The many faces of solitary fibrous tumor; diversity of histological features, differential diagnosis and role of molecular studies and surrogate markers in avoiding misdiagnosis and predicting the behavior

Solitary fibrous tumor: A case report of this multifaceted tumor

BACKGROUND

Solitary fibrous tumor (SFT) is a remarkably uncommon mesenchymal tumor. STAT6 level and a combination of clinical, pathological, and molecular features are required to arrive at a proper diagnosis.

CASE SUMMARY

In this report, we present an intriguing case involving a 43-year-old woman who initially exhibited symptoms of a bleeding retroperitoneal tumor, initially resembling a gastrointestinal stromal tumor, but later confirmed as an SFT. However, a year later, what was initially believed to be a recurrence of her SFT was instead identified as a desmoid tumor.

CONCLUSION

Distinguishing SFT from other tumors was pivotal. Correcting misdiagnoses of tumor type initially and of recurrence later was necessary for appropriate treatment of the correct desmoid type.

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

INTRODUCTION

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

CASE PRESENTATION

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

DISCUSSION

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

CONCLUSION

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

Case of submandibular schwannoma and review of literature

Schwannomas are slow growing, benign tumours arising from Schwann cells. They are usually solitary and are sometimes associated with Neurofibromatosis type 1 and 2. As reported by Okada et al., while approximately 25%-40% of extra-cranial schwannomas occur in the head and neck region, Schwannomas of the oral cavity are very uncommon, accounting for only 1% of all Schwannomas. We report a case of a sublingual schwannoma in a 47-year-old female, discovered incidentally during the workup for tinnitus. The radiological and histopathological findings, along with a literature review, are presented.

Total management of hemangiopericytoma/solitary fibrous tumor of the buttock: A case report

BACKGROUND

Solitary fibrous tumors can manifest at various anatomical sites, predominantly occurring at extrapleural sites with a peak incidence between 40 and 70 years. SFT necessitates long-term follow-up owing to its tumor characteristics. However, comprehensive reports covering the period from initial diagnosis to the patient's demise are lacking. Herein, we present a case of a malignant SFT of the buttocks that was treated at our hospital from the time of initial diagnosis to the end of life, with a literature review.

METHODS

A 54-year-old woman had a T1 low-to-isobaric and T2 isobaric-to-hyperintense mass in the psoas muscle on magnetic resonance imaging, diagnosed as an SFT. Wide excision was performed, followed by postoperative radiotherapy and chemotherapy. Multiple lung metastases were treated, while bone metastases appeared in the left femur. Multiple spinal metastases developed, causing respiratory distress due to pleural effusion. Best support care was initiated; however, a thrombus appeared in the inferior vena cava. Despite anticoagulant therapy, the patient died 11 years and 6 months after the initial surgery. Herein, marginal resection resulted in a relatively short operative time and average blood loss. The radiotherapy dose was 66 Gy; no complications occurred, and local recurrence was prevented. Tumor arthroplasty was performed to stabilize the affected limbs, and the patient required careful follow-up.

RESULTS

Despite the poor prognosis, the patient survived >11 years after surgery and had a favorable outcome.

CONCLUSION

Long-term monitoring for potential complications remains necessary.

Evaluation of preoperative magnetic resonance imaging features and diagnostic effectiveness of grades II and III intracranial solitary fibroma

OBJECTIVES

To explore the value of preoperative magnetic resonance imaging (MRI) characterization of intracranial solitary fibrous tumors (ISFT) and to evaluate the effectiveness of preoperative MRI features in predicting pathological grading.

MATERIALS AND METHODS

This retrospective analysis comprised the clinical and preoperative MRI characterization of 55 patients with ISFT in our hospital, including 27 grade II cases and 28 grade III cases confirmed by postoperative pathology. Variables included age, sex, tumor location, cross-midline status, signal characteristics of T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), T2-fluid-attenuated inversion recovery (T2-FLAIR), and diffusion‑weighted imaging (DWI), peritumoral edema, intralesional hemorrhage, focal necrosis/cystic degeneration, tumor empty vessel, maximum tumor diameter, maximum, minimum, and average values of apparent diffusion coefficient (ADCmax, ADCmin, and ADCmean), tumors enhancement mode, meningeal tail sign, skull invasion, cerebral parenchymal invasion, and venous sinus involvement. The independent samples t test or Mann-Whitney U test was performed to compare continuous data between the two groups, and the Pearson chi-squared test or Fisher's exact test was used to compare categorical data. In addition, bivariate logistic regression was performed to construct a comprehensive model, and receiver operating characteristic (ROC) curves were generated to calculate the areas under the curve (AUCs), thereby determining the value of each parameter in the differential diagnosis of grades II and III ISFT.

RESULTS

The mean age at onset was similar between patients with grades II and III ISFT (46.77 ± 14.66 years and 45.82 ± 12.07 years, respectively). The proportions of men among patients with grades II and III ISFT were slightly higher than those of female patients (male/female: 1.25 [15/12] and 1.33 [16/12], respectively). There were significant differences between grades II and III ISFT in the T2-FLAIR and DWI signal characteristics, maximum, minimum, and average values of the apparent diffusion coefficient (ADCmax, ADCmin, and ADCmean), tumor location, and skull invasion (P = 0.001, P = 0.018, P = 0.000, P = 0.000, P = 0.000, P = 0.010, and P = 0.032, respectively). However, no significant differences were noted between grades II and III ISFT in age, sex, cross-midline status, T1WI and T2WI signal characteristics, peritumoral edema, intralesional hemorrhage, focal necrosis/cystic degeneration, tumor empty vessel shadow, enhancement mode, meningeal tail sign, maximum tumor diameter, brain parenchyma invasion, or venous sinus involvement (all P > 0.05). Moreover, binary logistic regression analysis showed that the model accuracy was 89.1% when ADCmin was included in the regression equation. Moreover, ROC curve analysis showed that the AUC of ADCmin was 0.805 (0.688, 0.922), sensitivity was 74.1%, specificity was 75.0%, and the cutoff value was 672 mm2/s.

CONCLUSIONS

Grade III ISFT patients displayed more mixed T2-FLAIR signal characteristics and DWI signal characteristics than grade II patients, as shown by higher skull invasion and tumor mass collapse midline distribution and lower ADCmax, ADCmean, and ADCmin values. The ADCmin value was significant in the preoperative assignment of grades II and III ISFT, thereby contributing to enhanced accuracy in the imaging grading diagnosis of the disease.

Case report: A huge retroperitoneal solitary fibrous tumor closely related to the external iliac vessels misdiagnosed as an ovarian tumor

Background

Solitary fibrous tumor (SFT) is a rare soft tissue tumor originating from mesenchymal cells. Thus far, there have been no reported cases of SFT closely related to the iliac vessels.

Case presentation

An elderly woman was found to have had a lower abdominal mass for more than 20 years. The enhanced computerized tomography (CT) showed a progressively enhanced hypervascular mass. The external iliac blood vessels were closely related to the mass, which was misdiagnosed as an ovarian tumor. During laparotomy, the external iliac vein was seen to penetrate the tumor, and the external iliac artery was seen to penetrate the tumor capsule. The retroperitoneal tumor was diagnosed during the operation. The surgical plan of complete tumor resection, severing of the external iliac arteries and veins, and blood vessel replacement was implemented. Pathological immunohistochemistry showed positive results for STAT6 and CD34, confirming the diagnosis of giant retroperitoneal SFT. The risk is classified as high and requires long-term follow-up. There has been no local recurrence or distant metastasis almost 1 year after surgery.

Conclusion

The incidence of giant retroperitoneal SFT is rare, and the diagnosis can be confirmed through preoperative imaging examination and pathological examination. If the SFT capsule is intact, there is a chance of surgical resection. For SFTs that are penetrated by the iliac blood vessels, adequate preparation must be made before the surgery is performed. Removing the tumor and the iliac blood vessels at the corresponding site and then replacing it with artificial blood vessels is a feasible method with less risk of bleeding. In this case, imaging showed a progressively enhancing hypervascular mass in the lower abdomen, which was related to blood vessels. Preoperative biopsy and pathological testing can confirm the diagnosis. Neoadjuvant therapy or interventional therapy before surgery can shrink the tumor, making the surgical procedure relatively easy with less risk of bleeding.

Radiologic Features of Well-circumscribed Orbital Tumors With Histopathologic Correlation: A Multi-center Study

PURPOSE

To delineate specific imaging characteristics of solitary fibrous tumors, schwannomas, cavernous venous malformations, and well-circumscribed orbital lymphoma.

METHODS

Patients undergoing excisional biopsy of solitary fibrous tumor, schwannomas, cavernous venous malformations, or well-circumscribed orbital lymphoma with preoperative MRIs available for review were identified at 3 academic centers in the United States and Australia. An exploratory statistical analysis was performed to identify important radiologic features, which were subsequently included in a random forest model. Histopathologic correlates were evaluated in representative cases.

RESULTS

A total of 91 cases were included with a mean age of 52.9 ± 17.2 years. Nearly all solitary fibrous tumors were located in the anterior or mid orbit (87.5%) and they more commonly demonstrated intralesional heterogeneity on T2-weighted imaging (45.5%) ( p < 0.01). Compared with the other tumors, schwannomas tended to be intraconal (66.7%) and were often in the mid or posterior orbit (83.4%) ( p < 0.01). Cavernous venous malformations characteristically demonstrated progressive contrast enhancement (93.9%; p < 0.01). Most lesions in all 4 groups were hypointense on T1-weighted imaging (80%-100%; p = 0.14) and only well-circumscribed orbital lymphoma tended to also be hypointense on T2 (81.8%) ( p < 0.01). Finally, cases of lymphoma had significantly lower apparent diffusion coefficient ratios (0.9 ± 0.2) ( p < 0.001), while the other 3 groups were not significantly different from one another (cavernous venous malformations: 1.8 ± 0.4; schwannomas: 1.8 ± 0.5; and solitary fibrous tumor: 1.6 ± 0.6) ( p = 0.739).

CONCLUSIONS

Key features that aid in the differentiation of these 4 tumors from one another include T2 intensity and homogeneity, early contrast-enhancement pattern, and ADC ratio.

Giant intrapulmonary solitary fibrous tumor

Solitary fibrous tumor (SFT) is a soft tissue tumor of mesenchymal origin involving, most commonly, the pleura. Intrapulmonary SFT is a slow-growing tumor that rarely reaches giant forms. SFTs are asymptomatic and often randomly discovered by routine chest X-rays. The diagnosis requires histopathological and immunohistochemical (IHC) examinations. Most of the SFTs are benign and present an indolent course. Larger tumors are more likely to be malignant and consequently associated with a worse prognosis. Despite having histopathological criteria for malignancy, the behavior of SFTs is challenging to predict. We report a case of giant intrapulmonary SFT of intermediate risk.

Inflammatory myofibroblastic tumor from molecular diagnostics to current treatment

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm with intermediate malignancy characterized by a propensity for recurrence but a low metastatic rate. Diagnostic challenges arise from the diverse pathological presentation, variable symptomatology, and lack of different imaging features. However, IMT is identified by the fusion of the anaplastic lymphoma kinase (ALK) gene, which is present in approximately 70% of cases, with various fusion partners, including ran-binding protein 2 (RANBP2), which allows confirmation of the diagnosis. While surgery is the preferred approach for localized tumors, the optimal long-term treatment for advanced or metastatic disease is difficult to define. Targeted therapies are crucial for achieving sustained response to treatment within the context of genetic alteration in IMT. Crizotinib, an ALK tyrosine kinase inhibitor (TKI), was officially approved by the US Food and Drug Administration (FDA) in 2020 to treat IMT with ALK rearrangement. However, most patients face resistance and disease progression, requiring consideration of sequential treatments. Combining radiotherapy with targeted therapy appears to be beneficial in this indication. Early promising results have also been achieved with immunotherapy, indicating potential for combined therapy approaches. However, defined recommendations are still lacking. This review analyzes the available research on IMT, including genetic disorders and their impact on the course of the disease, data on the latest targeted therapy regimens and the possibility of developing immunotherapy in this indication, as well as summarizing general knowledge about prognostic and predictive factors, also in terms of resistance to systemic therapy.

Solitary fibrous tumor within the mesorectum: literature review based on a case report of resection by transanal minimally invasive surgery (TAMIS)

PURPOSE

Solitary fibrous tumors (SFT) are a rare entity of in majority benign neoplasms. Nevertheless, up to 20% of cases show a malignant tendency with local infiltration or metastasis. Commonly arising in the thoracic cavity, only few cases of SFT of the mesorectal tissue have been reported in the literature. Complete surgical resection, classically by posterior approach, is the treatment of choice. The purpose of this review is to demonstrate the safety and suitability of transanal minimally invasive surgery (TAMIS) as a surgical approach for the resection of benign pararectal solid tumors.

METHODS

We report the case of a 52-year-old man who was diagnosed incidentally with SFT of the distal mesorectum. Resection by TAMIS was performed. Based on this case, we describe the steps and potential benefits of this procedure and provide a comprehensive review of the literature.

RESULTS

Histopathology confirms the completely resected SFT. After uneventful postoperative course and discharge on day four, follow-up was recommended by a multidisciplinary board by clinical examination and MRI, which showed a well-healed scar and no recurrence up to 3 years after resection.

CONCLUSION

SFT of the mesorectum is a very rare entity. To our knowledge, this is the first report on a TAMIS resection for SFT, demonstrated as a safe approach for complete resection of benign pararectal solid tumors.

Reconstruction of Midface Defects after Radical Tumor Resection - a Rare Case Report of Solitary Fibrous Tumour of the Hard Palate

Introduction- Spindle cell neoplasm is a variant of squamous cell carcinoma. One of its subtypes is solitary fibrous tumor. Its occurrence in head and neck is very rare and rarer in hard palate. But if occurs, radical excision is the only choice as it has malignant potential but coverage of such large mid face defects imposes a challenge in front of a Plastic Surgeon as it demands both soft tissue coverage and skeletal support. Report of the case- A 33 year male presented to our department with swelling of left side face involving the anterior palate, maxilla, nose, and upper lip. With the help of the surgical oncology team, wide local excision of the neoplasm along with bilateral infrastructure maxillectomy, total rhinectomy, total upper lip resection and total hard palatectomy was done. This created large defect in the mid face which was covered with free anterolateral thigh flap. Biopsy was done which revealed the swelling as a solitary fibrous tumor of hard palate. All the margins were free of tumour. The flap settled well. Nostrils were secured with nasal stents. After 3 months, an expander was placed in forehead of the patient for future nasal reconstruction. After 3 months, nasal reconstruction was done using expanded forehead flap and costal cartilage. After 21 days flap detachment and insetting was done. White roll creation was also done. One more secondary procedure was done for flap thinning as patient had complain of nasal obstruction. After 6 months vascularised free fibula bone graft was introduced to reconstruct maxilla for future dental rehabilitation. The patient is in regular follow up and he is satisfied with the results. Discussion- Mid face defects involving perioral and nasomaxillar areas are very uncommon and require composite reconstruction. In such cases, microvascular free flap coverage is an irreplaceable option. Multiple stages might have to be done for further refinement. Conclusion- Reconstruction after oncological resection is always very demanding. With proper preoperative planning and skilled execution, the patient can be benefited functionally, aesthetically and psychosocially.

Orbital Solitary Fibrous Tumor in a Commercial Airline Pilot

BACKGROUND: In the literature, central serous retinopathy (CSR) accompanying solitary fibrous tumors (SFT) in a pilot has not been reported. In airline pilots, mass effect-related symptoms such as diplopia, ptosis, etc., seen with orbital tumors may endanger flight safety.CASE REPORT: A 62-yr-old male commercial airline pilot presented with blurred vision in the right eye. He had been receiving treatment for 2 mo because of CSR. His visual acuity was 10/20 in the right eye and 20/20 in the left. During examination, ptosis and exophthalmos were noticed in the right eye. Ocular movements were free in all cardinal directions and there was downward displacement in the right eye. There was no diplopia. Magnetic resonance imaging revealed a 1.5- to 2-cm well-defined contrast-enhancing mass in the lateral extraconal orbit. His medical flight certificate was suspended for 3 mo due to decreased visual acuity and superior visual defect. Superior orbitotomy was performed without any complication. Ptosis and CSR had regressed 1 wk after surgery. All systemic and ophthalmological examinations met aviation medical certificate requirements. He returned to flight on the condition of being checked every 3 mo. At the 1-yr follow-up, there was no sign of recurrences of SFT or CSR.DISCUSSION: SFTs are slow-growing neoplasms that can manifest symptoms related to mass effect. In the current literature, there are no reported cases of the coexistence of orbital SFT and CSR or pilots able to resume flight duties only 1 wk after a successful orbitotomy and tumor resection surgery.Altinbas M, Ozpınar A, Akbaba M, Nacaroglu SA, Sargolzaeimoghaddam M, Sargolzaeimoghaddam M. Orbital solitary fibrous tumor in a commercial airline pilot. Aerosp Med Hum Perform. 2024; 95(6):333-336.

A rare case of solitary fibrous tumor of the lung parenchyma: case report

Solitary fibrous tumor (SFT) of the lung is a rare neoplasm, usually originating from lung pleura. We present a case report of a 57-year-old male with no significant medical history who was incidentally diagnosed with an SFT of lung parenchyma on chest computed tomography scan. Radiological imaging revealed a well-defined mass in the left lower lobe of the lung. Biopsy and histopathological examination confirmed the diagnosis of solitary fibrous tumor. This case highlights the importance of considering SFT in the differential diagnosis of lung masses, as its clinical presentation and radiological features can mimic those of more common pulmonary malignancies.

Calcified uterine leiomyoma from an 18th-century nunnery in North Italy

OBJECTIVE

To develop a differential diagnosis of a mass retrieved alongside skeletal remains in the crypt of the church of Santissima Annunziata of Valenza (Province of Alessandria, Northern Italy).

MATERIAL

A calcified mass measuring 40 × 39 mm and 17.62 × 16.3817.62 × 16.38 mm.

METHOD

The analysis utilized macroscopic assessment and histologic examination (including histochemical and immunohistochemical analyses).

RESULTS

Morphological traits include an irregular and spongy external surface. Holes of different sizes lead toward the inner part of the object. A section of the mass shows an "intertwined bundle" pattern, confirmed by microscopic examination.

CONCLUSIONS

Differential diagnosis determined the mass to be consistent with calcified leiomyoma.

SIGNIFICANCE

Identifying uterine leiomyoma adds to the paucity of paleopathological literature on the condition and to calcified tumors more broadly. It also allows for an important discussion of women's gynecological health in the past and potentially among nulliparous women.

LIMITATIONS

Neither histochemical staining nor immunohistochemical analysis demonstrated the certain muscular nature of the specimens due to the rehydration and decalcification processes, for which there are no gold standards.

SUGGESTIONS FOR FURTHER RESEARCH

Calcified masses are common in the clinical literature but remain rare in paleopathological literature. Careful excavation and improved recognition of apparently calcified masses are necessary to improve recognition, diagnosis, and interpretation.

Rare Encounter: Giant Hemangiopericytoma of Thigh in a Young Male

A rare tumor called hemangiopericytoma develops from the pericytes, the cells that surround blood vessels. They frequently grow slowly and might be asymptomatic initially. Although they can develop anywhere in the body, these tumors are most frequently found in the head, pelvis, and legs. This uncommon tumor originates in soft tissues like fat, muscles, tendons, nerves, blood vessels, and other fibrous tissues. The tumor in adolescence can be benign or malignant; it frequently develops in the bones but has the potential to metastasize to the lungs. Imaging tests, such as MRIs or CT scans, are commonly used in diagnosis to determine the location and size of the tumor. We present a case of a 23-year-old male who complained of swelling in his left thigh that had persisted for two years. He underwent multiple biopsies which were inconclusive until wide local excision of the swelling was done. On histopathology, the excised tumor was suggestive of hemangiopericytoma. The patient was advised of radiotherapy for completion of the treatment.

Non-gastrointestinal stromal tumor, mesenchymal neoplasms of the gastrointestinal tract: a review of tumor genetics, pathology, and cross-sectional imaging findings

There is a diverse group of non-gastrointestinal stromal tumor (GIST), mesenchymal neoplasms of the gastrointestinal (GI) tract that demonstrate characteristic pathology and histogenesis as well as variable imaging findings and biological behavior. Recent advancements in tumor genetics have unveiled specific abnormalities associated with certain tumors, influencing their molecular pathogenesis, biology, response to treatment, and prognosis. Notably, giant fibrovascular polyps of the esophagus, identified through MDM2 gene amplifications, are now classified as liposarcomas. Some tumors exhibit distinctive patterns of disease distribution. Glomus tumors and plexiform fibromyxomas exhibit a pronounced affinity for the gastric antrum. In contrast, smooth muscle tumors within the GI tract are predominantly found in the esophagus and colorectum, surpassing the incidence of GISTs in these locations. Surgical resection suffices for symptomatic benign tumors; multimodality treatment may be necessary for frank sarcomas. This article aims to elucidate the cross-sectional imaging findings associated with a wide spectrum of these tumors, providing insights that align with their histopathological features.

A Rare Tumor of Intravascular Myopericytoma in the Right Renal Vein

Myopericytoma, a perivascular myoid neoplasm, is commonly found in the dermis or subcutaneous tissues; however, its occurrence in visceral organs is unusual. Here, we present an extremely rare tumor of intravascular myopericytoma of the right renal vein. A 44-year-old man was incidentally diagnosed with a mass in the right kidney during a routine checkup. A nephrectomy was performed because the urologist suspected renal cancer. A gross examination of the resected specimen revealed a well-circumscribed brown mass in the renal hilum. Histologically, the tumor showed a concentric multilayered proliferation of spindle cells surrounding blood vessels. Immunohistochemical staining showed that the spindle-shaped tumor cells were negative for desmin but positive for α-smooth muscle actin and h-caldesmon, indicating their myoid nature. We confirmed that the tumor was located in the right renal vein because it was encased within a thick wall that was desmin-positive and contained elastic fibers, as shown by Elastica van Gieson staining. The patient was diagnosed with an intravascular myopericytoma of the right renal vein. There are several differential diagnoses for renal mesenchymal tumors, including angiomyolipoma. This emphasizes the importance of considering these uncommon tumors when examining nephrectomy specimens.

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.

Solitary Fibrous Tumor of Head and Neck Region: A Series of Three Cases at an Uncommon Location With a Review of the Literature

Solitary fibrous tumors (SFTs) uncommonly involve the head and neck region. Head and neck SFTs (HNSFTs) exhibit diverse histological features and can mimic several neoplasms with different treatment and behavior. Herein, we report the clinicopathological features of three cases of HNSFT. Case 1 was a 29-year-old female who presented with a nasal cavity mass measuring 3.5 cm. The patient underwent surgical excision. Microscopic examination revealed classic histological and immunohistochemical (IHC) features of SFT. Unusual histological features included epithelioid morphology, clear cells, and edematous change. She developed local recurrence after 11 months, which was also treated with surgery. Case 2 was a 55-year-old male who developed a 1-cm mass at the buccal mucosa. Surgical excision of the tumor was performed. The tumor was completely circumscribed microscopically. Characteristic histological and IHC features of SFT were identified. Unusual histological features observed were an adenomatous pattern, clear cells, and myxoid change. The patient was alive and disease-free at the 12-month follow-up. Case 3 was a 59-year-old female presenting with a medial canthus mass measuring 1.4 cm. The patient underwent surgical excision. Histological and IHC features observed were diagnostic for SFT. Unusual histological features identified were wavy nuclei and multinucleated stromal giant cells. The patient was alive and disease-free at the 124-month follow-up. Diagnosis of SFT can be challenging in unusual locations like the head and neck region. In addition, the histological spectrum of HNSFT is diverse. Therefore, knowledge about unusual histological features and classic IHC expression is essential for establishing correct diagnosis. Long-term follow-up is recommended because of the risk of recurrence in HNSFT.

Solitary Fibrous Tumor of the Masticator Space with Unusual Extension: a Case Report

Background: We present the case of a patient with solitary fibrous tumor of the masticator space with unusual extension. Case presentation: A 43-year-old woman presented with a painless mass with intraoral extension on the right cheek. The B-scan sonograph and magnetic resonance imaging revealed the extension of the tumor. The biopsy performed under local anesthesia raised the suspicion of a solitary fibrous tumor. Tumor excision included a preoperative tumor embolization. The surgical removal of the tumor included a partial parotidectomy on the right side, insertion of masseteric and temporalis muscle, resection of the middle part of the zygomatic bone and stabilization of the bone with a plate, mobilization of the tumor from the maxillary sinus and the pterygopalatine fossa through an endoscopic approach and an approach via partial resection of the anterior wall of the maxillary sinus after identifying and sparing the infraorbital nerve. Ôhe histological findings confirmed the diagnosis of solitary fibrous tumor. The patient's treatment completed with radiation therapy, and 2.5 years later, there was recurrence in the right temporal area. Conclusion:To our knowledge, this is the second reported case of solitary fibrous tumor arising in the masticator space and the only case with extension intraorally and in the paranasal sinuses. Tumor embolization and complete surgical excision are the most frequently recommended treatments.

Solitary fibrous tumor occurring at unusual sites: A clinico-pathological series of 31 cases with emphasis on its wide morphological spectrum

Solitary fibrous tumor (SFT) is a relatively rare mesenchymal fibroblastic tumor occurring most commonly in adults with no gender predilection. Although the pathological diagnosis of SFT is usually straightforward, some difficulties may occasionally arise mainly due to the wide morphological spectrum exhibited by this tumor. In the present paper we aimed to evaluate the unusual clinicopathological features in a series of 31 SFTs arising from parenchymal organs, superficial soft tissues and deep soft tissues. Our results emphasize that SFTs may occur anywhere, including unusual sites such as periosteum of the thoracic spine, mesorectal tissue, hepatic hilum, paravescial space, kidney and breast. Moreover, a wide morphological spectrum was observed in tumors included in our series. The most striking morphological features observed included: extensive lipomatous component, myxoid stromal changes, epithelioid cell component, metaplastic mature bone, neurofibroma-like, myxofibrosarcoma-like and pseudoalveolar-like areas. Additionally, multinucleated giant cells and sarcomatous dedifferentiation were also identified. Our paper emphasizes that SFT may occur in unusual anatomical locations and exhibits a wide morphological spectrum. Pathologists must be aware of these features to avoid confusion with other benign and malignant neoplasms that may show overlapping morphological features.

Fat-forming solitary fibrous tumor of the orbit with typical imaging findings

Purpose

We describe a case of fat-forming solitary fibrous tumor (SFT) of the orbit with typical findings on imaging that may improve the awareness of orbital fat-forming SFT.

Observations

An 88-year-old female presented with exophthalmos and pain in her right eye. Preoperative imaging showed an oval, well-defined mass with soft-tissue density, interspersed with a well-circumscribed lesion. The lesion showed low-density in computed tomography (CT) scans, hyperintense in T1/T2 weighted images of magnetic resonance imaging (MRI) scans and hypointense in fat-suppressed images of MRI scans. The tumor was removed en bloc and diagnosed as low-grade malignant fat-forming SFT by pathological examination. There was no evidence of recurrence 9-month postoperatively.

Conclusions

The imaging feature of orbital fat-forming SFT is a well-defined solid tumor interspersed with adipose tissue. Such findings are vital for the preoperative diagnosis and the choice of the treatment.

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.

[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.

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.

Surgical Management of Craniospinal Axis Solitary Fibrous Tumors: A Single-Institution Case Series and Comprehensive Review of the Literature

BACKGROUND AND OBJECTIVES

Meningeal solitary fibrous tumors (SFTs) comprise 0.4% of primary central nervous system neoplasms and carry metastatic potential. Disease course and optimal management are largely unknown, and there is currently no literature rigorously describing neurological outcomes in surgically managed SFTs. We present one of the largest craniospinal SFT series, analyze patient outcomes, and extensively review the associated literature.

METHODS

All surgically managed SFTs at our institution between January 2005 and March 2023 were retrospectively reviewed. Patient demographics, tumor and radiographic features, treatment, and clinical outcomes were collected. Neurological function was quantified using Frankel grade and Neurologic Assessment in Neuro-Oncology scores. Descriptive statistics, multivariate analysis, log-rank test, and Kaplan-Meier survival analysis were performed.

RESULTS

Twenty-one patients satisfied inclusion criteria. Tumor locations included 15 supratentorial, three infratentorial, and three spinal. All patients underwent surgical resection, and 16 (76.2%) underwent radiation. Six (28.6%) patients had tumor recurrence, and three (14.3%) developed metastasis. Younger age and higher postoperative Frankel grade were significantly associated with increased overall survival (OS) ( P = .011, P = .002, respectively). All patients symptomatically improved or stabilized after surgery, and Neurologic Assessment in Neuro-Oncology score ( P = .001) and functional status significantly improved postoperatively (Karnofsky Performance Status: 65.2 ± 25.2 vs 91.4 ± 13.5, P = .001). Sex, adjuvant radiation, and extent of resection were not significantly associated with OS.

CONCLUSION

SFT of the central nervous system is a rare entity with a variable clinical course. Surgical resection was associated with improved postoperative functional and neurological status. Higher postoperative neurological function was significantly associated with OS. Further studies are warranted to validate a standardized treatment algorithm and investigate the efficacy of adjuvant radiation in SFT.

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

Introduction

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

Method

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

Results

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

Conclusion

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

Systematic Review Registration

CRD42023421358.

Genetic, Epigenetic and Transcriptome Alterations in Liposarcoma for Target Therapy Selection

Liposarcoma (LPS) is one of the most common adult soft-tissue sarcomas (STS), characterized by a high diversity of histopathological features as well as to a lesser extent by a spectrum of molecular abnormalities. Current targeted therapies for STS do not include a wide range of drugs and surgical resection is the mainstay of treatment for localized disease in all subtypes, while many LPS patients initially present with or ultimately progress to advanced disease that is either unresectable, metastatic or both. The understanding of the molecular characteristics of liposarcoma subtypes is becoming an important option for the detection of new potential targets and development novel, biology-driven therapies for this disease. Innovative therapies have been introduced and they are currently part of preclinical and clinical studies. In this review, we provide an analysis of the molecular genetics of liposarcoma followed by a discussion of the specific epigenetic changes in these malignancies. Then, we summarize the peculiarities of the key signaling cascades involved in the pathogenesis of the disease and possible novel therapeutic approaches based on a better understanding of subtype-specific disease biology. Although heterogeneity in liposarcoma genetics and phenotype as well as the associated development of resistance to therapy make difficult the introduction of novel therapeutic targets into the clinic, recently a number of targeted therapy drugs were proposed for LPS treatment. The most promising results were shown for CDK4/6 and MDM2 inhibitors as well as for the multi-kinase inhibitors anlotinib and sunitinib.

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 TGFβ 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.

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.

Sinonasal nodular fasciitis: report of a case with USP6 rearrangement

Nodular fasciitis (NF) is a benign myofibroblastic proliferation characterized by rapid growth, a self-limiting course, and USP6 gene rearrangement. Although it can arise in the head and neck region, very few cases of NF involving the sinonasal tract have been reported to date. Herein we report a case of NF involving the nasal cavity presenting as a polypoid well-defined mass causing obstructive symptoms in a male with a history of multiple local surgeries. Although the mass had an unusual clinical presentation, the histopathologic and immunohistochemical findings were consistent with NF. Fluorescent in situ hybridization performed with break-apart probes flanking the USP6 locus on chromosome 17p13 revealed the presence of USP6 gene rearrangement. The patient remained free of disease 124 months after surgical treatment. Considering its remarkably benign behavior despite its alarming clinical and histologic features, the distinction of NF from sinonasal malignant tumors is essential.

Locally advanced solitary fibrous tumour of the prostate

Solitary fibrous tumours (SFTs) are rare mesenchymal neoplasms composed of spindle cells, most often occurring in the pleura. SFTs arising from the prostate are exceptionally rare, with only around 40 cases reported in literature to date. We report a man in his 60s who was referred to our clinic for elevated prostate-specific antigen and presented with mild obstructive lower urinary tract and defecatory symptoms. Prostate needle-core biopsy revealed neoplastic spindle cells that strongly expressed CD34. Cross-sectional imaging demonstrated a 12 cm locally advanced heterogeneous prostate mass with intravesical extension and mass effect on the anterior rectum. Radical cystoprostatectomy with orthotopic neobladder reconstruction was performed, and the diagnosis of primary prostatic SFT was made based on histological characteristics and immunophenotyping. We present diagnostic, clinical management and prognostic considerations in patients with primary prostatic SFT.

Extra-meningeal solitary fibrous tumor: an evolving entity with chameleonic morphological diversity, a hallmark molecular alteration and unresolved issues in risk stratification assessment

Solitary fibrous tumor (SFT) is a rare type of mesenchymal lesion with variable clinical presentation in which specific clinicopathologic factors have been related to patient outcome. SFT shares an important morphologic and immunohistochemical overlap with other sarcomas, hence the differential diagnosis is challenging. Although molecular studies provide significant clues, especially in the differential diagnosis with other neoplasms, a thorough hematoxylin and eosin analysis and the integration of phenotypical, clinical, and radiological features remain an essential tool in SFT diagnosis. In this review, we discuss some emerging issues still under debate in SFT.

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 of head and neck region; A clinicopathological study of 67 cases emphasizing the diversity of histological features and utility of various risk stratification models

BACKGROUND

Head and neck SFT (HNSFT) exhibit diverse histological features and can mimic various neoplasms with different treatment and behavior. While risk stratification systems have been developed for this tumor at various anatomic sites, a specific scheme for head and neck tumors is lacking. Our aim was to describe the histologic patterns present in HNSFT cases as well as assess the utility of risk assessment models in this location.

METHODS

A retrospective review of pathology reports and microscopy glass slides of HNSFT cases diagnosed between January 2010 and August 2022 was performed.STAT6 was additionally performed on selected cases if needed. Follow up was obtained and various risk stratification models were applied.

RESULTS

Sixty seven cases of HNSFT were collected (age range from 11 to 87 years; median 42 years; M:F 1.6:1). Most common tumor sites were orbit (n = 21; 31.3 %), sinonasal tract (n = 18; 26.9 %), and oral cavity (n = 13; 19.4 %). Tumor size ranged from 1 to 16 cm (median 4cm). Apart from common histological features, tumor cells also showed focal epithelioid morphology, clear cell change and nuclear atypia in a subset of cases. Stromal findings included myxoid and lipomatous change, pseudoglandular spaces, pseudovascular spaces and multinucleated stromal giant cells. CD34 and STAT6 were expressed in 57/67 (85.1 %) and 56/56 (100 %) cases, respectively. Recurrence was observed in 4/26 (15.4 %) cases, while none (0/22) of the patients experienced distant metastasis (follow up 1-150 months; median 20.5 months). Clinical outcome was partially concordant with risk-categories of different risk stratification models.

CONCLUSION

Knowledge about histological diversity of HNSFT is essential for establishing correct diagnosis. Current risk stratification models do not perfectly predict outcome, and larger studies are needed to develop more accurate criteria for aggressive behavior.

Solitary fibrous tumour of the urinary bladder - A rare and potentially malignant neoplasm

Solitary fibrous tumours (SFTs) of the urinary bladder are a rare mesenchymal neoplasm that occasionally has malignant potential. The tumour is characterised by haphazardly arranged spindle-shaped to ovoid cells, with a prominent, branching, thin-walled, dilated vasculature and NAB2-STAT6 gene rearrangement. While most SFTs are indolent in nature, difficulty arises predicting which SFTs are potentially malignant. There are now validated risk stratification tools to help identify which SFTs are likely to metastasize and help clinicians determine management. The mainstay of treatment for SFTs remains surgery, with emerging evidence in the combined use of surgery and radiotherapy.

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.

Multiple solitary fibrous tumors of the pleura with multicentric and unilateral involvement: a case report

BACKGROUND

Solitary fibrous tumor of the pleura (SFTP) is a mesenchymal tumor. Patients with SFTP generally have only one lesion. We herein report an extremely rare case of multiple SFTPs that were multicentric and unilateral.

CASE PRESENTATION

The patient was a 21-year-old asymptomatic young man who was referred to our hospital due to abnormal shadows on a chest X-ray. Computed tomography showed 6 tumors of heterogeneous sizes in the left thoracic cavity. The tumors were suspected to be multiple benign or low-grade malignant thoracic tumors, and tumor resection was performed. The tumors had almost the same appearance, with uniform fibroblastic spindle cell proliferation, and arose from the pleura in microscopy. Immunohistochemical staining revealed that the tumor cells were positive for CD34, CD99, Bcl-2, and STAT6. Based on these findings, the tumors were diagnosed as multiple SFTPs with multicentricity. At 1 year and 6 months after the first surgery, 2 new lesions were found above the diaphragm, and these were resected. These tumors were arose from the pleura with a fibrous capsule structure. Their pathological findings were identical to the initial tumor without evidence of malignant transformation.

CONCLUSION

We experienced an extremely rare case of multiple SFTPs with multicentric and unilateral lesions.

Solitary fibrous tumor with IGF-II-induced non-islet cell tumor hypoglycemia: a case report and molecular characterization by next-generation sequencing

Background

Non-islet cell tumor-induced hypoglycemia (NICTH) is a rare, life-threatening medical condition caused by excessive insulin-like growth factor II (IGF-II) secretion from tumors of most commonly mesenchymal origin. Using next-generation sequencing, we have characterized the genome and transcriptome of the resected IGF-II-secreting solitary fibrous tumor from a patient with severe hypoglycemia accompanied by hypoglycemia unawareness.

Case presentation

A 69-year-old male patient presenting with abdominal discomfort was examined using computer tomography, revealing a large lesion at the lesser pelvis extending above the umbilicus. As no bone and lymph node metastases were detected, the patient was scheduled for laparotomy. Before surgery, the patient presented with symptoms of severe hypoglycemia. Suppressed C-peptide levels and subsequent hypokalemia indicated a possible case of NICTH. The patient was treated with methylprednisolone (8 mg) to assess hypoglycemia. After the surgery, mild hypoglycemia was present for the postoperative period, and no radiological recurrences were observed 3 and 12 months after discharge. Histopathological examination results were consistent with the diagnosis of malignant solitary fibrous tumor (SFT). Overexpression of IGF-II was confirmed by both immunohistochemistry and RNA sequencing. Further NGS analysis revealed an SFT characteristic alteration-NAB2-STAT6 fusion. Additionally, three deleterious missense variants were detected in oncogenes BIRC6, KIT, and POLQ, and one homozygous in-frame deletion in the RBM10 tumor suppressor gene.

Conclusion

While the NAB2-STAT6 fusions are well characterized, the mutational landscape of SFTs remains understudied. This study reports the importance of NGS to characterize SFTs as we detected four coding variants in genes (BIRC6, KIT, POLQ, and RBM10) associated with tumorigenesis that could potentially contribute to the overall pathogenesis of SFT.

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.

Expression of neuroendocrine markers in meningeal and extrameningeal solitary fibrous tumours - a potential diagnostic pitfall

Solitary fibrous tumours (SFTs) may show unusual morphologies and in such circumstances, unexpected immunoprofile can be misleading. Following an index case of myxoid meningeal SFT with neuroendocrine immunoprofile, we decided to assess a neuroendocrine profile in SFTs from various locations. The cohort of 9 meningeal and 28 extrameningeal SFTs was evaluated for CNS WHO grade (G1-G3) and four tiered Demicco risk stratification. Immunohistochemical detection of synaptophysin, chromogranin, INSM1, CD56, and CD57 was performed in each case and semiquantitatively assessed (0 - no expression; 1+ <10% positive; 2+ 11-50%; 3+ >51%); whole sections (meningeal SFTs) or tissue microarray (extrameningeal SFTs) were used for immunohistochemistry. The cohort included 13 men and 24 females. Meningeal SFTs included 5 WHO G1, 3 WHO G2 and 1 WHO G3 tumours. Extrameningeal SFTs included 21 low-risk, 4 intermediate risk and 2 high risk tumours. INSM1 immunoreactivity was observed in 12/37 cases (32%, 8 cases 1+, 3 cases 2+, 1 case 3+); synaptophysin was positive in 6/35 cases (19%, 5 cases 1+, 1 case 2+); CD56 was positive in 20/37 (54%, 16 cases 1+, 3 cases 2+ and 1 case 3+) and CD57 was expressed in 14/36 cases (39%, 5 cases 1+, 4 cases 2+ and 5 cases 3+). Chromogranin positivity was not observed. No significant association was observed between expression of neuroendocrine markers and tumour grade, Demicco risk group or meningeal and extrameningeal location. Extrapleural SFTs showed tendency for positivity of INSM1 (p=0.014, χ2) and CD57 (p=0.017, χ2), compared to pleural SFTs.

A giant orbital solitary fibrous tumor treated by surgical excision: a case report and literature review

BACKGROUND

Spindle cell tumors, called solitary fibrous tumors (SFTs), are of mesenchymal origin, and can develop in the orbit. As 'intermediate malignancy' tumors, only a small percentage show malignant behavior, such as invasion of surrounding tissue.

CASE PRESENTATION

A 57-year-old woman presented with a 19-year history of a giant right orbital mass. Orbital computed tomography (CT) revealed an inhomogeneously-enhancing mass compressing and engulfing the eyeball and optic nerve. She underwent lid-sparing orbital exenteration. Microscopic characteristics and immunohistochemistry (IHC) tests were indicative of a benign SFT. No recurrence was observed at the 4-year follow-up.

CONCLUSION

Early and complete tumor resection is recommended.

Orbital Primary Solitary Fibrous Tumor: A Proposed Recurrence Risk Prediction Model Based on 92 Cases

Orbital primary solitary fibrous tumors (OPSFTs) are rare. To further characterize the clinical and pathological features of OPSFTs, 92 cases of OPSFT were analyzed to develop a risk prediction model. OPSFTs were equally distributed between males (n = 45) and females (n = 47) with a mean patient age of 40.8 years (median 39 years; range 5-70 years) at initial diagnosis. The mean tumor size was 2.79 cm (median 2.5 cm). Microscopically, the tumor cells were irregularly arranged in spindle, ovoid, or round shapes with varying amounts of collagen and branching blood vessels. Immunohistochemical staining showed positive STAT6 nuclear expression in all cases, loss of CD34 expression in seven cases, and a mean Ki-67 label index of 5.25% (range 1%-30%). All patients were initially surgically resected and had a median follow-up of 99 months: 33 patients recurred, 6 of whom presented with multiple recurrences and 1 with distant metastases. A predictive model for the risk of recurrence based on tumor size, mitosis, Ki-67 label index, and dominant constituent cell (DCC) was developed based on our results. In conclusion, OPSFTs are rare but can be reliably diagnosed based on characteristic morphological features and STAT6 immunohistochemistry. The rate of local recurrence of orbital tumors tends to be higher than the rate of distant metastases, which can be predicted by a risk stratification model specific to orbital tumors. Long-term clinical follow-up is recommended as advanced disease is common.

Epithelioid and Clear Cell Solitary Fibrous Tumors: Clinicopathologic, Immunohistochemical, and Molecular Genetic Study of 13 Cases

Solitary fibrous tumors (SFTs) are ubiquitous soft tissue neoplasms known for their protean histology and potentially aggressive behavior. Although most cases are composed of a monotonous proliferation of spindle cells, some tumors show unusual cytologic features. We have studied 13 SFTs that were characterized by a predominant population of round epithelioid cells with abundant eosinophilic cytoplasm and clear cell changes. The tumors occurred in 8 women and 5 men, aged 36 to 80 years (mean=63 y), and were located within the orbit (3), lower extremity (3), retroperitoneum (2), abdominal cavity (2), and superficial soft tissues of the neck, pelvis, and pubis (1 each). The tumors measured from 3.5 to 24.5 cm. Using a risk assessment system, 6 cases were stratified as low-risk tumors; 3 of these showed no evidence of recurrence or metastases from 6 to 18 years, and 1 tumor in the orbit recurred and led to the patient's demise. Five cases were of intermediate risk; clinical follow-up showed no evidence of recurrence or metastases from 3 to 4 years in 3 patients, and 1 patient suffered a recurrence 4 years after diagnosis. Two cases were high risk; 1 patient died after 1 year and the second patient experienced local recurrence at 4 years. Immunohistochemical studies showed nuclear positivity for STAT6 in 10 cases. CD34 immunohistochemistry was positive in 11 cases. A NAB2::STAT6 rearrangement was present in all cases. Epithelioid and clear cell SFT should be considered in the differential diagnosis of soft tissue neoplasms with epithelioid and clear cell morphology.

Extraskeletal myxoid chondrosarcoma: p53 and Ki-67 offer prognostic value for clinical outcome - an immunohistochemical and molecular analysis of 31 cases

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant soft tissue tumor of unpredictable clinical behavior. The morphological spectrum of EMC based on histology alone can be difficult. There is no precise immunohistochemical (IHC) profile that together with the clinical parameters is able to predict the clinical outcome. We studied 31 cases confirmed as EMC. Clinical and follow-up data were recorded. Histopathological, molecular, and IHC studies were performed. Association among histopathological parameters was assessed using a chi-square test to determine homogeneity or linear trend for ordinal variables. The Kaplan-Meier proportional risk test (log rank) was used to study the impact of the histological, IHC, and molecular factors on progression-free survival (PFS) and disease-specific survival (DSS). Most EMCs showed a typical architectural pattern. Only a few cases presented an atypical histology (higher cellularity and solid pattern). IHC positivity (focal or diffuse) was present for CDK4 (100%), STAT-6 (90%), CD117 (84%), HNK-1 (81%), SATB2 (68%), and S-100 (58%). Synaptophysin and INSM1 were expressed in 22.6% and 38.7% of cases respectively. The EWSR1::NR4A3 rearrangement was found in 19 cases and 7 tumors presented the TAF15::NR4A3 fusion. Positive surgical margins together with atypical histology and expression of p53 and Ki67 correlated with worse clinical prognosis. EMCs express several IHC markers which are also seen in other soft tissue sarcomas. The molecular detection of NR4A3 rearrangement supports the differential diagnosis. Positive surgical margins together with atypical histology and positive expression of p53 and Ki-67 seem to predict a poor clinical outcome with worse prognosis, increased rate of recurrence, metastasis, and poor overall survival.

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.

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.