Solitary fibrous tumor

Doege-Potter syndrome due to a solitary fibrous tumor of the pleura: a case report

BACKGROUND

Doege-Potter syndrome is a rare paraneoplastic phenomenon associated with solitary fibrous tumors of the pleura (SFTPs). It is characterized by the presence of severe, sustained, and treatment-refractory hypoglycemia. Hypoglycaemia, which may be the sole symptom at disease onset, is mediated by the secretion of high-molecular-weight insulin-like growth factor (IGF-2). Most tumors exhibit benign behavior, with a 100% survival rate at 5 years. However, 10% of these tumors may display aggressive behavior with local or metastatic recurrence. We present a clinical case of a patient with a benign solitary fibrous tumor of the pleura who presented with symptomatic hypoglycemia and required pulmonary and pleural surgical resection to control the paraneoplastic phenomenon.

CASE PRESENTATION

A Hispanic 46-year-old man presented with a 15-day history of transient alterations in consciousness worsened by fasting. The relevant medical history included obstructive sleep apnea treated with continuous positive air pressure (CPAP) and previous smoking. In-hospital studies revealed noninsulinemic hypoglycemia and a benign SFTP. Complete surgical resection was performed while the patient received dextrose fluids and corticosteroids perioperatively for hypoglycemia. Subsequently, the hypoglycemia resolved, and the patient was followed-up without disease recurrence.

CONCLUSION

Doege-Potter syndrome is challenging to recognize. However, effective treatment can be achieved with a high survival rate. Raising awareness among healthcare professionals about the recognition of this paraneoplasic syndrome patients will improve diagnostic suspicion, biochemical confirmation, the development of diagnostic and therapeutic guidelines, and the creation of predictive indices for aggressive presentations requiring closer monitoring.

A giant solitary fibrous tumor of the abdominal pelvic cavity: A case report and literature review

RATIONALE

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor, especially the giant one from the abdominal pelvic cavity. We report on a rare case of a giant SFT of the abdominal pelvic cavity to review the existing literature in detail to improve the diagnosis and treatment of SFT.

PATIENT CONCERNS

The patient is a 52-year-old female who presented with 2 weeks of abdominal distension. Abdominal magnetic resonance imaging showed a giant mass (>20 cm) in the abdominal pelvic cavity, considered a mesenchymal tumor. She denies a history of tumor disease.

DIAGNOSES

A whole abdomen bulge and a mass of about 18 cm × 10 cm on the right side and middle side were found in the physical examination after admission. Abdominal enhanced computed tomography revealed a giant cystic-solid mass located on the middle and right side of the abdominal pelvic cavity, measuring approximately 20.4 cm × 11.7 cm, with multiple cystic changes and necrosis and compression of adjacent organs and tissues, and marked inhomogeneous enhancement.

INTERVENTIONS

The patient underwent an open abdominal pelvic cavity giant tumor operation to achieve a radical resection, and did not undergo chemotherapy or radiotherapy.

OUTCOMES

The patient underwent open complete resection of a giant abdominal pelvic tumor with no complications and was diagnosed as SFT according to the pathology, immunohistochemistry showed that the tumor tested positive for CD34(+), STAT-6(+), and Ki-67 (10%). Abdominal computed tomography scans were performed 6 months after resection, and no signs of recurrence or metastasis were found.

LESSONS

The clinical symptoms and imaging features of giant abdominal pelvic cavity SFT are not typical. Preoperative diagnosis is difficult and has the potential for malignancy. Based on the results of the current study, there is no standard treatment strategy around the world and the therapeutic effect of radiation therapy and chemotherapy is relatively limited. Thus, complete surgical resection and close clinical follow-up are advocated.

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.

Robotic-assisted laparoscopic resection of a pelvic solitary fibrous tumour causing distal ureteric compression

This case report describes a male in his late 40s with a 4 cm pelvic mass compressing the left distal ureter, resulting in left hydroureteronephrosis. Biopsy of the mass was suggestive of a solitary fibrous tumour. The patient underwent a robotic-assisted laparoscopic excision of the left pelvic mass. Intraoperatively, the mass was found to be densely adhered to the ureter, necessitating a left distal ureterectomy and ureteric reimplantation. Subsequent histopathological analysis revealed the mass was a solitary fibrous tumour with no evidence of malignancy.

Excision of a Solitary Fibrous Tumor in the Sciatic Notch with Sciatic Nerve Compression - A Rare Clinical Case

We present the clinical case of a 41-year-old woman with no relevant personal history. The patient complained of diffuse self-limiting abdominal pain, and we incidentally detected an extra-abdominal, extraperitoneal tumor mass at the level of the right sciatic notch. The abdominal complaints were gone during the initial follow-up, but the patient developed sciatica radiating to the right foot and electric shock-like pain. A computed tomography (CT)-guided biopsy revealed a low-grade mesenchymal neoplasm of the soft tissues with characteristics consistent with a solitary extrapleural fibrous tumor. The pelvis team of the orthopedics department received the patient for surgical excision of the lesion. The procedure occurred with no complications, and we excised the totality of the lesion with tumor-free margins. An anatomopathological examination was compatible with the biopsy assessment. The excision of the lesion resulted in complete resolution of the sciatic nerve compression-related symptoms.

A Giant Malignant Solitary Fibrous Tumor of the Pancreas: A Case Report and Review of the Literature

We present a case report of a giant solitary fibrous tumor (SFT) with a review of the literature and discuss its biological features and diagnosis. A 43-year-old man presented to our emergency department with abdominal pain and distension with an evolution of two days. Contrast-enhanced computed tomography (CT) showed a large, well-circumscribed semisolid mass (12 cm x 10 cm x 12 cm) localized in the pancreatic head. The histological diagnosis obtained by endoscopic ultrasound-guided trans-duodenal tumor biopsy with fine-needle aspiration showed proliferating short spindle-shaped cells, suggesting a mesenchymal neoplasia of low grade. We proceeded to a Whipple surgical technique. The histopathological study of the resected tumor confirmed proliferating spindle-shaped cells in the tissue, and one mitotic figure was observed in 10 high-power fields (HPFs). Immunostaining was positive for CD34 and STAT-6. The histological diagnosis was a malignant pancreatic SFT. In the six months posterior to the surgical procedure, the patient has been free of recurrent disease. Preoperative diagnosis is difficult and requires comprehensive evidence including clinical, immunohistochemistry, and histological features. Since there are currently no recognized best practices, we advise total surgical excision and careful clinical monitoring.

The Third-Time Recurrence of a Thoracic Solitary Fibrous Tumor in a Patient Presenting With Paraneoplastic Hypoinsulinemic Hypoglycemia (Doege-Potter Syndrome)

We present a case of a 76-year-old Caucasian female with a recurrent solitary fibrous tumor (SFT) of the pleura, showcasing a rare manifestation of hypoglycemia associated with Doege-Potter syndrome (DPS). Having undergone two previous surgeries for SFT, the patient presented to the emergency department with severe fatigue, recurrent episodes of loss of consciousness, and hypoglycemia, despite lacking a history of diabetes mellitus. Radiological evaluation revealed a substantial recurrent SFT in the left lung, prompting excision through a left posterolateral thoracotomy. Remarkably, the patient's altered mental status and hypoglycemia resolved postoperatively. The case meets the criteria for aggressive SFT behavior, warranting consideration for adjuvant radiation therapy to control the risk of recurrence. This report highlights the nuanced interplay between SFT recurrence, paraneoplastic syndromes like DPS, and the potential benefits of adjuvant therapeutic strategies in managing these complex clinical scenarios.

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.

Cardiac solitary fibrous tumor - an extremely rare but potentially fatal diagnosis

The background of this review is a description of the case of a 28-year-old man with an extremely rare cardiac solitary fibrous tumor (SFT). Although this tumor was removed surgically and in the 6-month follow-up examination no relapse was noted, recurrence was observed and confirmed in the magnetic resonance imaging 4 months later. SFT prevalence, symptoms and signs, treatment options and prognosis are reviewed.

Rarest of the Rare - Malignant Solitary Fibrous Tumour of the Breast: Case Report and Literature Review

Malignant solitary fibrous tumor of the breast is one of the rarest types of breast malignancy. To the best of our knowledge, only six cases have been reported so far. Here we have presented such a case from India, where a 52-year-old lady presented with a 10 cm x 8 cm breast lump. Diagnosis was achieved with the help of FDG PET, histopathology and immunohistochemistry, which showed nuclear positivity for STAT6. Fluorescent in situ hybridization (FISH) molecular study for SS18-SSX was used to rule out the differential diagnosis of synovial sarcoma. Guidelines for the management of this type of breast malignancy still do not exist. We have done a review of the literature in order to discuss which might be the best management in such cases. Evidence on this very rarest type of breast malignancy is still evolving. The interest in the case described here relies on its rarity, difficulties in achieving diagnosis and formulation of the proper management.

Exploring Solitary Fibrous Tumors at a Tertiary Cancer Center: Clinicopathological and Immunomorphologic Profile

Background Solitary fibrous tumor (SFT) is a distinct fibroblastic tumor that can occur at any anatomical site and can manifest a variety of histopathological features. NAB2-STAT6 gene fusion has recently emerged as a sensitive and specific molecular marker and its surrogate on immunohistochemistry, STAT6 has also displayed considerable efficacy. Nevertheless, its histologic diversity can result in diagnostic challenges, especially when classic features are not apparent. Methods A retrospective study was conducted at a tertiary cancer centre in North India over 3 years to document the clinicopathologic and immunomorphologic profile of SFTs. Immunohistochemical analysis of BCOR and p53 were gauged additionally and patients were stratified according to Modified Demicco and Salas criteria for risk of metastasis. Results Sixteen patients of SFT were identified, affecting middle-aged men and women equally. Though lung/pleura are known to be involved commonly, SFT affects other sites such as the kidney, brain, buccal mucosa, liver, and penis as well. The majority endured localized disease while a lesser number suffered locoregional/distant spread. Two patients revealed features of a malignant profile. Risk stratification according to the Modified Demicco and Salas criteria evinced comparable results. No discernible relationship however was highlighted between the immunohistochemical expression of BCOR, p53, and any significant SFT parameter. Conclusion Although SFTs are very rare substantially benign mesenchymal neoplasms, pathologists must be conversant with their histological diversity and be vigilant of their malignant attributes. The worth of STAT6 immunohistochemistry for precise diagnosis and long-term studies for delineating clinical behavior cannot be overemphasized.

Benign Solitary Fibrous Tumor of the Pleura

Solitary fibrous tumors of the pleura (SFTPs) are rare and typically benign neoplasms with limited reported cases. Despite their initial characterization as a pleura-based lesion, these neoplasms can occur in various anatomical locations. These tumors can present with paraneoplastic syndromes and have potential malignant transformations. Herein, we report a case of a 47-year-old female presenting with chest pain, cough, and weakness who was subsequently diagnosed with a benign SFTP. The patient required surgical intervention and underwent a wedge resection via video-assisted thoracoscopic surgery. The patient's recovery was uneventful, demonstrating effective management.

[Transoral robotic surgery in the management of solitary fibrous tumor at the entrance of the hypolaryngeal esophagus: a case report and literature review]

To explore the clinical diagnosis and treatment experience of isolated fibrotic tumor （SFT） occurring in the larynx, hypopharynx and esophageal inlet with a wide range.The patient, admitted to the Department of Otolaryngology-Head and Neck Surgery of Tangdu Hospital of Air Force Medical University was a female aged at 78 years, who was diagnosed with SFT primarily occured at laryngeal, hypopharynx and esophageal entrance. The clinical data, surgical methods, histopathology characteristics of the patient were analyzed respectively. It's proved that a tumor sized about 3.8 cm×2.8 cm×2.0 cm with slippy surface was found at the entrance of the laryngeal, hypopharynx and esophageal entrance, covering the laryngeal vestibule, glottis and right piriform fossa, which was completely resected by transoral robotic surgery. The postoperative pathological diagnosis was SFT. The patient recovered well after surgery and showed no recurrence within 16-month follow-up. SFT occurring in the larynx, hypopharynx, and esophageal inlet is very rare, and transoral da Vinci robotic surgical resection of the tumor in this area is feasible, and has the advantages of clear field of vision, less bleeding, less trauma, fewer complications, and quicker postoperative recovery.

Pulmonary Spindle Cell Carcinoma: As Rare as a Hen's Teeth

This case is about a 70-year-old man who presented with symptoms and laboratory reports that indicated differentials toward an infectious disease (pneumonia and tuberculosis). A lung mass was found in his chest X-ray and in the computerized tomography (CT) scan of his thorax. A biopsy was taken from the lung mass, and histopathological examination and immunohistochemical staining of the biopsy were done. The results revealed the presence of spindle cell carcinoma (SpCC) with vimentin and cytokeratin positivity. Spindle cell lung cancer is a rare type of non-small cell lung carcinoma, for which all available research indicates a poor prognosis. Due to the rarity of diagnosis, there is a dearth of information about the epidemiology and overall survival of affected patients.

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.

Solitary Fibrous Tumours of the Orbit - Clinical Pathology, Therapy and Prognosis

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.

Metastatic pancreatic solitary fibrous tumor: A case report

BACKGROUND

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that is most commonly found in the pleura but can also originate from non-pleural sites. Among the non-pleural localizations, the pancreas is extremely rare. In particular, metastasis to the pancreas from the central nervous system (CNS) is extremely rare, with only two cases reported so far. We report a case of recurrence in the pancreas 14 years after the initial complete surgical removal of a tumor in the CNS.

CASE SUMMARY

A 68-year-old man with a past medical history of recurrent meningeal hemangiopericytoma, currently referred to as SFT, presented to the hospital with jaundice. The patient was first diagnosed with an 8cm-sized meningeal hemangiopericytoma fourteen years ago and underwent osteoplastic craniotomy. After 16 mo, imaging showed recurrence and he underwent gamma knife radiosurgery (GKRS). 2 years later, imaging showed recurrence again leading to a second GKRS. 5 years later, recurrence was again suspected leading to a second craniotomy. Since then 3 years had passed, and imaging showed a 3.5cm-sized mass lesion on the pancreatic head with obstruction of the pancreatic and bile ducts. Endosonography with fine-needle aspiration biopsy was done preoperatively and aided in the diagnosis of SFT. The patient underwent pylorus-preserving pancreaticoduodenectomy. Pathologic findings of the resected pancreatic specimen, consistent with the previously resected brain specimen, confirmed the diagnosis of SFT.

CONCLUSION

The rarity and lack of knowledge about SFTs make suspecting and diagnosing this disease challenging. We believe that a report of metastatic pancreatic SFT from the CNS will contribute to a better understanding of this rare disease.

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

Adrenal Solitary Fibrous Tumor: A Case Report

Solitary fibrous tumor is a mesenchymal neoplasm that first appeared in the literature as a pleural lesion, but over the last decades, it has been reported in many extrathoracic sites. Primary solitary fibrous tumor in the adrenal gland is very uncommon. Its biological behavior is variable but mostly benign. We report here a case of an apparently healthy woman who, in the context of the study of limb paresthesias, was diagnosed with an adrenal incidentaloma. Laboratory tests were performed, and no hormone hyperfunction was detected. Subsequently, a right adrenalectomy was performed, and the pathological study confirmed a solitary fibrous tumor. To the best of our knowledge, this is the 19th case reported in the literature of a primary solitary fibrous tumor originating from the adrenal gland and, notably, the first documented instance in Spain.

Malignant retroperitoneal solitary fibrous tumor co-existing with Meigs' syndrome: A case report

Malignant solitary fibrous tumors in the retroperitoneum are rare, and their treatment strategies have not yet been established. A 61-year-old woman with dyspnea underwent laparotomy under a presumptive diagnosis of Meigs' syndrome. She underwent both adnexectomy and retroperitoneal tumor excision. The histologic diagnosis was of a fibrothecoma of both ovaries and a retroperitoneal solitary fibrous tumor that was considered malignant based on its mitotic activity. Local recurrence was observed 9 months postoperatively; re-excision was performed, and radiation therapy was administered. Four months later, metastasis to the left lung was detected, and a thoracoscopic resection was performed. Although pazopanib was administered subsequently, it was discontinued after 11 months because of proteinuria. She complained of dysphagia 3 weeks after the withdrawal of the drug, and a metastatic tumor was observed at the cranial base. Radiotherapy was initiated; however, she died of the disease 35 months after the primary surgery. Medical guidelines should be established for malignant solitary fibrous tumors to improve patient prognosis.

Solitary fibrous tumor in the temporalis muscle: a case report and literature review

Solitary fibrous tumor (SFT) is an infrequently occurring neoplasm most commonly observed in the pleura, but it can develop in the head and neck region in occasional cases. However, no reports have described SFT in the temporalis muscle. Herein, we present the first known case of SFT in the temporalis muscle. A 47-year-old man complained of a painless palpable mass on his right temple. Facial enhanced computed tomography identified a 4.0× 2.9× 1.4 cm mass presenting as a vascular tumor in the right temporalis muscle under the zygomatic arch. The mass was excised from the right temporalis muscle under general anesthesia. A histopathologic examination revealed that the mass was an SFT. No complications occurred after surgery, including functional disability or sensory loss. The patient was followed up for 3 months without complications. Although SFT in extrapulmonary regions is rare, it should be considered in the differential diagnosis of masses that occur in the temporal area.

Malignant Solitary Fibrous Tumor of the Inguinal Region: A Case Report

A solitary fibrous tumor (SFT) is a rare spindle cell neoplasm in adults, usually found in the pleural and thoracic cavities. We report an interesting case of a malignant solitary fibrous tumor in a 64-year-old male who presented with a history of swelling in his right inguinal region that gradually increased in size during the past three years. Computed tomography (CT) and magnetic resonance imaging (MRI) scans of the abdomen and pelvis showed a rounded solid mass originating from the right inguinal canal suggestive of sarcoma. Elective excision of the mass was done under general anesthesia with histopathology confirming the diagnosis of high-grade spindle cell sarcoma in keeping with a malignant solitary fibrous tumor. Postoperatively, the patient had no complications and was discharged on postoperative day 4. The patient was then treated with radiotherapy. He remained free of recurrence for two years postoperatively.

Solitary fibrous tumor developing in the right retroperitoneal space

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that is quite aggressive and prone to recurrence and metastasis. Most SFTs are benign, but the identification of the histological features that define the dedifferentiation of SFTs can predict the aggressiveness of the tumor and the presence of a reserved prognosis. We present a rare case of conventional SFTs with features of malignancy and highlight the diagnostic and therapeutic difficulties related to this case. Computed tomography aspect suggested a possible gastrointestinal stromal tumor. Surgical intervention was performed through median laparotomy and a tumor of approximately 15∕12 cm was found, developed from the level of the right retroperitoneal space, and pushing anteriorly the ascending colon, cecum, and terminal ileum. The immunohistochemical aspect correlated with the histopathological one suggests a SFT most likely malignant. In conclusion, the early diagnosis of SFTs is essential in establishing an appropriate treatment. Immunohistochemistry is indispensable in establishing the diagnosis of SFTs.

Surgical removal of an unusual huge solitary fibrous tumor in the mediastinum: a case report

BACKGROUND

Intrathoracic Solitary Fibrous Tumors (SFT) mainly arise from the pleura; however, these tumors may also originate from the mediastinum. We present a rare case of posterior SFT extending to several mediastinal sites and with an unusual large size, successfully treated with surgical resection.

CASE PRESENTATION

A 66-year-old female presented with an initial manifestation of ambiguous pain in the chest and dysphagia and later developed pitting edema in both lower extremities and cachexia five months before admission. Chest imaging confirmed a mediastinal mass (17 × 15 × 8 cm) which was surgically removed. Immunohistochemistry confirmed the diagnosis of a solitary fibrous tumor with positive B-cell lymphoma 2, STAT6, and CD99, negative S100 and smooth muscle actin, and low levels of Ki67 (5-7%). The patient's follow-up course was unremarkable.

CONCLUSION

Mediastinal SFTs may grow extremely huge, with the potential to invade multiple adjacent sites. Surgical removal of the tumor remains the mainstay of treatment in these cases.

Malignant solitary fibrous tumor of the urinary bladder progressing to widespread metastases and death: a rare case report and literature review

Solitary fibrous tumor (SFT) of the urinary bladder has been rarely reported and malignant bladder SFT is even rarer. Here we present a case of an African-American male with SFT of the urinary bladder (intermediate risk) initially treated by cystoprostatectomy at the age of 59 years. Eight years later, he developed recurrence with widespread metastases to the liver, lungs, and abdominal cavity. He then received temozolomide and bevacizumab with good disease control. However, treatment was paused due to declining performance status. Follow-up at 1 year demonstrated growth of the metastatic lesions. Despite restarting therapy, the patient expired, 11 years after the original diagnosis. Autopsy was performed and revealed widespread metastases within the abdominal cavity (abdominal sarcomatosis) as well as liver, bilateral lung, and diaphragmatic involvement. The cause of death was determined to be metastatic SFT. A comprehensive literature review was performed. Although SFTs are commonly considered benign, a subset of SFTs of the urinary bladder behave aggressively. Risk assessment and proper follow-up for recurrence and metastasis is necessary. The patient was also found at autopsy to have two gastrointestinal stromal tumors (GISTs) in the stomach and near the gastroesophageal junction. To the best of our knowledge, this is the first reported case of a primary urinary bladder SFT resulting in death or having concurrent, multifocal GISTs, and only the second case of a bladder SFT that developed metastases after the initial diagnosis.

B-cell lymphoma 2 family members and sarcomas: a promising target in a heterogeneous disease

Targeting the B-cell lymphoma 2 (Bcl-2) family proteins has been the backbone for hematological malignancies with overall survival improvements. The Bcl-2 family is a major player in apoptosis regulation and, has captured the researcher's interest in the treatment of solid tumors. Sarcomas are a heterogeneous group of diseases, comprising several entities, with high morbidity and mortality and with few specific therapies available. The treatment for sarcomas is based on platinum regimens, with variable results and poor outcomes, especially in advanced lesions. The high number of different sarcoma entities makes treatment standardization as well as the performance of clinical trials difficult. The use of Bcl-2 family members modifiers has revealed promising results in in vitro and in vivo models and may be a valid option, especially when used in combination with chemotherapy. In this article, a revision of these results and possibilities for the use of Bcl-2 family members inhibitors in sarcomas was performed.

Rare Solid Pancreatic Lesions on Cross-Sectional Imaging

Several solid lesions can be found within the pancreas mainly arising from the exocrine and endocrine pancreatic tissue. Among all pancreatic malignancies, the most common subtype is pancreatic ductal adenocarcinoma (PDAC), to a point that pancreatic cancer and PDAC are used interchangeably. But, in addition to PDAC, and to the other most common and well-known solid lesions, either related to benign conditions, such as pancreatitis, or not so benign, such as pancreatic neuroendocrine neoplasms (pNENs), there are solid pancreatic lesions considered rare due to their low incidence. These lesions may originate from a cell line with a differentiation other than exocrine/endocrine, such as from the nerve sheath as for pancreatic schwannoma or from mesenchymal cells as for solitary fibrous tumour. These rare solid pancreatic lesions may show a behaviour that ranges in a benign to highly aggressive malignant spectrum. This review includes cases of an intrapancreatic accessory spleen, pancreatic tuberculosis, solid serous cystadenoma, solid pseudopapillary tumour, pancreatic schwannoma, purely intraductal neuroendocrine tumour, pancreatic fibrous solitary tumour, acinar cell carcinoma, undifferentiated carcinoma with osteoclastic-like giant cells, adenosquamous carcinoma, colloid carcinoma of the pancreas, primary leiomyosarcoma of the pancreas, primary and secondary pancreatic lymphoma and metastases within the pancreas. Therefore, it is important to determine the correct diagnosis to ensure optimal patient management. Because of their rarity, their existence is less well known and, when depicted, in most cases incidentally, the correct diagnosis remains challenging. However, there are some typical imaging features present on cross-sectional imaging modalities that, taken into account with the clinical and biological context, contribute substantially to achieve the correct diagnosis.

Malignant Extrapleural Solitary Fibrous Tumor

Solitary fibrous tumors (SFTs) are rare spindle cell neoplasms of mesenchymal origin that are most commonly found in the pleura, although they have also been documented in extrapleural locations. SFTs affect males and females in equal distribution, and they typically occur between the fourth and seventh decades of life. Since SFTs are usually benign and asymptomatic, the majority of them are discovered incidentally on computed tomography (CT) or magnetic resonance imaging (MRI) imaging, unless they grow to a size that causes mass effect symptoms on other organs. Nonetheless, imaging is not sufficient to diagnose an SFT, and therefore, biopsy is recommended for further analysis. Advances in immunohistochemistry and molecular diagnostics have identified CD34 and NAB2-STAT6, respectively, as the most consistent markers for SFTs. The risk of SFT metastasis can be determined through the use of a four-variable risk-stratification model developed by Demicco et al., which is based upon the risk factors of patient age, tumor size, mitotic count per 10 high-power fields, and the degree of tumor necrosis. The management of SFTs involves a wide surgical resection of the tumor while preserving surrounding organs and structures. Post-operative surveillance involves imaging the primary tumor site for up to five years due to the risk of local recurrence. At this time, neither radiation therapy nor chemotherapy after resection have yet to show benefit, and therefore, they are not currently recommended. This case report discusses the management of a 68-year-old woman who was diagnosed with a malignant extrapleural SFT in her right medial upper thigh.

Recurrent Solitary Fibrous Tumor in a 73-Year-Old Male Presenting With Small Bowel Obstruction: A Case Report

Solitary fibrous tumors (SFTs) are rare soft tissue tumors that can arise in the abdomen, pleura, and central nervous system, among other sites. Surgical resection is the mainstay of management, although recurrence rates remain substantial. This case describes a 73-year-old male treated surgically for both a recurrent SFT and small bowel obstruction (SBO) secondary to adhesions. The patient had undergone numerous intra-abdominal operations for malignant SFT since 1994, highlighting the importance of meticulous resection at the initial presentation of local disease.

A diagnostic challenge; pelvic solitary fibrous tumor (SFT) mimicking Peri-Anal gastrointestinal stromal tumor (GIST): A case report

Key Clinical Message

The study reports a rare case of pelvic solitary fibrous tumor (SFT) that was initially considered as a peri-anal gastrointestinal stromal tumor due to similar radiologic/pathologic features. SFT diagnosis can be challenging due to its rarity and wide range of diagnoses that must be ruled out precisely.

Abstract

Solitary fibrous tumors (SFTs) are rare tumors that can occur in any part of the body. Although usually benign, malignant SFTs have been reported, especially outside the lungs. Radiology can help with diagnosis, but immunohistochemistry is necessary to distinguish SFTs from other possible diagnoses such as gastrointestinal stromal tumors (GISTs). This study presents a rare case of pelvic SFT initially considered to be a peri-anal GIST, highlighting the importance of accurate diagnosis given the rarity of SFTs and the need to rule out other potential diagnoses.

Reduction of Tumor Growth with RNA-Targeting Treatment of the NAB2-STAT6 Fusion Transcript in Solitary Fibrous Tumor Models

Solitary fibrous tumor (SFT) is a rare soft-tissue sarcoma. This nonhereditary cancer is the result of an environmental intrachromosomal gene fusion between NAB2 and STAT6 on chromosome 12, which fuses the activation domain of STAT6 with the repression domain of NAB2. Currently there is not an approved chemotherapy regimen for SFTs. The best response on available pharmaceuticals is a partial response or stable disease for several months. The purpose of this study is to investigate the potential of RNA-based therapies for the treatment of SFTs. Specifically, in vitro SFT cell models were engineered to harbor the characteristic NAB2-STAT6 fusion using the CRISPR/SpCas9 system. Cell migration as well as multiple cancer-related signaling pathways were increased in the engineered cells as compared to the fusion-absent parent cells. The SFT cell models were then used for evaluating the targeting efficacies of NAB2-STAT6 fusion-specific antisense oligonucleotides (ASOs) and CRISPR/CasRx systems. Our results showed that fusion specific ASO treatments caused a 58% reduction in expression of fusion transcripts and a 22% reduction in cell proliferation after 72 h in vitro. Similarly, the AAV2-mediated CRISPR/CasRx system led to a 59% reduction in fusion transcript expressions in vitro, and a 55% reduction in xenograft growth after 29 days ex vivo.

Robot-assisted laparoscopic removal of an extraperitoneal pelvic solitary fibrous tumor

•Pelvic SFTs are rare, typically benign soft tissue neoplasms that pose a diagnostic challenge for gynecologists.•Retroperitoneal pelvic SFTs can mimic gynecologic malignancies and should be considered in diagnosis of a solitary pelvic mass.•Pathologic diagnosis is typically confirmed by immunohistochemistry staining positively for CD34 and STAT6.•Complete surgical excision is recommended for these tumors and can be completed with a minimally invasive approach.•Close long-term follow-up is necessary due to possible recurrence or metastasis, especially for high-risk pathologic features.

Solitary Fibrous Tumor of the Prostate Shown on FAPI PET/CT

ABSTRACT

Solitary fibrous tumors are fibroblast tumors that occur mainly in the peritoneum, extremities, and pleura. Here, we report the MRI, FDG PET/CT, and FAPI PET/CT findings of a rare prostate solitary fibrous tumor. A 57-year-old man was pathologically diagnosed with a solitary fibrous tumor. To detect any systemic metastases or other primary lesions, the patient underwent FDG PET/CT and FAPI PET/CT examination sequentially. Mild FDG uptake was observed in the primary prostatic lesion, but there was a significant uptake of FAPI in the prostate. This case highlighted that FAPI PET/CT may outperform FDG PET/CT in identifying solitary fibrous tumors.

Chitinase 3-like 1 induces cancer cell migration in solitary fibrous tumors

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that is diagnosed through the detection of the NAB2-STAT6 fusion gene. SFT rarely progresses to malignant tumors; however, metastasis is exhibited in approximately 20% of patients with SFT. In this study, we found that chitinase 3-like 1 (CHI3L1), which induces cancer cell migration, was upregulated in NIH-3T3 cells that were transfected with the NAB2-STAT6 fusion gene. Moreover, the expression levels of the migration markers MMP2 and MMP9 were increased and the p-Akt level was also upregulated. In addition, it was observed that when CHI3L1 siRNA was transfected into NAB2-STAT6-transfected cells, cell migration and proliferation were reduced. Therefore, this study demonstrated that CHI3L1 activates Akt signaling to induce cell migration.

Translocations and Gene Fusions in Sinonasal Malignancies

PURPOSE OF REVIEW

During the past few years there has been an expansion in our understanding of gene fusions and translocations involved in cancer of the sinonasal tract. Here we review the downstream biologic effects, clinical characteristics, and pathologic features of these tumors. The molecular consequences and neo-antigens resulting from these chromosomal aberrations are considered and targets for current and future clinical trials discussed.

RECENT FINDINGS

Several new, clinically relevant, chromosomal aberrations have been discovered and evaluated to varying degrees in sinonasal tumors including DEK::AFF2, BRD4::NUT, ADCK4::NUMBL, and ETV6::NTRK3. Sinonasal malignancies demonstrate a diverse genetic landscape and varying clinical courses. Recent studies illustrate that gene fusions and translocations may play a role in carcinogenesis in certain sinonasal tumor subtypes and may be used to develop new biomarker-driven and patient-centered treatments.

68 Ga-PSMA-Avid Intranasal Solitary Fibrous Tumor

ABSTRACT

The utility of molecular imaging in solitary fibrous tumors has not been fully established. We present a rare case of recurrent intranasal solitary fibrous tumor incidentally localized on 68 Ga-PSMA PET/CT scan, which turned out to be metabolically inactive on 18 F-FDG PET/CT.

Solitary Fibrous Tumor of the Peritoneal Cavity and Greater Omentum: Case Report and Review of the Literature

Background

The solitary fibrous tumor is a rare soft tissue mesenchymal tumor which typically arises from the pleura but may be found anywhere in the body. Abdominal localizations are very rare. The solitary fibrous tumor is classified into two forms, pleural and extrapleural, and morphologically they resemble each other. The diagnostics of the tumor is usually accidental because usually there are no clinical symptoms. The main treatment of the solitary fibrous tumor is the surgical removal of the tumor while radiotherapy treatment and chemotherapy outcomes remain unclear due to the rarity of the tumor and lack of data.

Case presentation

We report the case of the 32-year-old man who was diagnosed with the solitary fibrous tumor of the peritoneal cavity. Laparotomy was performed. A grayish-white, stiff, coarse-grained tumor about 11 cm in diameter of the greater omentum was found and radical omentectomy with tumor removal were performed. Postoperative course was uneventful and the patient is well with no signs of recurrence on the CT scan of the chest and abdomen and MRI of the pelvis at 6 months after surgery.

Conclusions

The solitary fibrous tumor is a rare condition. It is a borderline-malignant tumor but may cause serious complications if not treated. Due to the absence of clinical symptoms, the tumor is usually detected accidentally. The radical surgical removal of the tumor is the most optimal treatment.

Bilobed flap reconstruction after en-bloc removal of solitary fibrous tumor of the lacrimal sac

Purpose

To report a rare case of a solitary fibrous tumor (SFT) of the lacrimal sac and discuss considerations for management of similar cases.

Observations

We present the case of a 41-year-old woman who presented with a primary lacrimal sac SFT for which she underwent en-bloc surgical resection. We discuss management options for SFTs and our surgical approach for this case: bilobed flap reconstruction of the medial canthus and inferior orbit.

Conclusions

We present an uncommon presentation of a rare tumor and a successful one-stage reconstruction with a bilobed flap.

A Rare Case of Solitary Fibrous Tumor of Maxilla: Findings on F-18 FDG and Ga-68 DOTANOC PET-CT

Solitary fibrous tumor (SFT) is a rare tumor of mesenchymal origin that most commonly involves the pleura but can be found anywhere in the body. SFT can range from indolent benign tumors to aggressive malignant tumors, and pre-operative diagnosis is based mainly on imaging. In this case report, we describe an extremely rare case of SFT of left maxilla on F-18 FDG PET-CT and Ga-68 DOTANOC PET-CT. Very few cases of PET-CT findings in SFT are reported in literature; and to our knowledge, none involving the maxilla. By highlighting the findings on F-18 FDG and GA-68 DOTANOC PET-CT, we aim to further add on to the role of both the tracers in the diagnosis and management of this tumor group.

Solitary Fibrous Tumors of the Lung: A Clinicopathological Analysis of 52 Cases

OBJECTIVE

To explore the clinicopathological features of solitary fibrous tumors (SFTs) of the lung.

METHODS

We collected the clinical data of 52 patients with SFTs of the lung confirmed by pathology, and summarized the clinical, radiological, and morphological features, the immunophenotypes, and the prognosis of SFTs.

RESULTS

Fifty-two cases of SFTs of the lung were enrolled in this study, including 51 cases of borderline and 1 case of malignancy, 22 males and 30 females. The average onset age was 52.7 years. The lower lobe of the left lung was the preferred site of SFTs, accounting for 30.77% (16/52). Chest CT showed regular and well-demarcated soft tissue density mass, and the tumor size of most cases (46/52, 88.46%) was 1-10 cm. Morphological features: The distribution of tumor cells showed sparse and dense areas. Tumor cells were spindle-shaped, in whorls or hemangiopericytoma-like conformation. Atypia, mitotic figures, and necrosis were found. Immunohistochemistry showed positive expression of CD34, STAT6, Vimentin, BCL2, and CD99. Ki-67 was ≤ 5% in borderline SFTs and >20% in a malignant SFT.

CONCLUSIONS

Solitary fibrous tumors of the lung occur more frequently in middle-aged and elderly people, and there is no significant difference in gender. The lower lobe of the left lung is the preferred site of SFTs. The size of most SFTs is 1-10 cm. Chest CT shows morphologically regular and well-demarcated soft tissue density mass. Pathologically, SFTs of the lung are mostly borderline and occasionally malignant. Immunohistochemistry shows the positive expression of CD34, STAT6, Vimentin, BCL2, and CD99.

Malignant Solitary Fibrous Tumours of the Pleura Are Not All the Same: Analysis of Long-Term Outcomes and Evaluation of Risk Stratification Models in a Large Single-Centre Series

Introduction: Malignant solitary fibrous tumours of the pleura (mSFTP) are extremely rare diseases (<5% of all pleural neoplasms) with unpredictable behaviour. Surgery remains the standard of care for these tumours; however, estimating patient prognosis and planning follow-up remain challenging. Several risk stratification models have been proposed, but a classification with diagnostic and prognostic potential has not been well standardised yet. The aim of this study was to analyse the clinicopathological data of mSFTP to investigate their prognostic features and to compare the performance of three risk stratification models proposed in the literature. Methods: Observational retrospective cohort study on all proven cases of mSFTP surgically resected with radical intent between 2000 and 2019 in a single centre. Demographic, surgical and pathological data were examined. All patients were risk-stratified by using three prediction models: modified Demicco, De Perrot and Tapias. Overall survival (OS) and disease-free survival (DFS) were analysed. Results: There were 21 men and 13 women (median age, 67 years, range, 23-83 years). Twenty-one patients (62%) were symptomatic. The median follow-up was 111 months (range, 6-258 months). The 5-year OS and DFS were 81.2% and 77.4%, respectively. Nine patients (26.5%) experimented recurrences. At univariate analysis, the presence of necrosis (p = 0.019), nuclear atypia (p = 0.006), dimension greater than 11.5 cm (median value of our cohort) (p = 0.037) and relapse/disease progression (p = 0.001) were independent prognostic factor of worse OS. The administration of adjuvant treatment was a protective independent factor for survival (p = 0.001). Radicality of resection (p = 0.005); tumour dimension (p = 0.013), presence of necrosis (p = 0.041) and nuclear atypia (p = 0.007) and pleural pattern (p = 0.011) were independent prognostic factors of worse DFS. Analysing the three risk stratification models, the Tapias score was revealed as the best index to predict both OS (p = 0.002) and DFS (p = 0.047) in patients with mSFTP. Conclusions: Using the risk stratification model proposed by Tapias, patients with the highest risk of recurrence could be identified at the time of surgery to establish a more frequent imaging surveillance and longer follow-up. The role of adjuvant treatment in mSFTP therapy has not been established yet, but further analysis on patients with a high risk of recurrence, stratified according to risk models, along with biomolecular panels may tailor future post-surgical therapies.

Doege-Potter syndrome in a patient with a giant abdominal solitary fibrous tumor: a case report and review of the literature

A 63-year-old man with spells of reduced consciousness in the morning and a giant abdominal mass presented to our institution for a second opinion. Investigation revealed non-diabetic hypoinsulinemic hypoglycemic events. Removal of the abdominal mass solved the hypoglycemia. Anatomopathological examination confirmed a solitary fibrous tumor (SFT). Doege-Potter syndrome was diagnosed. Doege-Potter syndrome is a potentially life-threatening rare paraneoplastic syndrome characterized by recurrent hypoinsulinemic hypoglycemia due to the overproduction of a prohormone form of insulin-like growth factor-II (pro-IGF-II) from a solitary fibrous tumor. First, we describe the clinical, laboratory and radiologic findings of the case. Second, a brief literature review on Doege-Potter syndrome is provided.

Solitary fibrous tumor of the central nervous system invading and penetrating the skull: A case report

Solitary fibrous tumor (SFT) of the central nervous system is a rare spindle cell tumor of mesenchymal origin. The present study reports the case of a 44-year-old male patient with SFT. Magnetic resonance imaging demonstrated that the majority of the intracranial tumors exhibited uneven low signals on T1-weighted imaging (T1WI) and low mixed signals on T2WI, and there was an enhancement on enhanced scanning. Furthermore, the distal part of the left occipital lobe exhibited hypersignals on T1WI and T2WI, and this was significantly enhanced following enhanced scanning. The lower part of the scalp exhibited low signals on T1WI and high signals on T2WI, and there was no notable enhancement following enhanced scanning. Magnetic resonance spectroscopy demonstrated an elevated choline/creatine peak in the solid part of the tumor. Under the microscope, the tumor exhibited characteristic 'staghorn-shaped' blood vessels. As SFT is difficult to differentially diagnose via imaging, immunohistochemical analysis of CD34, vimentin and signal transducer and activator of transcription 6 was performed for the definitive diagnosis of SFT. Of note, surgical resection was the preferred treatment for SFT; however, due to the rarity of the tumor, subsequent adjuvant therapy and prognosis require further investigation.

Metastasis of a Solitary Fibrous Tumor in the Mandible: A Case Report

BACKGROUND/AIM

The solitary fibrous tumor (SFT) is a mesenchymal neoplasm and belongs to the group of soft tissue sarcomas. The SFT is characterized by indolent, slowly progressive growth and manifests itself clinically by compression of neighboring structures. The treatment of choice is surgical removal of the tumor. In advanced stages, there is also the possibility of chemotherapy, systemic therapy, or immunotherapy, as well as radiotherapy. Depending on their location and severity, SFTs show different recurrence rates and survival functions.

CASE REPORT

The present case report shows an extremely rare localization of a low-risk SFT in the floor of the mouth. Despite complete surgical removal of the SFT, the patient showed a metastasis of the SFT in the mandible two years postoperatively. Therefore, this case report shows that even a low-risk SFT in the localized stage can metastasize despite of total surgical removal. Consequently, SFTs of the head and neck region require close clinical and imaging follow-up.

CONCLUSION

Although the localization of the SFT in the oral cavity is a rarity, this entity should be included in the differential diagnosis in the case of long-term space-occupying processes in the head and neck region. This report is the first regarding metastasis of a SFT to the mandible.

Solitary Fibrous Tumor of Hard Palate: A Case Report and Literature Review

Solitary fibrous tumor (SFT) is a mesenchymal tumor accounting for less than 2% of soft tissue tumors and has variable clinical behavior. It can arise in many anatomical locations of the body and in rare occasions in the oral cavity mostly in buccal mucosa and tongue. To date, a handful of such cases have been reported in the hard palate. We present a case of SFT in the hard palate of a 32-year-old man and describe the tissue morphology, immunohistochemistry workup, and follow-up together with literature review.

Primary Intracranial Solitary Fibrous Tumor With Metachronous Pulmonary and Bone Metastasis: A Case Report

An intracranial solitary fibrous tumor (SFT) is a rare and aggressive tumor with a high propensity for locoregional recurrence and distant metastasis. The formerly used collective term for this tumor, "solitary fibrous tumor/hemangiopericytoma", has recently fallen out of use and is now commonly replaced with the term "solitary fibrous tumor". We describe a rare case of intracranial SFT with simultaneous metastasis to the spine, the right humerus, and the lungs four years after resection and radiotherapy of the primary tumor.