Comprehensive analysis reveals potential therapeutic targets and an integrated risk stratification model for solitary fibrous tumors

Solitary fibrous tumors (SFTs) are rare mesenchymal tumors with unpredictable evolution and with a recurrence or metastasis rate of 10-40%. Current medical treatments for relapsed SFTs remain ineffective. Here, we identify potential therapeutic targets and risk factors, including IDH1 p.R132S, high PD-L1 expression, and predominant macrophage infiltration, suggesting the potential benefits of combinational immune therapy and targeted therapy for SFTs. An integrated risk model incorporating mitotic count, density of Ki-67+ cells and CD163+ cells, MTOR mutation is developed, applying a discovery cohort of 101 primary non-CNS patients with negative tumor margins (NTM) and validated in three independent cohorts of 210 SFTs with the same criteria, and in 36 primary CNS SFTs with NTM. Compared with the existing models, our model shows significantly improved efficacy in identifying high-risk primary non-CNS and CNS SFTs with NTM for tumor progression.Our findings hold promise for advancing therapeutic strategies and refining risk prediction in SFTs.

[Research progress of intraspinal solitary fibrous tumor]

Objective

To review the research progress of intraspinal solitary fibrous tumor (SFT).

Methods

The domestic and foreign researches on intraspinal SFT were extensively reviewed and analyzed from four aspects, including disease origin, pathological and radiological characteristics, diagnosis and differential diagnosis, and treatment and prognosis.

Results

SFT is an interstitial fibroblastic tumor with a low probability of occurrence in the central nervous system, especially in the spinal canal. In 2016, the World Health Organization (WHO) used the joint diagnostic term "SFT/hemangiopericytoma" according to the pathological characteristics of mesenchymal fibroblasts, which can be divided into three levels according to specific characteristics. The diagnosis process of intraspinal SFT is complex and tedious. It has relatively variable imaging manifestations and specific pathological changes of NAB2-STAT6 fusion gene, which often requires differential diagnosis with neurinoma, meningioma, etc. The treatment of SFT is mainly resection, which can be assisted by radiotherapy to improve the prognosis.

Conclusion

Intraspinal SFT is a rare disease. Surgery is still the main treatment. It is recommended to combine preoperative or postoperative radiotherapy. The efficacy of chemotherapy is still unclear. In the future, more studies are expected to establish a systematic diagnosis and treatment strategy for intraspinal SFT.

Solitary Fibrous Tumor: Integration of Clinical, Morphologic, Immunohistochemical and Molecular Findings in Risk Stratification and Classification May Better Predict Patient outcome

Although solitary fibrous tumors (SFTs) have an unpredictable evolution, some specific clinicopathologic factors have been associated with the final outcome. We retrieved clinical, pathological and molecular data of 97 patients with a histological diagnosis of SFT and Signal transducer and activator of transcription 6 (STAT6) positivity. We retrospectively studied the pathological factors predictive of recurrence/metastasis and compared them with the clinical outcome. A wide immunohistochemical study and molecular analysis to detect NAB2/STAT6 gene fusion, tumor protein-53 (TP53) and/or (telomerase reverse transcriptase) TERT promotor mutation were performed. The risk of metastasis was calculated using the Demicco risk stratification system (RSS). The results were combined and examined to assess the accuracy of risk stratification and classification. The most common location was in non-extremities; 66% were located in soft tissue or subcutaneous areas and 92.8% in deep locations. On microscopic analysis, 38.1% of tumors revealed hypercellularity with a predominant patternless and/or hemangiopericytic growth pattern; 13.4% had ≥4 mitoses/10HPF; 16.5% showed necrosis, and almost half the tumors showed at least focal myxoid areas. Dedifferentiation was observed in three tumors. Immunomarker expression in SFTs was as follows: CD34 92.9%, CD99 57.1%, Bcl2 67.9%, neuroendocrine markers (at least 1) 25.7%, Desmin 14.3%, CK(AE1/AE3) 3%, Apoptotic Protease Activating Factor (APAF-1) 87% and finally Ki-67 ≥ 10% in 14.4%. The NAB2/STAT6 gene fusion was detected in 50 tumors. After a median follow-up of 90 months, 9.3% recurred, 11.3% metastasized, 10.3% died of disease and 76.2% were free of disease. TERT mutations were detected in 40.6% of the SFTs; the TP53 mutation was detected in 17%, and only 9.3% showed both mutations. According to the Demicco RSS, 6.1%, 11.3% and 82.4% of the tumors were classified as high, intermediate or low-risk of metastasis, respectively. All high-risk tumors had ≥4 mitoses/10HPF, necrosis, Ki-67 ≥ 10, HTER and/or TP53 mutation and poor evolution. The intermediate risk SFTs with worse evolution displayed the HTER mutation. Almost all low-risk tumors had a favorable evolution, although four showed at least one adverse factor (Ki-67 ≥ 10, ≥4 mitoses/10HPF or high tumor size) and had a worse evolution. An integration of clinical, morphologic, immunohistochemical and molecular findings may improve risk stratification and classification and better predict patient outcome. The unfavorable course seems to be more frequent in high-risk SFTs, although it is not exceptional in low-risk SFTs either; hence, a long-term follow-up is required independently of the assigned risk stratification score. The inclusion of molecular findings in risk stratification systems could improve the precision in the classification of SFTs, especially those of intermediate risk. Future studies will be required to determine the most effective way to incorporate molecular analyses into RSS on SFTs. The coexistence of several adverse factors such as ≥4 mitoses/10HPF, necrosis, Ki-67 ≥ 10%, mutations in HTER and/or p53 may suggest a closer clinical follow-up regardless of the histological appearance of the tumor.

Intracranial solitary fibrous tumor/hemangiopericytoma: tumor reclassification and assessment of treatment outcome via the 2016 WHO classification

PURPOSE

As per the 2016 World Health Organization (WHO) guidelines on the classification of central nervous system tumors, solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) constitute a single disease entity, known as SFT/HPC. This study provides a clinical analysis of these tumors and describes the treatment outcomes of SFT/HPCs.

METHODS

This retrospective study included 76 patients with histopathologically proven SFT/HPC. Reclassification according to the 2016 WHO guideline was done for patients who were diagnosed with SFT or HPC based on the 2007 WHO classification. Recurrence-free survival (RFS) and overall survival (OS) were evaluated for all patients and subgroups.

RESULTS

The median follow-up period was 77.9 months. The median RFS and OS were 126.5 and 136.8 months, respectively. The 1-, 5-, 10-, and 15-year RFS rates were 93%, 72%, 40%, and 40%, respectively. The 1-, 5-, 10- and 15-year OS rates were 97%, 89%, 54%, and 35%, respectively. In multivariable analyses, stereotactic radiosurgery (SRS; p = 0.009, hazard ratio [HR] 6.986), female sex (p = 0.023, HR 1.76), and age over 45 (p = 0.037, HR 2.74) were associated with shorter RFS. Patients who underwent SRS as initial treatment had a shorter OS than that of patients who underwent primary resection (p < 0.001, HR 12.86).

CONCLUSIONS

High-grade tumors tended to have worse OS and occur extracranial metastases earlier than low-grade tumors. The median RFS was not different between grade II and III tumors. Male sex, younger age, and GTR were associated with a better RFS. A history of SRS before tumor resection was associated with a shorter RFS and OS.

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.

Diagnosis and treatment of solitary fibrous tumor/hemangiopericytoma of central nervous system. Retrospective report of 17 patients and literature review

To investigate the diagnosis, treatment and prognosis of solitary fibrous tumor (SFT)/ hemangiopericytoma (HPC) of central nervous system (CNS), we retrospectively reviewed records of 17 patients who were treated for CNS SFT/HPC at the Department of Neurosurgery, China-Japan Union Hospital of Jilin University from December 2010 to June 2016, and reevaluated their pathological diagnoses according to the 2016 WHO classification of CNS tumors. We then analyzed their clinical symptoms, imaging characteristics, treatments and outcomes. Clinical manifestations of CNS SFT/HPC were diverse, but mainly included headache, increased intracranial pressure, seizures, and focal neurological deficits. In MRI, CNS SFT/HPC usually shows heterogeneous signals, and unusual enhancements; we saw lobulated shapes in 13 patients and necrotic or cystic changes in 12 patients. Tumors of all 17 patients were resected surgically; 9 patients also received postoperative adjuvant radiotherapy. Mean follow-up time was 21 months (range: 2-67 months). The 17 surgeries included 11 total resections, 4 subtotal resection, and 2 partial resections. We followed up 12 patients; 9 of the patients who received total resections had no disease progression; among the 6 patients who did not receive total resections, 2 died of tumor recurrence, 1 has not shown any disease progression. Thus, extent of resection has an apparently crucial influence on prognosis. Postoperative radiotherapy should be chosen carefully, based on resection extent and pathologic grade.

Salvage preoperative embolization of an infratemporal solitary fibrous tumor: A case report with review of the literature

RATIONALE

Head and Neck Solitary fibrous tumors (SFT) are very rare. They could be misdiagnosed as hemangiopericytomas (HPC).

PATIENT CONCERNS

We report a 60 y o lady presenting with sinonasal mass, causing recurrent profuse bleeding.

DIAGNOSES

Hemangioperocytomas versus SFT were among the differentials, according to Radiological studies. Upon Biopsy, the diagnosis of SFT has been adopted.

INTERVENTIONS

Salvage pre-operative embolization resulted in bleeding control, bridging the patient to surgery.

OUTCOMES

Post-operative course was uneventful, and patient symptoms resolved.

LESSONS

This is the first case report of a sinonasal SFT, where pre-operative embolization has been employed as a salvage procedure. This treatment modality is promising, since it controls bleeding, bridges patient to surgery and decreases blood loss during the surgical procedure.

Solitary Fibrous Tumors of the Head and Neck: A Multi-Institutional Clinicopathologic Study

Solitary fibrous tumors (SFTs) of the head and neck are uncommon. Lesions previously diagnosed in the head and neck as hemangiopericytomas (HPCs), giant cell angiofibromas (GCAs), and orbital fibrous histiocytomas (OFHs) are now recognized as within the expanded spectrum of SFTs. To better understand the clinicopathologic profile of head and neck SFTs, we performed a multi-institutional study of 88 examples. There was no sex predilection (F:M ratio 1.2), and the median patient age was 52 years (range: 15 to above 89 y). The sinonasal tract and orbit were the most common sites involved (30% and 25%), followed by the oral cavity and salivary glands (15% and 14%). Original diagnoses included HPC (25%), SFT (67%), and OFH (6%), with 1 SFT and 1 OFH noted as showing GCA-like morphology. On review, the predominant histologic pattern was classic SFT-like in 53% and cellular (former HPC-like) in 47%; lipomatous differentiation (8%) and GCA-like pattern (7%) were less prevalent. Subsets demonstrated nuclear atypia (23%), epithelioid morphology (15%), or coagulative necrosis (6%). Infiltrative growth (49%) and osseous invasion (82%) were prevalent among evaluable cases. Of the 48 SFTs with follow-up (median: 43 mo), 19 showed recurrence (40%). Of these, 4 patients were alive with disease and 4 dead of disease. Size and mitotic rate were negative prognosticators using a joint prognostic proportional hazards regression model. Three patients experienced metastasis, to lungs, parotid, bone, and skull base, including one case showing overtly sarcomatous "dedifferentiation." As a group, SFTs present in a wide anatomic and morphologic spectrum in the head and neck. Only rare examples metastasize or cause death from disease. However, the fairly high local recurrence rate underscores their aggressive potential and highlights the importance of prospective recognition.

[Solitary Fibrous Tumors of the Nasal and Paranasal Sinuses]

Solitary fibrous tumors (SFT) are uncommon neoplasm that arises in most cases from the pleura. SFT has been rarely observed in the head and neck, but SFT of the paranasal sinuses is especially rare, with 39 previously reported cases to date including those reported in this abstract. Herein we describe three cases of SFT in the paranasal sinuses that were successfully treated endoscopically. Two of the three cases involved patients with no previous history of SFT. The lesion of one of the patients was pathologically diagnosed as SFT preoperatively, but the other was diagnosed as an angiogenic tumor without any biopsies. The tumors were completely resected after arterial embolization by a transnasal endoscopic procedure. The third case involved a 43-year old man, who had undergone medial maxillectomy through a lateral rhinotomy incision to resect SFT four years and seven months before. The tumor relapsed intracranially and, therefore, a craniotomy procedure followed by endoscopic skull base surgery was performed. Radiation therapy was performed postoperatively because the recurrent tumor was pathologically identified as malignant SFT, which had been classified benign at the time of the first resection. All three patients are presently alive with no evidence of disease.

[Hypoglycemia in a solitary fibrous tumor of the liver]

A 64-year-old patient developed sudden hypoglycemia leading to unconsciousness. Hypoglycemic episodes recurred on several occasions but were not accompanied by unconsciousness. Magnetic resonance imaging revealed a liver tumor in the right lobe sized 20.0 × 14.6 × 19.0 cm. No other masses were detected. Right hemihepatectomy was indicated but could not be performed due to heavy bleeding near the tumor. Histological examination showed a relatively cellular tumor made of elongated bland cells. The mitotic index was fewer than 4 mitoses per 10 HPF. The tumor was without necrosis or hemorrhage. The excised tumor was not encapsulated and showed no signs of invasive growth. On immunohistological examination, the tumor expressed NSE, CD34, CD99, Bcl2 and STAT6; Ki-67 was positive in approximately 20% of the cells. Both the histological pattern and immunophenotype were suggestive of solitary fibrous tumor of the liver. Given its size, cellularity and relatively high expression of the proliferation marker Ki-67, the tumor was classified as potentially malignant. The patient underwent embolization of arteries supplying the tumor with blood. The effect of the procedure on the tumor will only be assessed later. Hypoglycemia has resolved and the patient feels well.

Clinical Characteristics and Outcomes for Solitary Fibrous Tumor (SFT): A Single Center Experience

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm of fibrous origin. The 2013 WHO classification of soft tissue tumors defines malignant forms as hypercellular, mitotically active (>4 mitosis/10 high-power fields), with cytological atypia, tumor necrosis, and/or infiltrative margins. With an IRB-approved protocol, we investigated patient records and clinicopathologic data from our Sarcoma Database to describe the clinical characteristics of both benign and malignant SFT. All pathology specimens were reviewed by two pathologists. Descriptive statistics and univariate/multivariate survival analysis were performed. Patient records and Social Security Death Index were used to evaluate vital status. Of 82 patients, 47 (57%) were women and 73 (89%) were Caucasian. Median age was 62 years (range, 20 to 89). Thirty-two (39%) patients succumbed to the disease. Primary tumor site was lung/pleura in 28 (34%), abdomen/pelvis in 23 (28%), extremity in 13 (16%), and head/neck in 9 (11%) patients. Pathology was described as benign in 42 (51%) and malignant in 40 (49%) patients. Compared to benign SFT, malignant histology is associated with larger tumor size, higher mitotic counts, metastatic disease at diagnosis, and greater use of chemotherapy and radiation therapy. Gender, age, and tumor site were not significantly different between benign and malignant subtypes. By univariate analysis, only benign vs. malignant variant and complete resection positively impacted overall survival (P = 0.02 and P<0.0001, respectively). In the multivariable analysis of overall survival, receiving chemotherapy or not receiving surgery were two variables significantly associated with higher failure rate in overall survival: patients with chemotherapy vs. no chemotherapy (P = 0.003, HR = 4.55, with 95% CI: 1.68–12.34) and patients without surgery vs. with surgery (P = 0.005, HR = 25.49, with 95% CI: 2.62–247.57). Clear survival differences exist between benign and malignant SFT. While surgery appears to be the best treatment option for benign and malignant SFT, better systemic therapies are needed to improve outcomes of patients with metastatic, malignant SFT.

[A case of intraorbital solitary fibrous tumor resected successfully with preoperative arterial embolization]

The solitary fibrous tumor (SFT) is a rare spindle cell neoplasm derived from mesenchymal cells. It sometimes recurs clinically, and is categorized as an 'intermediate malignancy' tumor under the WHO (World Health Organization) classification of soft tissue tumors. Several studies have reported on intraorbital SFTs, but none of them has pointed out the utility of preoperative arterial embolization in the case of an intraorbital SFT. A 75-year-old man, who had received a dacryocystectomy for a benign tumor in the right lacrimal sac 30 years previously, visited our hospital complaining of lower eyelid swelling and lachrymation that had persisted for a year. CT and MRI revealed an intraorbital lesion, and the open biopsy specimen showed dense growth of spindle cells, which turned out to be an SFT by immunohistochemistry based on the findings. After preoperative embolization of the infraorbital artery, we removed the tumor with a skin incision on the lower rim of the orbit with little bleeding. The surgical specimen revealed that the tumor was close to a lacrimal canaliculus, which suggested the tumor originated from the lacrimal apparatus considering the patient's past history. He was followed up for three months without recurrences.

[Solitary fibrous tumor of the orbit: Possibly recurrent in the long-run]

Solitary fibrous tumor (SFT) is a rare etiology of progressive unilateral exophthalmia. The tumor is of mesenchymal origin and it is usually well defined. But recurrences can occur despite of complete surgical resection. Metastases have been observed. Tumors of the SFT spectrum are considered as benign or low-grade malignant. Histological features do not currently allow any prognosis. The most important prognostic factor is complete surgical resection. Craniofacial approaches provide a good view of the tumor extensions and orbital contents. Recurrent tumors must be surgically removed when possible. Complementary treatments have not proved effective. A very long-term follow-up is mandatory.

Recurrent solitary fibrous tumour of the thoracic spine. A case-report and literature review

Solitary fibrous tumours (SFTs) are rare tumours originating in the soft tissues. SFT development in the spine is an exceedingly rare event about which little is known. We describe a case of SFT of the thoracic spine in a 56-year-old woman. She presented with neurological deficits that required emergency resection, which was incomplete. Two subsequent local recurrences prompted further surgical procedures. At last follow-up, 12 months after the last procedure, function was satisfactory and there was no evidence of tumour recurrence. The management of SFTs is not well standardised, and no proven adjuvant treatments are available to date. Complete excision is effective in controlling disease progression. Prolonged follow-up is mandatory.

Radiology-pathology conference: malignant solitary fibrous tumor of the seminal vesicle

Mesenchymal neoplasms are rarely encountered in the seminal vesicle. Only four cases of the seminal vesicle solitary fibrous tumor have been reported in English literature, all of which were benign in nature. We are describing the clinicoradiological and pathological features of a locally aggressive malignant solitary fibrous tumor arising from the seminal vesicle, which posed the therapeutic challenge for the surgical management in a 52-year-old male patient. To our knowledge, this is the first reported case of the malignant solitary fibrous tumor arising from the seminal vesicle.

Solitary fibrous tumor of the petrous bone: a successful treatment option

The patient was a 48-year-old man complaining about right hemicranial pain and deafness of 1 year's duration. MRI showed a solid well-vascularized mass destroying the mastoid and petrous bone, and with an epidural component that pulled the right cerebellar hemisphere. The patient underwent a right modified type A infratemporal approach, which allowed complete resection of the tumor, with a low morbidity. The pathological diagnosis was solitary fibrous tumor. The patient received complementary treatment with radiotherapy. At 24 months after the initial treatment the patient is free of disease. We conclude that solitary fibrous tumor of the petrous bone can be satisfactorily treated with surgical excision followed by radiotherapy, with low morbidity and excellent facial function. To our knowledge this is the first description of a solitary fibrous tumor of the petrous bone. Due to the lack of consensus in treating rare tumors, we want to offer this management approach for treating this kind of tumor.

Solitary fibrous tumour of the orbit: an unusual presentation

Solitary fibrous tumour is a rare tumour that usually arises from the pleura and very uncommonly from the orbit. This unusual unilateral orbital mass can be differentiated from the more common haemangiopericytoma by the use of histopathological and immunohistochemical studies. The tumour is strongly Immunoreactive for CD34, which supports its diagnosis.

Solitary fibrous tumour of the pleura presenting with refractory non-insulin mediated hypoglycaemia (the Doege-Potter syndrome)

We report a case of a 61 year-old man who presented with refractory non-insulin mediated hypoglycaemia. A chest radiograph showed a right lung opacity, which was confirmed as a large intra-thoracic mass by computed tomography (CT) of the thorax. CT-guided biopsy with histological examination revealed features of a solitary fibrous tumour of low malignant potential. We discuss the association of solitary fibrous tumour of the pleura (SFTP) with hypoglycaemia, and the management of such rare tumours.

Giant solitary fibrous tumor of the pleura

BACKGROUND

Solitary fibrous tumor is the second primary malignancy of the pleura and can reach up to 39 cm in diameter; however, to be referred to as 'giant' it must occupy at least 40% of the affected hemithorax. Although this tumor usually shows a benign behavior, malignancy criteria have been described. The aim of the study was to assess the initial evaluation, diagnostic procedures, surgical management, treatment outcome, and prognosis.

METHODS

We performed a descriptive, observational, longitudinal, and retrospective study from 2002 to 2006 on patients who underwent surgery with a diagnosis of giant solitary fibrous tumor of the pleura.

RESULTS

Six patients were included; 83.3% were females. Mean age was 48 years. All patients were symptomatic, mainly dyspnea, cough and chest pain; 66.7% were left-sided. Preoperative angiography and embolization were performed in 83.3% cases with successful surgical resection. The predominant blood supply was derived from the internal mammalian artery. Intraoperative complication rate was 17%. A vascular pedicle was found in 66.7%. The largest lesion was 40 cm in diameter and weighed 4500 g. Only one case showed high mitotic activity. Mean follow-up to date is 14 months.

CONCLUSIONS

Symptomatology found was consistent with previous reports but in higher percentages. Accurate diagnosis is critical because surgical resection involves a potential cure; however, long-term follow-up is mandatory. Preoperative embolization is recommended due to tumor size.

Fibrous tumor of the lung: diagnostic and therapeutic considerations apropos of two cases

Solitary fibrous tumor (SFT) of the pleura and the lung is an uncommon spindle cell neoplasm arising from the visceral pleura in the majority of the cases. Current diagnostic and therapeutic considerations are discussed apropos of 2 recent cases. 1st case: A 46-year-old male, heavy smoker, presented with nonspecific complaints and a mass in the left posterior mediastinum at the level of the 5th thoracic vertebra. Computed tomography (CT) and magnetic resonance imaging (MRI) of the chest confirmed the position of the mass in proximity to the thoracic wall at that level. Through a left posterolateral thoracotomy, a 4 x 5 x 2 cm mass, mushroom-shaped, stalky, completely covered by the lung parenchyma, was resected. Histopathological examination revealed a SFT of the lung. 2nd case: A 54-year-old woman presented with symptoms of respiratory distress and persistent hypoglycaemia. CT scan of the chest showed a huge mass within the right hemithorax, compressing the mediastinum and the contralateral lung. The mass was initially detected on chest radiography and CT scan 3 years before resection. Fine needle biopsy (FNB) results were inconclusive and resection of the mass through a right thoracotomy established the diagnosis of malignant SFT. Resection of the mass resulted in recovery of respiratory function and the paraneoplastic hypoglycaemia. Radiologic features and inconclusive fine needle aspiration (FNA)/FNB results make preoperative diagnosis of SFTs of the pleura and lung difficult. Diagnosis of SFT will be established with certainty after surgery. Resection with clear margins is the main important prognostic factor.

Solitary fibrous tumor of the thyroid gland

Solitary fibrous tumor (SFT) is a rare spindle-cell neoplasm more commonly involving the pleura, but recognized also in other tissues. Nineteen patients with SFT arising from the thyroid gland have been reported in the literature. The present report reviews these cases and discusses epidemiology, etio-pathogenesis, clinical-pathologic characteristics, differential diagnosis, therapy, and prognosis of thyroid SFT.