Atypical and malignant solitary fibrous tumors in extrathoracic locations: evidence of their comparability to intra-thoracic tumors

Robotic-assisted laparoscopic resection of a pelvic solitary fibrous tumour causing distal ureteric compression

This case report describes a male in his late 40s with a 4 cm pelvic mass compressing the left distal ureter, resulting in left hydroureteronephrosis. Biopsy of the mass was suggestive of a solitary fibrous tumour. The patient underwent a robotic-assisted laparoscopic excision of the left pelvic mass. Intraoperatively, the mass was found to be densely adhered to the ureter, necessitating a left distal ureterectomy and ureteric reimplantation. Subsequent histopathological analysis revealed the mass was a solitary fibrous tumour with no evidence of malignancy.

Excision of a Solitary Fibrous Tumor in the Sciatic Notch with Sciatic Nerve Compression - A Rare Clinical Case

We present the clinical case of a 41-year-old woman with no relevant personal history. The patient complained of diffuse self-limiting abdominal pain, and we incidentally detected an extra-abdominal, extraperitoneal tumor mass at the level of the right sciatic notch. The abdominal complaints were gone during the initial follow-up, but the patient developed sciatica radiating to the right foot and electric shock-like pain. A computed tomography (CT)-guided biopsy revealed a low-grade mesenchymal neoplasm of the soft tissues with characteristics consistent with a solitary extrapleural fibrous tumor. The pelvis team of the orthopedics department received the patient for surgical excision of the lesion. The procedure occurred with no complications, and we excised the totality of the lesion with tumor-free margins. An anatomopathological examination was compatible with the biopsy assessment. The excision of the lesion resulted in complete resolution of the sciatic nerve compression-related symptoms.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Solitary Fibrous Tumor of the Kidney With Pure Round Cell Features: A Case Report With Review of Literature

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm known to occur at various soft tissue and visceral locations. Kidney is a rarely reported site for these tumors. Most of the SFTs described in the kidney exhibit a classical CD34-positive patternless spindle cell histology. Focal round cell morphology is seldom reported. Herein, we describe a 48-year-old male patient with renal SFT. This tumor had pure round cell morphology with a CD34-/STAT6+ immunophenotype. Fluorescent in situ hybridization and a multiplexed sequencing assay performed on an Illumina® HiSeq 4000 platform revealed NAB2 and STAT6 gene rearrangement. Renal tumors with round cell morphology are diagnostically challenging and SFT is not often considered in the differential diagnosis of a round cell tumor of the kidney. Moreover, a CD34-negative profile can be rather confounding while diagnosing such lesions. In such scenarios, a strong nuclear STAT6 immunostaining is extremely helpful in clinching the diagnosis. SFT should always be considered in the differential diagnosis of round cell tumors of the kidney due to significant diagnostic and therapeutic implications.

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

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

Orbital Solitary Fibrous Tumors: A 20-Year Cases Series Study in a Single Center

PURPOSE

To investigate the clinical manifestations, imaging, pathology, and prognosis of orbital solitary fibrous tumors (OSFTs). In addition, the surgical incisions and the treatment outcomes were also evaluated.

METHODS

A total of 89 patients with pathologically confirmed primary OSFTs were enrolled onto this study. Clinical and histopathological characteristics, imaging data, treatment modalities, and follow-up time, including tumor recurrence and death, were documented. The outcome measures included overall survival and disease-free survival time.

RESULTS

Among 89 eligible cases, the median age of presentation was 39 years (range: 5-80 years) at the initial diagnosis. The most common presenting symptom was painless proptosis (54, 60.67%), then palpable mass (31, 34.83%), swelling (29, 32.58%), and impaired ocular motility (27, 30.34%). Tumor-related severe impaired vision was found in 11 patients (12.36%), including no-light-perception blindness (6, 6.74%), light-perception (2, 2.25%), and hand-movement (1, 1.12%). The preoperative imaging (computed tomography and magnetic resonance imaging) accurate diagnostic rate of OSFTs was 17.98% (16, 95% CI: 0.098-0.261), and misdiagnosis rate was 25.84% (23, 95% CI: 0.166-0.351). Grossly intact masses were excised for 27 patients (30.34%). Among the 89 patients, 33 (37.08%) were recurrences, and the median of these recurrent patients' interval between the first and the last operation was 7.33 years (range: 0.12-29.69 years). In 81 patients with complete follow-up data, the median course of the disease was 9.64 years (range: 1.55-33.65 years) from the onset OSFT. The overall survival rate of the 81 patients was 93.83% with a median course of 8.48 years (range: 0.38-30.4 years) from diagnosis of OSFT, and the disease-free survival rate of 81 patients was 91.36% with a median follow-up of 4.76 years (range: 0.08-19.22 years) after the last surgery. Of all the 81 patients, 5 patients (6.17%) developed local recurrence, and 3 patients (3.70%) died from tumor-related diseases, including pulmonary metastasis (2, 2.47%) and complications from intracranial lesions (1, 1.23%). Ten patients (11.24%) received postoperational radiation therapy, including 125I seeds implantation (5, 6.17%) and external beam radiotherapy (5, 6.17%), and remained no recurrence.

CONCLUSIONS

In this series, OSFTs showed long courses and easy recurrence. Although it was very important to choose a proper surgical incision for intact resection of OSFTs at the initial surgery to avoiding recurrence, preoperative imaging is of very limited use since it is not able to identify OSFTs effectively. Postoperative radiotherapy may be beneficial to reduce the recurrence of OSFTs with malignant pathologic features.

Metastatic pancreatic solitary fibrous tumor: A case report

BACKGROUND

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that is most commonly found in the pleura but can also originate from non-pleural sites. Among the non-pleural localizations, the pancreas is extremely rare. In particular, metastasis to the pancreas from the central nervous system (CNS) is extremely rare, with only two cases reported so far. We report a case of recurrence in the pancreas 14 years after the initial complete surgical removal of a tumor in the CNS.

CASE SUMMARY

A 68-year-old man with a past medical history of recurrent meningeal hemangiopericytoma, currently referred to as SFT, presented to the hospital with jaundice. The patient was first diagnosed with an 8cm-sized meningeal hemangiopericytoma fourteen years ago and underwent osteoplastic craniotomy. After 16 mo, imaging showed recurrence and he underwent gamma knife radiosurgery (GKRS). 2 years later, imaging showed recurrence again leading to a second GKRS. 5 years later, recurrence was again suspected leading to a second craniotomy. Since then 3 years had passed, and imaging showed a 3.5cm-sized mass lesion on the pancreatic head with obstruction of the pancreatic and bile ducts. Endosonography with fine-needle aspiration biopsy was done preoperatively and aided in the diagnosis of SFT. The patient underwent pylorus-preserving pancreaticoduodenectomy. Pathologic findings of the resected pancreatic specimen, consistent with the previously resected brain specimen, confirmed the diagnosis of SFT.

CONCLUSION

The rarity and lack of knowledge about SFTs make suspecting and diagnosing this disease challenging. We believe that a report of metastatic pancreatic SFT from the CNS will contribute to a better understanding of this rare disease.

Solitary Fibrous Tumor of the Pancreas: Analysis of 9 Cases With Literature Review

Solitary fibrous tumor (SFT) has been increasingly reported in various anatomic sites. However, it is still extremely rare in the pancreas. Herein, we present the first series of primary pancreatic SFTs. Nine cases of primary pancreatic SFTs were analyzed. The mean age was 60 years (36 to 76 y) with no sex predilection. Six tumors were in the head, 3 were in the tail. On imaging studies, tumors were described as a hypervascular mass, 2 revealed cystic areas, and 3 were favored to be neuroendocrine tumors. On biopsy, 2 cases were diagnosed as atypical spindle cell tumor; one was misdiagnosed as suspicious for sarcoma, and another case as metastatic renal cell carcinoma. Two were diagnosed as low-grade sarcoma and low-grade stromal tumor on frozen sections. Grossly, tumors were well-demarcated with a median size of 4 cm (0.9 to 15 cm). Microscopically, they were composed of ovoid to spindle tumor cells with no significant mitotic activity and were arranged in alternating hypercellular and hypocellular areas. Staghorn-like vessels and entrapped pancreatic parenchyma were also detected within all tumors. Tumor cells revealed diffuse/strong nuclear STAT6 expression in 7 of 8, CD34 in 7 of 9, and bcl-2 in 4 of 4 tested cases. One tested tumor harbored NAB2 - STAT6 fusion. Eight patients with available follow-up data were free of disease at a mean follow-up of 76 months (3 to 189 mo). SFT should be considered in the differential diagnoses of mesenchymal neoplasms of the pancreas. Immunohistochemical nuclear STAT6 expression is a characteristic feature of SFT. Primary pancreatic SFTs seem to have favorable biological behavior in our series.

Solitary Fibrous Tumor of Breast and Axilla: Clinicopathological Profile of Five Tumors With Comparison of Risk Stratification Models

Introduction: Solitary fibrous tumor (SFT) is a fibroblastic tumor with malignant potential that is underpinned by a recurrent inv12(q13q13)-derived NAB2::STAT6 fusion. Breast and axilla are uncommon locations for this entity. Methods: Records of two academic institutions were electronically searched for breast and axillary SFTs. Clinical and pathologic data were reviewed. Literature review for breast or axillary SFTs was performed. Present study and previously reported tumors were stratified using five SFT risk models: original and modified Demicco metastatic risk, Salas local recurrence risk, Salas metastatic risk, and Thompson local recurrence risk. Results: Five patients with breast or axillary SFT were identified. Median age was 49 years, and median follow-up (available for four patients) was 82 months. Three patients showed no evidence of disease, and one developed recurrence. Literature review identified 58 patients with breast or axillary SFT. Median age was 54 years, and median follow-up (available for 35 patients) was 24 months. Thirty-one patients showed no evidence of disease, three developed recurrence, and one developed metastasis. Original and modified Demicco models and Thompson model showed the highest sensitivity; original and modified Demicco models and Salas metastatic risk model demonstrated the highest specificity. Kaplan-Meier models were used to assess recurrence-free probability (RFP). Original and modified Demicco models predicted RFP when stratified by "low risk" and "moderate/intermediate and high risk" tumor, though sample size was small. Conclusions: While many SFTs of breast and axilla remain indolent, a subset may develop recurrence and rarely metastasize. The modified Demicco risk model demonstrated optimal performance characteristics.

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.

Large Solitary Fibrous Tumor (SFT) of the penis- a case report and review of literature

BACKGROUND

Solitary fibrous tumors (SFTs) are very rare spindle cell neoplasms of mesenchymal origin with largely benign course of disease. Genital SFT's can be managed providing excellent functional and psychological outcomes by timely intervention.

CASE PRESENTATION

We report the largest and possibly the second only reported case of penile SFT in a 34 year male presenting with a gradually increasing perineal mass with clinically normal appearing phallus. MRI revealed a 9.8 × 3.2 cm soft tissue mass arising from left corpora cavernosae, the mass was excised en-bloc via a perineal approach under spinal anaesthesia. Histopathology revealed spindle cell tumor embedded in myxohyaline stroma along with hyalinized vascular channels demonstrating IHC positivity for CD34 and STAT6. The patient is disease free post 2 years of resection with no sexual or urinary dysfunctions.

CONCLUSION

Genital SFTs, although rare, should be considered in the differential diagnosis of well-circumscribed, painless, slow growing solid masses and histopathologists must be vigilant of its malignant characteristics.

Solitary fibrous tumor of the orbit in a 1-year-old patient: a case report

Solitary fibrous tumors (SFTs) are rare neoplasms of mesenchymal origin. While the mean age of presentation is 58 years old, we report the case of the youngest documented patient with an SFT of the orbit. A 13-month-old child was evaluated for eyelid asymmetry and then referred to the oculoplastic service. On examination, a soft tissue mass of the right inferomedial orbit was observed. MRI demonstrated a well-circumscribed, extraocular lesion in the inferomedial right orbit, potentially fibrous in nature. Excision was performed without complications. Pathologic examination demonstrated fibrous tissue proliferation with a staghorn vascular pattern, as well as benign fibrous cells with tapering nuclei and abundant pericellular reticulin. Immunohistochemistry (IHC) demonstrated that the cells stain diffusely positive for CD34 and vimentin. With the MRI findings, pathology, and IHC, the diagnosis was confirmed to be SFT. SFTs of the orbit, although rare, may occur in the pediatric population.

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

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

Solitary fibrous tumour of the gallbladder: A rare case report

INTRODUCTION AND IMPORTANCE

Solitary fibrous tumours are rare mesenchymal neoplasms with limited malignant potential that can occur anywhere in the body, with a predilection towards body cavities such as the pleura. It has been reported to arise in the peritoneum and the mesentery.

CASE PRESENTATION

This is a case of a female patient who presented with an incidental abdominal mass compressing the duodenum. Differential diagnosis included GIST and intra-operatively was found to be arising from the gallbladder. En-bloc cholecystectomy was done and diagnosed a solitary fibrous tumour.

CLINICAL DISCUSSION

This is the second case of gallbladder solitary fibrous tumour reported in the literature.

CONCLUSION

Awareness of this rare entity is important for diagnosis and treatment.

Solitary Fibrous Tumors of the Lung: A Clinicopathological Analysis of 52 Cases

OBJECTIVE

To explore the clinicopathological features of solitary fibrous tumors (SFTs) of the lung.

METHODS

We collected the clinical data of 52 patients with SFTs of the lung confirmed by pathology, and summarized the clinical, radiological, and morphological features, the immunophenotypes, and the prognosis of SFTs.

RESULTS

Fifty-two cases of SFTs of the lung were enrolled in this study, including 51 cases of borderline and 1 case of malignancy, 22 males and 30 females. The average onset age was 52.7 years. The lower lobe of the left lung was the preferred site of SFTs, accounting for 30.77% (16/52). Chest CT showed regular and well-demarcated soft tissue density mass, and the tumor size of most cases (46/52, 88.46%) was 1-10 cm. Morphological features: The distribution of tumor cells showed sparse and dense areas. Tumor cells were spindle-shaped, in whorls or hemangiopericytoma-like conformation. Atypia, mitotic figures, and necrosis were found. Immunohistochemistry showed positive expression of CD34, STAT6, Vimentin, BCL2, and CD99. Ki-67 was ≤ 5% in borderline SFTs and >20% in a malignant SFT.

CONCLUSIONS

Solitary fibrous tumors of the lung occur more frequently in middle-aged and elderly people, and there is no significant difference in gender. The lower lobe of the left lung is the preferred site of SFTs. The size of most SFTs is 1-10 cm. Chest CT shows morphologically regular and well-demarcated soft tissue density mass. Pathologically, SFTs of the lung are mostly borderline and occasionally malignant. Immunohistochemistry shows the positive expression of CD34, STAT6, Vimentin, BCL2, and CD99.

Solitary fibrous tumor of male breast: A case report and literature review

BACKGROUND

Solitary fibrous tumors (SFT) are uncommon mesenchymal neoplasms which can arise in any anatomical location. Pleural SFTs have been most frequently documented; however, breast SFT is an exceedingly rare entity and seldom present in male breast, with only 8 previously reported cases. Recently, STAT6 immunostaining was considered to be a definitive marker of SFT, however, no case of the male breast SFT showing STAT6 positivity preoperatively has been reported.

METHODS AND RESULTS

We describe a case of breast SFT in a 73-year-old male patient with a 12-month history of a palpable breast mass. The only associated clinical symptom was bilateral gynecomastia. An ultrasound scan examination revealed an oval, well-circumscribed and hypoechoic mass with hypervascularity. A core-needle biopsy was performed, and microscopic examination with immunohistochemistry confirmed the diagnosis of SFT. He underwent a complete surgical resection with clear margins, and there were no signs of high cellularity, remarkable mitotic activity, pleomorphism, hemorrhage or necrosis.

CONCLUSION

A perioperative immunohistochemical evaluation for diffuse and intense nuclear expression of STAT6 was helpful to distinguish SFT from myofibroblastoma. We, herein, describe the first case of SFT in a male breast, confirmed by STAT6 immunostaining positivity. We also conducted a literature review of all previous cases of breast SFTs.

Misleading Morphologic and Phenotypic Features (Transdifferentiation) in Solitary Fibrous Tumor of the Head and Neck: Report of 3 Cases and Review of the Literature

Solitary fibrous tumor (SFT) is a rare fibroblastic neoplasm with potentially malignant behavior that may develop in any anatomic site and may involve the head and neck (H&N) region as well. Although typical SFT has a relatively characteristic morphology, its morphologic spectrum is extraordinarily broad and also includes rare cases with dedifferentiation or transdifferentiation which result in aberrant morphologic and/or immunohistochemical features. However, since virtually all cases are molecularly characterized by NAB2::STAT6 gene fusions, molecular genetic methods or STAT6 immunohistochemistry can be effectively used in confirming the diagnosis. Herein, we report 3 diagnostically challenging H&N SFT cases with an unusual morphology and/or phenotypes closely mimicking other well-known H&N entities. The tumors originated in the oral minor salivary glands, the base of the tongue, and sinonasal tract and closely resembled hyalinizing clear cell carcinoma of the salivary gland, adenocarcinoma not otherwise specified and biphenotypic sinonasal sarcoma, respectively. All cases were positive for cytokeratins, variably expressed S100 protein, showed diffuse nuclear STAT6 positivity, and harbored NAB2::STAT6 gene fusions.

Cytomorphological Spectrum of Solitary Fibrous Tumor: Revisited

BACKGROUND

Solitary fibrous tumor (SFT) is a tumor of mesenchymal origin. Its diagnosis on cytology is challenging, owing to variation in cellularity, sparsely distributed cellular and stromal components and inapparent vasculature. The cytomorphologic findings have been rarely described in literature with a few case reports and occasional case series. We present the cytomorphologic features of SFT with special emphasis on immunochemical findings.

MATERIALS AND METHODS

We present cytological data from eight cases of histopathologically proven SFTs. The cytomorphologic features, immunochemical markers and differential diagnostic entities on fine needle aspiration cytology (FNAC) arediscussed.

RESULTS

FNA was performed at different anatomical sites. Cytology smears showed variable cellularity with tumor cells arranged in loose clusters and as singly scattered cells. Interlacing fascicles with palisading of cells was noted. The cells were predominantly spindle to elongated, having moderate cytoplasm with elongated wavy nuclei. These nuclei had fine to coarse chromatin, with inconspicuous to prominent nucleoli. There was prominent metachromatically staining, amorphous to fibrillary, collagenous to myxoid matrix materialassociated with tumor cells. Other findings included intranuclear pseudo-inclusions, multinucleated giant cells and atypical mitoses. Cytological diagnosis offered varied from 'spindle cell neoplasm' to 'spindle cell sarcoma' or 'suggestive of sarcoma'.Immunocytochemistry (ICC) done on cell block sections showed positivity for STAT6, CD34 and Bcl-2.

CONCLUSION

Cytological diagnosis of SFT can be challenging. A prudent search for characteristic cytomorphological features is of diagnostic help. The cytomorphology should be interpreted with caution with appropriate ICC panel including STAT6 and CD34.

Toward Better Understanding and Management of Solitary Fibrous Tumor

Solitary fibrous tumor (SFT) comprises a histologic spectrum of soft tissue neoplasms that are characterized by the unique NAB2-STAT6 gene fusion. Changes in diagnostic terminology and site-specific classification over the past few decades have resulted in a disjointed literature. Complete surgical excision with preservation of function remains the mainstay of treatment. New risk stratification systems including risk factors such as mitotic rate, age, tumor size, and presence of necrosis, among others, can be used to predict risk of recurrence or metastasis. Long-term follow-up after surgical resection is recommended. The clinical manifestations, diagnosis, management, and prognosis of SFT are reviewed here.

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.

Isolated pathologies of Tensor Fasciae Latae: Retrospective cohort analysis from a tertiary referral centre

INTRODUCTION

Tensor Fasciae Latae (TFL) and the iliotibial band (ITB) act as a single functional unit in maintaining pelvic stability whilst standing, walking, or running in human beings. The Tensor Fasciae Latae (TFL) muscle acts across the hip and the knee joint. Consequently, though its pathologies traditionally present with lateral hip pain, identifying the precise clinical diagnosis can be a challenge.

PATIENTS AND METHODS

A retrospective search for the keyword 'Tensor Fasciae Latae'/iliotibial band (ITB) was performed of our Radiology Information System (RIS) and Picture Archiving and Communication System (PACS), Computerised Radiology Information System (CRIS) at our tertiary orthopaedic referral centre of a for orthopaedic oncology over a period of 13 years (2007-2020). Data was collected from RIS, oncology database and local histopathology laboratory records. Patient demographics, clinical characteristics, complementary imaging and clinical management outcome were documented.

RESULTS

We identified 35 patients with a mean age of 66 years (range 19-94 years). There were 18 female and 17 male patients. Lateral hip lump and pain were the most frequent clinical finding/presentation features. A variety of pathologies such as benign and malignant tumours, including vascular and tumour mimic lesions involving the TFL muscle were identified. Atrophy and pseudohypertrophy of TFL was the commonest pathology found; accounting for two thirds of the cases.

CONCLUSION

Tensor Fasciae Latae (TFL) can be afflicted with a broad spectrum of pathologies. Radiological imaging especially cross-sectional imaging modality is crucial in guiding appropriate patient management of TFL conditions. Our analysis suggests isolated TFL lesion are more likely to be benign conditions, presenting commonly as hip pain and swelling.

Solitary Fibrous Tumors of the Female Genital Tract: A Study of 27 Cases Emphasizing Nonvulvar Locations, Variant Histology, and Prognostic Factors

We report 27 solitary fibrous tumors of the female genital tract emphasizing nonvulvar locations, variant histology, and prognostic factors. The patients ranged from 25 to 78 years (most were over 40), and tumors occurred in the vulva (7), vagina (2), cervix (2), corpus (6), fallopian tube/paratubal soft tissue (5), and ovary (5). They ranged from 1.5 to 39 (mean=10.5) cm and were typically solid, but 4 were predominantly cystic. All had a haphazard arrangement of spindled to ovoid cells, with most demonstrating alternating cellular and hypocellular areas and prominent vessels, but 13 lacked hypocellular areas, and 7 had focal diffuse growth with inconspicuous vasculature. Other patterns included corded (8), fascicular (5), trabecular (1), and nested (1). Microcysts (6), myxoid background (8), hyalinization (8), lipomatous differentiation (2), and multinucleated cells (6) were also present, and 10 tumors had necrosis. Vasculature included thin-walled branching "staghorn" (27), thick-walled (7), and hyalinized vessels (5) or dilated anastomosing vascular channels (3). Nuclear atypia ranged from mild (19), moderate (7), to severe (1), and mitoses from 0 to 24/10 HPF (mean=4). STAT6 was positive in all 25 tumors tested. One tumor showed dedifferentiation; the remainder were classified as benign (19) or malignant (7) based on mitotic rate (univariate stratification model) and as low risk (14), intermediate risk (8), or high risk (4) based on the Demicco multivariate risk stratification score. Follow-up (median=23 mo) was available for 16 patients. Six tumors recurred (2 intermediate risk, 3 high risk, and the dedifferentiated tumor), 5 in the abdomen; the dedifferentiated tumor metastasized to the lung. Multivariate risk stratification was superior to univariate classification, as 5 "benign" tumors were reclassified as intermediate risk using the multivariate model; of these, 2 recurred, and 1 patient died of disease. Upper female genital tract tumors occurred in older patients, were larger, and more frequently classified as high risk compared with those of the lower tract. A trend toward increased cellularity was also seen in the upper tract tumors. Only size (P=0.04), necrosis (P=0.04), and Demicco score (P=0.01) independently correlated with recurrence. Female genital tract solitary fibrous tumors demonstrate a wide range of variant morphologies and occur in diverse sites in addition to the vulva. Tumors were often misdiagnosed as other neoplasms; thus, awareness of solitary fibrous tumors occurring at these sites is crucial in prompting staining for STAT6 to establish this diagnosis. The Demicco risk stratification system effectively predicts behavior.

OUP accepted manuscript

Solitary fibrous tumour (SFT) is a rare mesenchymal tumour, usually originating from the serous surfaces, typically of the pleura and pericardium. However, it can also have localizations in soft tissues and visceral organs. We report the case of a 79-year-old woman affected by mesenteric SFT, localized in the sigmoid colon. We performed open excision of the abovementioned mass en-bloc with the sigmoid colon and left adnexal tissues. Pathological examination of surgical specimen revealed a diagnosis of SFT CD34+, high-risk of metastases. Mesenteric SFTs are even rarer forms of SFT and may be asymptomatic or cause intestinal occlusion. There is no consensus on the management of this tumour. Radical surgical excision is the only curative treatment, while adjuvant therapies are indicated in case of advanced disease. Due to the high metastatic risk of malignant forms, a long follow-up is mandatory in these cases.

Long-term extracranial metastatic relapse of an intraventricular solitary fibrous tumor: a case report

Solitary fibrous tumors (SFTs), an uncommon subtype of soft tissue sarcomas mesenchymal, are frequently diagnosed in the intra-thoracic region. Distant metastasis is detected in 10-40% of SFT patients with a predilection site to the lungs; nevertheless, these can occur rarely in the liver, brain, and bones. This entity was also reported in the abdomen, trunk, head, and neck, extremities but also, in the central nervous system (CNS). In the latter form of SFTs, the meninges were mostly affected while only a few cases were reported in the intraventricular and intraparenchymal region with distinct clinical and behavioral characteristics. In this article, we report the rare case of a relapsing intraventricular SFT with secondary extra-cranial metastases to the bones and soft tissues after 11 years of initial diagnosis, with focus on the available data in the literature on CNS SFTs.

Targeting-intratumoral-lactic-acidosis transcatheter-arterial-chemoembolization for non-islet cell tumor hypoglycemia secondary to a liver metastatic solitary fibrous tumor: A case report and literature review

Doege-Potter syndrome is a rare paraneoplastic syndrome characterized by non-islet cell tumor hypoglycemia secondary to a solitary fibrous tumor. Doege-Potter syndrome always presents with recurrent fasting hypoglycemia, which can occasionally be life-threatening. The best choice of treatment for Doege-Potter syndrome and solitary fibrous tumor is complete resection. However, when it is unfeasible, local-regional treatment can be used as a palliative therapy. Herein, we report a case of a 46-year-old man with Doege-Potter syndrome that occurred secondary to the liver and pancreatic metastatic solitary fibrous tumors. After he received six rounds of targeting-intratumoral-lactic-acidosis transcatheter-arterial-chemoembolization (TILA-TACE) treatment in our hospital, his hypoglycemia was clinically cured, and the liver metastatic tumor was well controlled. We suggest that TILA-TACE can be considered when curative resection is unfeasible for metastatic liver solitary fibrous tumors to help a patient obtain further surgery opportunities.

[Solitary fibrous tumor of the prostate: case report]

La tumeur fibreuse solitaire est une tumeur mésenchymateuse souvent bénigne et rare décrite pour la première fois dans la plèvre, la localisation prostatique est exceptionnelle. Nous rapportons le cas d´un patient de 77 ans qui a consulté pour symptômes du bas appareil urinaire à type de dysurie et pollakiurie. Le scanner et l´imagerie par résonance magnétique (IRM) ont montré l´origine prostatique de la lésion et précisé les rapports de cette masse avec les structures adjacentes saines, élément important pour la résécabilité de la tumeur. La biopsie transrectale avec une étude immunohistochimie ont confirmés le diagnostic, les cellules tumorales exprimaient le CD34, Bcl2 et CD 99. Le traitement était chirurgical par prostatectomie radicale.

Extra-thoracic, extra-meningeal solitary fibrous tumours - A case series and service review

BACKGROUND

Solitary fibrous tumours (SFT) are a type of mesenchymal tumour. Whilst the majority of cases follow an indolent course a significant proportion of patients suffer metastases or disease recurrence post-surgical excision. Due to the unpredictable clinical course follow up duration and intensity remains contentious.

AIMS

We aimed to determine current outcomes of management of this tumour, apply and assess current risk recurrence models to determine if our standard of care could be improved upon.

METHODS AND PATIENTS

A prospective database of patients treated at a regional musculoskeletal oncology service was assessed. Only extra-pleural, extra-meningeal SFTs were included in the study. Surgical outcome and post-operative investigations were scrutinised and the Pasquali and Demicco recurrence risk models were applied and assessed.

RESULTS

From 2009 to 2019 12 patients were identified, 8 female and 4 males. Their age at diagnosis ranged from 21 to 76 years. 11 patients underwent surgery with curative intent and no patient suffered disease progression or recurrence, with a mean follow up time of 41 months. One patient presented with metastatic disease and was managed palliatively.

CONCLUSIONS

Following this review of our case series and utilising risk recurrence models published in the literature we have changed our follow up protocol. In new cases of SFT the Pasquali prognostic model, with the addition of the presence or absence of necrosis, will be utilised. If a patient has benign features on initial biopsy we propose to not perform staging. Furthermore, if biopsy and final pathology results remain concordant, with no concerning features, and the patient has undergone complete excision reduced intensity follow up could be considered.Level of evidence Level IV, retrospective case series.

Cutaneous solitary fibrous tumor: Report of three cases with review of histopathological mimics

Solitary fibrous tumor (SFT) is a relatively uncommon spindle cell mesenchymal neoplasm that is most often based on the pleura but may rarely arise in extrapleural locations, including the skin. Herein, we describe three cases of cutaneous SFTs. SFT is characterized by epithelioid and spindle cells arranged in random patterns with focal prominent stromal collagen and pericytomatous vessels. Immunohistochemical evaluation is required for definitive distinction of SFT from other benign and malignant cutaneous spindle cell neoplasms. Although aggressive biologic behavior is uncommon, accurate diagnosis of it is required for prognostication and counseling. CD34, bcl-2, and CD99 stains are positive in SFT, but not specific. STAT6 is the most sensitive and specific immunohistochemical marker to confirm diagnosis of SFT.

[Monstrous Solitary Fibrous Tumor of the Pleura - A Case Report and Review of the Literature]

Localized solitary fibrous tumors are a rare entity and are mostly found in the thorax, but can also occur in the liver, skin, meninges, peritoneum, and pericardium. Making the diagnosis is often difficult because of the various micromorphologic outlooks. The histopathological assessment with differentiated immunohistochemistry is decisive. Surgical resection of the localized solitary fibrous tumors is the therapy of choice. The recurrence and metastasis rates depend on the histological dignity and are in total very low. Therefore, continuous follow-up examinations are indicated. We report on a 76-year-old female patient with a monstrous solitary fibrous tumor of the pleura who complained of exertional dyspnea and sharp pain in the right thoracic region for several weeks. Computed tomography showed a massive, heterogeneous pulmonary mass 22 cm in diameter in the middle and lower field of the right lung with compression of the diaphragm and mediastinum. The tumor was completely resected through a double thoracotomy in the 5th and 8th ICR. Intraoperatively, the tumor was stalked to the middle lobe. In order to completely remove the tumor, a wedge resection was also performed from the middle lobe. The tumor weighed 2.4 kg. The diagnosis of a solitary fibrous tumor of the pleura was made histologically and immunohistochemically. Postoperatively, the lung has fully expanded. There was no evidence of a relapse at the 3-month follow-up examination. The clinical symptoms, diagnosis, treatment options, risk of recurrence and the prognosis of these tumors are shown and discussed in accordance with the literature.

Clinicopathologic and Immunohistochemical Characteristics of Solitary Fibrous Tumor and Its Mimics: A Single-Center Experience

Background

Solitary fibrous tumor (SFT) is a fibroblastic tumor that has been originally reported as a pleural tumor but now has been defined as a tumor that can be seen everywhere in the human body. Histopathologically, many of the fibroblastic tumors can mimic SFT, and immunohistochemistry is necessary for differential diagnosis. Several markers have been used, and recently, STAT6 has been introduced as a diagnostic marker. No research study has been reported from Iran.

Objectives

In this report, we are trying to introduce our experience about the clinicopathologic findings of 35 cases of SFT during the last 10 years from our center with an emphasis on the diagnostic role of STAT6 in this tumor.

Patients and methods

During the last 10 years, we confirmed the diagnosis of 35 cases of SFT in the pathology archives of Shiraz University of Medical Sciences. These 35 cases were considered as cases. All the clinicopathologic findings were also extracted from the clinical charts of the patients. To evaluate the diagnostic role of STAT6, another 35 cases of spindle cell tumors were also extracted from the pathology archives as mimickers of SFT. STAT6 was stained in all of the 70 cases and controls.

Results and discussion

Our experience showed that SFT is more common in middle-aged men with a wide age range, although it is very rare in children. It can be present in every location with a wide size range from less than 1 cm to more than 15 cm. The presence of abnormal staghorn vessels is one of the main diagnostic histopathologic characteristics. STAT6 showed a sensitivity and specificity of 91% and 86% in the diagnosis of SFT. Other markers such as CD99, CD34, and BCL2 have also been considered useful in the differential diagnosis of this tumor, although the diagnostic accuracy seems to be lower than STAT6. High mitosis, presence of necrosis, and atypia are important criteria for predicting malignant and aggressive behavior in SFT. Among 35 cases in our study, 17% showed malignant behavior as recurrent or metastatic tumors.

Conclusion

Solitary fibrous tumor is a common soft tissue tumor that can be seen everywhere and needs careful histopathologic and immunohistochemical evaluation for the correct diagnosis and prediction of aggressive or benign behavior.

Doege-Potter Syndrome: A Presumptive Case of Metastatic Hemangiopericytoma with Persistent Hypoglycemia in a 27-Year-Old Male

Doege-Potter syndrome (DPS) is a rare paraneoplastic condition characterized by hypoinsulinemic hypoglycemia from a solitary fibrous tumor. The underlying mechanism is the secretion of a prohormone form of insulin-like growth factor II (IGF-II) by the tumor, which causes decreased release of glucose into the circulation. We report the case of a 27-year-old Filipino male with presumptive DPS from a recurrent right temporo-zygomatic hemangiopericytoma (HPC). The complexity of DPS requires a multidisciplinary approach. Early screening for metastases from HPC may prevent the undesirable sequelae of the disease process.

Solitary fibrous tumor of thoracic cavity, extra-thoracic sites and central nervous system: Clinicopathologic features and association with local recurrence and metastasis

Published risk stratification models of solitary fibrous tumor (SFT) have been associated with distant metastases outside the central nervous system (CNS), but have not been studied for tumors occurring in the CNS. In a retrospective review, we identified 72 cases of solitary fibrous tumor or hemangiopericytoma (HPC) diagnosed between January 2011 and December 2020 at our institution. The tumors involved the central nervous system (N = 17), thoracic cavity (N = 28), and extrathoracic sites (N = 27). The risk of local recurrence, distant metastasis, or death at 5 years was 57% (95% CI 23%, 76%) in the CNS, 24% (95% CI 2%, 41%) in the thoracic cavity, and 13% (95% CI 0%, 25%) in extrathoracic sites. By contrast, the risk of distant metastasis or death at 5 years was 13% (95% CI 0%, 29%) in CNS primaries, 5% (95% CI 0%, 14%) in thoracic primaries, and 14% (95% CI 0%, 27%) in extrathoracic primaries. Using the published 3- and 4-variable risk stratification models by Demicco et al., we retrospectively assessed our cases for risk of local recurrence, distant metastasis, and death. For tumors outside the CNS, we show that three- and four-variable risk stratification models were associated with recurrence-free survival in addition to the previously known association with distant metastasis (all P < 0.05). In contrast, inside the CNS, we show that neither risk model is a significantly associated with clinical behavior, and that WHO grade is likely the best available prognostic tool, though none of the differences were significant. The lack of significant differences can be likely explained by the younger median age (47 years vs 61 years) and smaller median tumor size (3.5 cm vs 5.6 cm), downgrading the risk stratification scores in CNS compared to non-CNS primaries. In conclusion, existing risk stratification models of SFT are not associated with clinical behavior for tumors arising inside the CNS, but are associated with local recurrence in addition to distant metastasis outside the CNS.

Mesenchymal tumours of the gastrointestinal tract

Mesenchymal tumours represent a heterogenous group of neoplasms encopassing benign, intermediate malignancy, and malignant entities. Sarcomas account for approximately 1% of human malignancies. In consideration of their rarity as well as of intrinsic complexity, diagnostic accuracy represents a major challenge. Traditionally, mesenchymal tumours are regarded as lesions the occurrence of which is mostly limited to somatic soft tissues. However, the occurrence of soft tissue tumours at visceral sites represent a well recognized event, and the GI-tract ranks among the most frequently involved visceral location. There exist entities such as gastrointestinal stromal tumours (GIST) and malignant gastointestinal neuroectodermal tumors that exhibit exquisite tropism for the GI-tract. This review will focus also on other relevant clinico-pathologic entities in which occurrence at visceral location is not at all negligible.

Rare Diseases of the Orbit

This article provides an overview of rare orbital diseases. Congenital malformations, inflammatory diseases, benign and malignant neoplasias are described. Although it represents a relatively small area of the body the orbit contains multiple different tissues. Therefore, a great variety of diseases can be found within the orbital space. That is the reason, why both the completeness and the level of detail in the description of particular diseases must be somewhat limited. Nevertheless, clinical manifestations, important aspects of diagnosis, treatment strategies, and, when specific data are available, the prognosis are described. The authors tried to highlight the most characteristic aspects of the different diseases to describe their relevant aspects in spite of the brevity of the subsections.

CD34-negative Solitary Fibrous Tumor: A Clinicopathologic Study of 25 Cases and Comparison With Their CD34-positive Counterparts

CD34-negative solitary fibrous tumors (SFTs) are rare and have not been comprehensively studied. We retrospectively reviewed all cases of SFT confirmed with STAT6 immunohistochemistry and/or STAT6 gene fusion between 2013 and 2020 and collected pertinent clinicopathologic parameters. Of a total of 244 cases, 25 (10%) lacked CD34 expression by immunohistochemistry. Compared with CD34-positive SFT, CD34-negative SFT are more likely to arise in the head and neck area (32% vs. 24%, P=0.02) and present as metastatic disease (28% vs. 1%, P<0.0001). A significantly higher percentage of CD34-negative SFT exhibit high-grade cytologic atypia (hypercellularity, round cell or anaplastic morphology, nuclear pleomorphism, etc.) (48% vs. 22%, P=0.0073). There are no significant differences in the distributions of age, sex, tumor size, mitotic count, tumor necrosis, or risk stratification between CD34-negative and CD34-positive SFT. In addition, only 56% of CD34-negative SFT display a typical hemangiopericytoma-like vascular pattern. Special histologic features among CD34-negative SFT include prominent alternating hypercellular or fibrous and hypocellular myxoid areas with curvilinear vessels mimicking low-grade fibromyxoid sarcoma, pulmonary edema-like microcystic changes, and prominent amianthoid collagen fibers. In conclusion, compared with their CD34-positive counterparts, CD34-negative SFT is more likely to present as metastatic disease, show high-grade nuclear atypia, and lack the characteristic hemangiopericytoma-like vasculature, posing a unique diagnostic challenge. The use of STAT6 immunohistochemistry and/or molecular studies may be prudent in soft tissue tumors that appear CD34 negative and lack conventional SFT histopathologic characteristics.

A novel risk score to predict early and late recurrence in solitary fibrous tumour

AIMS

Solitary fibrous tumours (SFTs) are rare mesenchymal neoplasms with recurrence rates of 10-30%. Current risk stratification systems for extrameningeal SFTs are based on cohorts with limited follow-up and are not suitable for prediction of late recurrences. In this study we aimed to develop a prognostic model accounting for both early and late recurrences using a relatively large patient cohort with long-term follow-up.

METHODS AND RESULTS

Clinicopathological factors were analysed in a cohort of 100 extrameningeal, STAT6-positive SFTs. Median follow-up for overall survival (OS) and recurrence-free interval (RFi) were 121 and 84 months, respectively. Disease relapse occurred in 31% of patients and median time to recurrence was 63 months. In univariate analysis mitotic count, necrosis, male gender and presence of severe atypia and pleomorphism were associated with inferior RFi. Mitotic count, necrosis and male gender were independent predictors of recurrence in multivariate analysis. Previously published risk models were also statistically associated with RFi in our cohort, but failed to reliably identify low-risk patients due to poor prediction of late recurrences. A novel risk score based on mitotic count, necrosis and gender was able to stratify patients into low-, intermediate- and high-risk groups for both early and late recurrences.

CONCLUSIONS

In this cohort of patients with extrameningeal SFT and long-term follow-up mitotic count, necrosis and gender were independent prognostic markers of recurrence. We propose a novel risk score based on these factors and accounting for late recurrences, which should be validated in external cohorts with sufficient follow-up time.

Laparoscopic excision of a solitary fibrous tumor originating from the abdominal wall: a case report

Solitary fibrous tumors (SFTs) are mesenchymal fibroblastic tumors, and forms of SFTs that originate from the abdominal wall are extremely rare. Here we report a case of a nonpalpable SFT along the abdominal wall. Abdominal magnetic resonance (MR) imaging showed a well-circumscribed mass measuring 5 cm in diameter with heterogeneous signal intensity on T2-weighted MR images; this mass was diagnosed as a benign abdominal tumor of unknown origin. Successful laparoscopic excision of the tumor was performed. Histological examination revealed a benign extrapleural SFT. No tumor recurrence was observed after 20-month follow-up. This is the first case of laparoscopic excision of an SFT originating from the abdominal wall. Our report highlights the safety and usefulness of laparoscopic excision of abdominal wall tumors such as SFTs. This approach is an underutilized surgical treatment that can be applied to select cases of SFT in the abdominal cavity.

Fate and Management of Incompletely Excised Solitary Fibrous Tumor of the Orbit: A Case Series and Literature Review

PURPOSE

There is an imperfect correlation between the histology and behavior of solitary fibrous tumor (SFT). In addition, recurrence is common, and dedifferentiation may occur over time. Preferred primary treatment is intact excision, but friable pseudocapsules and tenacious attachments can thwart this goal in the crowded, visually sensitive orbit. This study addresses the fate and appropriate management of incompletely excised orbital SFT.

METHODS

Among a single surgeon's 7-case experience with orbital SFT, 3 cases involved incomplete primary excision, either before (2 cases) or after (1 case) referral. We reviewed the clinicopathologic data in these 3 cases, with follow-up intervals of 18, 21, and 52 years after initial presentation. We reviewed the English-language literature on SFT, with special attention to evolving nomenclature, orbital involvement, recurrence, malignant transformation, and management options.

RESULTS

Benign versus malignant designations of SFT vary with histological and behavioral criteria. Approximately 150 orbital cases have been reported. Published rates of primary malignancy and recurrence across all histologic categories are 6% to 12% and 30% to 37%, respectively. We identified 43 well-documented recurrences (range, 6 months-33 years; median, 3 years) and 10 cases of histological dedifferentiation (range, 14 months-33 years). Because of SFT's rarity and needed follow-up intervals, the value of adjuvant therapy is not yet proven. In follow up of 18, 21, and 52 years after initial presentation, our 3 cases with incomplete excision showed either no recurrence (Case 1) or no morphological dedifferentiation (Cases 2, 3).

CONCLUSION

A treatment algorithm is predicated on the completeness of surgical excision and histological features. However, we recommend case-by-case multidisciplinary decisions in a tumor-board setting.

Malignant solitary fibrous tumor of the greater omentum: A case report and review of literature

BACKGROUND

Malignant solitary fibrous tumors (SFTs) account for 15%-20% of all SFTs, and malignant SFTs arising from the greater omentum are extremely rare. Most malignant SFTs of the greater omentum are diagnosed via pathological examinations after surgery. In this study, we report a case of malignant omental SFT and review the published literature on this rare malignancy.

CASE SUMMARY

A 64-year-old female presented with an abdominal mass, and underwent exploratory surgery, during which a huge tumor originating from the greater omentum and intraperitoneal implants were identified and resected. The results of the pathological examination, immunohistochemistry staining, and gene sequencing led to the diagnosis of malignant SFT of the greater omentum. The patient died one and a half years later due to tumor recurrence and metastasis.

CONCLUSION

This is the first report of the application of gene sequencing in the diagnosis of malignant SFTs of the greater omentum.

A Rare Case of Solitary Fibrous Tumour of the Pelvis in an 18-Year-Old Young Man: CT and MRI Features with Pathologic Correlations

Solitary fibrous tumors (SFTs) are mesenchymal neoplasms of fibroblastic origin, even if commonly seen in the pleura, they can occur anywhere in the body. SFT presents as a slow growing, often asymptomatic mass, generally affecting middle-aged adults regardless of the sex. We report a rare case of an 18-year-old man referred to our institution to perform computed tomography (CT) and magnetic resonance imaging (MRI), to investigate a pelvic mass incidentally discovered at abdominal ultrasound examination. A well circumscribed, heterogenous and hypervascular lesion was described at imaging, with absence of calcifications, hemorrhage, necrosis nor cystic degeneration. The mass removal was performed via the Da Vinci-assisted robotic surgery. Histopathological evaluation confirmed the diagnosis of SFT. CT and MRI can aid the identification of SFT, providing useful information which needs to be supported by histopathological analysis.

Case Report: A Malignant Liver and Thoracic Solitary Fibrous Tumor: A 10-Year Journey From the Brain to the Liver and the Spine

Solitary fibrous tumors are rare neoplasms that originate from mesenchymal tissues and have been found to occur in any site, including the spine and liver. Although most of solitary fibrous tumors have benign features, only 10-20% are malignant and prone to metastasis. No previous reports have described the malignant and metastatic Solitary fibrous tumor arising in both of the liver and thoracic vertebrae. In this article, we present the case of a 60-year-old woman who underwent gross total resection of a meningeal tumor in 2007. She presented 10 years later with a thoracic vertebral mass that caused relentless pain and a lesion in the right lobe of liver. She underwent marginal excision of the T3 tumor with T2-4 pedicular screw fixation in March 2017, then right hemi-hepatectomy was performed to remove the liver lesion in June 2017. Both of the lesions were confirmed to be a metastatic and malignant tumor after surgery. The literature lacks randomized controlled trials and large studies that define the natural history of malignant solitary fibrous tumors and recommendations of precise management plan for the disease. However, the best choice for treatment is gross total resection, which probably provide the optimal treatment to achieve long-term disease-free survival.

Solitary fibrous tumor with atypical features of the paravesical space: benign clinical course at the 10-years follow-up. Report of a case and review of the literature

Extra-pleural solitary fibrous tumor (SFT) is a relatively rare soft tissue neoplasm, with only rare cases reported in the pelvic cavity. Most SFTs are histologically benign, with only a few malignant cases reported in the literature so far. We report a rare case of SFT arising in the paravesical space of a 79-year-old man. Histologically the tumor corresponds to an “intermediate risk tumor” according to a risk stratification scheme for metastatic potential, which incorporates patient age, tumor size, mitotic activity and necrosis. Notably tumor showed a benign clinical course without evidence of local recurrence after a 10-years follow-up. Tumor was composed of both spindle and epithelioid cells variably set in a fibro-myxoid stroma, with focal pleomorphic, necrotic and highly mitotic (> 4 mitoses/10HPF) areas. Immunohistochemistry, showing a diffuse CD34 and STAT6 immunoreactivity, supported the diagnosis of SFT. The present case emphasizes that the clinical course of the pelvic SFTs with atypical morphological features is unpredictable on the basis of morphology alone, and thus the term “SFT with atypical features, including the risk stratification class” should be preferred to “malignant SFT”.

Endoscopic resection of solitary fibrous tumor of the ethmoid: Case report review of the literature

INTRODUCTION

Solitary fibrous tumour (SFT), as are benign neoplasms of fibroblastic cells. Nasosinusal localisation is exremely rare, difficult to diagnose and to manage.

CASE REPORT

We report a rare case of Solitary fibrous tumour in the nasal cavity in a 47-year-old- woman, with complete surgical resection.

DISCUSSION

SFTs are of mesenchymal origin, mainly from serous membranes. The head and neck region is affected with a percentage ranging from 5 to 27%. On the other hand, LTS unusually affects the nasal tract (NTS). Because of this rarity and its variable morphological appearance, it is difficult to distinguish TNS from other mesenchymal lesions.

CONCLUSION

Although there are no standard clinical guidelines, the preferred treatment for FLS is radical surgical resection.

The 2020 WHO Classification of Soft Tissue Tumours: news and perspectives

Mesenchymal tumours represent one of the most challenging field of diagnostic pathology and refinement of classification schemes plays a key role in improving the quality of pathologic diagnosis and, as a consequence, of therapeutic options. The recent publication of the new WHO classification of Soft Tissue Tumours and Bone represents a major step toward improved standardization of diagnosis. Importantly, the 2020 WHO classification has been opened to expert clinicians that have further contributed to underline the key value of pathologic diagnosis as a rationale for proper treatment. Several relevant advances have been introduced. In the attempt to improve the prediction of clinical behaviour of solitary fibrous tumour, a risk assessment scheme has been implemented. NTRK-rearranged soft tissue tumours are now listed as an "emerging entity" also in consideration of the recent therapeutic developments in terms of NTRK inhibition. This decision has been source of a passionate debate regarding the definition of "tumour entity" as well as the consequences of a "pathology agnostic" approach to precision oncology. In consideration of their distinct clinicopathologic features, undifferentiated round cell sarcomas are now kept separate from Ewing sarcoma and subclassified, according to the underlying gene rearrangements, into three main subgroups (CIC, BCLR and not ETS fused sarcomas) Importantly, In order to avoid potential confusion, tumour entities such as gastrointestinal stroma tumours are addressed homogenously across the different WHO fascicles. Pathologic diagnosis represents the integration of morphologic, immunohistochemical and molecular characteristics and is a key element of clinical decision making. The WHO classification is as a key instrument to promote multidisciplinarity, stimulating pathologists, geneticists and clinicians to join efforts aimed to translate novel pathologic findings into more effective treatments.

Giant solitary fibrous tumor of the pelvis: A case report and review of literature

INTRODUCTION

Solitary fibrous tumors (SFTs) are rare spindle cells neoplasms most likely arising from mesenchymal cells. Usually they involve the pleura. Even if extra-thoracic SFTs are rare, lately they are diagnosed with increased frequency.

CASE PRESENTATION

We describe the case of giant pelvic and retroperitoneal neoplasm, a rare solitary fibrous tumor, in a 51-year-old man that was admitted for abdominal pain.

DISCUSSION

On CT a SFT appears usually as a smooth, lobulated mass with occasional calcifications, but the imaging differential diagnosis with other mesenchymal tumors is very difficult, if not impossible.

CONCLUSION

The histological and immune-histochemical features of SFTs are helpful for the differential diagnosis. The malignant potential of this cancer is low, but it is very important to perform an optimized surgery and a close follow up in the patient. We believe that this case is particularly interesting and complex because of the difficulty of predicting the future biological behavior.

Solitary fibrous tumour of cervical spinal cord

Solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms of fibroblastic origin. They commonly arise from visceral pleura, but also arise from nonserosal sites such as meninges, central nervous system parenchyma, and spinal cord. In the spinal cord, SFTs commonly arise from the thoracic spinal cord, followed by cervical spinal cord, lumbar spinal cord, and sacrum. Histologically, SFTs can be similar to hemangiopericytoma, schwannoma, fibrous meningioma, fibroma, gliofibroma, and ependymoma. Immunohistochemistry (IHC) plays an important role in differentiating SFTs from other identical tumors. Here, we report a rare case of SFT of the cervical spinal cord, which was initially reported as hemangiopericytoma, and the diagnosis of SFT was confirmed by IHC.