitary fibrous tumor, desmoid-type fibromatosis, synovial sarcoma, and epithelioid hemangioendothelioma, novel markers now exist based on an understanding of the individual tumors' molecular characteristics. Primary pleural lymphomas are rare with poor prognosis. They represent localized specific diffuse large B-cell lymphomas, with either post-germinal center B-cell or plasma cell lineage, arising in the context of either immunodeficiency or immune sequestration and with viral infection.

Solitary fibrous tumor of the pineal region with delayed ectopic intracranial metastasis: A case report and review of the literature

RATIONALE

Solitary fibrous tumors of central nervous system are rare spindle-cell mesenchymal tumors. Although most are benign in nature, malignant transformation and extracranial metastasis have been reported. Up to now, only one case of CSF dissemination was described. Here we described an extremely rare case of intracranial Solitary fibrous tumors arising from the pineal region with a delayed ectopic metastasis.

PATIENT CONCERNS

A 35-year-old female presented with double vision, memory disturbance and unsteady gait was referred to our center. MRI showed an irregular mass in the pineal region.

DIAGNOSES

The patient was diagnosed as pineal tumor, with unknown pathology.

INTERVENTIONS

Gross total resection was achieved and the pathologic studies confirmed a solitary fibrous tumor. Thirty-nine months later local recurrence occurred and gamma-knife radiotherapy was offered. Seven months later, MRI found a metastasis in the left temporal lobe. Surgical resection was conducted and pathological analysis revealed changes in cell morphology, counts and Ki-67 level, confirmed the diagnosis of solitary fibrous tumor/hemangiopericytoma (WHO Grade III). The patient received post-operational radiotherapy.

OUTCOMES

The patient was followed up for 7 months with no signs of recurrence.

LESSONS

Here, we report an extremely rare case of primary solitary fibrous tumor of pineal region with delayed intracranial ectopic metastasis, together with literature review of metastatic solitary fibrous tumors. Strict surveillance is strongly recommended, considering the malignant potential of this seemingly benign disease entity. Complete resection of the tumor is the treatment of first choice and radiotherapy might be an effective adjuvant therapy for high grade SFT/HPCs.

Practical Issues for Retroperitoneal Sarcoma

Background

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

Methods

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

Results

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

Conclusions

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

Lungs and subcutaneous metastases from a solitary fibrous tumour of the pancreas

Solitary fibrous tumour is an uncommon mesenchymal neoplasm previously thought to only originate from the pleura; it is seen only rarely in an extra-pleural location. We report the first case of pancreatic solitary fibrous tumour in an 87-year-old woman that has metastasized to the lungs and subcutaneous tissue. We have identified a solitary mass excised from the groin region, which is positive for CD34 and vimentic marker with high proliferative rate, nuclear atypia and cellular necrosis. Imaging studies confirmed a slow-growing solitary mass in the uncinate lobe of the pancreas with evidence of lung metastasis.

A case of solitary fibrous pleura tumor associated with severe hypoglycemia: doege-potter syndrome

Solitary fibrous tumor of the pleura (SFTP) is a rare primary intrathoracic tumor that arises from mesenchymal tissue underlying the mesothelial layer of the pleura. It usually has an indolent clinical course. The hypoglycemia that accompanies SFTP was first described by Doege and Potter independently in 1930, hence the eponym Doege-Potter syndrome (DPS). The incidence of DPS is reported to be ~4%. In this report, we present a typical case of DPS that was cured through complete surgical resection.

Solitary fibrous tumor - clinicopathologic, immunohistochemical and molecular analysis of 28 cases

Background

Solitary fibrous tumor is a mesenchymal tumor of fibroblastic type, which can affect any region of the body. Recently, a recurrent gene fusion NAB2-STAT6 has been identified as molecular hallmark. The NAB2-STAT6 fusion leads to EGR1 activation and transcriptional deregulation of EGR1-dependent target genes and is a driving event in initiation of SFT. In this study, we report the clinicopathologic and RT-PCR findings and evaluated expression of STAT6 and EGR1 protein in a cohort of 28 SFTs.

Methods

28 patients with a median age of 54 years were included with SFTs originating at different sites, most occurring in the lung and pleura (9, 32%), 5 in soft tissues of the lower extremities (18%) and 5 in the head and neck (18%). For detection of the NAB2-STAT6 fusion gene, RT-PCR was performed using RNA extracted from formalin-fixed and paraffin-embedded tissues. Immunohistochemistry was performed on all cases with antibodies against STAT6 and EGR1.

Results

All patients were treated by surgery, 3 with adjuvant chemo- or radiotherapy. Follow-up data of 18 patients could be obtained of which 2 patients died of metastatic disease 13 months and 52 years after first diagnosis. Sixteen patients have no evidence of disease with a median follow up of 29.5 months (range 7 – 120 months). NAB2-STAT6 fusion transcripts were found in 19/28 cases (68%). The most common fusion was between NAB2 exon 4 and STAT6 exon 3 (11/19, 58%), mainly occurring in pleuropulmonary lesions. All cases showed strong nuclear expression of STAT6 (28/28, 100%) while EGR1 showed low-level variable nuclear expression in all samples, comparable with the EGR1 expression results of the control group.

Conclusions

The identification of the NAB2-STAT6 fusion in SFTs can provide important diagnostic information, especially in cases with aberrant morphology or when biopsy material is limited. STAT6 immunohistochemistry is another useful tool in diagnosing SFT. EGR1 immunohistochemistry indicates low-level protein expression in accordance with EGR1 activation due to distorted NAB2 activity.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_224

Meningeal hemangiopericytoma only diagnosed at the time of late bone metastasis

Hemangiopericytoma is a rare neoplasm. Primary meningeal hemangiopericytomas account for 1 to 7% of all meningeal tumors. In the literature, meningeal hemangiopericytomas are mainly case reports, which confirm an aggressive behavior with a high rate of local recurrence and extracranial metastasis. Metastasis can be seen many years after initial surgical excision of the primary tumor, and the most common sites include the bone, liver and lung. We present a pathological study of four meningeal hemangiopericytomas with bone metastases. All patients are male with a mean age of 46.5 years. Metastases only involved bone. Three out of four lesions were initially misdiagnosed as meningiomas. Only one case was initially correctly diagnosed as meningeal hemangiopericytoma. All patients underwent surgery with complete resection. Only the patient immediately diagnosed with meningeal hemangiopericytoma received postoperative radiation therapy. Three patients had bone metastases without local recurrence including the one who received radiation therapy. One patient recurred locally after 7 years, and bone metastasis was found at the same time. Our cases confirm that meningeal hemangiopericytomas are a separate entity and have a high recurrence rate despite complete surgical resection, with extracranial metastases, mainly to bone, even after long intervals.

Recurrent intrathoracic solitary fibrous tumor: Remarkable response to radiotherapy

Solitary Fibrous Tumor of the Pleura (SFTP) is an uncommon neoplasm which grows slowly. For some cases, surgery is warranted. However, for unresectable ones, the standard strategy has not been established yet. We presented a rare case of recurrent malignant intrathoracic solitary fibrous tumor. It was impossible to resect the tumor. Radiotherapy alone achieved a significant improvement effect.

Clinicopathological findings in a case series of abdominopelvic solitary fibrous tumors

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

Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics

Solitary fibrous tumor (SFT) is composed of spindled to ovoid cells in a patternless architecture with prominent stromal collagen and hemangiopericytoma-like vessels. Some tumors show hypercellularity, nuclear atypia, and significant mitotic activity; the latter feature in particular often portends an aggressive clinical course. SFT can sometimes be difficult to distinguish from other benign mesenchymal tumors and sarcomas. The most characteristic (albeit nonspecific) immunohistochemical finding in SFT is CD34 expression. A NAB2-STAT6 gene fusion, resulting in a chimeric protein in which a repressor domain of NGFI-A binding protein 2 (EGR1 binding protein 2) (NAB2) is replaced with a carboxy-terminal transactivation domain from signal transducer and activator of transcription 6, interleukin-4 induced (STAT6), was recently identified as a consistent finding in SFT. However, as these genes are located in close proximity on 12q13, this fusion can only rarely be detected by conventional chromosomal banding or fluorescence in situ hybridization analysis. Nuclear expression of the carboxy terminal part of STAT6 is a consistent finding in SFT of the meninges (so-called 'meningeal hemangiopericytoma'). We investigated STAT6 expression by immunohistochemistry in SFTs and other soft tissue tumors arising outside the central nervous system to validate the diagnostic utility of this novel marker. Whole-tissue sections of 231 tumors were evaluated, including 60 cases of SFT as well as other benign and malignant mesenchymal neoplasms and sarcomatoid mesotheliomas. Fifty-nine of 60 SFT cases (98%) showed nuclear expression of STAT6, which was usually diffuse and intense. All other tumor types were negative for STAT6, except for three dedifferentiated liposarcomas and one deep fibrous histiocytoma, which showed weak staining. In conclusion, STAT6 is a highly sensitive and almost perfectly specific immunohistochemical marker for SFT and can be helpful to distinguish this tumor type from histologic mimics.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

MRI Features of Spinal Solitary Fibrous Tumors

Spinal solitary fibrous tumors (SFT) are very rare neoplasms occurring in the spinal canal, with only 38 cases reported in ten years since the first description. We describe two cases of SFT of the spine and review 33 well-documented cases in the literature to define distinctive radiological and surgical features raising the suspicion of a spinal SFT before histological verification. A 67-year-old man with cervical myeloradiculopathy had a large extramedullary tumor of the cervical spinal canal extending from C4 to C7. On MRI the tumor was isointense on T1-sequences and hypointense on T2-sequences, and had marked contrast enhancement. At surgery, the tumor was intradural extramedullary, with no dural or root attachment, but it was adherent to the cord. Complete tumor removal was achieved with good outcome. A 75-year-old man with progressive thoracic myelopathy had an intramedullary tumor at C6 and C7 level, which was hypointense on T1- and T2-weighted images of MRI. At surgery, the tumor was intramedullary and strongly adherent to the cord; it was successfully removed. Both tumors were composed of elongated cells with a collagen-matrix background. Immunohistochemical staining was positive for vimentin, CD34, and bcl-2, and negative for EMA and S-100 protein. A careful analysis of our own and the other reported cases of spinal SFTs may disclose some peculiar features of this rare tumor. A spinal intramedullary or extramedullary tumor, hypointense on T2-weighted images of MRI, which intraoperatively shows hard consistency, scarce vascularization, no nerve root involvement, no or weak dural attachment, absence of arachnoidal interface, and adherence to the spinal cord may suggest the diagnosis of SFT.

Mesotheliomas with small cell features: report of eight cases

Mesotheliomas with small cell morphology are rare and only one study of such cases has been published. As a result of their rare occurrence, some investigators have cast doubt on the existence of such a histologic variant of mesothelioma. This investigator reports a series of eight cases of epithelioid mesothelioma with small cell features, all of which originated in the pleura. Seven of the patients were men and one was a woman. Four patients had a history of asbestos exposure. Histologically, four of the mesotheliomas were epithelioid and four biphasic. The proportion of small cells seen in these cases constituted 80 to 100% of the tumor included in the biopsy material and 15 to 20% of the tumor present in the pneumonectomy specimens. Immunoreactivity for calretinin, keratin 5/6, keratin 7, pan-keratin, WT1, podoplanin, and mesothelin was seen in all cases tested for these markers. All of the cases were negative for MOC-31, Ber-EP4, CEA, CD15, TAG-72, TTF-1, chromogranin A, synaptophysin, CD99, and desmin. The mean survival of the six patients for whom this information was available was 8.2 months. It is important for pathologists to be aware that mesotheliomas can present small cell features and, because of this, they can be confused with other malignancies that can exhibit similar morphology. The value of immunohistochemistry in the differential diagnosis of these tumors is discussed.

A locally aggressive solitary fibrous tumor of the leg: Case report and literature review

INTRODUCTION

The solitary fibrous tumor (SFT) is a rare soft tissue tumor with a substantially benign clinical behavior. However, malignant neoplasms with local recurrence or distant metastases have been reported.

PRESENTATION OF THE CASE

The authors present a case of an aggressive SFT of the leg, in a 55 years old Caucasian man. Radiological, histological and molecular findings are reported. The differential diagnosis, therapy and outcome of this rare tumor are also discussed.

DISCUSSION

An extensive review of literature showed SFT's clinical behavior as substantially benign, anyway aggressive or malignant neoplasms have been described. The potential risk of local recurrence and distant metastasis thus suggests wide surgical resection and careful long-term follow-up. Differential diagnosis may be quite laborious as SFT can mimic a variety of benign and malignant mesenchymal tumors; immunohistochemical analysis for CD34, CD99, vimentin and bcl-2 is then mandatory.

CONCLUSION

Our clinical experience confirmed that SFT may have an aggressive behavior, however, conservative surgical treatment may be successful in the long term.

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.

Solitary fibrous tumour of the larynx: a case report

INTRODUCTION

Solitary fibrous tumour (SFT) of the larynx is a rare benign mesenchymal tumour of adults. The diagnosis is based on a combination of histological and immunohistochemical signs.

CASE REPORT

The authors report the case of a patient with chronic laryngeal dysphonia and dyspnoea related to supraglottic SFT.

DISCUSSION/CONCLUSION

The main challenge of surgery is to ensure healthy resection margins to avoid recurrence while preserving the functions of the upper aerodigestive tract. Surgery is the treatment of choice and provides an excellent prognosis. Long-term clinical follow-up is required to detect rare recurrences.

Immunohistochemistry in diagnosis of soft tissue tumours

Immunohistochemistry in soft tissue tumours, and especially sarcomas, is used to identify differentiation in the neoplastic cells. In some cases, specific antigens are expressed; however, an initial panel of antibodies is often required in order to establish the broad lineage, with a subsequent, more focused, panel to allow classification. Immunohistochemical evaluation must be employed with the clinical picture, the morphology, and, when necessary, other ancillary techniques such as molecular genetics and cytogenetics. Whereas some diagnoses are evident on morphology, many soft tissue neoplasms are seen microscopically as spindle cell, epithelioid cell, small round cell or pleomorphic tumours that need to be further characterized. This article reviews selected applications of immunohistochemistry in the diagnosis of each of the principal morphological groups, concentrating on areas of most use in daily practice.

Ectopic primary type A thymoma located in two thoracic vertebras: a case report

BACKGROUND

The thymus arises in the ventral portion of the third and fourth pharyngeal pouch. It descends into the anterior mediastinum at 6th week of gestation. Any errors occurring during this process can cause dissemination of aberrant nodules that are responsible for most atypical thymomas.

CASE PRESENTATION

The authors report a unusual case of type-A thymoma located in D10 and D11 vertebral bodies.The histology showed a uniform growth of short, spindle shaped, mitotically inactive cells. A few small, normal lymphocytes were seen scattered or in small groups. The immunohistochemical investigation for neuroectodermal, neuroendocrine, vascular and muscular markers were negative. It also confirmed the presence of CD3+, CD5+ T lymphocytes and the absence of immature T-lymphocyte markers.

CONCLUSIONS

The case described shows a thymic hystogenesis for spindle cell tumours. To our knowledge no other cases of vertebral thymomas have been described in international literature.

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.

Clinicopathological Features of Solitary Fibrous Tumours in the Extremities: Four Case Reports and a Literature Review

This paper reports on the clinicopathological features of four patients with solitary fibrous tumours arising from the extremities and presents a review of the relevant literature. The patients consisted of three women and one man, with a mean age of 47.8 years. Standard pre-operative work-up data were examined, including: history, clinical examination, plain radiography, computed tomography scans of the lesion and chest, magnetic resonance imaging, angiography, technetium-99m bone scan, thallium-201 scintigraphy and routine laboratory tests. Immunohisto chemical staining was performed for CD34, Bcl-2 protein, vimentin, S-100 protein, desmin and smooth muscle actin, and pathological material was reviewed for the presence of histologically malignant components. Immunohistochemically, all of the tumours were diffusely positive for CD34. Clinical and radiological findings of solitary fibrous tumours affecting the extremities are reminiscent of those of aggressive or malignant soft tissue tumours. Pathological and immunohistochemical studies are important in making the correct diagnosis.

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.

Cytogenetic, fluorescence in situ hybridization, and immunohistochemistry studies in a malignant pleural solitary fibrous tumor

Pleural solitary fibrous tumor is a normally benign fibroblastic neoplasm; its recurrences and metastasis are associated with clinical and morphological characteristics of variable interpretation and efficacy of surgical treatment. Immunohistochemistry techniques have contributed decisively to the correct diagnosis of the lesion and define its prognosis. In the present case, cytogenetic and fluorescence in situ hybridization analyses revealed multiple chromosomal aberrations, including a del(9)(q21qter) and a marker chromosome ish der(9)(ABL+). The present data support but do not resolve the possible involvement of a gene on 9q22 in the biological behavior of these tumors, and the ABL rearrangements and deletions of 1p and 10p suggest another possible malignant component.

Primary pleural neoplasia: entities other than diffuse malignant mesothelioma

CONTEXT

Overwhelmingly, the most common neoplasm involving the pleura is metastatic carcinoma. In contrast, diffuse malignant mesothelioma occurs relatively rarely; however, it is nonetheless the most common neoplasm primary to the pleura. Metastatic carcinoma and diffuse malignant mesothelioma each have their own prognostic and therapeutic characteristics. Other primary pleural neoplasms occur uncommonly or rarely, with their own prognostic and therapeutic characteristics.

OBJECTIVE

To review primary pleural neoplasms other than diffuse malignant mesothelioma, to better ensure correct diagnosis and optimal assessment of prognosis and treatment.

DATA SOURCES

Literature review and primary material from the authors' institutions.

CONCLUSIONS

A nonexhaustive group of uncommon to rare benign and malignant primary pleural neoplasms--other than diffuse malignant mesothelioma--are presented, of which one must be aware in order to maintain an appropriate index of suspicion to include them in the differential diagnosis of a pleural tumor.

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 male breast: a case report and review of the literature

Extrapleural solitary fibrous tumors are very rare and occasionally they appear in extraserosal soft tissues or parenchymatous organs. In such cases the right preoperative diagnosis is often difficult and challenging, because both radiological and cytological examinations are not exhaustive. For these reasons, surgical excision is frequently the only way to reach the correct diagnosis and to achieve definitive treatment. A few cases of solitary fibrous tumors have been also described in the breast. Although rare, this lesion opens difficulties in preoperative diagnosis entering in differential diagnosis with other benign lesions as well as with breast cancer. In this article we describe a case of a solitary fibrous tumor of the breast in a 49-year-old man. Problems related to differential diagnosis and the possible pitfalls that can be encountered in the diagnostic iter of such rare tumor are discussed.

A solitary fibrous tumor in the broad ligament of the uterus

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that occurs preferentially in the pleura. Although it has been described at some extrathoracic sites, its occurrence in the female genital tract is extremely rare. We are the first to report on an unusual case of a large (14cm in the largest diameter) SFT localized in the broad ligament of the uterus in a 50-year-old woman. The patient underwent surgical tumor extirpation and has remained well without any sign of local tumor recurrence after 6 years of follow-up. We discuss the clinical aspects, the gross macroscopic appearance, the histologic findings, and the differential diagnosis, and provide a review of the literature.

Comparison of sporadic sclerotic fibroma and solitary fibrous tumor in the oral cavity

Sporadic sclerotic fibroma (SF) and solitary fibrous tumor (SFT) arising in the oral cavity are very rare. In this report, we describe two cases of oral pathology, one involving SF and the other involving SFT. Both cases presented with well- circumscribed, firm nodules with similar gross findings. However, the histologic findings of the SF and SFT showed rather distinct features. The SF was composed of hyalinized sclerotic collagen bundles arranged in a whorled pattern, whereas the SFT was formed by spindles cells arranged in hypo- and hypercellular areas. The immunohistochemical findings were similar in both cases; there was positivity for vimentin, CD34, and CD99, but bcl-2 positivity was only seen in the SFT. Although their histopathologies are similar, SF and SFT should be considered in the differential diagnosis of soft tissue tumors in the oral cavity.