CD34-Negative Malignant Renal Solitary Fibrous Tumor: Case Report and Diagnostic Insights.

Solitary fibrous tumors (SFTs) are rare fibroblastic neoplasms with diverse biological behaviors and widespread distribution. Primary renal SFTs are uncommon, and their malignant variants, especially those that are CD34 negative, are even rarer. This study presents a case of malignant renal SFT in a 57-year-old female, focusing on its immunomorphological features. On gross examination, the tumor's large size (11.5 cm) was remarkable. Microscopic analysis showed high cellularity, diffuse sheets of moderately pleomorphic ovoid cells, prominent staghorn vessels, tumor cell necrosis, and a high mitotic count. Immunohistochemistry revealed strong positivity for STAT6, vimentin, and Bcl-2 and, notably, negativity for CD34. The presence of the NAB2::STAT6 gene fusion was confirmed through fluorescence in situ hybridization. This case emphasizes the need to consider SFT in the differential diagnosis of unusual renal tumors, even when CD34 is negative. The infrequency, morphological diversity, and resemblance to other tumors make diagnosing renal SFTs challenging. Accurate identification and classification as benign or malignant are crucial for proper clinical management and prognosis.

Intracranial Solitary Fibrous Tumor: A Case of a 21-Year-Old Male With Olfactory Hallucination.

Meningeal solitary fibrous tumors (SFTs) are a rare central nervous system neoplastic process, resulting in frequent misdiagnosis as meningioma prior to pathologic analysis. Appropriate diagnosis is essential to lowering morbidity and mortality, as Grade II or III SFTs are aggressive neoplasms that possess metastatic potential. The existing data may suggest that intracranial SFTs primarily afflict those in their fourth through sixth decades of life. However, we present the case of a patient outside this demographic presenting with symptoms that we were unable to identify in any prior reports. A 21-year-old male in the United States Navy presented to the emergency department (ED) with a two-month history of progressive headaches, leading to nausea and emesis. The patient also endorsed a daily incidence of the same olfactory hallucination followed by several minutes of palpitations, flushing, and dizziness. His neurologic exam was unremarkable, but imaging in the ED revealed a large mass abutting the right medial sphenoid wing. The radiographic appearance of the mass with a dural tail led to a preoperative diagnosis of meningioma. However, pathologic analysis following gross total resection identified the mass as an SFT. A brief literature review complementary to this case underscored the high variability of intracranial SFT case presentations with a relative scarcity of epidemiologic data due to rarity. This review identified that it was common to initially diagnose SFTs as meningioma, similar to this particular case. This emphasizes the importance of an appropriate pathologic diagnosis. This case adds to the existing literature as anecdotal evidence of SFT occurring in a young patient and a unique symptom profile most notable for olfactory hallucination and dysautonomia as features of focal seizure.

Malignant Solitary Fibrous Tumor of the Mediastinum with Multiple Recurrences and a Rare Metastasis to the Thyroid Gland: A Case Report.

Solitary fibrous tumors (SFTs) are rare neoplasms arising from mesenchymal cells. Although most SFTs are benign, rare cases of metastasis have been reported at various sites. Complete surgical resection is the mainstay of treatment for both primary and recurrent or metastatic SFTs. Herein, we present a case of an SFT initially identified in the anterior mediastinum that later developed multiple metastases, even to the thyroid gland. The patient underwent repeated surgical resection and is currently being followed up in an outpatient setting.

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.

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

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

Tumor fibroso pleural ¿son realmente benignos? ¿Cuándo deben operarse? / Pleural fibrous tumor, are they really benign? When should they have operation?

El tumor fibroso pleural es un tumor habitualmente asintomático, benigno y de lento crecimiento, que en un pequeño porcentaje de los casos tiene un comportamiento más agresivo. Para definir los criterios de malignidad es necesario un análisis inmunohistoquímico. El tratamiento de elección es la resección quirúrgica completa con márgenes de seguridad ya sea por toracotomía o por videotoracoscopia en función del tamaño. Se encuentra en estudio la utilización de terapia adyuvante radioterápica o quimioterápica que en el momento actual no cuenta con resultados significativos. Presentamos dos casos que fueron tratados de forma quirúrgica, con extirpación completa siendo el primero definido como maligno según los criterios histológicos y el segundo benigno, pero de alto riesgo. Solo uno de ellos recibió terapia adyuvante. (AU)

Solitary fibrous pleural tumor is a usually asymptomatic, benign and slow-growing tumor, which in a small percentage of cases has a more aggressive behavior. To define the malignancy criteria, an immunohistochemical analysis is necessary. The gold standard treatment is a complete surgical resection with safety margins either by thoracotomy or by videothoracoscopy depending on the size. The use of radiotherapy or chemotherapy as an adjuvant therapy is under study, which at the present time does not have significant results. We present two cases that were treated surgically, with complete removal, one being classified as malignant according to histological criteria and the other benign but high risk. Only one of them received adjuvant therapy. (AU)

Malignant solitary fibrous tumor of the penis: A case report of rare malignancy.

Malignant Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that consists of spindle cell components. The occurrence of SFT in the genitourinary tract is extremely rare. So, there is no clear algorithm for the management of this case. We report A 33-year-old male who complained of recurrent penile swelling in the last 7 months after underwent surgery 3 months earlier. The tumor re-enlarged from the surgical wound's previous sutures. Total penectomy was performed followed by bilateral inguinal lymphadenectomy. Perineostomy was performed for urinary diversion. Long-term follow-up after surgery is suggested due to the risk of recurrences and metastasis.

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.

Retroperitoneal malignant solitary fibrous tumor with second recurrence and lymphatic metastases: A case report.

Malignant solitary fibrous tumor (SFT) in the retroperitoneum is rare. The present study reported on the case of a 67-year-old man who had retroperitoneal SFT for ~13 years, which resulted in two recurrences and lymphatic metastases. After the second recurrence, the patient presented with hematochezia and multiple retroperitoneal masses were found through computed tomography (CT). Histopathological examination showed that the tumor was mainly comprised of short spindle cells, arranged into sparse and dense areas. Mitotic figures were observed, generally 6-8 mitoses/10 high power fields, along with local necrosis. The tumor invaded the circumferential liver, intestines, lymphatic vessels and lymph nodes. Combined with the immunohistochemical results, it was diagnosed as a malignant SFT, which regrew just 2 months after the latest surgery. Retroperitoneal SFTs with repeated relapses, infiltrative growth and lymphatic metastasis suggest the need for careful and long-term follow-up.

Malignant Solitary Fibrous Tumor of the Nasal Cavity and Orbit: A Case Report.

Solitary fibrous tumors are well-recognized in the pleura and their occurrence in the nasal cavity is uncommon. They show a hemangiopericytoma-like vasculature, a "patternless pattern" of growth, and lesions characterized by both hypercellularity and hypocellularity. As a malignant form of SFT, mesenchymal neoplasm is extremely uncommon and poorly understood, although there are no established standards for making this diagnosis, it is nonetheless accepted. It can develop either de novo or within an already-existing benign SFT, and there are few published accounts of the cytopathologic characteristics of these tumors.In this case, a patient complained of tenderness on the right nasal root and diplopia for six months. Here, we report on a case of malignant solitary fibrous tumors in the nasal cavity, which extended into the orbit, and review the radiologic and pathologic features.

Solitary fibrous tumor of the masticator space - Report of a rare case.

The solitary fibrous tumor (SFT) is a potentially malignant spindle cell neoplasm of the mesenchymal origin that was originally described as a thoracic lesion originating from the pleural tissue. Recently, numerous extrapleural sites of origin have been described, also affecting the head and neck region. SFTs are benign in most cases, but 10%-15% of extrapleural SFTs show malignant behavior in the form of recurrent or metastatic disease. We present the case of a 25-year-old female who presented with an asymptomatic left-sided facial swelling of over three years. She had a diffuse swelling in the left preauricular region, extending to the temporal region deep to the zygomatic arch. On magnetic resonance imaging, the vascular lobulated mass occupied the masticator space, infratemporal fossa, and parapharyngeal space, eroding the mandible. An ultrasound-guided fine-needle aspiration cytology was suggestive of SFT, positive for signal transducer and activator of transcription 6 and negative for TLE1. After preoperative embolization, the tumor was excised through a midline lip split approach with posterior segmental mandibulectomy and reconstruction with a titanium plate. Histopathological report was consistent with SFT. Due to high-risk features, she was advised adjuvant radiation therapy. SFTs of the head and neck are exceedingly rare and those with aggressive behavior even more so. To our knowledge, this is the only case of SFT arising in the masticator space. Diagnosis is often difficult and not definitive without immunohistochemistry. In most cases, complete surgical excision is the only treatment necessary. Regardless, all patients require close clinical follow-up for several years.

Case report: 125I seed implantation for rare malignant solitary fibrous tumor in the pelvic cavity: a case report.

Solitary fibrous tumor (SFT) is a rare spindle cell tumor, benign or low-grade malignant, with an extremely low possibility of occurrence of malignant solitary fibrous tumor (MSFT). Surgery is an effective way for treating SFT, but it is often difficult to resect completely due to a large size, with a high recurrence rate and mortality rate after operation. Additionally, SFT is relatively resistant to chemotherapy, and there is a lack of effective systemic drug treatment. These lead to certain difficulties in the treatment of SFT. We report a case of a rare MSFT in the pelvic cavity. With a history of recurrence after two surgeries, this patient underwent surgical removal combined with 125I seed implantation at our hospital in the context that the tumor could not be completely removed because it was large and adhered to surrounding tissues; after up to 43 months of progression-free survival (PFS), the patient underwent 125I seed implantation alone, and achieved a complete remission, with a PFS up to 35 months. 125I seed implantation can be a safe and effective treatment option for unresectable MSFT as well as a potential solution to repeated local recurrence.

A first report of a rare TP53 variant associated with Li-Fraumeni syndrome manifesting as invasive breast cancer and malignant solitary fibrous tumor.

BACKGROUND: Li-Fraumeni is a rare autosomal dominant cancer predisposition syndrome. The basis is a germline mutation of TP53 gene which encodes tumor suppressor protein resulting in early onset of tumors, most often breast cancer, soft tissue sarcomas, brain tumors, adrenocortical carcinomas, and leukemia. CASE REPORT: We present a case of a young woman with a positive family history for cancer diagnosed with malignant solitary fibrous tumor and luminal B-like invasive breast cancer. Breast cancer and sarcomas account for the majority of tumors associated with Li-Fraumeni syndrome, yet solitary fibrous tumor is a rare clinical entity with no established guidelines for treatment. Even though both primary tumors were successfully resected, the sarcoma relapsed in the form of lung metastases. The NGS analysis revealed single nucleotide variant (c.1101-1G>A) in TP53 gene, affecting the acceptor splice site at intron 10. Until now, only one case of this genetic variant has been documented with conflicting interpretations of pathogenicity. CONCLUSIONS: The knowledge of TP53 mutation status is essential since the management of these patients requires different approach to avoid excessive toxicity due to the risk of developing secondary malignancy. Using the clinical criteria to screen for affected individuals facilitates appropriate early genetic counseling of patients and their families. Following the American College of Medical Genetics criteria, we believe that the reported single nucleotide variant (c.1101-1G>A) in TP53 gene should be considered pathogenic.

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.

Retroperitoneal fibrous tumor recurring as lung metastases after 10 years: a case report.

BACKGROUND: Solitary fibrous tumor (SFT) is a relatively rare mesenchymal tumor that mainly affects adults. Its prognosis is good after curative resection, but distant recurrences after 10 years or longer have been reported. Recurrent SFT usually arises as a local lesion; distant metastasis is rarely reported. Here, we report lung metastases that recurred a decade after excising a retroperitoneal primary SFT. CASE PRESENTATION: A 44-year-old woman had an SFT resected from her right retroperitoneum at our hospital. Ten years later, at age 54, she underwent a lung resection after CT showed three suspected metastases in her left lung. All three were histologically diagnosed as lung metastases from the retroperitoneal SFT. However, whereas the primary SFT had 1-2 mitotic cells/10 high power fields (HPF), the metastatic lesion increased malignancy, at 50/10 HPF. CONCLUSION: Patients who have had resected SFTs should be carefully followed up, as malignancy may change in distant metastasis, as in this case.

Pazopanib-associated secondary adrenal insufficiency in a patient with malignant solitary fibrous tumor.

INTRODUCTION: Pazopanib is an agent that is being successfully used in soft tissue sarcomas. Some endocrine side effects may develop during pazopanib treatment. Here, we presented a case diagnosed with secondary adrenal insufficiency while being investigated for etiology of hypoglycemia which developed after pazopanib. CASE REPORT: A 69-year-old male patient was operated in June 2019 due to a lung mass 26 × 18 × 10 cm in size. Pathological diagnosis revealed a solitary fibrous tumor with malignant behavior. The patient received three lines of chemotherapy. After pazopanib treatment, a hypoglycemic attack was reported.Management and outcome: Blood cortisol and ACTH (Adrenocorticotropic hormone) levels were not increased at the time of the hypoglycemic attack, and levels of other pituitary hormones were found to be normal. Electrolyte levels were in normal range. Since the counteracting hormone did not reach a sufficient level, it was considered secondary adrenal insufficiency. Hypoglycemic attacks did not occur during follow-up while taking steroid therapy and pazopanib. DISCUSSION: A single case of primary adrenal insufficiency has been reported in the literature. We here present a case who developed hypoglycemia after pazopanib and was diagnosed with drug-associated secondary adrenal insufficiency. When hypoglycemia develops during pazopanib treatment, we must be aware of adrenal insufficiency.

Case Report: Molecular Characterization of Aggressive Malignant Retroperitoneal Solitary Fibrous Tumor: A Case Study.

Solitary fibrous tumors (SFT) are mesenchymal neoplasms with a favorable prognosis usually originating from the visceral pleura. Rarely, they may occur at various extrapleural sites and show malignant behavior coupled with dedifferentiation. NAB2-STAT6 fusion gene and STAT6 nuclear expression are biomarkers for diagnosis of SFT in addition to CD34, Bcl-2, and CD99. Furthermore, several reports have shown specific NAB2-STAT6 fusion variants and loss of STAT6 protein expression are associated with malignancy. We report a rare case of retroperitoneal SFT which rapidly progressed to death within 35 days after admission. Autopsy found a primary tumor containing both benign and malignant histologies, with multiple metastatic sites similar to the malignant, dedifferentiated tumor. STAT6 was detected in the primary differentiated tumor but not in the primary dedifferentiated tumor or lung/liver metastases. However, the NAB2-STAT6 fusion gene (NAB2ex6/STAT6ex16 variant) was detected in the primary tumor and lung/liver metastases. Intriguingly, fusion gene expression at the transcriptional level was downregulated in the dedifferentiated tumors compared to the differentiated tumor. We further performed target DNA sequencing and found gene mutations in TP53, FLT3, and AR in the dedifferentiated tumors, with TP53 mutations especially found among them. We demonstrate that downregulation of NAB2-STAT6 fusion gene at the transcriptional level is associated with malignant SFT for the first time. Moreover, the present study supports the idea that TP53 mutations promote malignancy in SFTs.

Transcatheter arterial embolization of malignant pelvic solitary fibrous tumor: case report and literature review.

Pelvic malignant solitary fibrous tumor (SFT) is a relatively rare disease, and literature on radical resection with transcatheter arterial embolization of pelvic SFT is lacking. In this work, we report on a 55-year-old man with a presacral mass who was hospitalized at our department. Computed tomography and magnetic resonance imaging indicated pelvic space-occupying lesions that were 12 cm × 10 cm in size and pelvic lesions that were not clearly demarcated from the right posterior wall of the bladder and the right ureter. This result suggested severe secondary hydronephrosis of the right renal pelvis. The patient underwent transcatheter iliac arterial embolization. Radical tumor resection was performed, and the results of pathological examination confirmed the diagnosis of malignant pelvic SFT. There was no SFT recurrence in this patient at 1-year follow-up. Herein, we report on the treatment of a patient with malignant pelvic SFT, a rare condition, who underwent successful radical resection after transcatheter arterial embolization. Transcatheter arterial embolization can block the blood supply of the SFT as much as possible and improve the possibility of tumor resection. In the future, pelvic SFTs can be considered improving the resection rate by transcatheter arterial embolization before surgery.

Clinicopathological features to distinguish malignant solitary fibrous tumors of the prostate from prostatic stromal tumors.

Mesenchymal tumors of the prostate are rare but encompass a wide differential diagnosis. In our study, we aimed to investigate the clinicopathological features that can be used to differentiate malignant solitary fibrous tumors (mSFTs) occurring in the prostate from prostatic stromal tumors. A total of 15 patients with mesenchymal tumors of the prostate were identified in Nanjing Drum Tower Hospital from 2009 to 2019, including 3 mSFTs, 9 stromal tumors of uncertain malignant potential (STUMPs), and 3 prostatic stromal sarcomas (PSSs). Immunohistochemical stains for signal transducer and activator of transcription 6 (STAT6), aldehyde dehydrogenase 1 (ALDH1), CD34, desmin, smooth muscle actin (SMA), progesterone receptor (PR), CD117, and cytokeratin (CK) were performed on representative sections from each tumor, and the clinical features, histology, and immunophenotype of these three groups were analyzed. There was no significant difference in mean patient age of patients diagnosed with mSFTs, STUMPs, and PSSs. mSFTs and PSSs showed significantly increased tumor size (p < 0.05), Ki-67 proliferation index (p < 0.0001), and mitotic activity (p < 0.05) when compared with STUMPs. mSFTs showed significantly higher expression of STAT6 compared with both PSSs and STUMPs (p < 0.0001, p < 0.0001). PR showed significantly more expression in STUMPs than in mSFTs or PSSs (p < 0.0001, p < 0.0001). Desmin and SMA showed significantly more expression in STUMPs than in mSFTs (p < 0.05). ALDH1, CD117, CK, and CD34 showed no significant difference in staining between mSFTs, STUMPs, and PSSs. Therefore, a limited panel of STAT6, PR, and Ki-67 may be useful in distinguishing between mSFTs, STUMPs, and PSSs.

Intracranial malignant solitary fibrous tumor metastasized to the chest wall: A case report and review of literature.

BACKGROUND: Solitary fibrous tumor (SFT) is a rare fibroblastic mesenchymal neoplasm that affects spindle cell soft tissues with broad-spectrum biological behavior; it is predominantly benign, and rarely metastasizes. SFT occurs mainly in the tissue structure of the serosa in the pleura and the thorax, and can be found throughout the body, though extra-thoracic localization, including the cephalic region, is un-common. We reported the first case of intracranial malignant SFT metastasized to the chest wall. CASE SUMMARY: An 81-year-old Japanese man was referred to our hospital due to progressive gait disturbance and appetite loss. His medical history included partial resection due to brain tumor, four times, and 50-Gray radiation therapy at another hospital, starting when he was 74 years old. An unenhanced head computed tomography (CT) scan revealed an 8 cm × 5.1 cm × 6.5 cm mixed-density mass at the left frontal lobe, accompanying a midline shift, and an unenhanced chest-abdomen CT scan revealed a 6 cm × 4.1 cm × 6.5 cm low-density mass in the left chest wall. A CT-guided percutaneous lung biopsy was performed, and the pathological findings were SFT corresponding to brain tumor. Finally, the correct diagnosis of his brain tumor in history of past illness revealed to be SFT, and the unremovable tumor, namely present brain lesions enlarged and metastasized to the chest wall. We established a definitive diagnosis of intracranial malignant SFT metastasized to the chest wall. We notified him and his family of the disease, and offered palliative care. He passed away on the 29th hospital day. CONCLUSION: This case suggests the need for careful, detailed examination, and careful follow-up when encountering patients presenting with a mass.