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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.

We illustrated a rare case of malignant solitary fibrous tumor (MSFT) with epithelioid morphology in the occipital region of a 59-year-old female, in which a rare NAB2ex7-STAT6 exon15/16 double fusion subtype was detected by the Next-generation sequencing (NGS) and STAT6 immunohistochemistry (IHC) was diffusely and strongly positively expressed, without recurrence after 20 months of postoperative follow-up. The morphological and molecular genetic aspects and the differential diagnosis are described, and the relevant literature was assessed in order to broaden our understanding and diagnostic capability of this malignancy [ABSTRACT FROM AUTHOR]

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

Solitary fibrous tumor 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. [ABSTRACT FROM AUTHOR]

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 tumors (SFT) are rare spindle cell mesenchymal neoplasms of presumably fibroblastic origin with undefined malignancy potential and rare metastasis. Their most frequent localization is in the pleura, where they have been first described. The incidence of solitary fibrous tumors localized in liver is extremely low. The clinical picture of SFT is nonspecific and is not due to the anatomical location of the tumor and it's size.In the majority of cases these tumors are benign. However, a number of them still may have signs of malignancy: an aggressive course with possible local recurrence and distant metastasis. The main method of treatment of hepatic solitary fibrous tumor (as well as SFT of other localization) with it's resectability is surgery. Radical removal of the tumor in the majority of cases leads to recovery. Subsequently, the operated patients should be subjected to strict dynamic observation with regularity as in malignant neoplasms (MN).The importance for chemotherapy and radiation therapy in the treatment of hepatic solitary fibrous tumor has not been determined in clinical guidelines to date.There are isolated reports of the use of chemotherapy or radiation therapy for the treatment of cases when tumor resection is not radical or there are signs of malignant neoplasm.In literature, there are numerous reports of a combination of a solitary fibrous tumor of any localization with malignant neoplasms of other organs in the same patients.In this report, we represent a clinical case of a 64-year-old woman, who had a solitary fibrous tumor of the liver and highly differentiated rectal adenocarcinoma. The patient underwent resection of the first segment of the left lobe of the liver. After a month and a half, transanal excision of the villous tumor of the rectum. The pathologic and immunohistochemical examination of the liver tumor revealed a malignant solitary fibrous tumor. After researching villous tumor of the rectum - a highly differentiated adenocarcinoma with a depth of invasion of the submucous layer of the intestinal wall up to 1/3 (T1sm1 according to Kikuchi). During dynamic observation for twenty-five months after the operation, the patient has no signs of tumor recurrence and metastasis.

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.

Solitary fibrous tumors (SFTs) of the head and neck are very rare, with less than 600 reported cases in English literature. We present a case of a 37-year-old female with a diagnosis of malignant solitary fibrous tumor (MSFT) of the infratemporal fossa. The patient underwent a right partial maxillectomy and resection of a right infratemporal fossa lesion via transoral approach as well as post-operative radiation therapy. Several months after radiation, the patient developed swelling of the right temporal region with displacement and swelling of the right eye that correlated to her complaint of worsening diplopia. The patient was found to have another tumor mass in the right temporal region with invasion of the temporal bone and lateral orbit wall as well as metastasis to the lungs and neck. A radical resection of the right temporal tumor with free flap reconstruction was performed. The patient tolerated the surgery well and is undergoing adjuvant chemotherapy. This is the fourth case of a MSFT of the infratemporal fossa known in the literature. Due to the rarity of MSFTs, prognosis and adjuvant therapy have not been fully investigated. The current best management of the patient is long-term close follow-up.

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. [ABSTRACT FROM AUTHOR]

Abstract 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.

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.

Abstract 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.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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.

We illustrated a rare case of malignant solitary fibrous tumor (MSFT) with epithelioid morphology in the occipital region of a 59-year-old female, in which a rare NAB2ex7-STAT6 exon15/16 double fusion subtype was detected by the Next-generation sequencing (NGS) and STAT6 immunohistochemistry (IHC) was diffusely and strongly positively expressed, without recurrence after 20 months of postoperative follow-up. The morphological and molecular genetic aspects and the differential diagnosis are described, and the relevant literature was assessed in order to broaden our understanding and diagnostic capability of this malignancy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Huang, Liu, Chen, Hao, Luo, Yuan, Huang and Tang.)

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., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Ramineni et al.)

Intravascular large B-cell lymphoma (IVLBCL) is a very rare type of extranodal large B-cell lymphoma that selectively grows within vessels and can spread to any organs or tissues. A very few cases of synchronicity with malignant tumor have yet been described. We report a rare case of IVLBCL accompanying a pleural malignant solitary fibrous tumor (MSFT). A 76-year-old man presented with a chronic dry cough, fever, minor general state deterioration and pancytopenia. Imaging revealed a large pleural mass. Histologically, the mass consisted of a MSFT. However, CD20+ malignant round cells were scattered within lumina of intratumoral blood vessels, evidencing a synchronous IVLBCL occurrence. Molecular analysis of the lymphoid clone identified MYD88 and CD79B gene mutations. After pleural mass excision, global health’s patient improved with cytopenia correction. However, a general state deterioration appeared 4 months after surgery, associated with a large retroperitoneal mass presenting the same pathological and molecular patterns identical to the initial IVLBCL clone.

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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., Competing Interests: The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the United States Army, Navy, or Department of Defense. The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Several of the authors are employees of the US government. This work was prepared as part of their official duties. Title 17 U.S.C. 105 provides that “Copyright protection under this title is not available for any work of the United States Government.” Title 17 U.S.C. 101 defines United States Government work as work prepared by a military service member or employee of the United States Government as part of that person’s official duties., (Copyright © 2024, Rudolph et al.)

Extrauterine pelvic hemangiopericytomas are rare tumors with malignant potential. Herein, we report a case of a 55-year-old male who presented with hydronephrosis and obstructive urinary symptoms. Cystoscopy, imaging and biopsy were unable to provide a definitive preoperative diagnosis. He underwent pelvic mass resection, and final pathology revealed malignant hemangiopericytoma. The patient is being closely monitored with serial imaging, and remains disease-free at 23 months of post-operative follow-up without adjuvant therapy. Our experience and evidence from the existing literature suggests that given the rarity of these tumors, adherence to standard oncologic principles is necessary to ensure adequate resection and appropriate follow-up.

Background: Thoracic solitary fibrous tumors (TSFTs) are uncommon mesenchymal tumors. The data regarding surgical outcomes and prognostic factors are scarce. This retrospective paper is to analyze surgical outcomes, clinical characteristics and prognosis of TSFT. Methods: A single-center retrospective study of the data of 70 patients with TSFT who underwent surgical resection in our department between August 2008 and October 2014 was conducted. Results: A total of 70 TSFTs (58 benign, 12 malignant) were included and all patients underwent complete surgical resection except one recurrent patient with initial treatment. TSFTs originated from the pleura (n = 43), lung (n = 9), mediastinum (n = 16), esophagus (n = 1) and diaphragm (n = 1), respectively. Mass excision was only performed in 29 patients, en bloc excision including surrounding structures was performed in 41 patients. During follow-up, no tumor recurrence occurred in benign TSFT patients. All recurrences occurred in 6 malignant patients, and 5 of them died because of local recurrence and distant metastasis. Median follow-up was 95 months (range, 3–133 months). The 5-year overall survival (OS) of TSFT patients was 94.3%. The 5-year relapse-free survival and OS of malignant TSFT patients were 58.3% and 66.7%, respectively. Conclusion: The gold standard of TSFT treatment is complete surgical resection. VATS is safe and reliable for treating selected TSFT patients. Aggressive surgical resection could be underwent in such patients of local recurrence or solitary metastatic tumor. A long-term follow-up is necessary due to the risk of recurrence. [ABSTRACT FROM AUTHOR]

We illustrate a case of synchronous malignant solitary fibrous tumor of the thoracic cavity, and widely invasive thyroid Hurthle cell carcinoma. The Hurthle cell carcinoma was found to harbor distinct areas of malignant solitary fibrous tumor. This is a unique case of tumor-to-tumor metastasis that, to the best of our knowledge, has not been previously reported. [ABSTRACT FROM AUTHOR]

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., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

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. [ABSTRACT FROM AUTHOR]

Solitary fibrous tumors are an uncommon slow growing benign neoplasm originally described as a pleural neoplasm but can also be found in the lung, mediastinum, peritoneum, or any other sites including the head and neck. Malignant solitary fibrous tumors (MSFT) are extremely rare and only few cases have been published in the literature. There have been 19 cases reported of MSFT in the head and neck, but there are no reports of MSFT located within the scalp in the English language literature. We present a case of MSFT arising in the scalp and describe our experience with the clinical presentation, surgical management, and outcome in this pathological condition. [ABSTRACT FROM AUTHOR]