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

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

Solitary Fibrous Tumor in the Retroperitoneal Space Arising from the Diaphragm

BACKGROUND/AIM

We present a case of solitary fibrous tumor, arising from the diaphragm in the retroperitoneal space, that was resected with robotic assistance.

CASE REPORT

An 85-year-old female patient was referred to our hospital for evaluation of a suspected right renal tumor. Abdominal contrast-enhanced computed tomography revealed a tumor (maximum diameter, 36 mm) protruding from the superior pole of the right kidney. The patient was scheduled for robot-assisted, retroperitoneoscopic, partial nephrectomy based on a preoperative diagnosis of renal cell carcinoma. Intraoperative findings revealed that the tumor originated from the diaphragm and had no continuity with the renal parenchyma. Pathological examination revealed a solitary fibrous tumor.

CONCLUSION

Solitary fibrous tumors are rare soft-tissue neoplasms with a distinct molecular feature of the fusion of nerve growth factor-inducible A gene-binding protein 2 with signal transducer and activator of transcription 6 gene (NAB2::STAT6). We believe that this is the first reported case of a solitary fibrous tumor arising from the diaphragm in the retroperitoneal space.

Malignant recurrent orbital solitary fibrous tumor

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

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.

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

RATIONALE

A solitary fibrous tumor (SFT) is an uncommon soft tissue tumor that was first discovered in the pleura. Although SFTs have been documented in other extra-pleural sites, an SFT in the thyroid gland is highly unusual. An SFT of the thyroid gland can be difficult to diagnose, and there is little information about their Underlying biological behavior.

PATIENT CONCERNS

We present a case of a 63-year-old man with a progressively growing left-neck mass detected 1 month ago, which was pathologically confirmed to be a benign SFT of the thyroid gland.

DIAGNOSIS

Postoperative pathological examination of the tumor revealed an SFT. Immunopathological examination was consistent with the diagnosis of an SFT.

INTERVENTIONS

The patient underwent surgical resection of the SFT.

OUTCOMES

The patient was recurrence-free during 1.5 years of follow-up.

LESSONS

Surgical excision is beneficial in SFTs that show no histological signs of malignancy, such as pleomorphism, enhanced mitotic activity, necrosis, bleeding, or capsular invasion. However, because the biologic activity remains unknown, meticulous long-term monitoring is required.

Solitary fibrous tumor of the thyroid: report of three cases with a focus on cytological features and histological clues for malignancy

Solitary fibrous tumor is a mesenchymal tumor of intermediate malignant potential characterized by a recurrent NAB2::STAT6 fusion and STAT6 nuclear expression. Primary thyroid solitary fibrous tumor is relatively uncommon, with 45 cases described in the English literature to date. Although its histologic features are characteristic, its diagnosis in the thyroid can be problematic, especially in small biopsies or cytology specimens. We herein present three new cases of thyroid solitary fibrous tumor, one of which is malignant, with new insights on the morphological spectrum and malignant potential of this tumor. We additionally provide a review of the literature with a focus on the clues and challenges of a preoperative cytological diagnosis of this tumor, which can nowadays be supported by STAT6 nuclear expression, when appropriately suspected.

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

ABSTRACT

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

68 Ga-DOTATOC PET/CT Imaging of a Muscular Solitary Fibrous Tumor

ABSTRACT

A 73-year-old woman was referred for 68 Ga-DOTATOC PET/CT staging of a grade 2 pancreatic neuroendocrine tumor, which showed the primary pancreatic tumor, liver metastases, one left pleural metastasis, and high uptake in a mass of the right triceps brachii muscle. Two years before, she underwent 18 F-FDG PET/CT and 111 In-pentetreotide scan, respectively, with low and high uptake of each radiotracer in the triceps mass. Histopathological analysis revealed a solitary fibrous tumor. Immunohistochemistry showed no staining for SSTR-2 and SSTR-5, suggesting tumor overexpression of another somatostatin receptor. This case highlighted a potential pitfall on 68 Ga-DOTATOC PET/CT.

68 Ga-PSMA-Avid Intranasal Solitary Fibrous Tumor

ABSTRACT

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

Carbon-ion Radiotherapy for Inoperable Solitary Fibrous Tumor of the Skull Base: A Case Report

BACKGROUND/AIM

The curative treatment for solitary fibrous tumors (SFTs) consists of surgery. However, surgery for SFTs in the skull base is difficult due to the anatomy and curative surgery may not be possible. Carbon-ion radiotherapy (C-ion RT) might be useful in the treatment of inoperable SFTs in the skull base because of its biological and physical nature. This study presents the clinical outcomes of C-ion RT for an inoperable SFT of the skull base.

CASE REPORT

A 68-year-old female patient experienced hoarseness, deafness on the right side, right facial nerve paralysis, and dysphagia. Magnetic resonance imaging revealed a tumor located in the right cerebello-pontine angle with destruction of the petrous bone, and immunohistochemical studies of the biopsy specimen showed a grade 2 SFT. Firstly, the patient underwent tumor embolization and surgery. However, 5 months after surgery, magnetic resonance imaging revealed regrowth of residual tumor. Subsequently, the patient was referred to our hospital for C-ion RT because curative surgery was unsuitable. The patient received 64 Gy (relative biological effectiveness) of C-ion RT in 16 fractions. Two years after C-ion RT, the tumor showed a partial response. The patient was still alive at the last follow-up without evidence of local recurrence, distant metastasis, or late toxicities.

CONCLUSION

These findings suggest that C-ion RT is a suitable treatment option for inoperable SFTs of the skull base.

Malignant solitary fibrous tumor of maxilla presenting as proptosis: A case report

ABSTRACT

Solitary fibrous tumor (SFT) is a fibroblastic mesenchymal neoplasm that rarely metastasizes. SFTs was first described in relation to pleura. However, occurrence of this tumor type has been reported in other sites like peritoneum, liver, adrenal gland, meninges and oral cavity. In head and neck region, oral cavity is the most common site of involvement. Most of the solitary fibrous tumors are benign and present as an asymptomatic slow growing mass. Surgery remains the mainstay of treatment. Hereby, we describe a case of 71-year-old male with malignant solitary fibrous tumor arising from right maxilla invading the right orbit presenting as proptosis.

Solitary fibrous tumour of the sacrum: A report of 2 cases with review of the literature

INTRODUCTION

Solitary fibrous tumour (SFT) of the sacrum is a very rare disease. So far, there have been few reports on this disease. Here, we reported 2 such cases and reviewed the other 7 reports in the literature.

CASE SERIES

Case 1, a 48-year-old man presented with lumbosacral pain for 2 months and numbness in the left plantar region for more than 1 month. The report of CT scan indicated that the sacrum was destroyed and the soft tissue mass projected into the pelvis. Histopathology showed that the cells were fusiform or short fusiform, arranged in strips, sheets, and wavy patterns. Case 2, a 40-year-old woman presented with hip joint pain and lower extremity dyskinesia for more than 2 months. The result of the MRI examination demonstrated a mass on the right sacral foramen and anterior sacrum. The characteristics of histopathology are ovoid or spindle-shaped cells with focal nuclear pleomorphism and prominently branched, hemangiopericytoma-like vascular patterns. In addition, immunohistochemical showed that CD34, Bcl-2, CD99, STAT6 and vimentin were positive, while Desmin, MSA, EMA, S100 were negative in both cases.

CONCLUSION

Previous literatures have revealed that SFTs of the sacrum are rare neoplasms. Case 1 and a part of these lesions previously reported seem to be malignant and should be treated with surgery. Radiation or chemotherapy was adopted if necessary. Since SFT of the sacrum is prone to recur and metastasis, long-term follow-up should be considered. To a certain extent, new risk stratification models can predict prognosis more accurately.

Symptomatic Sinus Bradycardia in a Patient with Solitary Fibrous Tumor/Hemangiopericytoma Treated with Pazopanib

Pazopanib, a multi-targeted tyrosine kinase inhibitor, is associated with cardiovascular adverse events, such as hypertension, cardiac dysfunction, and thromboembolism. However, symptomatic pazopanib-related bradycardia is uncommon. We herein report a case of symptomatic bradycardia of 35 beats per minute in a patient with solitary fibrous tumor/hemangiopericytoma (SFT/HPC) treated with pazopanib for 1 month. His heart rate recovered to a normal range soon after pazopanib cessation. He restarted pazopanib at a reduced dose, which was continued without SFT/HPC progression or bradycardia recurrence. This case highlights the possibility of bradycardia induced by pazopanib and the importance of monitoring the patient's heart rate.

[Recommendations for the organ donation from patients with brain or medullary primitive tumors on behalf of the Association of the Neuro-oncologists of French Expression (ANOCEF) and the Club of Neuro-oncology of the French Society of Neurosurgery]

Requests of organs to be transplanted increase. As a matter of urgency, it is not always easy to decide if a patient carrier of a brain tumor can be candidate in the donation. After a review of the literature, the members of the Association of the Neuro-oncologists of French Expression (ANOCEF) and the Club of Neuro-oncology of the French Society of Neurosurgery propose consensual recommendations in case of donor carrier of primitive tumor intra-cranial or intra-medullary. A contact with the neuro-oncologist/neurosurgeon will allow to discuss the indication in case of glioma of grade I/II/III, according to the grade, the current status (absence of progressive disease), the number of surgeries and of lines of treatment. The taking is disadvised in case of glioma of grade IV (glioblastoma), of lymphoma or meningioma of grade III. No contraindication for the meningiomas of grade I, and individual discussion for the meningiomas of grade II. It is advisable to remain careful in case of hemangiopericytoma and of meningeal solitary fibrous tumor. The patients in first complete remission of a medulloblastoma or intra-cranial primitive germinoma seem good candidates for the taking of organ if the follow-up is of at least 10 years (3 years for non germinomas). In every case, a multidisciplinary discussion is desirable when it is materially possible.

THE EXPERIMENTAL PRODUCTION OF VASCULAR TUMOURS IN THE RAT

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Intracranial hemangiopericytoma in a child

Hemangiopericytoma in the central nervous system is a rare tumor occurring predominantly in supratentorial sites. Classification may be confusing because the tumor may mimic the histological pattern of other vascular neoplasms. The particular feature of hemangiopericytoma are pericytes of blood vessels; they distinguish it as a separate and distinct tumor. The case of a 3 3/4-year-old child with a 3 3/4-year course is reported with a tumor in the middle fossa, the diencephalon, and the brainstem. The cystic tumor was resected twice. The child is presently alive with neurological deficit. The clinical, radiographic and histological findings are presented. The role of aggressive surgical treatment is emphasized.