Sclerosing epithelioid fibrosarcoma with der(10)t(10;17)(p11;q11)

Sclerosing Epithelioid Fibrosarcoma

Sclerosing epithelioid fibrosarcoma (SEF) is a distinctive sarcoma that may arise in nearly any soft tissue site or bone. While there has been past controversy as to whether it is related to low-grade fibromyxoid sarcoma (LGFMS), it has been shown to behave far more aggressively than LGFMS. SEF has a propensity to metastasize to the lungs and bone and arise within the abdominal cavity. Histologically, it is characterized by uniform nuclei embedded in a densely collagenous stroma simulating osteoid. By immunohistochemistry, it is often strongly positive for MUC4. The majority (75%) have EWSR1 gene rearrangement, most commonly with CREB3L1 as a fusion partner, although a variety of FUS/EWSR1 and CREB3L1/CREB3L2/CREB3L3 fusions have been described in addition to others. SEF is currently recalcitrant to nearly all chemotherapy and radiation therapy.

Molecular Alterations in Pediatric Fibroblastic/Myofibroblastic Tumors: An Appraisal of a Next Generation Sequencing Assay in a Retrospective Single Centre Study

BACKGROUND

Pediatric fibroblastic/myofibroblastic tumors (PFMTs) can be challenging to definitively classify. Large case series or diagnostic updates have not been recently published despite identification of molecular alterations that could improve diagnostic accuracy. Our review of the literature found that over two-thirds of the more than 30 types of PFMTs harbor recurrent molecular alterations. We performed an institutional review of PFMTs to highlight limitations of a predominantly morphological classification, and evaluated the utility of a next-generation sequencing assay to aid diagnosis.

METHODS

PFMTs identified over a period of 12 years were reviewed, categorized per the new WHO classification, and tested using the Oncomine Childhood Cancer Research Assay.

RESULTS

Eighty-seven specimens from 58 patients were reviewed; 50 were chosen for molecular analysis, 16 (32%) lacking definitive classification. We identified alterations, some novel, in 33% of assayed cases. Expected alterations were identified for most known diagnoses and mutations were identified in 6 of 16 tumors (38%) that were initially unclassified.

CONCLUSION

We confirmed a significant subset of PFMTs remain difficult to classify using current criteria, and that a combined DNA/RNA assay can identify alterations in many of these cases, improving diagnostic certainty and suggesting a clinical utility for challenging cases.

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.

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

First described in 1995 by Meis-Kindbloom et al. as a variant of fibrosarcoma simulating carcinoma, sclerosing epithelioid fibrosarcoma (SEF) is a malignant soft tissue sarcoma characterized by epithelioid cells in dense sclerotic stroma, frequent immunoreactivity for MUC4 and heterogeneous genetic profile with recurrent EWSR1 gene rearrangement. It typically affects middle-age adults with a predilection for the lower extremity. It is believed that SEF is closely related to low-grade fibromyxoid sarcoma (LGFMS), both tumors show overlapping features in morphology, immunophenotype, and molecular profile. In this review, we discuss the clinical, morphologic, and immunohistochemical features of SEF with particular emphasis on its molecular diversity and relation to LGFMS.

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.

MUC4 is a sensitive and extremely useful marker for sclerosing epithelioid fibrosarcoma: association with FUS gene rearrangement

Sclerosing epithelioid fibrosarcoma (SEF) is a rare aggressive fibroblastic neoplasm composed of cords of epithelioid cells embedded in a dense collagenous stroma. The reported immunophenotype of SEF is nonspecific. Some SEF cases show morphologic and molecular overlap with low-grade fibromyxoid sarcoma (LGFMS), suggesting a relationship between these tumor types. MUC4 has recently been identified as a sensitive and specific marker for LGFMS; MUC4 expression was also observed in 2 tumors with hybrid features of SEF and LGFMS. We investigated MUC4 expression in SEF and other epithelioid soft tissue tumors to determine (1) the potential diagnostic utility of MUC4 for SEF and (2) the association between MUC4 expression and FUS rearrangement in SEF. Whole sections of 180 tumors were evaluated: 41 cases of SEF (including 29 "pure" SEF and 12 hybrid LGFMS-SEF), 20 epithelioid sarcomas, 11 clear cell sarcomas, 11 metastatic melanomas, 10 perivascular epithelioid cell tumors, 10 alveolar soft part sarcomas, 10 epithelioid angiosarcomas, 10 epithelioid hemangioendotheliomas, 10 epithelioid gastrointestinal stromal tumors, 10 myoepithelial carcinomas, 17 ossifying fibromyxoid tumors, 10 leiomyosarcomas, and 10 biphasic synovial sarcomas. Immunohistochemical analysis was performed after antigen retrieval using a mouse anti-MUC4 monoclonal antibody. Fluorescence in situ hybridization (FISH) was performed on 33 SEF cases using FUS break-apart probes. A subset of cases was also evaluated for EWSR1 and CREB3L2/L1 rearrangements by FISH. Strong diffuse cytoplasmic staining for MUC4 was observed in 32 of 41 (78%) cases of SEF, including all 12 hybrid tumors. FUS rearrangement was detected in 8 of 21 (38%) MUC4-positive cases of SEF with successful FISH studies. The prevalence of FUS rearrangement was similar in hybrid LGFMS-SEF (2 of 6; 33%) and SEF without an LGFMS component (6 of 15; 40%). FUS rearrangement was not detected in any cases of MUC4-negative SEF. Two hybrid tumors had both EWSR1 and CREB3L1 rearrangements. MUC4 expression was also seen in 9 of 10 (90%) biphasic synovial sarcomas, predominantly in the glandular component. All other tumor types were negative for MUC4, apart from focal reactivity in 5 ossifying fibromyxoid tumors, 2 epithelioid gastrointestinal stromal tumors, and 1 myoepithelial carcinoma. MUC4 is a sensitive and relatively specific marker for SEF among epithelioid soft tissue tumors. MUC4 expression occurs more frequently than FUS rearrangement in SEF. The finding of EWSR1 and CREB3L1 rearrangements in 2 cases of hybrid LGFMS-SEF suggests that SEFs are genetically heterogenous. MUC4-positive SEFs with FUS rearrangement are likely closely related to LGFMS. MUC4-positive SEFs that lack FUS rearrangement may be related to LGFMS but could have alternate fusion partners, including EWSR1. SEF without MUC4 expression may represent a distinct group of tumors. MUC4 expression correlates with glandular epithelial differentiation in biphasic synovial sarcoma and is very limited in other epithelioid soft tissue tumors.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

FUS rearrangements are rare in 'pure' sclerosing epithelioid fibrosarcoma

Several recent reports have described low-grade fibromyxoid sarcoma with sclerosing epithelioid fibrosarcoma-like areas. We evaluated cases of pure sclerosing epithelioid fibrosarcoma lacking areas of low-grade fibromyxoid sarcoma for FUS rearrangement to determine whether this entity could be related to low-grade fibromyxoid sarcoma. Available formalin-fixed paraffin-embedded tissue of 27 sclerosing epithelioid fibrosarcoma from 25 patients was retrieved and tabulated with clinical information. Unstained slides from formalin-fixed paraffin-embedded blocks were prepared and fluorescence in-situ hybridization was performed using a commercial FUS break-apart probe. The median patient age at presentation was 50 (range, 14-78) years, with 14 males and 10 females. Sclerosing epithelioid fibrosarcoma most commonly involved the extremities (n=8) or chest (n=6). Sixteen patients had a median follow-up of 17 (range, 1-99) months; seven were alive and well at 12 (range, 5-30) months; three alive with disease at 28 (range, 9-99) months; five dead of disease at a median of 22 (range, 1-36) months and one was dead of unknown causes. Twelve patients were known to have metastases; the most common site was lung (n=7), followed by bone (n=3), lymph nodes (n=2) and peritoneum (n=1). Only 2 of 22 (9%) analyzable cases of sclerosing epithelioid fibrosarcoma showed rearrangement in the FUS locus by fluorescence in-situ hybridization. Although cytogenetically confirmed low-grade fibromyxoid sarcoma can have sclerosing epithelioid fibrosarcoma-like areas, FUS rearrangement, which is characteristic of low-grade fibromyxoid sarcoma, appears to be relatively rare in pure sclerosing epithelioid fibrosarcoma.

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.

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.

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.

Translocation-positive Low-grade Fibromyxoid Sarcoma: Clinicopathologic and Molecular Analysis of a Series Expanding the Morphologic Spectrum and Suggesting Potential Relationship to Sclerosing Epithelioid Fibrosarcoma

Low-grade fibromyxoid sarcomas (LGFMS) bear either the t(7,16) (q32-34;p11) or t(11,16) (p11;p11) translocations, resulting in FUS-CREB3L2 or FUS-CREB3L1 fusions, respectively. Heretofore, fusion transcripts were mainly detected in frozen tissues, using reverse transcription-polymerase chain reaction. In this study, we aimed to develop a reliable method to detect these in paraffin-embedded tissues, and to examine the clinicopathologic characteristics of a series of translocation-positive LGFMS. Sixty-three neoplasms with typical morphologic features of LGFMS and 66 non-LGFMS tumors selected for their resemblance to LGFMS (LGFMS-like tumors) were examined. RNA of sufficient quality could be extracted from 111/129 (86%) cases (59 LGFMS, 52 non-LGFMS). Of all, 48/59 (sensitivity, 81%) LGFMS contained detectable transcripts (45 FUS-CREB3L2, 3 FUS-CREB3L1). Most relevant clinicopathologic features of fusion-positive LGFMS included predominance in lower extremities (22/48; thigh: 13/48), deep situation (46/48), and occasional presence of unusual histologic features, for example, hypercellular areas (16/48), foci of epithelioid cells (13/48), and giant rosettes (6/48). Most tumors expressed EMA (41/45), at least focally, CD99 (38/41) and bcl-2 (36/41) while being essentially negative for CD34 (2/45), mdm2 (1/41), smooth muscle actin (1/45), S100 protein (0/46), desmin (0/44), h-caldesmon (0/42), keratins (0/44), and CD117 (0/40). Eleven presumed LGFMS were fusion negative. Of all, 7/52 non-LGMFS neoplasms contained FUS-CREB3L2 transcripts, of which 4 had been diagnosed as sclerosing epithelioid fibrosarcoma. In conclusion, FUS-CREB3L1/L2 fusion transcripts can be detected in paraffin-embedded LGFMS in a sensitive manner, using reverse transcription-polymerase chain reaction. Most fusion-positive LGFMS are EMA-positive and CD34/S100/smooth muscle actin negative. The presence of epithelioid cells and fusion transcripts in both LGFMS and a subset of sclerosing epithelioid fibrosarcoma suggest that these neoplasms might be related.

Low-grade fibromyxoid sarcoma presenting clinically as a primary ovarian neoplasm: a case report

Low-grade fibromyxoid sarcoma is an uncommon, deceptively bland mesenchymal neoplasm that typically occurs in the deep soft tissues of the proximal extremities of young to middle-aged patients. Intra-abdominal low-grade fibromyxoid sarcomas are distinctly rare. We describe the first reported example of this sarcoma involving the ovary. The 42-year-old patient presented with progressing abdominal pain and urinary frequency. Computed tomographic imaging of the abdomen and pelvis showed a 14-cm left-sided pelvic mass. The patient underwent surgical resection and, intraoperatively, a left ovarian mass was identified that extended to both the left hypogastric artery and the left ureter. The resected specimen consisted of a 17-cm tan, fleshy mass containing grossly recognizable nodules of gelatinous, myxoid tissue and a small rim of normal ovary. Microscopic examination of the neoplasm revealed a cytologically bland spindle cell proliferation set in a collagenized stroma that abruptly transitioned to nodules of a myxoid stroma with a well-formed capillary vasculature, features characteristic of low-grade fibromyxoid sarcoma. On the basis of the diagnosis, the patient was clinically staged as a retroperitoneal sarcoma with secondary ovarian involvement. The patient has stable residual disease 11 months postoperatively. This case adds to the literature of intra-abdominal low-grade fibromyxoid sarcoma and expands the list of malignant mesenchymal neoplasms that may involve the ovary.

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.