Sclerosing epithelioid fibrosarcoma: in-depth review of a genetically heterogeneous tumor

Myoepithelioma-like hyalinizing epithelioid tumors of the palm: A case report

Myoepithelioma-like hyalinizing epithelioid tumors (MHETs) are distinct soft tissue neoplasms characterized by their unique histological presentation, including myoepithelioma-like hyalinization and an epithelioid-cell pattern. A defining molecular characteristic of these tumors is the presence of a novel OGT::FOXO gene fusion. Their distinct morphology makes diagnosis challenging because they can be mistaken for other soft tissue tumors. We report the case of a 71-year-old man who was admitted to our hospital with a 1-year history of a palpable mass on the left palm. Physical examination revealed a well-defined, mobile mass on the lateral aspect of the left palm, measuring 2.0 × 3.0 cm, with moderate consistency. The tumor was surgically excised, and postoperative pathology based on immunohistochemical staining and tissue morphology confirmed the diagnosis of MHET. The tumor cells exhibited diffuse positivity for CD34 and focal positivity for EMA. At the 3-month follow-up post-surgery, there was no evidence of recurrence or distant metastasis. MHETs are typically observed as superficial, well-circumscribed masses without the histological features of malignancy. Given the distinct tissue morphology and the recent identification of this tumor type, clinicians and pathologists must be aware of these features to facilitate accurate diagnosis and inform treatment strategies.

Sclerosing epithelioid fibrosarcoma: a new mesenchymal non-meningothelial tumor involving the central nervous system?

Sclerosing epithelioid fibrosarcoma (SEF) is a rare mesenchymal neoplasm defined in the WHO classification of soft tissue tumor as a "rare malignant fibroblastic neoplasm characterized by epithelioid fibroblasts arranged in cords and nests and embedded in a dense sclerotic hyalinized stroma." These morphological features are associated with a unique immunohistochemical pattern (particularly MUC4 hyperexpression) and with characteristic gene rearrangements, mostly involving EWSR1 and CREB3L1 or CREB3L2. If it usually arises in deep soft tissues of various locations, SEF has also been reported in bones or viscera. Nevertheless, to our knowledge, no primary brain location has been described. Here, we report a left occipital SEF arising in a middle-aged woman with no evidence of systemic location after a comprehensive clinic-radiological assessment. We discuss the main differential neuropathological diagnoses and provide a comprehensive genetic and epigenetic description of this tumor comparatively to the more frequent systemic locations.

Metastatic Sclerosing Epithelioid Fibrosarcoma at Diagnosis: A Case Report

Sclerosing epithelioid fibrosarcoma (SEF) is a rare and aggressive neoplasm composed of epithelioid cells arranged in strands and nests embedded in a highly sclerotic collagenous stroma. We report a case of a 36-year-old man who started with lumbar pain, with extension to both legs, night sweats, and weight loss. He underwent magnetic resonance imaging (MRI) of the lumbar spine; computed tomography (CT) scan of the chest, abdomen, and pelvis; and [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan. The CT scan revealed a 13 cm thoracic mass, the MRI presented with diffuse neoplastic invasion of the vertebrae, and the PET showed hepatic, bone, and possibly pulmonary metastases. The histological diagnosis was compatible with SEF. The disease progressed very quickly, namely, with an episode of spinal cord compression, which made the patient paraplegic. He underwent surgery and, subsequently, radiotherapy (RT). Due to the clinical and analytical evolution, it was not possible to initiate systemic treatment and the patient ultimately passed away. In conclusion, SEF is an aggressive type of sarcoma that affects middle-aged patients, with high rates of distant metastases and mortality. The usual treatment is surgery followed by either radiotherapy or chemotherapy. However, further clinical trials are needed to find more systemic target therapies.

Sclerosing Epithelioid Fibrosarcoma Harboring the EWSR1 - CREB3L1 Gene Fusion: The Importance of Molecular Classification in Pediatric Sarcomas

BACKGROUND

Sclerosing epithelioid fibrosarcoma (SEF) is a very rare soft tissue sarcoma that most commonly presents in middle-aged and elderly adults but has been rarely seen in children. SEF is a very aggressive tumor with over 50% of patients experiencing local recurrence and 40% to 80% of patients experiencing distant metastatic spread. This disease has been shown to be resistant to chemotherapy and is classically treated with surgical excision.

CASE

We describe the case of a 10-year-old girl with Graves' disease who presented with protruding eyes (to a greater extent on the left side) and was found to have a large mass in her left inferior rectus muscle that was diagnosed as SEF. After treatment with incomplete resection, due to the benign-appearing nature of the tumor on imaging, and proton radiation therapy, she remains disease-free at 18 months post-therapy.

DISCUSSION

SEF is typically identified via genetic testing and recognition of the EWSR1 - CREB3L1 gene fusion as well as MUC4 expression via immunohistochemistry. DNA methylation profiling, which has traditionally been used in brain tumors, can also efficiently identify this tumor, and we recommend expanding the use of this technology for difficult to classify pediatric sarcomas.

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 (SEF) versus Low Grade Fibromyxoid Sarcoma (LGFMS): Presentation and outcome in the nationwide NETSARC+ series of 330 patients over 13 years

Sclerosing Epithelioid Fibrosarcoma (SEF) and Low Grade Fibromyxoid Sarcoma (LGFMS) are ultrarare sarcomas sharing common translocations whose natural history are not well known. We report on the nationwide exhaustive series of 330 patients with SEF or LGFMS in NETSARC+ since 2010.

PATIENTS AND METHODS

NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTB). Since 2010, (i) pathological review has been mandatory for sarcoma,and (ii) tumour/patients' characteristics have been collected in the NETSARC+ nationwide database. The characteristics of patients with SEF and LGFMS and their outcome are compared.

RESULTS

35/73 (48%) and 125/257(49%) of patients with SEF and LGFMS were female. More visceral, bone and trunk primary sites were observed in SEF (p < 0.001). 30% of SEF vs 4% of LGFMS patients had metastasis at diagnosis (p < 0.0001). Median size of the primary tumor was 51 mm (range 10-90) for LGFMS vs 80 (20-320) for SEF (p < 0.001). Median age for LGFMS patients was 12 years younger than that of SEF patients (43 [range 4-98] vs 55 [range 10-91], p < 0.001). Neoadjuvant treatment was more often given to SEF (16% vs 9%, p = 0.05). More patients with LGFMS were operated first in reference centers (51% vs 26%, p < 0.001). The R0 rate on the operative specimen was 41% in LGFMS vs 16% in SEF (p < 0.001). Median event-free survival (EFS) of patients with SEF and LGFMS were 32 vs 136 months (p < 0.0001). The median overall survival (OS) was not reached. Fifty-months OS was 93% vs 81% for LGFMS vs SEF (p = 0.05). Median OS was 77 months after first relapse, similar for SEF and LGFMS. In multivariate analysis, age, tumor size, metastasis at diagnosis were independent prognostic factors for OS in LGFMS.

CONCLUSIONS

Although sharing close molecular alterations, SEF and LGFMS have a different natural history, clinical presentation and outcome, with a higher risk of metastatic relapse in SEF. Survival after relapse is longer than with other sarcomas, and similar for SEF and LGFMS.

Sclerosing epithelioid fibrosarcoma associated with WRN gene variant presenting as chronic dyspnea and pathologic cervical fracture: a case report and review of the literature

BACKGROUND

Sclerosing epithelioid fibrosarcoma is an aggressive sarcoma subtype with poor prognosis and limited response to conventional chemotherapy regimens. Diagnosis can be difficult owing to its variable presentation, and cases of sclerosing epithelioid fibrosarcoma are rare. Sclerosing epithelioid fibrosarcoma typically affects middle-aged individuals, with studies inconsistently citing gender predominance. Sclerosing epithelioid fibrosarcoma typically arises from the bones and soft tissues and often has local recurrence after resection and late metastases. Immunohistochemical staining typically is positive for mucin-4. Werner syndrome is due to an autosomal recessive mutation in the WRN gene and predisposes patients to malignancy.

CASE PRESENTATION

A 37-year-old Caucasian female presented to the emergency department with 4 months of dyspnea and back pain. She had been treated for pneumonia but had persistent symptoms. A chest, abdomen, and pelvis computed tomography showed near-complete right upper lobe collapse and consolidation, mediastinal lymphadenopathy, lytic spinal lesions, and a single 15-mm hypodense liver nodule. The patient underwent a transthoracic right upper lobe biopsy, bronchoscopy, endobronchial ultrasound with transbronchial lymph node sampling, and bronchoalveolar lavage of the right upper lobe. The bronchoalveolar lavage cytology was positive for malignant cells compatible with poorly differentiated non-small cell carcinoma; however, the cell block materials were insufficient to run immunostains for further investigation of the bronchoalveolar lavage results. Consequently, the patient also underwent a liver biopsy of the liver nodule, which later confirmed a diagnosis of sclerosing epithelioid fibrosarcoma. Next-generation sequencing revealed a variant of unknown significance in the WRN gene. She was subsequently started on doxorubicin.

CONCLUSION

Sclerosing epithelioid fibrosarcoma is a very rare entity, only cited approximately 100 times in literature to date. Physicians should be aware of this disease entity and consider it in their differential diagnosis. Though pulmonary involvement has been described in the context of sclerosing epithelioid fibrosarcoma, this malignancy may affect many organ systems, warranting extensive investigation. Through our diagnostic workup, we suggest a possible link between sclerosing epithelioid fibrosarcoma and the WRN gene. Further study is needed to advance our understanding of sclerosing epithelioid fibrosarcoma and its clinical associations as it is an exceedingly rare diagnosis.

Response to Immunotherapy in Sclerosing Epithelioid Fibrosarcoma: Case Report and Literature Review

Sclerosing epithelioid fibrosarcoma (SEF) is an extremely rare subtype of sarcoma that appears histologically low-grade yet usually has a clinically aggressive course with a high rate of local recurrence and distant metastasis. However, these recurrences and metastases often occur years after initial treatment. Metastases can be to the lung as well as extra-pulmonary sites. In this case report, we discuss a patient who developed SEF in the deep soft tissue with metastases. This patient underwent checkpoint inhibitor therapy, with disease response. Thus, SEF is a sarcoma subtype with a unique tumor biology, and immunotherapy may be a promising avenue for treatment.

Fibroblastic and Myofibroblastic Soft-Tissue Tumors: Imaging Spectrum and Radiologic-Pathologic Correlation

Fibroblastic and myofibroblastic tumors are a variable group of neoplasms ranging from benign to malignant. These lesions may affect patients of any age group but are more frequently encountered in the pediatric population. Patient clinical presentation depends on the location, growth pattern, adjacent soft-tissue involvement, and pathologic behavior of these neoplasms. In the 2020 update to the World Health Organization (WHO) classification system, these tumors are classified on the basis of their distinct biologic behavior, histomorphologic characteristics, and molecular profiles into four tumor categories: (a) benign (eg, fibrous hamartoma of infancy, nodular fasciitis, proliferative fasciitis, fibroma of the tendon sheath, calcifying aponeurotic fibroma); (b) intermediate, locally aggressive (eg, desmoid fibromatosis); (c) intermediate, rarely metastasizing (eg, dermatofibrosarcoma protuberans, myxoinflammatory fibroblastic sarcoma, low-grade myofibroblastic sarcoma, infantile fibrosarcoma); and (d) malignant (eg, sclerosing epithelioid fibrosarcomas; low-grade fibromyxoid sarcoma; myxofibrosarcoma; fibrosarcoma, not otherwise specified). Detection of various components of solid tumors at imaging can help in prediction of the presence of corresponding histopathologic variations, thus influencing diagnosis, prognosis, and treatment planning. For example, lesions with a greater myxoid matrix or necrotic components tend to show higher signal intensity on T2-weighted MR images, whereas lesions with hypercellularity and dense internal collagen content display low signal intensity. In addition, understanding the radiologic-pathologic correlation of soft-tissue tumors can help to increase the accuracy of percutaneous biopsy and allow unnecessary interventions to be avoided. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

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.

The clinicopathological spectrum of sclerosing epithelioid fibrosarcoma: report of an additional series with review of the literature

We present a case series of sclerosing epithelioid fibrosarcoma (SEF) to further characterise its clinical and pathological features. Twenty-one patients with SEF were included in this study. There were 12 males and nine females (range 25-63 years; median 38 years). Tumours were located in the kidney (n=5), thigh (n=3), chest wall (n=3), head and neck (n=2), bone (n=2), abdominal wall (n=1), psoas major (n=1), retroperitoneum (n=1), omentum (n=1), popliteal space (n=1) and lung (n=1). Tumour sizes ranged from 2.5 to 16 cm (median 7 cm). Microscopically, epithelioid tumour cells were arranged in nests and cords and embedded in a dense sclerotic stroma. Some tumours showed myxoid areas, fibroma-like areas, acinar growth patterns and haemangiopericytoma-like appearance. A few tumour cells presented a rhabdomyoid shape. Calcification, ossification, cystic and necrosis were observed in some cases. The diagnosis was confirmed by immunoreactivity for MUC4, and by further fluorescence in situ hybridisation (FISH) or next generation sequencing (NGS) analysis. Clinical follow-up was available for 16 cases (median, 24 months; range 6-62 months). Seven patients developed metastases to lung (n=3), bone (n=3), brain (n=2) and back (n=1). Four patients developed a local recurrence. Three patients died of disease. Overall survival (OS) of SEF was related to patient age (p=0.001) and progression-free survival (PFS) was related to tumour size (p=0.046). In addition to soft tissue, SEF is more likely to involve the viscera and the abdominal cavity and has morphological variants. Familiarity with its distinctive clinical and pathological features helps avoid misdiagnosis.