Recurrent Sinonasal CD34-Negative Malignant Solitary Fibrous Tumor Diagnosed on STAT6 Immunohistochemistry and NAB2-STAT6 Fusion

Myxoid Solitary Fibrous Tumor of the Nasal Vestibule: An Unusual Histological Subtype in the Head and Neck Region

Solitary fibrous tumors (SFTs) are mesenchymal neoplasms associated with the characteristic NAB2::STAT6 gene fusion. They frequently occur in extra-thoracic sites and are not uncommon in the head and neck (HN) region. Myxoid SFT is a rare morphological subtype of SFT, the features of which overlap with those of other myxoid-appearing tumors, making the diagnosis challenging. We describe the distinctive histopathological and immunohistochemical features of myxoid SFT that occurred in a 32-year-old man with a recurrent swelling in the nasal vestibule. Histological examination showed a nodular tumor composed of short spindle-shaped cells in an abundant myxoid stroma. Nuclei were ovoid, with minimal pleomorphism. Occasional intervening slender vascular channels were present; staghorn vasculature was absent. Tumor cells were diffusely immunopositive for STAT6, CD34, and BCL2, while S100, SOX10, EMA, ER, and CD10 were negative, confirming the diagnosis of myxoid SFT. Thus, myxoid SFTs are unusual in the HN, with potential for misdiagnosis. Due to their propensity for local recurrence if incompletely excised, a high index of suspicion is required to include them in differential diagnosis of myxoid mesenchymal neoplasms occurring at this location. STAT6 is a reliable immunohistochemical marker that aids in diagnosis, reducing the necessity for molecular testing.

Solitary Fibrous Tumor of Nasal Cavity: A Case Report

Solitary fibrous tumors (SFTs) belonging to a distinct group of mesenchymal tumors, was originally described by Klemper and Rabin in the pleura in year 1931. However, it can also be extra-pleural in origin. With tongue being the most common site involved in this region, epiglottis, larynx, thyroid, external auditory canal, lacrimal sac, hypoglossal nerve, parotid gland, sublingual gland, Para pharyngeal space, nasopharynx, scalp, gingiva, orbit and infratemporal fossa as well as paranasal sinuses and nasal cavities can also get involved. But SFTs involving nasal cavities and nasopharynx are quite uncommon, accounting for < 0.1% of all Sino-nasal neoplasms. Until now there have only been 40 cases of nasal SFT reported in literature. We report the case of an extraserosa solitary fibrous tumor arising from the nasal cavity with extension to the sphenoid sinus, a much rarer presentation of its type. Our case report is one of its type, emphasizing the need conducting further studies on the nature and management of the disease.

[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 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.

Surgical treatment outcomes of solitary fibrous tumors in the head and neck: A retrospective study

The aim of this study was to better characterize head and neck solitary fibrous tumors (SFTs) and to evaluate surgical treatment. This retrospective study included patients who presented with head and neck SFTs. Clinical, radiological, and histological information and data regarding the treatments performed were collected. The risk of locoregional and distant metastases was calculated, and for orbital SFTs a specific classification was used. Overall, 34 patients were included. The majority of the SFTs were found in the oral cavity (n = 10), followed by the neck region (n = 8). The mean time to recurrence was 67.4 months. All patients underwent primary surgical resection. Recurrence was observed in five patients with a low risk of locoregional recurrence and distant metastasis. The treatment of choice is complete resection. Recurrence seems to be highly correlated with positive surgical margins. The safety margin should be increased when removing the lesion, and long-term follow-up should be performed.

Solitary fibrous tumor of the tongue

Solitary fibrous tumor (SFT) is a benign mesenchymal neoplasm originally described in pleura with a rare presentation in the oral cavity. Herein, we report a case of a 28-year-old male patient who presented an asymptomatic slow-growing mass in the anterior part of the tongue. Intraoral examination revealed a well-circumscribed mass covered by normal mucosa with a fibrous consistency. Due to non-specific clinical findings, the initial diagnostic hypotheses include benign submucosal neoplasms such as leiomyoma, neurofibroma, SFT, and others. An excisional biopsy was performed. Microscopically, the tumor was surrounded by a thick fibrous capsule; hypo and hypercellular areas were arranged in a storiform pattern with a stroma formed by collagen and abundant vascularization. Tumor cells showed immunopositivity for CD34 and STAT-6 and no expression of CD99, AML, S-100, and Ki-67. According to these findings, the diagnosis of SFT was established. After 24 months, the patient is asymptomatic and has no evidence of recurrence. Although oral involvement is rare, SFT should be included in the differential diagnosis of oral submucosal lesions.

Solitary Fibrous Tumors of the Head and Neck: A Single-Institution Study of 52 Patients

Objective

To evaluate the clinicopathologic characteristics of head and neck solitary fibrous tumors and features that may predict tumor recurrence.

Study Design

Retrospective review.

Setting

University of California–Los Angeles Medical Center.

Methods

A single-center retrospective study was conducted on pathologically confirmed cases of head and neck solitary fibrous tumors between 1996 and 2021. Patient demographics, clinical course, and histopathologic features were evaluated. Recurrence-free survival was estimated via Kaplan-Meier analysis.

Results

A total of 52 patients were reviewed. The average patient age was 54.7 years (range, 15-89). The most common subsite was the orbit (53.8%, n = 28), but other involved areas included the nasopharynx, paranasal sinuses, and scalp. The median tumor size was 2.95 cm (range, 1.3-11.2). Strong STAT6 (100%) and CD34 (97.9%) expression was observed on immunohistochemistry. Almost all patients were initially managed with wide local excision; 82% of patients (n = 14) had positive margins on pathologic review; and 15% (n = 4) had recurrence at a median 28.5 months (range, 10-113). White patient race was the only significant predictor of tumor recurrence. Patient age (≥55 years), tumor size (≥4), high mitotic rate, and disease subsite were not associated with recurrence.

Conclusion

Head and neck solitary fibrous tumors demonstrate a significantly larger local recurrence rate as compared with their rate of metastasis. They can recur many years following initial therapy, warranting long-term surveillance and follow-up to assess for tumor recurrence.

Solitary fibrous tumors: Clinical and imaging features from head to toe

Solitary fibrous tumors (SFTs) are rare fibroblastic mesenchymal tumors that are usually benign with variable malignant potential. They can develop in any organ due to their spindle cell origin. The exact etiology of solitary fibrous tumors is unknown. The majority of SFTs are benign with 10-30% of them exhibiting aggressive and malignant features. The aggressiveness of this type of tumor is not associated with its histological features, which makes surgical resection the treatment of choice. We will review the clinical and radiological features and possible differential diagnoses of SFTs according to their anatomical sites following the World Health Organization 2020 classification.

A rare case of sinonasal solitary fibrous tumour in a patient with concurrent papillary thyroid carcinoma: A case report

INTRODUCTION AND IMPORTANCE

A solitary fibrous tumour (SFT) is a rare neoplasm that commonly arises in the pleura and can occur in other extrathoracic sites. Extrapleural SFT, particularly in the sinonasal cavity, is extremely rare. There are no definite diagnostic criteria for sinonasal SFT as it is rare. Histologic analysis with immunohistochemistry plays an important role in diagnosing SFT.

CASE PRESENTATION

We report herein a case of SFT of the sinonasal cavity, which later spread to the oral cavity in a 67-year-old male with underlying papillary thyroid carcinoma (PTC) stage IV. He complained of recurrent epistaxis from a mass in his left nasal cavity for two weeks. The mass grew bigger, and spread to the oral cavity, causing dysphagia and upper airway obstruction. Tracheostomy was done under local anaesthesia and a biopsy of the mass was taken to rule out metastasis from the PTC. However, histopathological examination revealed a mesenchymal tumour of fibroblastic type, consistent with an SFT. He was planned for surgical resection of the tumour. However, he refused the operation and was lost to follow-up.

CLINICAL DISCUSSION

We describe the clinical presentation of this rare tumour of the sinonasal and oral cavity, including upper airway obstruction, and the importance of immunohistochemical markers such as CD34 and BCL-2 in diagnosing SFT. Complete resection of the tumour is the definitive treatment for SFT.

CONCLUSION

SFT of the sinonasal and oral cavity is extremely rare. Upper airway obstruction may occur due to the location of the tumour in the airway region. Immunohistochemistry is crucial to distinguish this tumour from other mesenchymal tumours.

Fascin-1 is associated with recurrence in solitary fibrous tumor/hemangiopericytoma

Fascin-1, an actin-bundling protein, is associated with poor prognosis in patients with various types of human carcinoma. However, research is limited on the role of fascin-1 in sarcoma. Solitary fibrous tumor (SFT) and hemangiopericytoma (HPC) are rare sarcomas derived from the mesenchyme. Although the prognosis of SFT/HPC is generally favorable, fatalities are possible with repeated recurrence and distant metastasis. The current study included a total of 20 Japanese patients, who were diagnosed with SFT/HPC and underwent surgery at Kochi University Hospital from January 2000 to December 2019. The statistical relationship between recurrence and the following variables were examined: Sex, age of onset, tumor origin, tumor size, necrosis, mitosis ≥1/10 high power field (HPF; magnification, x400), Ki-67 >5% and Fascin-1. A significant association was determined between recurrence and necrosis, mitosis ≥1/10 HPF (magnification, x400), Ki-67 >5%, and Fascin-1 ≥‘strongly positive’ (P<0.05). The results demonstrated that Fascin-1 immunostaining may be a highly effective and useful evaluation factor for predicting poor prognosis in patients with SFT/HPC, a fatal sarcoma of humans.

Sinonasal IgG4-related disease: a rare and emerging entity broadening the differential diagnosis in the sinonasal universe

BACKGROUND

IgG4-related disease (IgG4-RD) is a multi-organ immune-mediated disorder characterized by fibroinflammatory mass-forming lesions, mimicking malignancy or infection. While well-documented in salivary glands, orbit and thyroid in the head and neck, sinonasal IgG4-RD is rare.

METHODS

Cases of sinonasal IgG4-RD were retrieved, and clinicopathological features reviewed.

RESULTS

Seven cases of sinonasal IgG4-RD were identified over a 2-year period, including three males and four females, with an age range of 13-48 years (median: 32 years). Patients presented with cheek swelling, pain and visual disturbances. Serum IgG4 levels were mildly elevated. Storiform fibrosis, obliterative phlebitis and plasma cell infiltration were seen in varying proportions. Destruction of bone and subepithelial mucoserous glands was present. ALK-1 negativity distinguished from inflammatory myofibroblastic tumor.

CONCLUSION

Sinonasal IgG4-RD expands the growing spectrum of IgG4-RD. A high degree of suspicion is required to include IgG4-RD in differential diagnosis of sinonasal masses, and perform detailed histological and immunohistochemical workup for accurate diagnosis.

Pelvic cavity malignant solitary fibrous tumor with dedifferentiation and multifocal cytokeratin expression

Pelvic cavity small-sized malignant solitary fibrous tumors are rare. Surgeons easily misjudge these tumors as benign lesions, and they are usually resected by laparoscopic surgery. When accompanied by dedifferentiation, malignant solitary fibrous tumors are difficult to diagnose by pathologists. Here, we describe a challenging case. A 47-year-old man was accidentally found to have a pelvic mass after three months. Surgeons assumed a diagnosis of a benign tumor according to the Computed Tomography and Ultrasonography reports. The patient underwent laparoscopic surgery to resect the tumor. After the operation, the patient was diagnosed as having a malignant solitary fibrous tumor with dedifferentiation. The patient had a recurrence one year later. This pelvic cavity malignant solitary fibrous tumor was a rare case because of its dedifferentiation and cytokeratin expression. The expression of cytokeratin and the absence of vimentin and CD34 were pitfalls to diagnosis. In this case, there was still a high amount of malignancy despite the small size of the tumor. Clinical image and pathologic multidisciplinary analysis and core needle biopsies before surgery had a great effect on diagnosis and therapy of this disease. The case is a cautionary tale not only for pathologists but also for surgeons.

Locally advanced malignant solitary fibrous tumour successfully treated with conversion chemotherapy, operation and postoperative radiotherapy: a case report

Preoperative diagnosis of solitary fibrous tumour (SFT) may not provide a complete tumour picture and may be inaccurate. There is no standard treatment for locally advanced or metastasised malignant SFT (MSFT). Here, the case of a 17-year-old male patient with final pathology diagnosis of MSFT is reported. Preoperative biopsy pathology results suggested an Ewing sarcoma that was positive for CD99 antigen, vimentin, friend leukaemia integration 1 transcription factor, apoptosis regulator Bcl-2, and synaptophysin; and negative for CD34 antigen, S-100 protein (S-100), smooth muscle antigen, cytokeratin, and Wilms tumour 1 associated protein. The Ki67 positive rate was 8%, so the patient initially received eight cycles of conversion chemotherapy (vincristine, etoposide, ifosfamide and pirarubicin for one cycle, and vincristine, doxorubicin, and cyclophosphamide/ifosfamide and etoposide for 7 cycles in total). The tumour shrunk significantly and was surgically removed. The final pathology diagnosis was MSFT that was positive for CD99 and signal transducer and activator of transcription 6, and negative for CD34, tumour protein 63, S-100, desmin, and epithelial membrane antigen. Fluorescence in situ hybridization showed no gene translocation in EWS RNA binding protein 1, SS18 subunit of BAF chromatin remodelling complex or FUS RNA binding protein. The patient finally accepted adjuvant radiotherapy of 5600 cGy. Disease-free survival has been > 1 year, with no recurrence or metastasis detected to date. MSFT is rare and treatment for locally advanced or metastatic MSFT remains controversial. The efficacy of the present therapeutic strategy requires further research.

Solitary Fibrous Tumors in the Head and Neck: Comprehensive Review and Analysis

Solitary fibrous tumors (SFT) arising in the head and neck region are uncommon yet well-recognized entities. Their biologic behavior and management still need to be elucidated. Systematically reviewing all published cases of SFT involving the head and neck region since 1991, a pooled meta-analysis was conducted to evaluate various demographic and tumor characteristics. 587 SFT in the head and neck have been reported; 343 met pooled analysis inclusion criteria. 61% of cases presented as a new mass; 89% were painless. Median onset of symptoms prior to evaluation was 8 months. Pre-operative local invasion and malignant histological features (hemorrhage, necrosis, mitoses > 4/10 hpf) were not statistically associated with decreased recurrence-free survival. Positive surgical margins was the only factor associated with shorter recurrence-free survival (p < 0.001). The evidence presented herein reveals novel associations between clinical presentation and tumor characteristics that provide otolaryngologists with new insight into SFT tumor behavior, thus prompting further investigations.