Primary sclerosing epithelioid fibrosarcoma of the sacrum: a case report and review of the literature

Sclerosing epithelioid fibrosarcoma of the jaw: a case report and literature review

INTRODUCTION

Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare form of bone and soft tissue sarcoma. It occurs mainly in the deep soft tissue of the lower extremities, with few cases reported in the head and neck region. Tumors involving the oral and maxillofacial region (OMFR) and intraosseous examples are rare.

CASE PRESENTATION

We present a 52-year-old male with a radiolucent lesion at the apex of the left mandibular second molar tooth with the clinical impression of a periapical granuloma. The patient has a history of SEF of the skull, which was treated by chemotherapy and radiation. Histopathologic examination revealed islands of highly cellular, basophilic bone and osteoid surrounded by loose fibrous stroma, which contains large lobules and islands of round to oval cells with distinct cell borders and faintly granular eosinophilic cytoplasm. Tumor cells were strongly positive for MUC4 and INI-1. Based on these findings, a diagnosis of high-grade malignancy consistent with SEF was made, and correlation with the primary lesion was recommended.

CONCLUSION

SEF is a rare tumor seen in OMFR, and therefore, it should be included in the differential diagnosis of any high-grade malignancy. Immunohistochemical stain for MUC-4 evaluation is important for the diagnosis of SEF.

Metastatic sclerosing epithelioid fibrosarcoma

Sclerosing epithelioid fibrosarcoma is a rare fibrosarcoma variant in which more than half of patients experience local recurrence or metastatic spread. In the current literature, there is limited and nonspecific imaging data, contributing to frequent misdiagnosis and delays in treatment intervention. Given the poor prognosis associated with this malignancy and the high probability of metastases, accurate and prompt diagnoses are critical. In this article, we report the case of a 27-year-old female diagnosed with metastatic sclerosing epithelioid fibrosarcoma following the discovery of a growing palpable mass on her right gluteus maximus muscle. We focus on the use of radiological imaging modalities in optimizing diagnosis and correlate our imaging and pathological findings.

Sclerosing epithelioid fibrosarcoma of bone with hybrid features: clinicopathologic, radiologic, and molecular analysis of three cases

Sclerosing epithelioid fibrosarcoma (SEF) occurring as a primary bone tumor is exceptionally uncommon. Even more rare are cases of SEF that show morphologic overlap with low-grade fibromyxoid sarcoma (LGFMS). Such hybrid lesions arising within the bone have only rarely been reported in the literature. Due to their variegated histomorphology and non-specific radiologic features, these tumors may pose diagnostic difficulties. Herein we describe three molecularly confirmed primary bone cases of sclerosing epithelioid fibrosarcoma that demonstrated prominent areas showing the features of LGFMS and with areas resembling so-called hyalinizing spindle cell tumor with giant rosettes (HSCTGR). Two patients were female and one was male aged 26, 47, and 16, respectively. The tumors occurred in the femoral head, clavicle, and temporal bone. Imaging studies demonstrated relatively well-circumscribed radiolucent bone lesions with enhancement on MRI. Cortical breakthrough and soft tissue extension were present in one case. Histologically the tumors all demonstrated hyalinized areas with SEF-like morphology as well as spindled and myxoid areas with LGFMS-like morphology. Two cases demonstrated focal areas with rosette-like architecture as seen in HSCTGR. The tumors were all positive for MUC4 by immunohistochemistry and cytogenetics, fluorescence in-situ hybridization, and next-generation sequencing studies identified EWSR1 gene rearrangements confirming the diagnosis in all three cases.Hybrid SEF is exceedingly rare as a primary bone tumor and can be difficult to distinguish from other low-grade spindled and epithelioid lesions of bone. MUC4 positivity and identification of underlying EWSR1 gene rearrangements help support this diagnosis and exclude other tumor types.

Sclerosing Epithelioid Fibrosarcoma of the Spine: Diagnosis and Treatment of a Rare Entity

Sclerosing epithelioid fibrosarcoma (SEF) is a rare subtype of sarcoma with high rates of local recurrence and distant metastasis. Morphologically, it resembles other mesenchymal and non-mesenchymal tumors, making it a diagnostic challenge. Treatment relies mostly on surgery with adjuvant chemotherapy or radiotherapy (RT). A 46-year-old woman who presented with lumbar pain and weight loss underwent a computed tomography (CT) scan, magnetic resonance imaging (MRI), and a [18F]-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) scan, which showed a lesion involving the L5 vertebra. An incisional biopsy of the lesion established the diagnosis of SEF, with diffuse expression of MUC4 and focal expression of EMA. The patient was treated with neoadjuvant RT followed by surgery. Histology was congruent with the previous diagnosis and demonstrated post-radiation changes. In conclusion, SEF is an aggressive type of sarcoma that is easily misdiagnosed, so it is important to consider it in the differential diagnosis to avoid unbeneficial treatments and a detriment to patient survival.

Sclerosing epithelioid fibrosarcoma of the foot: A case report

Sclerosing epithelioid fibrosarcoma (SEF) is a rare and distinctive variant of fibrosarcoma. To date, about 100 cases only have been documented. Histopathologically, it resembles a variety of benign, pseudosarcomatous and other malignancies. Early diagnosis and treatment are vital for improving the treatment outcomes.

Metastatic sclerosing epithelioid fibrosarcoma in an adult male from a tertiary care centre in India: a case report

BACKGROUND

Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare subtype of soft tissue sarcoma and the data from India is sparse. It is an unusual variant of fibrosarcoma that commonly arises in the soft tissues of the limb, head and neck, trunk and occasionally in the visceral organs and bones. This entity is commonly reported in the middle age group, men and women alike. Pathological clinchers include MUC 4 (Mucin 4, cell surface associated) positivity by immunohistochemistry, FUS-CREB3L1 fusion and EWSR1 rearrangement. This disease is notoriously known for its local recurrence and metastatic spread. Response to systemic therapy is poor and relapses are frequent. The role of targeted and immunotherapy is not well defined.

CASE PRESENTATION

Here we report a 46-year-old gentleman who presented to the Sarcoma Medical Oncology Clinic in our centre. He had primary involvement of right pubic bone with metastasis to liver, lung and diffuse lytic bony lesions. His diagnosis was reviewed multiple times before coming to final diagnosis of SEF. His molecular test for EWSR1 rearrangement was positive by fluorescence in-situ hybridisation. He did not respond to palliative doxorubicin, pazopanib and gemcitabine and docetaxel.

CONCLUSION

Through this case report, we would like to highlight the rarity of this sarcoma, its classical pathological features, its close relationship to low-grade fibromyxoid sarcoma and the limited therapeutic options available. Hence, there is a need for further research in this entity.

Primary extradural tumors of the spinal column: A comprehensive treatment guide for the spine surgeon based on the 5th Edition of the World Health Organization bone and soft-tissue tumor classification

BACKGROUND

In 2020, the World Health Organization (WHO) published the 5th version of the soft tissue and bone tumor classification. Based on this novel classification system, we reviewed the current knowledge on all tumor entities with spinal manifestations, their biologic behavior, and most importantly the appropriate treatment options as well as surgical approaches.

METHODS

All tumor entities were extracted from the WHO Soft-Tissue and Bone Tumor Classification (5th Edition). PubMed and Google Scholar were searched for the published cases of spinal tumor manifestations for each entity, and the following characteristics were extracted: Growth pattern, ability to metastasize, peak age, incidence, treatment, type of surgical resection indicated, recurrence rate, risk factors, 5-year survival rate, key molecular or genetic alterations, and possible associated tumor syndromes. Surgical treatment strategies as well as nonsurgical treatment recommendations are presented based on the biologic behavior of each lesion.

RESULTS

Out of 163 primary tumor entities of bone and soft tissue, 92 lesions have been reported along the spinal axis. Of these 92 entities, 54 have the potential to metastasize. The peak age ranges from conatal lesions to 72 years. For each tumor entity, we present recommended surgical treatment strategies based on the ability to locally destruct tissue, to grow, recur after resection, undergo malignant transformation as well as survival rates. In addition, potential systemic treatment recommendations for each tumor entity are outlined.

CONCLUSION

Based on the 5th Edition of the WHO bone and soft tumor classification, we identified 92 out of 163 tumor entities, which potentially can have spinal manifestations. Exact preoperative tissue diagnosis and interdisciplinary case discussions are crucial. Surgical resection is indicated in a significant subset of patients and has to be tailored to the specific biologic behavior of the targeted tumor entity based on the considerations outlined in detail in this article.

Metastatic Pediatric Sclerosing Epithelioid Fibrosarcoma

Sclerosing epithelioid fibrosarcoma (SEF) is a rare and aggressive soft-tissue sarcoma thought to originate in fibroblasts of the tissues comprising tendons, ligaments, and muscles. Minimally responsive to conventional cytotoxic chemotherapies, >50% of SEF patients experience local recurrence and/or metastatic disease. SEF is most commonly discovered in middle-aged and elderly adults, but also rarely in children. A common gene fusion occurring between the EWSR1 and CREB3L1 genes has been observed in 80%–90% of SEF cases. We describe here the youngest SEF patient reported to date (a 3-yr-old Caucasian male) who presented with numerous bony and lung metastases. Additionally, we perform a comprehensive literature review of all SEF-related articles published since the disease was first characterized. Finally, we describe the generation of an SEF primary cell line, the first such culture to be reported. The patient described here experienced persistent disease progression despite aggressive treatment including multiple resections, radiotherapy, and numerous chemotherapies and targeted therapeutics. Untreated and locally recurrent tumor and metastatic tissue were sequenced by whole-genome, whole-exome, and deep-transcriptome next-generation sequencing with comparison to a patient-matched normal blood sample. Consistent across all sequencing analyses was the disease-defining EWSR1–CREB3L1 fusion as a single feature consensus. We provide an analysis of our genomic findings and discuss potential therapeutic strategies for SEF.

The rare primary bone sarcomas: imaging-pathological correlation

Rare primary bone sarcomas are challenging entities both radiologically and pathologically. These include the diagnoses of spindle cell sarcoma (leiomyosarcoma, fibrosarcoma, synovial sarcoma, and malignant peripheral nerve sheath tumor), pleomorphic liposarcoma, and undifferentiated pleomorphic sarcoma. The radiographic and cross-sectional imaging features of each of these tumors are presented, along with current key pathological concepts. Frequently non-specific, the radiological appearances must be correlated with all clinical and pathological information available to enable an accurate diagnosis.

Primary sclerosing epithelioid fibrosarcoma of the spine: a single-institution experience

AIMS

To present our experience on spinal sclerosing epithelioid fibrosarcoma (SEF) and review the existing literature pertaining to SEF of the spine.

METHODS AND RESULTS

Six cases of spinal SEF were reviewed, and a literature search of all primary SEFs of the spine was performed. All tumours occurred in adults (median age, 41 years) and were located all along the spine, the lumbar vertebrae being the most commonly involved. All patients presented with pain that they had experienced for months. The mean tumour size at diagnosis was 52 mm. Five tumours showed a spectrum of microscopic features consistent with pure SEF, and one showed a hybrid morphology with areas of low-grade fibromyxoid sarcoma. All were diffusely and strongly positive for mucin 4. Two cases were initially misdiagnosed as epithelioid haemangioendothelioma and aggressive chondroblastoma. Fluorescence in-situ hybridisation showed rearrangements of either FUS or EWSR1 in four cases. Reverse transcription polymerase chain reaction showed the presence of FUS-CREB3L1 and EWSR1-CREB3L1 fusion transcripts in two cases and one case, respectively. Of five patients with follow-up data available, two developed one or more local recurrences and three patients had metastatic disease. Distant metastases were mainly to other osseous locations, followed by lungs and lymph nodes. At last follow-up, three patients had died of disease and one was alive with multiple metastases.

CONCLUSIONS

SEF is an aggressive sarcoma that can involve the spine. It is important to recognise the spine as the primary location of SEF, in order to avoid misdiagnosis as more common primary spinal neoplasms, which can impact on therapeutic approaches.

Sclerosing Epithelioid Fibrosarcoma: A Distinct Sarcoma With Aggressive Features

Since its original description in 1995, the concept of sclerosing epithelioid fibrosarcoma (SEF) as a distinctive tumor has evolved in the literature. Subsequent studies suggested that the presence of low grade fibromyxoid sarcoma (LGFMS)-like zones, occasional FUS gene rearrangements, and immunoreactivity for MUC4 all pointed to a close inter-relationship with LGFMS; however, more recent studies showed that SEF is genetically distinct from LGFMS with predominantly EWSR1-CREB3L1 fusion and complex secondary genomic alterations. To better understand the relationship between these tumors, we studied 51 cases of SEF, the largest reported series to date, and directly compared them to a previously published series of LGFMS from the same institution. The male-to-female ratio was 1.4:1 with a median age of 45 years. Tumors occurred primarily in the lower extremity (12), intra-abdominal area/visceral organs (9) and chest wall/paraspinal region (9) with a median size of 8.2 cm. The median follow-up was 49 months in 45 patients: 12 developed local recurrences and 36 developed metastases, mainly to lung and bone. Molecular studies showed EWSR1 gene rearrangement in 13 cases, 3' deletion of EWSR1 in 6, monosomy for EWSR1 in 2; FUS gene rearrangements in 3; EWSR1-CREB3L1 fusion in 7; EWSR1-CREB3L2 fusion in 1; and YAP1-KMT2A fusion in 2. Overall survival of SEF was significantly less compared with LGFMS (P≤0.0001). These results indicate that SEF is a distinct sarcoma that behaves more aggressively than LGFMS with a shorter survival, higher metastatic rate, and greater propensity to involve deep soft tissue and bone.

Case Report: Radiological Features of Sclerosing Epithelioid Fibrosarcoma in the Right Fibula

Background

Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare, aggressive malignant subtype of fibrosarcoma. Only dozens of cases of primary SEF in the bone have been reported so far, without case involving fibula reported in literature to date. Herein we report the first case of primary SEF in the right fibula in a 19-year-old man. In this case report, we firstly give a comprehensive description of fibula SEF, including its complete clinical course and radiological findings.

Case Presentation

A 19-year-old man presented with a half-year history of soreness in the right lower leg. Contrast-enhanced computed tomography (CE-CT) and magnetic resonance imaging (MRI) of the right lower leg were performed. Based on the radiological examinations, a diagnosis of malignant tumor arising in the fibular diaphysis was made. Final diagnosis of primary SEF in the right fibula was confirmed by histopathological and immunohistochemical examinations after surgical resection. The patient had no signs of recurrence or metastasis during a 24-month follow-up.

Conclusion

We report an exceedingly rare case of primary SEF in the right fibula and its radiological features with CE-CT and MRI.

Sclerosing epithelioid fibrosarcoma of bone: morphological, immunophenotypical, and molecular findings of 9 cases

Primary sclerosing epithelioid fibrosarcoma (SEF) of bone is a rare and scarcely reported neoplasm. We document clinicopathological and molecular features of 9 additional cases. Five males and 4 females had a mean age of 39 years (14-71 years). Most tumors affected flat/irregular bones; only 3 cases involved a long bone. By radiology, it has characteristic radiographic features of a predominantly lytic expansile lesion with a sclerotic rim. Referring diagnoses were SEF (n = 2), low-grade osteosarcoma (n = 2), chondrosarcoma (n = 1), and chondromyxoid fibroma (n = 1). Histologically, five cases revealed classical morphology of SEF of soft tissue. Remaining cases were classified as hybrid SEF/low-grade fibromyxoid sarcoma, characterized by spindle or stellate cells, prominent stroma, and giant hyalinized areas. Various morphological deviations such as prominent vasculature (n = 3), osteoid-like material (n = 4), or parallel bone trabeculae (n = 2) were observed. Immunohistochemically, all cases showed diffuse and strong MUC4 expression. SATB2 was observed in 5/8 cases. Using FISH, EWSR1, and FUS rearrangements were detected in 4 cases and 1 case, respectively. EWSR1-CREB3L1 fusion was identified in 1 additional case by next-generation sequencing. Recurrence and metastasis were observed in 1 case and 2 cases, respectively. All but one patient were alive with disease for a mean interval of 31 months. SEF of bone is a relatively indolent sarcoma of adults, most commonly located in the flat/irregular bones. Due to overlapping histological features, it is often misdiagnosed as osteosarcoma or a chondroid tumor. Most SEF of bone exhibit EWSR1 rearrangements, but rare cases may harbor a FUS gene fusion.

Imaging Features of Sclerosing Epithelioid Fibrosarcoma of the Pancreas: A Case Report

Background: Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare fibrosarcoma variant. There is no complete imaging data on SEF involving the pancreas. Herein we report the computed tomography (CT) and magnetic resonance imaging (MRI) data of a patient with SEF that primarily involved the pancreas.

Case Presentation: A 64-year-old man was found to have a solid mass in the tail of the pancreas on unenhanced CT. He had no constitutional symptoms. Contrast-enhanced abdominal CT and MRI were performed, and the results of the latter provided the diagnosis of a pancreatic neuroendocrine tumor. Laparoscopic distal pancreatectomy and splenectomy were performed. Anatomopathological examination and immunohistochemistry confirmed that the tumor was a SEF of the pancreas. The patient had no signs of recurrence or metastasis during a 12-months follow-up.

Conclusion: We report an extremely rare case of SEF in the pancreas and its characterization with CT and MRI.

Clinical and molecular characterization of primary sclerosing epithelioid fibrosarcoma of bone and review of the literature

Sclerosing epithelioid fibrosarcoma (SEF) is a rare sarcoma subtype characterized by monomorphic epithelioid cells embedded in a densely sclerotic collagenous matrix. The overwhelming majority of tumors arise in soft tissues; however, rare cases have been documented to occur primarily in bone. The hallmarks of soft tissue SEF include MUC4 immunoreactivity and the presence of an EWSR1-CREB3L1 fusion. Rare cases with alternative fusions have also been reported such as EWSR1-CREB3L2 and FUS-CREB3L2 transcripts. The molecular alterations of skeletal SEF have not been well-defined, with only rare cases analyzed to date. In this study we investigated the clinicopathologic and molecular features of seven patients presenting with primary osseous SEF. There were 3 males and 4 females, with a mean age at diagnosis of 38 years. All cases had microscopic features within the histologic spectrum of SEF and showed strong and diffuse MUC4 positivity, while lacking SATB2 expression. However, due to its unusual presentation within bone, four cases were initially misinterpreted as either osteosarcoma, Ewing sarcoma or chondroblastoma. Half of the patients with follow-up data developed metastasis. The cases were tested by targeted RNA sequencing, MSK-IMPACT, and/or fluorescence in situ hybridization, showing EWSR1-CREB3L1 in six cases and EWSR1-CREB3L2 in one case. The fusion transcripts were composed of EWSR1 exon 11 to either exon 6 of CREB3L1 or CREB3L2. In summary, due to their rarity in the bone, skeletal SEF are often misdiagnosed, resulting in inadequate treatment modalities. Similar to their soft tissue counterpart, bone SEF follow an aggressive clinical behavior and show similar EWSR1-CREB3L1/CREB3L2 fusions.

Sclerosing Epithelioid Fibrosarcoma of the Coccyx: A Case Report and Review of Literature

Coccydynia in adult patients is not uncommon and is frequently neglected. Coccydynia is mostly associated with fall on buttocks. In long-standing cases, coccydynia can be debilitating. Rarely coccydynia can be due to more sinister causes and surgeons should be aware of all differential diagnosis. We present a case of an elderly female who presented with a complaint of pain over coccyx which was not subsiding with conventional treatment methods. Biopsy was done and a diagnosis of sclerosing epitheloid fibrosarcoma was made. We describe an unusual case of coccydynia secondary to this tumour with the histopathology finding and surgical management.

Sclerosing Epithelioid Fibrosarcoma of the Jaw: Late Recurrence from a Low Grade Fibromyxoid Sarcoma

Sclerosing epithelioid fibrosarcoma (SEF) is an uncommon variant of fibrosarcoma that is characterized by a distinct morphology. It most frequently presents in the deep soft tissues of the lower extremities, often in intimate association with fascia and periosteum, although reports of the head and neck involvement have been reported. A minority of cases show morphological, immunohistochemical and molecular overlap with low grade fibromyxoid sarcoma (LG-FMS). Herein, we describe a case of a bland spindle cell neoplasm presenting in the jaw that was initially incompletely excised. Over the course of 20 years the tumor subsequently recurred with a SEF morphology. Molecular testing performed on both specimens subsequently confirmed the presence of an EWSR1-CREB3L1 gene fusion. This report highlights the diagnostic difficulty with LG-FMS, particularly in unusual anatomic locations; reiterates the potential for the uncommon EWSR1-CREB3L1 fusion product in LG-FMS; and, reaffirms the potential for progression and/or overlap between LG-FMS to SEF over time.

Diagnosis, Classification, and Management of Soft Tissue Sarcomas

BACKGROUND

Soft tissue sarcomas are challenging to oncologists due to their unique character, the infrequency of their occurrence, and the difficulties in predicting outcomes. Advances in imaging, as well as improvements in surgical techniques and adjunctive treatment methods, have improved care for patients with these unusual disorders.

METHODS

The various types of soft tissue tumors are defined, and the statistics for the Orthopaedic Oncology Group in relation to them are reviewed and compared with literature references.

RESULTS

The overall survival rate for 1,220 tumors treated at our institute from June 1972 to June of 2001 was 72%, with a wide range. Patients with leiomyosarcomas, clear cell sarcomas, and malignant fibrous histiocytomas had a poorer survival rate, while those with fibrosarcomas, liposarcomas, and neurofibrosarcomas fared better. Outcome was affected by patient age, tumor anatomic site, tumor stage, and a history of recurrence.

CONCLUSIONS

Competent imaging, predictive immunological and genetic studies, improved surgery, and newer methods of adjunctive and neoadjunctive treatment should result in improvements in outcomes for patients with these tumors.

Skull sclerosing epithelioid fibrosarcoma: A case report and review of the literature

Sclerosing epithelioid fibrosarcoma (SEF) is an unusual variant of fibrosarcoma that was previously considered to be a low-grade tumor with an indolent course. The tumor occurs most commonly in the soft tissue of the limb, trunk, head and neck, and occasionally in the bone and visceral organs. The skull is a rare primary site for SEF, with only 3 cases reported to date. The current study reports a case of SEF occurring in the occipital bone of a 24-year-old man, who lacked neurological symptoms. Imaging revealed a large mass emanating from the occipital bone and involving the superior sagittal sinus, torcular herophili and adjacent brain tissue. Histological and immunohistochemical characteristics confirmed the diagnosis of SEF. The patient experienced local recurrence and distant metastasis at 10 and 15 months, respectively, subsequent to the resection of the primary mass. The current case and review of the literature suggest that skull SEF may behave clinically as an aggressive malignant sarcoma. Radiological findings indicated the biological and histopathological characteristics of the tumor. Thus, its clinical behavior and certain imaging features may suggest this diagnosis.

Primary sclerosing epithelioid fibrosarcoma of kidney with variant histomorphologic features: report of 2 cases and review of the literature

The authors present two cases of primary sclerosing epithelioid fibrosarcoma (SEF) of the kidney. Both patients had a mass in the upper part of the left kidney without any primary extrarenal neoplastic lesions. Grossly, the tumors were solid masses both measuring 7.5 cm in the greatest diameter. Histologically, one of the lesions exhibited a predominantly lobular growth of round or oval small uniform epithelioid cells in variable cellularity. Circular zones of crowded tumor cells alternating with hypocellular collagenous tissue in a concentric fashion around entrapped native renal tubules were distinctive. The second case was distinctive with significant cytological atypia in the neoplastic cells and prominent reactive proliferations in the trapped renal tubules. Immunohistochemically, vimentin, bcl-2 and MUC4 were diffusely positive in both. They were negative for S-100 protein, CD34, and desmin, whereas CD99 were positive in one lesion. Fluorescence in situ hybridization assay using dual staining probes detected EWSR1-CREB3L1 fusion in each lesion, which is characteristic molecular findings of SEF. One patient presented widespread distant metastases at the time of diagnosis. In the other, no tumor deposits were detected other than primary. Both patients have been alive with 30 and 10 month follow-ups, respectively. These tumors are 6th and 7th cases of primary renal SEF in the literature confirmed by FISH study, which exhibit unique and remarkable histomorphologic features.

¹⁸F-fluorodeoxyglucose PET/CT features and correlations with histopathologic characteristics in sclerosing epithelioid fibrosarcoma

Sclerosing epithelioid fibrosarcoma (SEF) is a clinicopathologically distinct variant of fibrosarcoma that is capable of recurrence and metastasis. Awareness of imaging features and histopathologic characteristics will be helpful for differential diagnosis from other common tumors. Here, we report a case of SEF metastasizing to the pancreas as a solitary mass mimicking primary pancreatic cancer, and summarize the reported cases with FDG PET/CT from the literature (n=4). PET/CT showed abnormal FDG accumulation (n=2), mild FDG uptake (n=1), or photopenic (n=1). The FDG PET/CT features are closely related to histopathologic characteristics regarding its differentiation and aggressiveness.

Sclerosing epithelioid fibrosarcoma of the bone: a case report of high resistance to chemotherapy and a survey of the literature

Sclerosing epithelioid fibrosarcoma (SEF) is a rare soft tissue sarcoma mostly occurring in extraosseous sites. SEF represents a clinically challenging entity especially because no standardized treatment regimens are available. Intraosseous localization is an additional challenge with respect to the therapeutical approach. We report on a 16-year-old patient with SEF of the right proximal tibia. The patient underwent standardized neoadjuvant chemotherapy analogous to the EURAMOS-1 protocol for the treatment of osteosarcoma followed by tumor resection and endoprosthetic reconstruction. Histopathological analysis of the resected tumor showed >90% vital tumor cells suggesting no response to chemotherapy. Therefore, therapy was reassigned to the CWS 2002 High-Risk protocol for the treatment of soft tissue sarcoma. To date (22 months after diagnosis), there is no evidence of relapse or metastasis. Our data suggest that SEF may be resistant to a chemotherapy regimen containing Cisplatin, Doxorubicin, and Methotrexate, which should be considered in planning treatment for patients with SEF.

Sclerosing epithelioid fibrosarcoma of the liver infiltrating the inferior vena cava

Sclerosing epithelioid fibrosarcoma (SEF) is a rare and distinct variant of fibrosarcoma, composed of epithelioid tumor cells arranged in strands, nests, cords, or sheets embedded within a sclerotic collagenous matrix. We report a 39-year-old man with SEF of the liver, which infiltrated the inferior vena cava (IVC). The SEF of the liver was successfully resected, and the infiltrated IVC was also removed together with the liver tumor. Histopathological examination of the tumor showed typical histopathology of SEF. Immunohistochemically, the tumor was positive for vimentin. Recurrence was noted 7 mo after surgery. After chemotherapy, the recurrent tumor was resected surgically, and histopathological examination showed similar findings to those of the primary tumor. To our knowledge, this is the first report of SEF of the liver with tumor invasion of the IVC.

Multiple bone metastasis of sclerosing epithelioid fibrosarcoma 12 years after initial surgery-increasing ki-67 labeling index

Sclerosing epithelioid fibrosarcoma (SEF) is a rare sarcoma of low-grade malignancy. There has been no report to describe the comparison of histological features of SEF between primary and metastatic lesions in spite of high local recurrence rate. We report the histological changes and increasing Ki-67 labeling index of the primary and metastatic lesions of SEF. The patient was a 31-year-old man. At 18, a tumor in the abdominal wall was excised. At 23, the tumor recurred which was removed again. At 30, he was referred to our hospital because of swelling and pain in the chest. Histological examination of the chest wall tumor showed epithelioid cells arranged like alveolar pattern with dense collagen stroma. These findings were consistent with those of SEF. Abdominal and the rib tumors showed the same immunohistochemistrical expression. It is noteworthy that the tumor cells of the rib lesion showed increased cellularity, and its Ki-67 activity was higher as compared with the abdominal tumor, suggestive of progression of malignancy of SEF.

Sclerosing epithelioid fibrosarcoma: case presentation and a systematic review

In sclerosing epithelioid fibrosarcoma (SEF), a rare variant of low-grade fibrosarcoma, treatment results and therapeutic options are poorly characterized. We systematically analyzed the data of all 89 patients (43 female, 46 male; mean age, 47 years [range, 14-87 years]) reported in the literature concerning clinical presentation, histopathology, differential diagnosis, treatment, survival rates, and prognosis, and we present an additional case. Information detailing treatment, disease control, and followup was available in 60 (67%), 75 (84%), and 68 patients (76%), respectively. Case history was variable with one-third of patients reporting a painful, enlarging mass. Ten patients (13%) presented with metastases, 23 (31%) had metastases develop after diagnosis, and 28 (37%) had local recurrence. Low cellularity, mild pleomorphy, and sclerotic hyaline matrix of SEF suggest a benign clinical behavior, and cell morphology allows for the wide differential diagnosis of benign, pseudosarcomatous, and malignant proliferations. In addition to surgery, 11 patients (15%) had chemotherapy, 22 (29%) had postoperative radiation therapy, and three (4%) had a combination of both. Twenty-three patients (34%) died from their disease after a mean of 46 months, 24 (35%) were alive with disease, and 20 (31%) were alive without evidence of disease. Patients with SEF of the head and neck had the worst prognosis.

LEVEL OF EVIDENCE

Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Sclerosing epithelioid fibrosarcoma of the cecum: a radiation-associated tumor in a previously unreported site

Data from the nuclear reactor explosion in Chernobyl and the atomic bomb detonations in Hiroshima and Nagasaki demonstrated an association between ionizing radiation and tumoriogenesis. There is a significant association between external beam radiation and radiation-induced sarcoma. Sclerosing epithelioid fibrosarcoma is a rare form of malignant fibrosarcoma that is low grade and indolent with distinct immunohistopathologic characteristics that usually occurs in the soft tissues of the extremities. A 62-year-old man from Kiev who aided in the cleanup at Chernobyl presented with crampy abdominal pain, nausea, and vomiting. His workup revealed a cecal mass, and the final pathology from his laparotomy confirmed sclerosing epithelioid fibrosarcoma with metastasis to the liver. In addition to a review of the literature, we report the first case of sclerosing epithelioid fibrosarcoma arising from the large bowel. Exposure to ionizing radiation from Chernobyl could have played a role in the development of his tumor.

Oral and maxillofacial sclerosing epithelioid fibrosarcoma: report of five cases

Sclerosing epithelioid fibrosarcoma (SEF) has distinctive morphology and occurs mainly in deep soft tissue of adult extremities. Approximately 59 cases of SEF have been reported, with only 12 previously described in head and neck locations. Lesions involving the oral and maxillofacial region (OMFR) and intraosseous examples are rare. We present five cases of OMFRSEF. The OMF Pathology Department Registry was searched for cases coded from 1990 to the present as "SEF," "fibrosarcoma not otherwise specified" or "neoplasm of uncertain histiogenesis." Inclusion required OMFR location, an abundantly sclerotic sarcoma with epithelioid features, and lack of other phenotype by immunohistochemistry. Five cases of SEF included 3 males and 2 females. The age of the patients were: 19, 22, 35, 47 and 47 years. Tumor location included the infra-temporal fossa, buccal mucosa (recurrence extending into bone), anterior mandible (intraosseous primary, focally extending into soft tissue), and left parotid and submandibular gland (with metaplastic bone) regions. Tumor sizes ranged from 1.0 to 5.7 cm, median 3.5 cm. Histologically, the tumors were well delineated and multinodular, separated by fibrous septae. The spindled to primarily epithelioid tumor cells formed moderately cellular sheets and cords of irregularly contoured medium to large, round to oval, occasionally overlapping nuclei, indistinct nucleoli, wispy eosinophilic (retracting) cytoplasm, and distinctive cytoplasmic borders, embedded in osteoid-like stroma. Hemangiopericytoid (HPC-like) vessels were observed. Despite numerous apoptotic cells, mitoses were generally low; necrosis was present in two cases. Three tumors were graded as 2/3 and two 1/3. Immunohistochemically, the tumor cells were positive for vimentin, 1 case focally for CD34, whereas all cases were negative for S100 protein, keratins, EMA, desmin, and SMA. Wide or radical excision was performed with no adjuvant therapy. Follow-up revealed that 4 cases recurred at a range of 12-120 months. One case had no recurrent/residual disease at 3 months. Metastatic disease was present in 2 cases, to chest wall and lumbar/thoracic spine at 12 and 21 months, respectively. One patient died of disease complications at 15 months. OMFRSEF occur in adults in various locations, but with a common propensity to involve bone; there is recurrent potential and morbidity with higher grade lesions. The differential diagnosis for these tumors in this site includes sclerosing carcinoma, Ewing/PNET, osteosarcoma, osteoblastoma, and benign and malignant myoepithelial salivary gland tumors. The collagen, focal spindle cell features, HPC-like vasculature, and weak focal CD34 reactivity in one case might have raised a possible relationship between OMFRSEF and low grade malignant solitary fibrous tumor, but the intraosseous propensity, epithelioid features and relative lack of CD34 make this a distinctive entity.

Epithelioid and Epithelial Neoplasms of Bone

Context.—Epithelioid and epithelial neoplasms seen in bone are rare and include epithelioid variants of vascular lesions, osteoblastoma, osteosarcoma, chordoma, and chondroblastoma as well as adamantinoma and metastatic carcinoma.

Objective.—To provide an overview of tumors with epithelioid histology and address the clinical context and diagnostic issues.

Data Sources.—Pertinent literature is reviewed with emphasis on recent and controversial issues.

Conclusions.—The differential diagnosis in epithelioid/ epithelial lesions of bone is limited. The primary consideration in many cases is distinguishing primary from metastatic lesions.

Sclerosing epithelioid fibrosarcoma of the pituitary

Primary pituitary sarcoma in the absence of previous radiation therapy is very rare, only eight cases having been reported. We present the first reported case of sclerosing epithelioid fibrosarcoma of the pituitary, a 56-year-old woman presenting with diplopia and panhypopituitarism. Magnetic resonance imaging showed a 1.2 x 0.4 x 0.5-cm sellar mass invading the right cavernous sinus. Despite surgery and radiation therapy, our patient developed intracranial metastases and died 2 years after the initial diagnosis. Sclerosing epithelioid fibrosarcoma is an infrequently occurring, distinct variant of soft tissue fibrosarcoma. Its immunophenotype includes vimentin and occasionally CD-34, B cell lymphoma-2, S-100 protein, or keratin expression. Although initially thought to be a low-grade lesion, sclerosing epithelioid fibrosarcomas may also behave in a high-grade manner.

[Pleural metastases of sclerosing epithelioid fibrosarcoma]

Sclerosing epithelioid fibrosarcoma is a rare tumor recently described. The histological presentation can be confused with certain soft tissue benign tumors and certain sarcomas. Metastatic spread is usually late in the natural course of the disease. We report a case of recurrent sclerosing epithelioid fibrosarcoma with pleural metastases which developed ten years after surgical resection of the primary tumor. The tumor was formed by small uniform round epithelioid cells with a clear cytoplasm. The tumor cells were strongly positive for vimentin. This clinical case is discussed in light of other cases reported in the literature.