Solitary Fibrous Tumor of the Pleura: Outcomes of 157 Complete Resections in a Single Center

Solitary fibrous tumors from A to Z: a pictorial review with radiologic-pathologic correlation

Solitary fibrous tumors (SFTs) represent a rare subset of mesenchymal neoplasms, affecting 1-2 per million people, with no gender preference. They demonstrate indolent behavior, frequent asymptomatic presentation, and widespread anatomical involvement. At imaging, SFTs typically appear as well-defined, predominantly hypervascular masses with varying degrees of cystic change and necrosis, though calcification is rare. Avid heterogeneous enhancement is typical following intravenous contrast administration, with multiple blood vessels observed at the periphery. Although findings on CT and MRI alone are generally nonspecific, a frequent feature of SFTs at MRI is the presence of rounded or linear low signal intensity foci on T1- and T2-weighted images, corresponding to the fibrous and collagenous content. Nevertheless, because the imaging features of SFTs overlap with those of many benign and malignant tumors, histologic confirmation is required for the final diagnosis. A comprehensive understanding of SFTs' multifaceted clinical, pathological, and radiological presentations across various organs is crucial for accurate diagnosis and effective management. CRITICAL RELEVANCE STATEMENT: A comprehensive understanding of the classic radiological and pathological features of solitary fibrous tumors across various organs is crucial for accurate diagnosis and effective management. KEY POINTS: Solitary fibrous tumors (SFTs) are rare hypervascular fibrous tumors with indolent behavior. Imaging features of SFTs overlap with many other tumors, necessitating histologic confirmation. Understanding SFTs' radiological presentations is crucial for accurate diagnosis and effective management.

Management of a malignant solitary fibrous tumor of lung by uniportal video-assisted pneumonectomy: a case report

BACKGROUND

Solitary fibrous tumor (SFT) is a rare condition first described by Klemperer and Robin in 1931. Malignant SFTs account for approximately 80% of all SFT cases, and the five-year survival for malignant SFTs is 81%. Few reports have described SFT management using uniportal video-assisted pneumonectomy.

CASE PRESENTATION

A 35-year-old male patient with a tumor in the left pulmonary was assessed using preoperative three-dimensional computed tomography (3D-CT) reconstruction and treated via uniportal video-assisted pneumonectomy. A pathological diagnosis of SFT was confirmed.

CONCLUSIONS

The 3D-CT reconstruction may help to provide an appropriate operative strategy for surgeons. It is necessary to control the main pulmonary arterial trunk to avoid hemorrhage when preoperative evaluation does not exclude the possibility of intraoperative hemorrhage. The choice of surgery area is affected by SFT size and location.

Advances in the molecular biology of the solitary fibrous tumor and potential impact on clinical applications

Solitary fibrous tumor (SFT) is a rare fibroblastic mesenchymal neoplasm. The current classification has merged SFT and hemangiopericytoma (HPC) into the same tumor entity, while the risk stratification models have been developed to compensate for clinical prediction. Typically, slow-growing and asymptomatic, SFT can occur in various anatomical sites, most commonly in the pleura. Histologically, SFT consists of spindle to oval cells with minimal patterned growth, surrounded by stromal collagen and unique vascular patterns. Molecularly, SFT is defined by the fusion of NGFI-A-binding protein 2 (NAB2) and signal transducer and activator of transcription 6 (STAT6) genes as NAB2-STAT6. This fusion transforms NAB2 into a transcriptional activator, activating early growth response 1 (EGR1) and contributing to SFT pathogenesis and development. There are several fusion variants of NAB2-STAT6 in tumor tissues, with the most frequent ones being NAB2ex4-STAT6ex2 and NAB2ex6-STAT6ex16/ex17. Diagnostic methods play a crucial role in SFT clinical practice and basic research, including RT-PCR, next-generation sequencing (NGS), FISH, immunohistochemistry (IHC), and Western blot analysis, each with distinct capabilities and limitations. Traditional treatment strategies of SFT encompass surgical resection, radiation therapy, and chemotherapy, while emerging management regimes include antiangiogenic agents, immunotherapy, RNA-targeting technologies, and potential targeted drugs. This review provides an update on SFT's clinical and molecular aspects, diagnostic methods, and potential therapies.

Surgical management of giant solitary fibrous tumors of the pleura: Two case reports

INTRODUCTION

Solitary fibrous tumor of the pleura (SFTP) is a rare primary tumor originating from mesenchymal cells located beneath the mesothelial-lined pleura. A special entity is the giant SFTP which presents unique challenges in surgical management.

CASE PRESENTATION

Two cases of giant SFTPs in middle-aged patients are presented. Both patients presented with a recent worsening dyspnea and had imaging findings consistent with giant masses occupying the entire pleural cavity with a complete collapse of the homolateral lung and substantial contralateral deviation of heart and mediastinum. The pathological results of CT-guided transthoracic core needle biopsy was SFTP in both cases. Surgical resection was performed, and they both required two thoracotomies for complete tumor removal. Successful complete en bloc resection of the tumors was achieved with a total postoperative recovery. The first resected tumor was 30 × 20 cm and weighed 3500 g, the second was 33*x25 cm in size and weighed 4000 g. Both patients respiratory condition improved after the operation and no recurrence were noted in the follow-up.

DISCUSSION

SFTPs are removed using various approaches: thoracotomy, sternotomy with the possibility of hemiclamshell extension, video-assisted thoracoscopic surgery (VATS), and robotic-assisted surgery. The challenge when operating giant SFTP (> 15 cm) is double: adhesions and compression to the lung tissue and surrounding mediastinal structures and the hyper vascular nature of the tumor. For giant SFTPs an open approach is preferable. Resection should be complete with negative margins due to the high risk of recurrence.

CONCLUSION

These cases emphasize the significance of personalized surgical strategies for managing giant SFTPs, providing valuable insights for clinicians addressing similar cases.

Solitary fibrous tumours of the pleura: do we need a different perspective on malignancy?

OBJECTIVES

Solitary fibrous tumours of the pleura (SFTP) are historically considered to be benign soft tissue neoplasms. However, a clinical relevant number of these neoplasms have malignant histological features. The objective of this study was to evaluate the percentage of SFTP presenting unfavourable clinical behaviour in order to predict negative long-term outcome.

METHODS

A retrospective review of 74 patients treated at 4 hospitals between 1990 and 2013 was performed. The median follow-up was 10 years (range: 1-20 years). Risk of tumour recurrence and metastases (unfavourable clinical behaviour) with regard to histology using the Kaplan-Meier and Cox proportional hazards methods.

RESULTS

The mean age was 61 years (SD 12.75 years). There were 31 male patients (58%) and 43 female patients (42%). Tumour size ranged from 1 to 30 cm (mean 9.09 cm; SD 6.22 cm). Complete resection (R0) was achieved by minimally invasive thoracoscopic resection in 29% and thoracotomy in 57%; 25% of SFTPs showed histological evidence of malignancy, according to England criteria. Recurrence occurred in 21% and 10% of patients had metastases; 83% of patients with metastases and 39% of patients with recurrence died within 5 years. The median recurrence-free survival for histologically benign SFTP was not reached, compared to 8 years for malignant SFTP. The five-year overall survival rate was 84%. Mitotic rate ≥1/10 HPF, high cellularity, nuclear atypia, Ki-67 level >5% and poorly circumscribed (sessile) growth pattern were associated with poor long-term outcome.

CONCLUSIONS

Pathological differentiation of SFTP morphology into pedunculated, well circumscribed and poorly circumscribed (sessile) growth pattern is recommended. Due to the misleading classification into histologically benign and malignant, all unpedunculated SFTP should be classified as potentially aggressive. Lifelong follow-up is mandatory.

Risk factors for recurrent disease after resection of solitary fibrous tumor: a systematic review

Introduction

Solitary fibrous tumor (SFT) is a rare soft tissue tumor found at any site of the body. The treatment of choice is surgical resection, though 10%-30% of patients experience recurrent disease. Multiple risk factors and risk stratification systems have been investigated to predict which patients are at risk of recurrence. The main goal of this systematic review is to create an up-to-date systematic overview of risk factors and risk stratification systems predicting recurrence for patients with surgically resected SFT within torso and extremities.

Method

We prepared the review following the updated Prisma guidelines for systematic reviews (PRISMA-P). Pubmed, Embase, Cochrane Library, WHO international trial registry platform and ClinicalTrials.gov were systematically searched up to December 2022. All English studies describing risk factors for recurrence after resected SFT were included. We excluded SFT in the central nervous system and the oto-rhino-laryngology region.

Results

Eighty-one retrospective studies were identified. Different risk factors including age, symptoms, sex, resection margins, anatomic location, mitotic index, pleomorphism, hypercellularity, necrosis, size, dedifferentiation, CD-34 expression, Ki67 index and TP53-expression, APAF1-inactivation, TERT promoter mutation and NAB2::STAT6 fusion variants were investigated in a narrative manner. We found that high mitotic index, Ki67 index and presence of necrosis increased the risk of recurrence after surgically resected SFT, whereas other factors had more varying prognostic value. We also summarized the currently available different risk stratification systems, and found eight different systems with a varying degree of ability to stratify patients into low, intermediate or high recurrence risk.

Conclusion

Mitotic index, necrosis and Ki67 index are the most solid risk factors for recurrence. TERT promoter mutation seems a promising component in future risk stratification models. The Demicco risk stratification system is the most validated and widely used, however the G-score model may appear to be superior due to longer follow-up time.

Systematic Review Registration

CRD42023421358.

Surgery for Solitary Fibrous Tumors of the Pleura: A Review of the Available Evidence

Solitary fibrous tumors of the pleura (pSFT) are a relatively rare neoplasms that can arise from either visceral or parietal pleura and may have different aggressive biological behaviors. Surgery is well known to be the cornerstone of the treatment for pSFT. We reviewed the existing literature, focusing on the role of surgery in the management and treatment of pSFT. All English-written literature has been reviewed, focusing on those reporting on the perioperative management and postoperative outcomes. Surgery for pSFT is feasible and safe in all experiences reported in the literature, but surgical approaches and techniques may vary according to the tumor dimensions, localization, and surgeons' skills. Long-term outcomes are good, with a 10-year overall survival rate of more than 70% in most of the reported experiences; on the other hand, recurrence may happen in up to 17% of cases, which occurs mainly in the first two years after surgery, but case reports suggest the need for a longer follow-up to assess the risk of late recurrence. Malignant histology and dimensions are the most recognized risk factors for recurrence. Recurrence might be operated on in select patients. Surgery is the treatment of choice in pSFT, but a radical resection and a careful postoperative follow-up should be carried out.

A Large Pleural Solitary Fibrous Tumor Successfully Resected Using Uniportal Video-Assisted Thoracoscopic Surgery

Solitary fibrous tumors (SFTs) are rare neoplasms arising from submesothelial connective tissue. Typically affecting elderly individuals, SFTs can exhibit malignant characteristics despite most cases being benign. Diagnosis often occurs incidentally on routine chest radiographs, and patients are usually asymptomatic unless the tumor causes compression of adjacent structures. While imaging studies aid in identification, confirmation of the diagnosis requires bronchoscopy with tissue sampling and immunohistochemistry. Surgical excision remains the primary treatment for SFTs, with complete resection being associated with a better prognosis. Our case highlights the successful management of a massive SFT using uniportal video-assisted thoracoscopic surgery (VATS). Regular chest computed tomography (CT) follow-up is important for monitoring SFTs and ensuring timely intervention when necessary. We present the case of a 54-year-old female with a massive SFT presenting as a pleural tumor in the right lower lobe. The patient was initially asymptomatic, and the diagnosis was made incidentally during routine chest CT follow-up. Uniportal VATS was successfully performed for the excision of the tumor measuring 10x9x6 cm. Our case highlights the successful application of uniportal VATS for the thoracoscopic removal of a huge pleural solitary fibrous tumor.

A giant breast malignant solitary fibrous tumor: A rare case report and brief review

Solitary fibrous tumors (SFTs), which were first identified in the pleura and later at multiple anatomical locations, are rare mesenchymal neoplasms. The characteristics of SFTs include well-circumscribed margins, intense vascularity and a relatively indolent clinical course. SFTs originating from the breast are rare. To the best of our knowledge, only 33 cases of breast SFTs, including five malignant tumors, have been reported to date. In the present study, a rare case of complete resection of a giant malignant SFT is reported. A 48-year-old female patient who visited Weifang People's Hospital (Weifang, China) had a 2-year history of a right palpable breast lesion. The patient reported no other symptoms, such as skin changes or nipple discharge. An ultrasound examination revealed a giant, well-circumscribed, heterogeneous and hypoechoic lesion with central and peripheral blood flow. Owing to the large size of the lesion, mammography and magnetic resonance imaging were not feasible. Core needle biology showed that the lesion was a malignant spindle cell tumor. Following this, mastectomy and sentinel lymph node biopsy were performed. The sentinel lymph nodes exhibited metastasis. A definitive diagnosis of malignant SFT was made by microscopic examination with immunohistochemistry. The treatment strategy for benign breast SFTs should be complete surgical excision, whereas for malignant SFTs, it should include radical resection along with radiotherapy and chemotherapy. Owing to the indolent nature and late recurrence and metastasis of malignant breast SFTs, regular patient follow-up for a longer duration is essential.

Surgical considerations in the resection of solitary fibrous tumors of the pleura

Solitary fibrous tumors (SFTs) are rare mesenchymal pleural neoplasms with an overall good prognosis and low recurrence rate if completely resected and if degree of differentiation is favorable. Within the last decade, advances in research have led to more reliable methods of differentiating SFTs from other soft tissue tumors. Historically, several markers were used to distinguish SFTs from similar tumors, but these markers had poor specificity. Recent evidence showed NAB2-STAT6 fusion gene to be a distinct feature of SFTs with 100% specificity and sensitivity. Surgical resection, with an emphasis on obtaining negative margins, is the mainstay of treatment for SFTs. Preoperative planning with detailed imaging is imperative to delineate the extent of disease and vascular supply. One important radiologic distinction to aid delineation of a pleural-based tumor compared to a pulmonary parenchymal-based tumor is the angle that the tumor forms with the chest wall, which is obtuse for a pleural-based tumor, and acute for tumors of the lung parenchyma. Often, preoperative tissue diagnosis is not available, and surgery is both diagnostic and curative. Intraoperatively, emphasis should be on complete resection with negative margins. SFTs are resected via several approaches: thoracotomy, sternotomy with the option of hemi-clamshell extension, video-assisted thoracoscopic surgery, and robotic approach, which is increasingly being used and is our preference. We recommend a minimally invasive approach for most lesions, and have resected SFTs of the pleura that are up to 12 cm with the robotic approach. However, the current literature often cites 5 cm as the cut off for an open thoracotomy. Nevertheless, even with larger tumors, a minimally invasive robotic approach is our preference and practice. For giant SFTs (> 20 cm), an open approach may be preferable. Multiple thoracotomies and rib resection may be required to gain adequate exposure and ensure complete resection in these tumors. However, it is noteworthy that most of these tumors have a soft consistency and thus, once bagged, can easily be removed minimally invasively, and thus minimally invasive approach should not be completely ruled out. Recurrence in SFTs usually results from incomplete resection and redo surgery may portend a favorable prognosis.

Toward Better Understanding and Management of Solitary Fibrous Tumor

Solitary fibrous tumor (SFT) comprises a histologic spectrum of soft tissue neoplasms that are characterized by the unique NAB2-STAT6 gene fusion. Changes in diagnostic terminology and site-specific classification over the past few decades have resulted in a disjointed literature. Complete surgical excision with preservation of function remains the mainstay of treatment. New risk stratification systems including risk factors such as mitotic rate, age, tumor size, and presence of necrosis, among others, can be used to predict risk of recurrence or metastasis. Long-term follow-up after surgical resection is recommended. The clinical manifestations, diagnosis, management, and prognosis of SFT are reviewed here.

Novel Therapeutic Options for Solitary Fibrous Tumor: Antiangiogenic Therapy and Beyond

SFT is an ultrarare mesenchymal ubiquitous tumor, with an incidence rate <1 case/million people/year. The fifth WHO classification published in April 2020 subdivided SFT into three categories: benign (locally aggressive), NOS (rarely metastasizing), and malignant. Recurrence can occur in up to 10-40% of localized SFTs, and several risk stratification models have been proposed to predict the individual risk of metastatic relapse. The Demicco model is the most widely used and is based on age at presentation, tumor size, and mitotic count. Total en bloc resection is the standard treatment of patients with a localized SFT; in case of advanced disease, the clinical efficacy of conventional chemotherapy remains poor. In this review, we discuss new insights into the biology and the treatment of patients with SFT. NAB2-STAT6 oncogenic fusion, which is the pathognomonic hallmark of SFT, is supposedly involved in the overexpression of vascular endothelial growth factor (VEGF). These specific biological features encouraged the successful assessment of antiangiogenic drugs. Overall, antiangiogenic therapies showed a significant activity toward SFT in the advanced/metastatic setting. Nevertheless, these promising results warrant additional investigation to be validated, including randomized phase III trials and biological translational analysis, to understand and predict mechanisms of efficacy and resistance. While the therapeutic potential of immunotherapy remains elusive, the use of antiangiogenics as first-line treatment should be considered.

Case Report: Molecular Characterization of Aggressive Malignant Retroperitoneal Solitary Fibrous Tumor: A Case Study

Solitary fibrous tumors (SFT) are mesenchymal neoplasms with a favorable prognosis usually originating from the visceral pleura. Rarely, they may occur at various extrapleural sites and show malignant behavior coupled with dedifferentiation. NAB2-STAT6 fusion gene and STAT6 nuclear expression are biomarkers for diagnosis of SFT in addition to CD34, Bcl-2, and CD99. Furthermore, several reports have shown specific NAB2-STAT6 fusion variants and loss of STAT6 protein expression are associated with malignancy. We report a rare case of retroperitoneal SFT which rapidly progressed to death within 35 days after admission. Autopsy found a primary tumor containing both benign and malignant histologies, with multiple metastatic sites similar to the malignant, dedifferentiated tumor. STAT6 was detected in the primary differentiated tumor but not in the primary dedifferentiated tumor or lung/liver metastases. However, the NAB2-STAT6 fusion gene (NAB2ex6/STAT6ex16 variant) was detected in the primary tumor and lung/liver metastases. Intriguingly, fusion gene expression at the transcriptional level was downregulated in the dedifferentiated tumors compared to the differentiated tumor. We further performed target DNA sequencing and found gene mutations in TP53, FLT3, and AR in the dedifferentiated tumors, with TP53 mutations especially found among them. We demonstrate that downregulation of NAB2-STAT6 fusion gene at the transcriptional level is associated with malignant SFT for the first time. Moreover, the present study supports the idea that TP53 mutations promote malignancy in SFTs.

Surgical and radiation treatment of a paravertebral malignant solitary fibrous tumor: a case report and literature review

Malignant solitary fibrous tumors (MSFT) are rare neoplasms, and typically exhibit an aggressive course. While complete surgical resection is the primary treatment modality, the role of adjuvant radiation treatment in larger tumors is not well-established. Despite limited reported cases which demonstrated extended disease-free periods with adjuvant radiation, its utilization is conflictingly both recommended or discouraged across the literature due to the absence of high-quality published data. This is a report to add to the slowly growing body of literature to support the use of adjuvant radiation in these tumors. Specifically, a case of a 64-year-old man who developed rash and mild back pain after a total hip arthroplasty. He was found to have a large paravertebral MSFT, and was treated with surgical resection followed by adjuvant radiation due to size and focally positive margins. He has continued to have no evidence of disease 21 months after treatment. This case of successful treatment and continued disease-free interval with resection and adjuvant radiation contributes valuable supporting data to the management of this rare disease entity. Furthermore, a review of available literature on MSFT treatment is conducted to illustrate the inconsistency in post-surgical management, and demonstrate the necessity of additional detailed reports from a radiation treatment perspective.

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.

Preoperative prediction of the localization of a solitary fibrous tumor using four-dimensional computed tomography: a case report

Solitary fibrous tumors of the pleura (SFTP) are relatively rare primary pleural tumors. Four-dimensional computed tomography (4D-CT) is reportedly useful in assessing parietal pleural invasion and adhesion in patients with lung cancer. We report a case in which 4D-CT was performed to evaluate SFTP localization and parietal pleural invasion and adhesions. A 62-year-old female presented with an abnormality on a chest radiograph. Chest CT revealed a well-demarcated solid nodule in the left lower lobe adjacent to the pleura. We considered that the tumor was intrapulmonary or arose from the visceral pleura, without adhesion or invasion to the chest wall based on 4D-CT. Primary lung cancer was suspected, and the tumor was resected. Pathological diagnosis revealed an SFTP. This case suggests that 4D-CT is useful in predicting the localization of SFTP and other thoracic tumors, assessing chest wall adhesion and invasion, and making surgical strategies.

Recurrence rates of surgically resected solitary fibrous tumours of the pleura: a systematic review and meta-analysis

OBJECTIVES

Recurrence rates of solitary fibrous tumours of the pleura (SFTP) after surgical resection vary widely in the published literature. Our objective was to systematically review the existing literature to determine an accurate estimate of SFTP recurrence rates after surgical resection and to determine risk factors associated with recurrence.

METHODS

PubMed, EMBASE and the Cochrane library were systematically searched for randomized controlled trials and observational studies (prospective or retrospective) through 20 June 2020 that reported the recurrence rates after surgical resection. The outcome of interest was recurrence.

RESULTS

Of the 23 included studies comparing 1262 patients, the overall recurrence of SFTP in patients who underwent surgical resection was 9% [95% confidence interval (CI) 7-12%; I2 = 52%]. In addition, pooled benign and malignant recurrence rates were 3% (95% CI 2-5%; I2 = 8%) and 22% (95% CI 15-32%; I2 = 52%), respectively. A benign SFTP was associated with a significantly lower recurrence rate than a malignant SFTP [odds ratio (OR) 0.11; 95% CI 0.06-0.20; I2 = 0%]. There was no significant difference in the recurrence rates between lesions originating from parietal versus visceral pleura (OR 1.30; 95% CI 0.28-6.02; I2 = 59%). Female sex was associated with increased recurrence (OR 5.29; 95% CI 1.66-16.92; I2 = 0%).

CONCLUSIONS

Collectively, this systematic review demonstrated a 9% SFTP post-resection recurrence rate. Furthermore, the recurrence rates for benign and malignant SFTP were 3% and 22%, respectively. Histological malignancy and female sex were associated with higher risk.

Resectability, Recurrence, and Risk Stratification of Giant Solitary Fibrous Tumors in the Thoracic Cavity

BACKGROUND

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors most commonly arising from the pleura in the thoracic cavity. The impact of tumor size on risk of recurrence in thoracic SFTs is not well understood.

METHODS

A single institution review was performed on all resected thoracic SFTs (1992-2019) with giant SFT defined as ≥ 15 cm. Clinical information, pathologic characteristics, and long-term survival data were collected, and predictors of recurrence and survival were evaluated with regression and Kaplan-Meier analysis.

RESULTS

There were 38 thoracic SFTs resected from patients, with the majority of tumors (n = 23, 60.5%) originating from visceral pleura. There were nine (23.7%) giant SFTs with a mean size 20.4 cm (range 17-30 cm). Mean follow-up time was 81.0 months (range 1-261 months), during which 4 of 38 (10.5%) patients experienced a recurrence within the thorax (range 51-178 months). The presence of tumor necrosis (p = 0.021) and ≥ 4 mitoses per high-powered field (p = 0.010) were associated with SFT recurrence on univariate regression. Overall 5-year, 10-year, and 20-year survival was 78.2%, 72.6%, and 42.4%, respectively, and SFT-related mortality occurred in three patients at 83, 180, and 208 months postoperatively. There were no recurrences or SFT-related mortality among patients with giant SFT.

CONCLUSION

This study represents one of the largest contemporary single institution reviews of long-term outcomes of giant thoracic SFT. Our data suggest that size is not a risk factor for recurrence in thoracic SFTs and long-term survival is excellent for giant SFTs.

Programmed Death Ligand 1 and Immune Cell Infiltrates in Solitary Fibrous Tumors of the Pleura

BACKGROUND

Approximately 10% to 15% of patients with solitary fibrous tumors of the pleura (SFTP) have recurrence after resection. Many are not candidates for reresection and lack effective treatments. We explored the expression of programmed death ligand 1 (PD-L1) as a biomarker for candidacy for treatment with immune checkpoint inhibitors.

METHODS

We reviewed the medical records of 52 patients with primary SFTP and 5 with recurrent SFTP. We performed immunohistochemistry on tumor tissue to determine the expression of PD-L1 and infiltration by cluster of differentiation 8 (CD8)-positive immune cells.

RESULTS

Any PD-L1 expression was observed in 11 primary SFTP (21.2%). Overall, PD-L1 expression level was less than 1% in 10 patients (19.2%) and greater than 1% in 1 (1.9%). Tumor infiltration by CD8-positive immune cells was absent or rare in 13 patients (25%), less than 5% in 31 (59.6%), and 5% to 25% in 8 (15.4%). There were no associations between PD-L1 expression or immune cell infiltrates and known risk factors for recurrence or a prognostic risk score classification. Time to recurrence was strongly associated with the risk score classification (P < .001), but it was not associated with PD-L1 expression (P = .296) or immune cell infiltrates (P = .619). In recurrent SFTP, PD-L1 was expressed in 4 of 10 tumors (40%; all <1% expression). There was no correlation in PD-L1 expression between primary and recurrent SFTP samples.

CONCLUSIONS

A small subset of SFTP express PD-L1 at low levels (<1%) but exhibit colocalization of CD8-positive immune cells suggesting an inducible expression mechanism. The role of PD-L1 merits exploration in the clinical setting in patients with advanced SFTP when alternative treatments or clinical trials are considered.

Management of solitary fibrous tumours of the pleura: a systematic review and meta-analysis

Background

Solitary fibrous tumours of the pleura (SFTP), or pleural fibromas, are rare tumours that generally, but not universally, follow a benign course. Surgical resection is the standard treatment, but there are no evidence-based guidelines regarding the management of these tumours.

Methods

Five databases were searched from inception to April 1, 2019 for studies reporting on SFTP management.

Results

Twenty-seven studies met the inclusion criteria (1542 patients, all non-comparative case series); 98% of these patients underwent resection and all SFTP included were pathologically diagnosed. 394 out of 1299 cases (30.5%, 95% CI 27.8–32.8%) were malignant with recurrence rates of between 0% and 42.9%. A pleural effusion was always associated with a negative outcome, but no other features were consistently reported to have negative associations. Preoperative biopsies incorrectly reported malignant histology in two studies. Over 25% of cases of recurrence occurred when a complete (R0) resection had been achieved. The first recurrence occurred >5 years after the initial resection in at least 23% of cases.

Conclusions

There is strong evidence to support long-term surveillance after surgical resection of SFTP, even where a complete (R0) resection has been achieved; however, there is no clear evidence to inform clinicians regarding the selection of patients who should undergo resection. The rates of malignant SFTP and SFTP recurrence are higher than previously reported. Only those that were pathologically diagnosed or resected were included, which may bias the data towards more aggressive tumours. Data collection on radiologically diagnosed SFTP is required to draw conclusions regarding the timing and need for intervention.

Long-term surveillance should be undertaken after a resection of solitary fibrous tumours of the pleura but further work is needed to determine which patients are likely to follow a malignant clinical course to decide timing and necessity of a resectionhttps://bit.ly/2U10SaA

Strategy for initial en bloc resection of a giant mediastinal solitary fibrous tumor: Judicious usage of cardiopulmonary bypass

A solitary fibrous tumor (SFT) is a rare mediastinal neoplasm associated with a high recurrence rate. Total excision on initial surgery is an established indicator of a positive outcome. Here, we report the case of a 52-year-old man who was admitted to our hospital with symptoms of cough, chest pain, and dyspnea for two months. Chest computed tomography (CT) scan revealed a middle mediastinal mass which infiltrated adjacent vital structures, and surgery was performed with the assistance of cardiopulmonary bypass (CPB) and median sternotomy. The mass was completely removed and histopathology confirmed the presence of a mesenchymal tumor. The patient had an uneventful recovery without any perioperative symptoms, hoarseness, or dysfunction of the diaphragm. Sixty-nine months after surgery, a CT scan confirmed that the patient remained disease-free without necessitating the introduction of chemotherapy or radiotherapy. Here, to the best of our knowledge, we report the first case of a giant invasive mediastinal SFT that was completely resected during initial surgery under CPB with a remarkable outcome.

Thoracic solitary fibrous tumors: an analysis of 70 patients who underwent surgical resection in a single institution

BACKGROUND

Thoracic solitary fibrous tumors (TSFTs) are uncommon mesenchymal tumors. The data regarding surgical outcomes and prognostic factors are scarce. This retrospective paper is to analyze surgical outcomes, clinical characteristics and prognosis of TSFT.

METHODS

A single-center retrospective study of the data of 70 patients with TSFT who underwent surgical resection in our department between August 2008 and October 2014 was conducted.

RESULTS

A total of 70 TSFTs (58 benign, 12 malignant) were included and all patients underwent complete surgical resection except one recurrent patient with initial treatment. TSFTs originated from the pleura (n = 43), lung (n = 9), mediastinum (n = 16), esophagus (n = 1) and diaphragm (n = 1), respectively. Mass excision was only performed in 29 patients, en bloc excision including surrounding structures was performed in 41 patients. During follow-up, no tumor recurrence occurred in benign TSFT patients. All recurrences occurred in 6 malignant patients, and 5 of them died because of local recurrence and distant metastasis. Median follow-up was 95 months (range, 3-133 months). The 5-year overall survival (OS) of TSFT patients was 94.3%. The 5-year relapse-free survival and OS of malignant TSFT patients were 58.3% and 66.7%, respectively.

CONCLUSION

The gold standard of TSFT treatment is complete surgical resection. VATS is safe and reliable for treating selected TSFT patients. Aggressive surgical resection could be underwent in such patients of local recurrence or solitary metastatic tumor. A long-term follow-up is necessary due to the risk of recurrence.

Pleural Solitary Fibrous Tumors-A Retrospective Study on 45 Patients

Introduction: The purpose of this paper is to study the type, the clinical presentation, and the best diagnostic methods for pleural solitary fibrous tumors (PSFTs), as well as to evaluate which is the most appropriate treatment, especially as PSFTs represent a rare occurrence in the thoracic pathology. Material and Method: A retrospective study was conducted on a group of 45 patients submitted to surgery between January 2015 and December 2019. In most cases, the diagnosis was established through imaging studies-thoracic computed tomography (CT) scan with or without contrast-but also using magnetic resonance imaging (MRI) or positron emission tomography (PET) scans when data from CT scans were scarce. All patients were submitted to surgery with curative intent. Results: Most patients included in this study were asymptomatic, with this pathology being more common in patients over 60 years of age, and more common in women. The occurrence of malignant PSFT in our study was 17.77% (8 cases). All cases were submitted to surgery with curative intent, with a single case developing further recurrence. In order to achieve complete resection en bloc resection of the tumor with the chest wall, resection was performed in two cases, while lower lobectomy, pneumectomy, and hemidiaphragm resection, respectively, were needed in each case. Postoperative mortality was null. Conclusion: Thoracic CT scan remains the most important imagistic investigation in diagnosing. MRI is superior to thoracic CT, especially in cases that involved the larger blood vessels within the thorax, spinal column, or diaphragm. Complete surgical resection is the gold standard in treatment of PSFT, and the prognosis in benign cases is very good.

Massive malignant solitary fibrous tumor of the diaphragm: A case report

INTRODUCTION

Malignant solitary fibrous tumor (MSFT) of the diaphragm is extremely rare, and to the best of our knowledge, only three cases have been reported in the past two decades. In all these cases, the diaphragms were usually reconstructed with artificial diaphragm patch because of the extensive resection.

PATIENT CONCERNS

We reported a male patient with complaints of dyspnea, chest pain and massive pleural effusion in the left chest detected by chest X-ray. A huge mass of 20 × 20 cm was seen in the left lower chest in the computed tomography (CT) scan.

DIAGNOSIS

The diagnosis of MSFT originating in the diaphragm was made by post-operative immunohistochemical examination.

INTERVENTIONS

After draining 4000 ml of pleural effusion by Pleurx catheter to relieve the pressure symptom, the patient underwent en-block resection by left posterolateral thoracotomy. A pedicle tumor originating in the left diaphragm was found, which was smooth, lobular, did not invade surrounding tissues or organs, and received blood supply from the left phrenic vessels. The diaphragm was successfully sutured without tension and did not require artificial reconstruction as the defect was small.

OUTCOMES

After 2 months follow-up, the left lung was restored to normalcy, and no pleural effusion or new occupying neoplasm was found in follow-up CT.

Histological and molecular features of solitary fibrous tumor of the extremities: clinical correlation

Solitary fibrous tumor is a rare mesenchymal neoplasm that exhibits a broad spectrum of biological behaviors. Few studies relative to clinical-pathologic features and predictive factors have been reported, all involving a mixed population of tumors occurring at different anatomic sites. In this study, we described a cohort of 41 patients with solitary fibrous tumor of the extremities and evaluated the prognostic role of clinical and histological features, presence of C228T and C250T mutations at the TERT promoter region, and NAB2-STAT6 fusion variants. Patients were stratified according to the latest risk stratification model proposed by Demicco. The two patients with metastasis at presentation were in the high-risk group; the one with metastasis after surgery was classified in the intermediate-risk group. TERT promoter mutations were detected in 9 out of 38 DNA available. All patients with metastasis were characterized by a TERT promoter mutation. TERT promoter mutation was associated with mitoses > 4 per high-power field (p = 0.001), necrosis (p = 0.049), and size > 10 cm (p = 0.031). NAB2-STAT6 fusion variants were detected in 27 out of 41 cases without any prognostic value. In conclusion, we confirmed that the patients with solitary fibrous tumor of the limbs have a better prognosis than other solitary fibrous tumors, with a very low percentage of metastatic events. Besides, our data support an association between TERT promoter mutations and histologically malignant features, suggesting a possible molecular role in stratifying patients into intermediate- to high-risk tumor.

Recurrence of a malignant solitary fibrous tumor of the pleura 17 years after primary tumor resection - A case report

Most recurrences of solitary fibrous tumor of the pleura (SFTP) occur within 2 years. Here we report a rare case of bilateral recurrence in a 61 year old female, 17 years after the original surgery for a right sided malignant SFTP. On repeat CT scan a 10 cm right mass and two small left lower lobe nodules were found. Patient underwent staged reoperations. She was also found to have a secondary smaller right tumor intraoperatively. All four tumors were confirmed to be recurrent SFTP on pathologic examination with identical immunohistochemistry to the original tumor.

Solitary fibrous tumors of the pleura: A single center experience at National Cancer Center, China

BACKGROUND

This study explored the clinicopathological features, predictive factors of malignancy, effectiveness of video assisted thoracic surgery (VATS), and prognosis of solitary fibrous tumor of the pleura (SFTP).

METHODS

A single-center retrospective study of the data of 82 patients with SFTP who were surgically treated in our department between January 2003 and December 2015 was conducted.

RESULTS

A total of 82 SFTPs (70 benign, 12 malignant) were included and all patients underwent complete en bloc resection. SFTPs originated from the visceral pleura in 47 (57%) and the parietal pleura in 35 (43%) patients. In our cohort, malignant tumors were often symptomatically large, and the patients with malignant SFTPs (mSFTPs) often had a family history of neoplasms. Patients in the VATS group (n = 22) had tumors with significantly smaller diameters, required a shorter surgical duration and shorter hospital stay, and experienced less intraoperative blood loss and less postoperative chest tube drainage compared to the thoracotomy group (n = 60). No tumor recurrence was found in benign SFTP (bSFTP) patients. The long term survival and disease-free survival rates of mSFTP patients were 76% and 53%, respectively.

CONCLUSION

Larger tumor diameter and a family history of neoplasm may be predictive factors for mSFTP; however, this conclusion needs to be verified in large cohort. VATS is safe and reliable for treating selected SFTP patients. Local recurrence is associated with mSFTP patient death, thus close follow-up of such patients is crucial.

Surgical therapy and next-generation sequencing-based genetic alteration analysis of malignant solitary fibrous tumor of the pleura

Background

Solitary fibrous tumor of the pleura (SFTP) is a rare pleural neoplasm arising from mesenchymal cells, accounting for <5% of pleural neoplasms. Approximately 10% of cases of SFTP demonstrate malignant potential, leading to local recurrence after radical surgery and subsequent metastasis.

Methods

A large malignant-like mass was found in the left thoracic cavity of a 61-year-old woman. Following radical resection of the mass, the patient was diagnosed with malignant SFTP by histologic and immunohistochemical analyses. In addition, a next-generation sequencing-based mutation test was used to reveal the mutational profile of the tumor. The genetic alteration panel was analyzed with reference to public data on the ClinVar and COSMIC databases, after which the public SFTP data were analyzed for frequency of altered genes. Finally, through overlay of the abovementioned two sets, the genetic alteration accounting for SFTP initiation was anticipated to be identified.

Results

In the mutation panel of our malignant SFTP group, kinase insert domain receptor (KDR) and fms-related tyrosine kinase 1 (FLT1) scored high in pathogenesis but had only a medium frequency; the NAB2–STAT6 fusion appeared to be the dominant genetic alteration in public SFTP samples.

Conclusion

The high frequency of NAB2–STAT6 fusion indicates its prominent role in SFTP, while somatic mutations such as FLT1-R593W and KDR-V297I may also contribute to the malignant angiogenic phenotype. The present study affirmed the heterogeneity of SFTP, and more sophisticated classification methods will be needed to explore its underlying mechanisms.

Summary

We believe that improvement in the prognosis of SFTP relies on early diagnosis, margin-free resection, and long-term follow-up. Through genetic analysis, it appears that both NAB2–STAT6 fusion and somatic mutations such as FLT1-R593W and KDR-V297I contribute to SFTP development.

The Approach to Solitary Fibrous Tumors: Are Clinicopathological Features and Nomograms Accurate in the Prediction of Prognosis?

Introduction. Currently, factors such as size, mitotic rate, and degree of necrosis have been shown to influence survival in patients with solitary fibrous tumors (SFTs); however, there remains no consensus regarding the associations between tumor characteristics and the malignant nature of these tumors. The aim of this article was to identify factors that would help in prognosticating SFTs and to validate the MD Anderson Cancer Center (MDACC) SFT nomogram in the largest known series of SFTs treated in an Asian population. Methods. A retrospective review of all patients with a diagnosis of SFT treated surgically in our institution between 2005 and 2015 was carried out. Basic demographics, clinicopathological, and surgical factors were analyzed for association with clinical outcomes. Factors that predicted for distant recurrence (DR) and poor survival were identified as high-risk features. The MDACC nomogram was validated by assessing the extent of discrimination, quantified using Harrell’s concordance index (C-index). Results. Fifty-nine patients were included in analysis. Significant univariate associations for DR were found for mitotic rate ( P = .05) and presence of necrosis ( P = .04). Significant univariate associations for overall survival were found for presence of recurrence ( P = .035), presence of necrosis ( P = .072), and mitotic rate ( P = .033). The C-index associated with the nomogram was 0.75. Conclusion. There is a negative association for DR and overall survival, with the mitotic rate and presence of necrosis. We propose that SFTs with these features should be regarded as high risk. The MDACC nomogram generally predicts well for patients in an Asian population.

Subxiphoid approach for extracting a giant solitary fibrous tumour of the pleura

We describe a case of resection of a solitary fibrous tumour of the pleura using video-assisted thoracic surgery and removal of the giant tumour using a subxiphoid incision without the need for minithoracotomy. Use of the subxiphoid approach as a retrieval port is simple and feasible.

Intrathoracic solitary fibrous tumor - an international multicenter study on clinical outcome and novel circulating biomarkers

Intrathoracic solitary fibrous tumor (SFT) is a rare disease. Radical resection is the standard of care. However, estimating prognosis and planning follow-up and treatment strategies remains challenging. Data were retrospectively collected by five international centers to explore outcome and biomarkers for predicting event-free-survival (EFS). 125 histological proven SFT patients (74 female; 59.2%; 104 benign; 83.2%) were analyzed. The one-, three-, five- and ten-year EFS after curative-intent surgery was 98%, 90%, 77% and 67%, respectively. Patients age (≥59 vs. <59 years hazard ratio (HR) 4.23, 95 confidence interval (CI) 1.56–11.47, p = 0.005), tumor-dignity (malignant vs. benign HR 6.98, CI 3.01–16.20, p <0.001), tumor-size (>10 cm vs. ≤10 cm HR 2.53, CI 1.10–5.83, p = 0.030), de Perrot staging (late vs. early HR 3.85, CI 1.65–8.98, p = 0.002) and resection margins (positive vs. negative HR 4.17, CI 1.15–15.17, p = 0,030) were associated with EFS. Furthermore, fibrinogen (elevated vs. normal HR 4.00, CI 1.49–10.72, p = 0.006) and the neutrophil–to-lymphocyte-ratio (NLR > 5 vs. < 5 HR 3.91, CI 1.40–10.89, p = 0.009) were prognostic after univariate analyses. After multivariate analyses tumor-dignity and fibrinogen remained as independent prognosticators. Besides validating the role of age, tumor-dignity, tumor-size, stage and resection margins, we identified for the first time inflammatory markers as prognosticators in SFT.

Solitary Fibrous Tumors of Chest: Another Look with the Oncologic Perspective

Solitary fibrous tumors are mesenchymal lesions that arise at a variety of sites, most commonly the pleura. Most patients are asymptomatic at diagnosis, with lesions being detected incidentally. Nevertheless, some patients present due to symptoms from local tumor compression (eg. of the airways and pulmonary parenchyma). Furthermore, radiological methods are not always conclusive in making a diagnosis, and thus, pathological analysis is often required. In the past three decades, immunohistochemical techniques have provided a gold standard in solitary fibrous tumor diagnosis. The signature marker of solitary fibrous tumor is the presence of the NAB2-STAT6 fusion that can be reliably detected with a STAT6 antibody. While solitary fibrous tumors are most often benign, they can be malignant in 10-20% of the cases. Unfortunately, histological parameters are not always predictive of benign vs malignant solitary fibrous tumors. As solitary fibrous tumors are generally regarded as relatively chemoresistant tumors; treatment is often limited to localized treatment modalities. The optimal treatment of solitary fibrous tumors appears to be complete surgical resection for both primary and local recurrent disease. However, in cases of suboptimal resection, large disease burden, or advanced recurrence, a multidisciplinary approach may be preferable. Specifically, radiotherapy for inoperable local disease can provide palliation/shrinkage. Given their sometimes -unpredictable and often- protracted clinical course, long-term follow-up post-resection is recommended.

Rare Solitary Fibrous Tumor in the Pediatric Neck: A Case Report and Review of the Literature

Solitary fibrous tumors (SFT) are a rare type of mesenchymal-derived tumor not commonly found in the pediatric population, especially in the head and neck. Tumors of this nature are most commonly seen in the adult population and are identified with unique immunohistochemical markers, specifically signal transducer and activator of transcription 6 (STAT6) and hematopoietic progenitor cell antigen (CD34). Including SFTs in the differential diagnosis while working up a mass can be difficult considering their relatively non-descript appearance on imaging and the low yield immunohistochemical staining that must be ordered to confirm diagnosis. The current literature identifies only a handful of cases of SFTs occurring in the pediatric population, with a majority arising from the pleura. We present the case of a 13-year-old male who underwent radical excision of a left occipital triangle neck mass after radiological and pathological workup failed to conclusively make a diagnosis. Postoperative pathologic analysis revealed it to be an SFT. Due to the exceptionally rare presentation of SFTs in pediatric patients, the aim of this case report is to discuss diagnostic measures, solitary fibrous tumor etiology, as well as a recent risk stratification system used for the evaluation of postoperative disease progression. Our hope is that clinicians will include SFTs in their differential diagnosis when working up a neck mass in the pediatric population.

Low tissue levels of miR-125b predict malignancy in solitary fibrous tumors of the pleura

Background

Solitary fibrous tumors of the pleura (SFTP) are rare neoplasia of the chest. A subset of SFTP follows a malignant course, sometimes several years after complete resection. Traditional scoring systems based on clinical and histological features are poor predictors of biological behavior. This study aimed to investigate tumor-associated miRNAs expression as novel biomarkers to predict the clinical behavior of SFTP.

Methods

Formalin-fixed and paraffin-embedded SFTP tissues blocks from patients surgically resected between 1992 and 2013 at two tertiary care teaching hospitals were included. SFTP tumors were categorized as either malignant or benign variants according to the WHO classification. Following miRNAs levels were measured: let-7a, miR-16b, miR-17, miR-21, miR-31, miR-34a, miR-92a, miR-125a, miR-125b, miR-195-5b, miR-203a, and miR-223. Differential gene expressions which were calculated with the threshold cycle (C_t) method were compared among the two variants.

Results

Thirty-eight patients (40% male, mean age 62.2 (±10.9) years) were included. Expression levels of miR-125b showed a significant difference between benign compared to malignant variants (−3.08 ± 0.93 vs. -2.22 ± 1.36, p = 0.0068). Furthermore, lower levels of miR-125b were found to be associated with increased tumor size (p = 0.0414). Thus, downregulation of miR-125b indicates malignant transformation. All other investigated miRNAs were not associated with grading of SFTP.

Conclusions

Our data suggest a potential role of miR-125b in the pathogenesis of tumor growth and malignant transformation of SFTP, respectively. Further studies have to address the potential use of miRNA-125b as a biomarker or therapeutic target in SFTP.

Solitary Fibrous Tumors: 2016 Imaging Update

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

The clinicopathological significance of NAB2-STAT6 gene fusions in 52 cases of intrathoracic solitary fibrous tumors

NAB2-STAT6 gene fusion drives STAT6 nuclear expression and is the pathognomonic hallmark of solitary fibrous tumors (SFTs). However, no study has systematically analyzed the clinicopathological features, STAT6 immunoexpression status, or the fusion variants of NAB2-STAT6 in intrathoracic SFTs. Fifty-two intrathoracic SFTs were retrieved to appraise histopathology, assess STAT6 immunoexpression, and determine NAB2-STAT6 fusion variants by RT-PCR. Location-relevant histologic mimics served as controls. Thirty-one pleura-based, 12 mediastinal/pericardial, and nine intrapulmonary lesions were histologically categorized into eight malignant, eight atypical, and 36 conventional or cellular SFTs, including two fat-forming and two giant cell angiofibroma-like SFTs. STAT6 distinctively decorated the tumoral nuclei in 51 (98%) SFTs. However, no nuclear staining was observed in the histological mimics. NAB2-STAT6 fusion was detected in 34 SFTs. Twenty-nine (85.3%) exhibited the major NAB2ex4-STAT6ex2/3 variant and 5 (14.7%) the minor NAB2ex6-STAT6ex16/17. NAB2ex4-STAT6ex2 was significantly associated with older age (P = 0.01) and pleuropulmonary tumors (P = 0.025). After a median follow-up of 33.9 (range, 0.3-174.6) months, adverse outcomes occurred in one atypical and five malignant SFTs, including two local relapses, one intrapulmonary metastasis, and three extrathoracic metastases. Inferior disease-free survival was univariately associated with atypical/malignant histology (P = 0.001) and a mitosis >4/10 HPFs (P = 0.0012) but was unrelated to fusion variants. In conclusion, the majority of intrathoracic SFTs exhibited STAT6 nuclear staining, and NAB2ex4-STAT6ex2/3 was the predominant fusion type. However, clinical aggressiveness is associated with atypical/malignant histology primarily contributed by increased mitosis but was unrelated to the NAB2-STAT6 fusion variants.

Solitary Fibrous Tumor of the Pleura: A Rare Cause of Pleural Mass

BACKGROUND

A solitary fibrous tumor of the pleura is a rare but usually benign mesenchymal tumor arising from the pleura. Patients are often asymptomatic, resulting in the majority of tumors being detected incidentally on chest imaging. We present a case of a large solitary pleural tumor and review the typical radiographic and pathologic findings associated with this finding.

CASE REPORT

A 63-year-old white man with chronic obstructive pulmonary disease (COPD) was found to have a large pleural mass on chest radiography during a pre-operative assessment. The tumor was biopsied and findings were consistent with solitary fibrous tumor of the pleura.

CONCLUSIONS

SFTPs are generally considered benign tumors although there is a risk of malignant transformation and recurrence. Imaging studies play an important role in identifying the tumor and planes of resection, and histologic diagnosis is critical in differentiating SFTP from other type of pleural masses. Surgical resection is main therapy of choice.

Solitary fibrous tumor of the pleura - analysis of 18 cases

Introduction

Solitary fibrous tumors of the pleura (SFTP) are primary tumors arising from mesenchymal cells. Immunohistochemical studies have demonstrated that the origin of these tumors is mesenchymal rather than mesothelial. The aim of this study is to present our experience with diagnosing and treating patients with SFTP.

Material and methods

We analyzed 18 patients treated at the Department of Thoracic Surgery of the Medical University of Lodz. The patients’ medical histories and the results of postoperative histopathological investigation of the tumors were analyzed. Postoperative histopathological samples were evaluated with regard to the current criteria of malignancy.

Results

In 17 patients, the tumors were surgically removed. Benign and small lesions (less than 3 cm in size) were removed by video-assisted thoracoscopic surgery (VATS). In 5 cases, malignant tumors were found in the postoperative material.

Conclusions

Solitary fibrous tumors of the pleura is a tumor with frequently asymptomatic clinical course. Treatment consists in resection which includes the adjacent structures, especially if the tumor is malignant.