Rare presentation of solitary fibrous tumour in the floor of the mouth.

A male in his 20s, a tobacco chewer, presented to the outpatient department with a history of painless, slowly progressive swelling in the floor of the mouth. After a thorough history and clinical examination, MRI was done and the tumour was completely excised. Histopathological examination revealed the mass to be a solitary fibrous tumour, confirmed with immunohistochemical markers. On subsequent follow-ups, the patient was found to be asymptomatic with no clinical signs of recurrence.

Endobronchial solitary fibrous tumors: An enigma for diagnosis.

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms constituting less than 2% of all soft tissue tumors. They typically originate in the thoracic cavity, mainly in the pleura, but can also occur in other various sites such as lung parenchyma, pericardium, and bronchus. In this study, a 49-year-old non-smoking female with a history of allergies presented to our pulmonary clinic with a chronic cough. An explorative bronchoscopy revealed an intrabronchial mass in the left superior bronchi, and a 68 Ga-DOTATOC positron emission computed tomography suggested a carcinoid tumor. Subsequent pulmonary segmentectomy unveiled a well-circumscribed polypoid lesion diagnosed as a low-grade bronchus SFT through histopathological and immunohistochemical assessments. The patient was asymptomatic after surgical excision and showed no other lesion during the 6-month follow-up. The endobronchial location of SFT is uncommon, with only a few reported cases in the literature, underscoring the necessity of considering various differential diagnoses, including carcinoid, mucoepidermoid carcinoma, endobronchial pleomorphic adenoma, hamartoma, leiomyoma, and metastasis, depending on location and imaging features. This report underscores the importance of careful histological and immunohistochemical evaluation in understanding and appropriately stratifying the risk associated with polypoid lesions.

Conditional survival analysis and dynamic survival prediction for intracranial solitary-fibrous tumor/hemangiopericytoma.

BACKGROUND: As the form of World Health Organization Central Nervous System (WHO CNS) tumor classifications is updated, there is a lack of research on outcomes for intracranial combined solitary-fibrous tumor and hemangiopericytoma (SFT/HPC). This study aimed to explore conditional survival (CS) pattern and develop a survival prediction tool for intracranial SFT/HPC patients. METHODS: Data of intracranial SFT/HPC patients was gathered from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. The patients were split into training and validation groups at a 7:3 ratio for our analysis. CS is defined as the likelihood of surviving for a specified period of time (y years), given that the patient has survived x years after initial diagnosis. Then, we used this definition of CS to analyze the intracranial SFT/HPC patients. The least absolute shrinkage and selection operator (LASSO) regression and best subset regression (BSR) were employed to identify predictive factors. The Multivariate Cox regression analysis was applied to establish a novel CS-based nomogram, and a risk stratification system was developed using this model. RESULTS: From the SEER database, 401 patients who were diagnosed with intracranial SFT/HPC between 2000 and 2019 were identified. Among them, 280 were included in the training group and 121 were included in the internal validation group for analysis. Our study revealed that in intracranial SFT/HPC, 5-year survival rates saw significant improvement ranging from 78% at initial diagnosis to rates of 83%, 87%, 90%, and 95% with each successive year after surviving for 1-4 years. The LASSO regression and BSR identified patient age, tumor behavior, surgery and radiotherapy as predictors of CS-based nomogram development. A risk stratification system was also successfully constructed to facilitate the identification of high-risk patients. CONCLUSION: The CS pattern of intracranial SFT/HPC patients was outlined, revealing a notable improvement in 5-year survival rates after an added period of survival. Our newly-established CS-based nomogram and risk stratification system can provide a real-time dynamic survival estimation and facilitate the identification of high-risk patients, allowing clinicians to better guide treatment decision for these patients.

A case of fat-forming solitary fibrous tumor that is prone to be confused with liposarcoma.

Fat-forming solitary fibrous tumor is a rare and specific subtype of solitary fibrous tumor. In this case, a mass of 8.3 cm in diameter was found in a 59-year-old male patient's right retroperitoneum, as revealed by abdominal contrast-enhanced computed tomography (CT) images. The tumor exhibited a well-circumscribed nature and histological features characterized by a combination of hemangiopericytomatous vasculature and mature adipose tissue, comprising around 70% of the total tumor composition. Immunohistochemistry staining revealed diffuse positive expression of STAT6 and CD34 in the tumor cells. Based on these findings, the final diagnosis was determined to be a fat-forming solitary fibrous tumor located in the retroperitoneum. It is important to consider other potential differential diagnoses, including angiomyolipoma, dedifferentiated liposarcoma, spindle cell lipoma, and atypical lipomatous tumor/well-differentiated liposarcoma.

A case report on a nasal and oral cavity involving large solitary fibrous tumor and comprehensive review of case literature.

Solitary fibrous tumor (SFT) represents an uncommon spindle cell sarcoma predominantly situated within soft tissue, with a notably infrequent occurrence in the nasal cavity and paranasal sinuses. In this report, we present a case involving a middle-aged male with a sizable solitary fibrous tumor affecting both the nasal and oral cavities.

Solitary fibrous tumor: Can the new Huang risk stratification system for orbital tumors improve prognostic accuracy in other tumor locations?

Solitary fibrous tumors (SFTs) are known for their heterogeneous morphology, characterized by a variety of cell shapes and different growth patterns. They can also arise in various anatomical locations, most commonly in extremities and deep soft tissues. Despite this diversity in morphology and location, all SFTs share a common molecular signature involving the NAB2::STAT6 gene fusion. Due to their unpredictable clinical behavior, establishing prognostic factors is crucial. This study aims to evaluate an orbital risk stratification system (RSS) proposed by Huang et al. for use in extraorbital SFTs using a database of 97 cases. The Huang model takes into consideration tumor size, mitotic figures, Ki-67 index, and dominant constituent cell (DCC) as key variables. Survival analysis confirmed the model's predictive value, with higher-risk scores being associated with poorer outcomes. However, in contrast to the orbital SFTs studied by Huang et al., our study did not find a correlation between tumor size and recurrence in extraorbital cases. While the Huang model performs slightly better than other RSS, it falls short on achieving statistical significance in distinguishing recurrence risk groups in extraorbital locations. In conclusion, this study validates the Huang RSS for use in extraorbital SFTs and underscores the importance of considering DCC, mitotic count, and Ki-67 together. However, we found that including tumor size in this model did not improve prognostic significance in extraorbital SFTs. Despite the benefits of this additional RSS, vigilant monitoring remains essential, even in cases classified as low-risk due to the inherent unpredictability of SFT clinical outcomes.

Establishment and characterization of a patient-derived solitary fibrous tumor/hemangiopericytoma cell line model.

Solitary fibrous tumor/Hemangiopericytoma (SFT/HPC) is a rare subtype of soft tissue sarcoma harboring NAB2-STAT6 gene fusions. Mechanistic studies and therapeutic development on SFT/HPC are impeded by scarcity and lack of system models. In this study, we established and characterized a novel SFT/HPC patient-derived cell line (PDC), SFT-S1, and screened for potential drug candidates that could be repurposed for the treatment of SFT/HPC. Immunohistochemistry profiles of the PDC was consistent with the patient's tumor sample (CD99+/CD34+/desmin-). RNA sequencing, followed by Sanger sequencing confirmed the pathognomonic NAB2exon3-STAT6exon18 fusion in both the PDC and the original tumor. Transcriptomic data showed strong enrichment for oncogenic pathways (epithelial-mesenchymal transition, FGF, EGR1 and TGFß signaling pathways) in the tumor. Whole genome sequencing identified potentially pathogenic somatic variants such as MAGEA10 and ABCA2. Among a panel of 14 targeted agents screened, dasatinib was identified to be the most potent small molecule inhibitor against the PDC (IC50, 473 nM), followed by osimertinib (IC50, 730 nM) and sunitinib (IC50, 1765 nM). Methylation profiling of the tumor suggests that this specific variant of SFT/HPC could lead to genome-wide hypomethylation. In conclusion, we established a novel PDC model of SFT/HPC with comprehensive characterization of its genomic, epigenomic and transcriptomic landscape, which can facilitate future preclinical studies of SFT/HPC, such as in vitro drug screening and in vivo drug testing.

Solitary Fibrous Tumours of the Orbit - Clinical Pathology, Therapy and Prognosis. / Solitär fibröse Tumoren der Orbita ­ klinisch-pathologische Charakteristik, Therapie und Prognose.

BACKGROUND: Solitary fibrous tumours are rare. The aim of this study is to describe the clinical features, therapy and outcome of affected patients and to identify factors associated with recurrence. METHODS: Retrospective study of a cohort of 20 patients who underwent surgery for orbital solitary fibrous tumour at the University Department of Oral and Maxillofacial Surgery between 2002 and 2023. Demographic, clinical, and therapeutic data as well as tumour follow-up results were collected. Tumour volume and molecular genetic mutations were retrospectively determined. RESULTS: The median patient age was 49.5 years at initial surgery. The left orbit was affected in 65% of cases. The most common clinical symptom was proptosis (80%). This was reported with a mean lateral difference of 3.9 mm (range: 1 - 10 mm). The tumours were localised predominantly in the intra- and extraconal space, craniolateral quadrant and middle third. The median tumour volume was 7.66 cm³ (range 2.15 - 12.57 cm³). In all patients, the diagnosis was made by pathological examination. All tumours investigated showed a NAB2-STAT6 mutation. The most frequently detected mutation was the fusion NAB2 exon 4 - STAT6 exon 2. All patients were initially managed with frontolateral orbitotomy. Incomplete resection (R1-status) occurred in 35% (n = 7). The recurrence rate was 25% (n = 5), with a median disease-free interval of 45.5 months (range 23 - 130). 80% (n = 4) of recurrences were initially R1-resected. CONCLUSION: Orbital solitary fibrous tumours are rare tumours and are clinically manifested by signs of displacement of orbital structures. Diagnosis is made by histology and immunohistochemistry and can be proven with the molecular genetic detection of the NAB2-STAT6 mutation. The therapy of choice is complete surgical resection. R1-resection is more likely in the intraconal location as well as in location in the posterior third of the orbit - due to difficult surgical accessibility. The greatest risk factor for the development of recurrence is incomplete surgical excision. Late recurrences are possible, which is why a long-term connection to a specialised clinic is necessary.

CD34-Positive Spindle Cell Tumor With CTNNB1 Mutation: An Unusual Spindle Cell Variant of Sinonasal Glomangiopericytoma.

Sinonasal glomangiopericytoma is an uncommon mesenchymal tumor with a perivascular myoid phenotype, which is categorized as a borderline/low-grade malignant soft tissue tumor by the current World Health Organization Classification of Head and Neck tumors. Here, we present the case of a 53-year-old woman with an unusual spindle cell morphology of sinonasal glomangiopericytoma arising in the nasal cavity, mimicking solitary fibrous tumor. Microscopically, the tumor showed a cellular proliferation of spindle cells in fascicles including a focal long sweeping arrangement or whorls, or with a storiform growth pattern, associated with hemangiopericytoma-like gaping blood vessels embedded in a fibrous stroma. This arrangement of the spindle cells faintly indicated a solitary fibrous tumor rather than sinonasal glomangiopericytoma. Immunohistochemically, the tumor was positively reactive to not only beta-catenin (in the nuclei) but also CD34, although signal transducers and activators of transcription 6 was negative. Mutational analysis using Sanger sequencing detected a CTNNB1 mutation. We finally diagnosed the tumor as a sinonasal glomangiopericytoma, showing an unusual spindle cell variant. Such unusual spindle cell morphology with CD34-immunoreactivity potentially leads to an incorrect diagnosis of solitary fibrous tumor because such prominent fascicles including long sweeping structures, reminiscent of desmoid-type fibromatosis, have scarcely been described in the literature. Hence, careful morphological scrutiny using appropriate diagnostic adjuncts is necessary for correct diagnosis.

Malignant recurrent orbital solitary fibrous tumor.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor of fibroblastic origin commonly occurring in pleura. It can occur at many extrapleural sites but is rare in orbit. Most cases are benign and recurrence is not unusual in the head and neck and orbit and is usually due to incomplete surgical excision. However, malignant transformation (MT) in orbital SFT is extremely unusual. We present a case of orbital SFT in adult male who developed recurrence with MT eight years after initial surgical excision. He underwent left orbital exenteration. The recurrent tumor revealed features of malignancy with areas exhibiting morphology typical of SFT. The immunochemistry confirmed the diagnosis of SFT with MT. The patient was given adjuvant radiation and was disease free for the last 18 months. Identification of malignancy in orbital SFT is important for the patient to receive appropriate postoperative treatment, as seen in the present case.

Metastasis of solitary fibrous tumor to the parotid gland diagnosed on aspiration cytology supplemented with immunocytochemistry.

Solitary fibrous tumor (SFT) can occur in varied anatomic locations, most commonly being the extremities-superficial and deep soft tissues, followed by retroperitoneum, visceral organs, and the bone. Head and neck region may harbor a few with a predilection for the orbit and sinonasal tract, oral cavity, and rarely the salivary glands. The parotid gland is most involved among all salivary glands. Overall, SFT in salivary glands is rare and mostly seen as a primary tumor. The occurrence of metastasis to the parotid gland is exceedingly uncommon. We present cytological findings of SFT, metastatic to the parotid gland in a young 31-year-old lady where the diagnosis was confirmed with the help of immunocytochemistry (ICC) on the cell block. The smears were highly cellular and showed predominantly discrete round to oval tumor cells with mild pleomorphism, coarse chromatin, inconspicuous nucleoli, and scanty cytoplasm. Mitosis and focal areas of necrosis were noted. Lymphoglandular bodies were absent ruling out a non-Hodgkin lymphoma. Features were of a poorly differentiated malignant tumor with differentials being sarcoma, myoepithelial carcinoma, and carcinoma ex-pleomorphic adenoma. A panel of ICC was done and positivity for signal transducer and activator of transcription 6 (STAT6) helped in clinching the correct diagnosis of SFT.

Giant Solitary Fibrous Tumor of the Ascending Aortic Wall Causing Reversible Heart Failure: A Case Report and Review of the Literature.

A 56-year-old woman was admitted to our hospital with a 2-week history of chest tightness and fatigue, and an echocardiogram revealed a massive polyserous cavity effusion. A massive (13.5 cm maximum diameter) intrapericardial mass was discovered using computed tomography (CT) and cardiovascular magnetic resonance imaging (MRI) in the ascending aortic wall. A pericardial biopsy was performed and diagnosed as a solitary fibrous tumor (SFT). After successful mass resection, an immunohistochemical test was positive for CD34, STAT-6, CD34, and Bcl2, which indicates a giant benign solitary fibrous tumor of the ascending aortic wall. After three years of follow-up, the patient is symptom-free, and histological indications of malignancy were absent. A giant benign solitary fibrous tumor is extremely rare in the heart, especially from the ascending aorta wall, and experience with this tumor location is limited, so close follow-up at regular intervals is considered necessary. We present this case, followed by a literature review on SFTs involving the heart and management approaches.

A case report of solitary fibrous tumor of the thyroid gland and literature review.

RATIONALE: A solitary fibrous tumor (SFT) is an uncommon soft tissue tumor that was first discovered in the pleura. Although SFTs have been documented in other extra-pleural sites, an SFT in the thyroid gland is highly unusual. An SFT of the thyroid gland can be difficult to diagnose, and there is little information about their Underlying biological behavior. PATIENT CONCERNS: We present a case of a 63-year-old man with a progressively growing left-neck mass detected 1 month ago, which was pathologically confirmed to be a benign SFT of the thyroid gland. DIAGNOSIS: Postoperative pathological examination of the tumor revealed an SFT. Immunopathological examination was consistent with the diagnosis of an SFT. INTERVENTIONS: The patient underwent surgical resection of the SFT. OUTCOMES: The patient was recurrence-free during 1.5 years of follow-up. LESSONS: Surgical excision is beneficial in SFTs that show no histological signs of malignancy, such as pleomorphism, enhanced mitotic activity, necrosis, bleeding, or capsular invasion. However, because the biologic activity remains unknown, meticulous long-term monitoring is required.

Infantile (congenital) anaplastic intracranial solitary fibrous tumor/hemangiopericytoma-A case report with brief literature review.

Solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a rare primary central nervous system (CNS) tumor, included in the World Health Organization (WHO) 2016 classification. Very few cases have been described in the literature so far, especially the infantile type. It is a mesenchymal tumor of the fibroblastic type, characterized by the fusion of NAB 2 and STAT 6 genes. A 10-month-old boy presented to our neurosurgery department with complaints of increasing head circumference since 1 month of age. The magnetic resonance imaging (MRI) showed a space-occupying lesion measuring 8.2 cm × 7 cm × 6.9 cm in the fronto-temporo-parietal region with a clinical diagnosis of glioma/atypical teratoid rhabdoid tumor (ATRT). The microscopy revealed a spindle cell tumor arranged in a patternless pattern with variable cellularity, increased mitosis, and areas of coagulative necrosis. The immunohistochemistry showed vimentin, CD 34, STAT6, CD99 positivity whereas Glial fibrillary acidic protein, Epithelial membrane antigen, and S-100 negativity. Hence, a diagnosis of anaplastic SFT/HPC (grade-III) was rendered. The patient improved after gross total resection (GTR). The primary intracranial congenital SFT/HPC are extremely rare, often a clinico-radiologically misdiagnosed entity. Thus, the immunohistochemistry/molecular study in addition to histology is mandatory for accurate diagnosis.

Solitary Fibrous Tumors of the Mesocolon: A Report of Two Cases and Review of Literature.

Solitary fibrous tumors (SFTs) are an uncommon group of neoplasms. The visceral pleura is the most common site of origin of these tumors. The colonic mesentery is an unusual site of origin of SFTs. A pre-operative diagnosis of SFT is challenging as there are no pathognomonic clinical or radiological signs. Most patients reported thus far were diagnosed post-operatively with the aid of immunohistochemical markers. Complete surgical excision is the treatment of choice for SFTs. Recurrences are uncommon. However, they can occasionally show aggressive behavior. In this report, we describe two cases of rare colonic mesentery SFTs.

Massive solitary fibrous intrathoracic tumor presented as primary lung cancer.

Solitary fibrous tumours (SFT) are rare soft tissue tumours with a primarily benign course. Complete surgical resection is the mainstay treatment. In this case report, a 75-year-old man had a massive intrathoracic SFT which was subsequently surgically resected without complications. Although the clinical presentation and CT features of these tumours can mimic lung cancer, the clinical course is significantly more favourable. Diagnostic examination and surgical treatment of intrathoracic SFT should be considered even in patients with increased post-operative risk.

Recurrent malignant solitary fibrous tumor of pelvis: A case report and treatment approach.

RATIONALE: Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that typically arise from the pleura but can also occur in various locations throughout the body. Although there are increasingly more reports of extra-pleural SFTs, reports of SFTs in bone are very rare, and a malignant SFT accompanying recurrence of pelvis has not yet been reported. PATIENT CONCERNS: We herein present the case of a 15-year-old male who experienced intermittent numbness in his right buttock, accompanied by radiating pain in his lower limbs for 6 months. Radiological examinations revealed an expansive, heterogeneous enhanced mass in the sacral and iliac regions, with a branch of the right internal iliac artery feeding the tumor. DIAGNOSES: The histological examination suggest a diagnosis of a malignant SFT with high proliferation activity. INTERVENTIONS: The sacral mass was surgically excised. OUTCOMES: Following the surgery, the patient experienced a local recurrence of the tumor at 9 months and was administered adjuvant imatinib treatment. Recent magnetic resonance imaging contrast-enhanced displayed shrinkage of the tumor, which may provide certain evidence for chemotherapy for the treatment of recurrence of malignant SFTs in the pelvic region. LESSONS: Complete surgical excision is the recommended treatment for this rare disease entity, and the role of adjuvant therapies is controversial due to their rarity. Our case underscores the challenges in managing recurrent malignant SFTs and highlights the importance of a thorough diagnostic workup. Further research is needed to establish the role of adjuvant therapies in the management of these tumors.

Solitary fibrous tumor: Two cases report with a focus on the differential diagnosis / Tumor Fibroso Solitário: Relato de dois casos com foco no diagnóstico diferencial

Solitary fibrous tumor (SFT) is a neoplasm of fibroblastic/myofibroblastic origin with intermediate biological behavior. We report here two cases of SFT affecting an unusual anatomical site in 58-year-old and 40-year-old female patients and discuss the differential diagnosis of this lesion. In case 01, the lesion showed the clinical appearance of an asymptomatic "blister" with normal color, rubbery consistency, measuring 0.3 cm, and affected the lower lip; while in case 02, a symptomatic red nodular lesion with a soft consistency and measuring 0.5 cm affected the floor of the mouth. Excisional biopsies were performed. Microscopically, two well-delimited benign neoplasms were observed, exhibiting the proliferation of ovoid to spindle-shaped mesenchymal cells, vascular spaces with staghorn arrangement, and the absence of mitosis figures. Immunohistochemistry was performed in case 01 to assist in the diagnosis. Weak and diffuse immunostaining was observed for α-SMA and intense and diffuse immunopositivity for Bcl-2 and CD34. Based on histopathological and immunohistochemical features, a diagnosis of SFT was rendered in both cases. The low occurrence and nonspecific clinical features of oral SFT may make its clinical diagnosis difficult. Also, morphological and immunohistochemical are essential for differential diagnosis with other mesenchymal neoplasms.(AU)

O tumor fibroso solitário (TFS) é uma neoplasia de origem fibroblástica/miofibroblastica com comportamento biológico intermediário. Nesse artigo relatamos dois casos de TFS afetando sítios anatômicos incomuns em pacientes do sexo feminino de 58 anos e 40 anos e discutir os seus diagnósticos. No caso 01 clinicamente a lesão apresentou um aspecto de "bolha" assintomática, coloração normal da mucosa, consistência borrachoide medindo 0,3 cm, em região de lábio inferior, enquanto que no caso 02, como uma lesão sintomática, vermelha, nodular com consistência mole e medindo 0,5 cm afetando o assoalho bucal. As biópsias excecionais foram realizadas. Microscopicamente, observamos duas lesões neoplásicas bem delimitadas exibindo uma proliferação de células mesenquimais variando de ovoides a fusiformes, vasos sanguíneos em formato de "chifre de veado", com ausência de figuras de mitoses. No caso 01 foi realizado análise imuno-histoquímica para auxiliar no diagnóstico. Foi observado uma marcação fraca e difusa de α-SMA e uma intensa e difusa imunopositividade para o Bcl-2 e CD34.Baseado nos achados histopatológicos e imuno-histoquímicos o diagnóstico de TFS foi estabelecido em ambos os casos. A baixa ocorrência e os achados clínicos inespecíficos do TFS oral podem dificultar o diagnóstico clínico. Além disso, as análises morfológicas e imuno-histoquimicas são essenciais para realização do diagnóstico diferencial com outras neoplasias mesenquimais.(AU)_

Solitary fibrous tumor of the tympanic membrane a case report and systematic review.

PURPOSE: Otological solitary fibrous tumors (SFT) are exceedingly rare. There has been no report of SFT localized to the tympanic membrane. To report on a rare case of solitary fibrous tumor of the tympanic membrane and provide systematic review of the literature pertaining the demographics and pathophysiology of otological SFTs. MATERIALS AND METHODS: This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. A search of PubMed, Google Scholar, and Cochrane Library databases was conducted to identify English-language articles on solitary fibrous tumor of the ear, with emphasis on the tympanic membrane, published through 2022. A combination of Boolean operators and the following keywords were included in the search strategy: "solitary fibrous tumor", "tympanic membrane", and "ear". RESULTS: We found 12 previous reports of solitary fibrous tumors of the ears, none of which were in the tympanic membrane. All cases underwent surgical resection, with or without perioperative embolization, or radiation. There was no evidence of distant diseases in any cases. CONCLUSIONS: In the context of a tympanic membrane mass with associated pain and hearing loss, our findings suggest that solitary fibrous tumor should be included in the differential diagnosis.