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

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.