NR4A3 fusion proteins trigger an axon guidance switch that marks the difference between EWSR1 and TAF15 translocated extraskeletal myxoid chondrosarcomas

Chondrosarcoma: New Molecular Insights, Challenges in Near-Patient Preclinical Modeling, and Therapeutic Approaches

Chondrosarcoma (CS), the second most common malignant bone tumor after osteosarcoma, accounts for 20-30% of all malignant bone tumors. It mainly affects adults, middle-aged, and elderly people. The CS family includes various entities displaying peculiar biological, genetic, and epigenetic characteristics and clinical behaviors. Conventional CS is the most common subtype. High-grade, dedifferentiated, and mesenchymal CS, as well as unresectable and metastatic CS, exhibit poor prognoses due to their intrinsic resistance to radiotherapy and chemotherapy, underscoring the urgent need for novel therapeutic strategies. CS research is dealing with several challenges. Experimental studies can rely on animal and patient-derived models, but the paucity of representative near-patient preclinical models has hampered predictive drug screening research. This review describes the main clinical and molecular features of CS subtypes, discussing recent data on the genetic alterations and molecular mechanisms involved in CS pathogenesis and progression. The review provides an overview of the current in vitro and in vivo CS models, discusses their advantages and limitations, and highlights the recent efforts in the development of new targeted therapies against CS dependencies, including IDH1/2 mutations, NAD+ dependency, and SIRT1-HIF-2α axis, or exploring DR5 targeting, antiangiogenic therapies, epigenetic drugs, and immunological approaches. All such strategies, in combination with advanced preclinical modeling and personalized multi-omic profiling, hold promise for improving the survival of patients with advanced CS.

Potential Roles of Nr4a3-Mediated Inflammation in Immunological and Neurological Diseases

As a protein of the orphan nuclear receptor Nr4a family, Nr4a3 has no identified natural ligands. However, its biological activity can be mediated by inducing conformational changes through interactions with specific certain small molecules and receptors. Nr4a3 is activated as an early stress factor under various pathological conditions and plays a regulatory role in various tissues and cells, participating in processes such as cell differentiation, apoptosis, metabolism, and homeostasis. At present, research on the role of Nr4a3 in the pathophysiology of inflammation is considerably limited, especially with respect to its role in the central nervous system (CNS). In this review, we discuss the role of Nr4a3 in multiple sclerosis, Alzheimer's disease, retinopathy, Parkinson's disease, and other CNS diseases. This review shows that Nr4a3 has considerable potential as a therapeutic target in the treatment of CNS diseases. We provide a theoretical basis for the targeted therapy of CNS diseases and neuroinflammation, among other conditions.

Expanding the Spectrum of NR4A3 Fusion-Positive Gynecologic Leiomyosarcomas

Recurrent gene fusions have been observed in epithelioid and myxoid variants of uterine leiomyosarcoma. PGR::NR4A3 fusions were recently described in a subset of epithelioid leiomyosarcomas exhibiting rhabdoid morphology. In this study, we sought to expand the clinical, morphologic, immunohistochemical, and genetic features of gynecologic leiomyosarcomas harboring NR4A3 rearrangements with PGR and novel fusion partners. We identified 9 gynecologic leiomyosarcomas harboring PGR::NR4A3, CARMN::NR4A3, ACTB::NR4A3, and possible SLCO5A1::NR4A3 fusions by targeted RNA sequencing. Tumors frequently affected premenopausal women, involving the uterine corpus, uterine cervix, or pelvis. All were similarly characterized by lobules of monomorphic epithelioid and/or spindled cells arranged in sheets, cords, trabeculae, and micro- and macrocysts associated with abundant myxoid matrix and hemorrhage, creating labyrinth-like or pulmonary edema-like architecture. Myogenic differentiation with frequent estrogen receptor and progesterone receptor staining and no CD10 expression characterized all tumors. All cases showed high NR4A3 RNA expression levels and NOR1 (NR4A3) nuclear staining similar to salivary gland acinic cell carcinomas and a subset of extraskeletal myxoid chondrosarcomas harboring NR4A3 rearrangements. NOR1 (NR4A3) immunohistochemistry may serve as a useful diagnostic marker of NR4A3 fusion-positive gynecologic leiomyosarcomas.

Identification of Novel/Rare EWSR1 Fusion Partners in Undifferentiated Mesenchymal Neoplasms

Recurrent gene fusions (GFs) in translocated sarcomas are recognized as major oncogenic drivers of the disease, as well as diagnostic markers whose identification is necessary for differential diagnosis. EWSR1 is a 'promiscuous' gene that can fuse with many different partner genes, defining different entities among a broad range of mesenchymal neoplasms. Molecular testing of EWSR1 translocation traditionally relies on FISH assays with break-apart probes, which are unable to identify the fusion partner. Therefore, other ancillary molecular diagnostic modalities are being increasingly adopted for accurate classification of these neoplasms. Herein, we report three cases with rare GFs involving EWSR1 in undifferentiated mesenchymal neoplasms with uncertain differential diagnoses, using targeted RNA-seq and confirming with RT-PCR and Sanger sequencing. Two GFs involved hormone nuclear receptors as 3' partners, NR4A2 and RORB, which have not been previously reported. NR4A2 may functionally replace NR4A3, the usual 3' partner in extraskeletal myxoid chondrosarcoma. The third GF, EWSR1::BEND2, has previously been reported in a subtype of astroblastoma and other rare entities, including a single case of a soft-tissue tumor that we discuss in this work. In conclusion, our findings indicate that the catalogue of mesenchymal neoplasm-bearing EWSR1 fusions continues to grow, underscoring the value of using molecular ancillary techniques with higher diagnostic abilities in the routine clinical setting.

TAF15::NR4A3 gene fusion identifies a morphologically distinct subset of extraskeletal myxoid chondrosarcoma mimicking myoepithelial tumors

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma of uncertain differentiation predominantly arising in deep soft tissue. Its conventional morphologic appearance manifests as a relatively well-circumscribed, multilobular tumor composed of uniform short spindle-to-ovoid primitive mesenchymal cells with deeply eosinophilic cytoplasm arranged in anastomosing cords within abundant myxoid matrix. The genetic hallmark of EMC has long been considered to be pathognomonic gene rearrangements involving NR4A3, which when fused to TAF15, often have high-grade morphology with increased cellularity, moderate to severe cytologic atypia, and rhabdoid cytomorphology. Herein, we describe two cases of EMC with TAF15::NR4A3 fusion that appear morphologically distinct from both conventional and high-grade EMC. Both cases had an unusual biphasic appearance and showed diffuse positivity for p63, mimicking myoepithelial tumors. DNA methylation profiling demonstrated that both cases clearly cluster with EMC, indicating that they most likely represent morphologically distinct variants of EMC. The clinical significance and prognostic impact of this morphologic variance remains to be determined. Molecular testing, including DNA methylation profiling, can help to confirm the diagnosis and avoid confusion with mimics; it adds another layer of data to support expanding the morphologic spectrum of EMC.

Extraskeletal myxoid chondrosarcoma of the gingival: a rare case report and review of the literature

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant tumor described in the head and neck region, especially in the gingival. We present one case arising in the gingival of right mandible, and briefly reviewed the related literature.

CASE PRESENTATION

A 24-year-old male patient with a lesion of 3.5*2.0 cm in buccal gingival of right posterior mandible for 2 months. The tumor was composed of cartilaginous structures and myxoid matrix. Immunohistochemical(IHC) showed that the tumor cells to be positive for vimentin, focally positive for S-100, negative for calponin, SMA, SOX10. The Ki-67 labelling index was 80%. Fluorescent in situ Hybridization (FISH) was positive for NR4A3 rearrangement.

CONCLUSIONS

Due to its unusual site and low incidence in the oral region, a combination of histological findings, immunohistochemistry, and molecular pathology as well as differential diagnosis with other diseases should be taken into consideration in the process of clinical diagnosis and treatment.

Whole genome sequencing for metastatic mutational burden in extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC) is an ultra-rare cancer that makes up less than 3% of all soft tissue sarcomas. It most often arises in the soft tissues of the proximal limbs and has a higher incidence in males. Though EMC has a good prognosis, it has an indolent course with high rates of local recurrence as well as metastasis to the lungs. EMC is characterized in 70% of cases by an EWS1-NR4A3 translocation, leading to constitutive expression of NR4A3. Structural variants (SVs) in EMC, especially large-scale genomic alterations, have not been well studied and studies are severely limited by sample size. In this study, we describe Whole Genome Sequencing (WGS) of a rare case of matched EMC primary tumor, lung metastasis, and pelvic metastasis to identify genomic alterations. We examined somatic variants, copy number variants (CNVs), and larger scale SVs such as translocations and breakend points. While the primary tumor and lung metastasis had similar somatic variations and CNVs, the pelvic metastasis had more unique SVs with especially increased mutational burden of SVs in chromosome 2. This suggests that different molecular drivers appear in more advanced, relapsing EMC compared with the primary tumor and early lung metastasis. Genomic studies such as ours may identify novel molecular complexities in rare cancers that may be leveraged for therapeutic strategies and precision medicine.

HOXA5 is a key regulator of class 3 semaphorins expression in the synovium of rheumatoid arthritis patients

OBJECTIVE

Class 3 semaphorins are reduced in the synovial tissue of RA patients and these proteins are involved in the pathogenesis of the disease. The aim of this study was to identify the transcription factors involved in the expression of class 3 semaphorins in the synovium of RA patients.

METHODS

Protein and mRNA expression in synovial tissue from RA and individuals at risk (IAR) patients, human umbilical vein endothelial cells (HUVEC) and RA fibroblast-like synoviocytes (FLS) was determined by ELISA, immunoblotting and quantitative PCR. TCF-3, EBF-1 and HOXA5 expression was knocked down using siRNA. Cell viability, migration and invasion were determined using MTT, calcein, wound closure and invasion assays, respectively.

RESULTS

mRNA expression of all class 3 semaphorins was significantly lower in the synovium of RA compared with IAR patients. In silico analysis suggested TCF-3, EBF-1 and HOXA5 as transcription factors involved in the expression of these semaphorins. TCF-3, EBF-1 and HOXA5 silencing significantly reduced the expression of several class 3 semaphorin members in FLS and HUVEC. Importantly, HOXA5 expression was significantly reduced in the synovium of RA compared with IAR patients and was negatively correlated with clinical disease parameters. Additionally, TNF-α down-regulated the HOXA5 expression in FLS and HUVEC. Finally, HOXA5 silencing enhanced the migratory and invasive capacities of FLS and the viability of HUVEC.

CONCLUSION

HOXA5 expression is reduced during the progression of RA and could be a novel therapeutic strategy for modulating the hyperplasia of the synovium, through the regulation of class 3 semaphorins expression.

Extraskeletal Myxoid Chondrosarcomas: The Uncommon Clinicopathologic Manifestations and Significance of TAF15::NR4A3 Fusion

Extraskeletal myxoid chondrosarcoma (EMC) is an ultrarare sarcoma typically exhibiting myxoid/reticular histology and NR4A3 translocation. However, morphologic variants and the relevance of non-EWSR1::NR4A3 fusions remain underexplored. Three challenging pan-Trk-expressing cases, featuring cellular to solid histology, were subjected to RNA exome sequencing (RES), unveiling different NR4A3-associated fusions. Alongside RES-analyzed cases, fluorescence in situ hybridization was performed to confirm 58 EMCs, with 48 available for pan-Trk immunostaining and KIT sequencing. Except for 1 (2%) NR4A3-rearranged EMC without identifiable partners, 46 (79%), 9 (16%), and 2 (3%) cases harbored EWSR1::NR4A3, TAF15::NR4A3, and TCF12::NR4A3 fusions, respectively. Five EWSR1::NR4A3-positive EMCs occurred in the subcutis (3) and bone (2). Besides 43 classical cases, there were 8 cellular, 4 rhabdoid/anaplastic, 2 solid, and 1 mixed tumor-like variants. Tumor cells were oval/spindle to pleomorphic and formed loose myxoid/reticular to compact sheet-like or fascicular patterns, imparting broad diagnostic considerations. RES showed upregulation of NTRK2/3, KIT, and INSM1. Moderate-to-strong immunoreactivities of pan-Trk, CD117, and INSM1 were present in 35.4%, 52.6%, and 54.6% of EMCs, respectively. KIT p. E554K mutation was detected in 2/48 cases. TAF15::NR4A3 was significantly associated with size >10 cm (78%, P = .025). Size >10 cm, moderate-to-severe nuclear pleomorphism, metastasis at presentation, TAF15::NR4A3 fusion, and the administration of chemotherapy portended shorter univariate disease-specific survival, whereas only size >10 cm (P = .004) and metastasis at presentation (P = .032) remained prognostically independent. Conclusively, EMC may manifest superficial or osseous lesions harboring EWSR1::NR4A3, underrecognized solid or anaplastic histology, and pan-Trk expression, posing tremendous challenges. Most TAF15::NR4A3-positive cases were >10 cm in size, ie, a crucial independent prognosticator, whereas pathogenic KIT mutation rarely occurred.

Epithelioid and spindle rhabdomyosarcoma with TFCP2 rearrangement in abdominal wall: a distinctive entity with poor prognosis

BACKGROUND

Epithelioid and spindle rhabdomyosarcoma (ES-RMS) with TFCP2 rearrangement is a recently discovered rare variant of rhabdomyosarcoma composed of epithelioid and spindle cells, because it shows extraordinarily adverse prognosis and is easily misdiagnosed as other epithelioid or spindle cell tumors.

METHODS

A rare case of ES-RMS with TFCP2 rearrangement was presented and English literatures in Pubmed online up to 01 July 2022 were gathered by two authors for a systematic review according to the inclusion and exclusion criteria.

CASE PRESENTATION/RESULTS

We report a case of ES-RMS in an early 30s-years-old female, the neoplastic cells are remarkably immunoreactive with CK(AE1/AE3), and partially with ALK protein. Unexpectedly, the tumor shows TFCP2 rearrangement with coexistence of increased copy numbers of EWSR1 and ROS1 gene and MET gene mutation. Besides, Next-generation sequencing for genetic mutational profiling revealed frequent MET exon14 mutations in chromosome 7, most of which are C > T nonsynonymous SNV, and exon42 of ROS1 in chromosome 6 showed frequent G > T mutation up to 57.54%. In addition, neither MyoD1 mutation nor gene fusions were detected. Moreover, the patient shows high tumor mutational burden (TMB) up to 14.11 counts/Mb. Finally, as many cases of ES-RMS including our case had local progression or metastasis, we find, similar to epithelioid rhabdomyosarcoma (median survival time is 10 month), ES-RMS shows a more aggressive behavior and adverse prognosis (median survival time is 17 month) than spindle cell/sclerosing rhabdomyosarcoma (median survival time is 65 month) according previous studies.

CONCLUSIONS

ES-RMS with TFCP2 rearrangement is a rare malignant tumor and easily confused with other epithelioid or spindle cell tumors, it may harbor additional gene alteration in addition to TFCP2 rearrangement, such as MET mutation, increased copy numbers of EWSR1 and ROS1 gene, high TMB. Most importantly, it may show very poor outcome with extensive metastasis.

A novel fusion variant LSM14A::NR4A3 in extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue neoplasm of uncertain lineage characterized by the pathognomonic rearrangement of the NR4A3 gene, which in most cases is fused with EWSR1. Other NR4A3 fusion partners have been described, namely TAF15, FUS, TCF12, and TGF. Some studies suggest that EMCs with non-EWSR1 variant fusion are associated with high-grade morphology and worst clinical behavior compared to EWSR1::NR4A3 tumors, supporting the potential significance of particular fusion variant in EMC. We report a case of a 34-year-old male who presented with calf EMC and subsequently developed a slowly progressive metastatic disease 3 years after diagnosis. Whole-transcriptome analysis with total RNA sequencing enabled identification of a novel fusion transcript LSM14A::NR4A3, expanding the molecular spectrum of EMC.

Family cancer history and smoking habit associated with sarcoma in a Japanese population study

Sarcoma is a rare cancer, and little is known about the etiology, lifestyle epidemiology, and actual circumstances of treatment in hospitals in Japan. Understanding these issues is essential for the effective prevention and treatment of sarcoma. We therefore investigated the incidence of a personal and family cancer history in a total of 1320 sarcoma patients at the National Cancer Center Hospital. In addition, obesity, hypertension, dyslipidemia, diabetes mellitus, drinking, smoking, age and sex were compared in a descriptive study of 1159 of these sarcoma patients who were ≥ 20 years of age, and 7738 controls derived from the National Health and Nutrition Examination Survey in Japan. A total of 8% of sarcoma patients had a personal history of another cancer, and 30% of soft tissue sarcoma patients had a family cancer history in a first-degree relative (malignant peripheral nerve sheath tumor, 52%; leiomyosarcoma, 46%). A smoking habit was associated with the development of sarcoma (odds ratio [OR], 2.05; 95% confidence interval, 1.78-2.37; p < 0.01). According to the histology, the ORs for undifferentiated pleomorphic sarcoma (UPS) of bone, UPS of soft tissue, and liposarcoma were 5.71, 3.04, and 2.92, respectively. A family cancer history may be associated with certain soft tissue sarcomas, and a smoking habit was significantly associated with the development of sarcomas; however, further studies are necessary.

Case Report: Gene Heterogeneity in the Recurrent and Metastatic Lesions of a Myxoid Chondrosarcoma Patient With Aggressive Transformation

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue sarcoma. In view of the indolent course throughout the prolonged natural history of EMC, it was considered as a low-grade soft-tissue sarcoma. However, recent studies have revealed a high recurrence and metastatic potential in EMC, and the invasiveness of EMC may progress during the protracted clinical course. The mechanism for this aggressive transformation remains unknown. Here, we present a rare case of EMC with aggressive behavior. This case was confirmed via pathology and NR4A3 fluorescent in situ hybridization. To verify the genetic characteristics of this rare case, a total gene sequencing analyses was performed in the recurrent and metastatic lesions. Intriguingly, different gene mutations were determined in the recurrent and metastatic lesions, which implied the genetic heterogeneity among the different lesions might be related to the aggressiveness of EMC. Furthermore, we discuss a few potential agents against the mutated genes in this case, which may provide novel insights regarding the targeted therapy of EMC.

Primary intracranial extraskeletal myxoid chondrosarcoma: A case report and review of literature

BACKGROUND

Primary intracranial extraskeletal myxoid chondrosarcoma (EMC) is an extremely rare low- to intermediate-grade malignant soft tissue sarcoma, and only 15 cases have been reported in the literature. Due to its rarity, clinical data and research on this tumor type are extremely limited, the pathogenesis and histological origin are still unclear, and the diagnostic and standard clinical treatment strategies for intracranial EMC remain controversial and undefined.

CASE SUMMARY

We reported a case of a 52-year-old male who was admitted to the hospital with headache and dizziness for 1 mo, and his health status deteriorated during the last week. CT of the head showed a well-defined low-density lesion situated in the left cavernous sinus. Brain magnetic resonance imaging (MRI) showed a 3.4 cm × 3.0 cm sized, well-defined, round-shaped and heterogeneously enhanced lesion located in the left cavernous sinus. The entire lesion was removed via supratentorial craniotomy and microsurgery. Postoperative pathological diagnosis indicated primary intracranial EMC. Subsequently, the patient underwent 45 Gy/15 F stereotactic radiotherapy after discharge. At present, it is 12 mo after surgery, with regular postoperative follow-up and regular MRI examinations, that there are no clinical symptoms and radiographic evidence indicating the recurrence of the tumor, and the patient has returned to normal life.

CONCLUSION

Currently, the most beneficial treatment for primary intracranial EMC is gross total resection combined with postoperative radiotherapy. Long-term follow-up is also necessary for patients.

Accuracy of core needle biopsy for histologic diagnosis of soft tissue sarcoma

The biopsy technique of choice in soft tissue sarcoma (STS) diagnosis is controversial. We examined the diagnostic accuracy of percutaneous core needle biopsy (CNB) and compared it to open incisional biopsy. A retrospective study included 91 incisional biopsies and 102 CNBs. A pair-match investigation was conducted on 19 patient pairs, comparing sensitivity, specificity, and diagnostic accuracy. Furthermore, we investigated the role of molecular pathology in sarcoma diagnostics. In 81/91 (89%) patients with incisional biopsy, the entity was confirmed by definitive pathology, whereas this was the case in 89/102 (87%) CNB patients (p = 0.52). Grading remained unchanged in 46/55 (84%) of incisional and 54/62 (87%) of CNBs (p = 0.61). The pair matched analysis showed that the correct entity was determined in 96% of incisional and 97.6% of core needle biopsies. The time between the initial consultation and the interdisciplinary tumor board's treatment recommendation was shorter in core needle biopsies (8.37 vs. 15.63 days; p < 0.002). Incisional biopsies led to two wound infections and one hematoma, whereas wound infection occurred in one patient after CNB. CNB leads to faster diagnosis while reaching the same histological accuracy and is less burdensome for patients. Still, surgeons need to remain aware of the possibility of biopsy failure.

A rare case of vulvar extraskeletal myxoid chondrosarcoma: mimics and diagnostic clues

Only 14 cases of extraskeletal myxoid chondrosarcoma (EMC) of the vulva have been documented in the literature. We report a case of a 63-year-old woman with EMC of the vulva confirmed by both EWSR1 and NR4A3 fluorescence in situ hybridization, the latter of which is a more specific probe for this entity. The unusual location of this tumor of prominent myxoid morphology gave rise to a wide differential diagnosis, which necessitated thorough histologic evaluation and confirmatory ancillary testing in the form of immunohistochemistry and cytogenetic studies. This article aims to review extraskeletal myxoid chondrosarcoma of the vulva and various diagnostic clues to help differentiate it from its histologic mimics. This is the fifth case of vulvar EMC in the literature with confirmation of a NR4A3 gene rearrangement.

Sarcoma treatment in the era of molecular medicine

Sarcomas are heterogeneous and clinically challenging soft tissue and bone cancers. Although constituting only 1% of all human malignancies, sarcomas represent the second most common type of solid tumors in children and adolescents and comprise an important group of secondary malignancies. More than 100 histological subtypes have been characterized to date, and many more are being discovered due to molecular profiling. Owing to their mostly aggressive biological behavior, relative rarity, and occurrence at virtually every anatomical site, many sarcoma subtypes are in particular difficult-to-treat categories. Current multimodal treatment concepts combine surgery, polychemotherapy (with/without local hyperthermia), irradiation, immunotherapy, and/or targeted therapeutics. Recent scientific advancements have enabled a more precise molecular characterization of sarcoma subtypes and revealed novel therapeutic targets and prognostic/predictive biomarkers. This review aims at providing a comprehensive overview of the latest advances in the molecular biology of sarcomas and their effects on clinical oncology; it is meant for a broad readership ranging from novices to experts in the field of sarcoma.

Extraskeletal Myxoid Chondrosarcoma: State of the Art and Current Research on Biology and Clinical Management

Simple Summary

The aim of this review is to provide an overview of the biological basis of pathogenesis and current research in extraskeletal myxoid chondrosarcoma (EMC), together with the state of the art of treatment for localized and advanced disease. EMC is an ultra-rare sarcoma sub-type, more often arising from the soft tissues, marked by specific molecular features consisting in rearrangement of the NR4A3 gene, identified in recent years and very useful to distinguish EMC from other mimics. Available pharmacological treatments in particular are discussed, with a focus on the most recent results and future perspectives.

Abstract

Extraskeletal myxoid chondrosarcoma (EMC) is an ultra-rare mesenchymal neoplasm with uncertain differentiation, which arises mostly in the deep soft tissue of proximal extremities and limb girdles. EMC is marked by a translocation involving the NR4A3 gene, which can be fused in-frame with different partners, most often EWSR1 or TAF1. Although EMC biology is still poorly defined, recent studies have started shedding light on the specific contribution of NR4A3 chimeric proteins to EMC pathogenesis and clinical outcome. Standard treatment for localized disease is surgery, plus or minus radiation therapy with an expected prolonged survival even though the risk of relapse is about 50%. In advanced cases, besides the standard chemotherapy currently used for soft tissue sarcoma, antiangiogenic agents have recently shown promising activity. The aim of this review is to provide the state of the art of treatment for localized and advanced disease, with a focus on pharmacological treatments available for EMC. The biological basis of current research and future perspectives will be also discussed.

Long-term Outcomes for Extraskeletal Myxoid Chondrosarcoma: A SEER Database Analysis

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMCS) is a rare tumor that typically has an indolent course but high rate of recurrence. We queried the Surveillance, Epidemiology, and End Results (SEER) database to assess factors associated with metastasis, treatment, and survival.

METHODS

We queried the SEER 1973-2016 database for patients with myxoid chondrosarcoma (ICD-O-3: 9231/3). Kaplan-Meier analyses and Cox proportional hazard models assessed effects on overall survival (OS) of demographics and clinical characteristics. Logistic regression assessed associations between tumor location and distant disease. Primary analysis was a complete case analysis; multiple imputation (MI) was used in a sensitivity analysis.

RESULTS

Locoregional disease (LRD) was found in 373 (85%) of patients. In univariate analysis with LRD, surgery correlated with superior OS [HR = 0.27; 95% confidence interval (CI), 0.16-0.47]; chemotherapy and radiotherapy associated with inferior OS (HR = 1.90; 95% CI, 1.11-3.27 and HR = 1.45; 95% CI, 1.03-2.06, respectively). No treatment modality associated with OS in the adjusted, complete case model. In the adjusted sensitivity analysis, surgery associated with superior outcomes (HR = 0.36; 95% CI, 0.19-0.69). There was no OS difference by primary tumor site. 10-year OS with distant disease was 10% (95% CI, 2%-25%).

CONCLUSIONS

Surgery in LRD associated with improved OS in univariate analysis and adjusted models correcting for missing data. There was no OS benefit with chemotherapy or radiotherapy.

IMPACT

This represents the largest report of EMCS with long-term follow-up. Despite the reputedly indolent nature of EMCS, outcomes with metastatic disease are poor. We provide OS benchmarks and guidance for stratification in future prospective trials.

Extraskeletal myxoid chondrosarcoma: combining cytopathology with molecular testing to achieve diagnostic accuracy

INTRODUCTION

Advances in the genetics of soft tissue neoplasia have allowed for the diagnostic recognition of specific tumor types from small biopsy specimens, including those procured using the fine needle aspiration (FNA) biopsy technique. Extraskeletal myxoid chondrosarcoma (EMC) is a malignant mesenchymal neoplasm characterized by NR4A3 and, less specifically, by EWSR1 gene rearrangements. A series of EMC cytologic specimens was examined to demonstrate the diagnostic value of incorporating fluorescence in situ hybridization (FISH) testing in cytologic cases of suspected EMC.

MATERIALS AND METHODS

A search was made of our cytopathology and surgical pathology databases for cases diagnosed as EMC. FNA biopsy cytology, exfoliative cytology, imprint cytology, and FISH analysis were performed and examined using standard techniques.

RESULTS

A total of 16 cases of EMC were retrieved from 15 patients (male/female ratio, 2.8:1; mean age, 62 years). Of the 15 patients, 10 were new patients with primary tumors, 2 had locally recurrent tumors, and 4 had metastases. The sites included the extremities in 10 cases, the trunk in 4, serous effusion in 1, and a mediastinal lymph node in 1 case. The specific cytologic diagnoses were EMC (14 cases; 88%), suspicious for EMC (n = 1), and malignant cells (n = 1). All cases for which FISH testing was successfully used were specifically recognized as EMC. Aspirates and imprint smears consisted of uniformly rounded cells set in an opaque myxoid/chondromyxoid stroma (less abundant and more diaphanous in the effusion sample), sometimes arranged in short anastomosing cords. FNA of 1 case of an EMC cellular variant mimicked a malignant small rounded cell tumor.

CONCLUSION

EMC can be added to the growing list of soft tissue neoplasms that are specifically recognizable using cytopathology, coupled with judicious application of ancillary molecular testing.

Extraskeletal Myxoid Chondrosarcoma with Molecularly Confirmed Diagnosis: A Multicenter Retrospective Study Within the Italian Sarcoma Group

BACKGROUND

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma of uncertain origin, marked by specific chromosomal translocations involving the NR4A3 gene, and usually characterized by an indolent course. Surgery (with or without radiotherapy) is the treatment of choice in localized disease. The treatment for advanced disease remains uncertain. In order to better evaluate prognostic factors and outcome, a retrospective pooled analysis of patients with EMC treated at three Italian Sarcoma Group (ISG) referral centers was carried out.

METHODS

All patients with localized EMC surgically treated from 1989 to 2016 were identified. Diagnosis was centrally reviewed according to WHO 2013. Only patients with NR4A3 rearrangement were included.

RESULTS

Sixty-seven patients were identified: 13 (20%) female, 54 (80%) male. Median age was 56 years (range 18-84). Numbers and type of translocation were: 50 (80%) NR4A3-EWS, 10 (16%) NR4A3-TAF15, 1 (2%) NR4A3-TCF12, and 1 (2%) NR4A3-TFG. Median follow-up was 55 months (range 2-312). Five- and ten-year overall survival rates were 94% (86-100 95%CI) and 84% (69-98 95%CI). Thirty-five (52%) patients relapsed: 9 had local recurrence (LR) and 26 had distant metastasis (5 with concomitant LR). The 5- and 10-year disease-free survival rates (DFS) were 51% (38-65 95%CI) and 20% (7-33 95%CI). Size of the primary tumor was significantly related to distant metastasis-free survival (DMFS) (p = 0.004). Patients carrying the NR4A3-EWS translocation had a trend in favor of better DFS (p = 0.08) and DMFS (p = 0.09) compared with the patients with NR4A3-TAF15.

CONCLUSIONS

Prolonged survival can be expected in patients with EMC, in spite of a high rate of recurrence. Size is significantly associated with distant relapse. The type of NR4A3 translocation could influence outcome.

Extraskeletal Myxoid Chondrosarcoma: Clinical and Molecular Characteristics and Outcomes of Patients Treated at Two Institutions

Background: Extraskeletal myxoid chondrosarcoma (EMC) is a rare subtype of STS, which usually arises in extremities. It carries reciprocal translocations involving the NR4A3 gene. It displays an indolent behavior, but studies with long follow-up showed a high proportion of local and distant recurrences. For patients with progressing metastatic disease anthracycline-based chemotherapy is the standard front-line regimen, though has limited activity. There is some evidence on possible activity of antiangiogenetics.

Methods: This is a retrospective study conducted at Istituto Oncologico Veneto and at Institut Gustave Roussy. All patients with a confirmed diagnosis of EMC from January 1980 to December 2018 were extracted from a prospectively maintained database.

Results: 59 patients were identified, 37 male (62.7%) and 22 female (37.3%) with a M/F ratio of 1.7/1. We performed molecular analysis in 23 cases, all carried a EWSR1-NR4A3. Out of 49 patients treated with curative intent, 28.6% developed local recurrence and 40.8% patients developed metastases. In patients who had been radically resected (R0) local recurrence occurred in 7.6% of cases and metastases occurred in 15.4% of cases; in patients treated with R1 surgery, rates of relapse were higher. Twenty patients received chemotherapy for metastatic disease; best response was partial response with clinical benefit in 50% of patients. Fourteen patients received a second line of chemotherapy, with 46.1% disease control rate. A drug holiday was proposed to 8 patients with a mean duration of 22.8 months. Median overall survival was 180 months for the study population and 76 months for metastatic patients. No significant prognostic role was found for all studied variables, yet a trend of better survival for complete surgery, location in extremities of primary tumor and solitary lung metastases was observed. Chemotherapy for metastatic disease was negatively associated with survival.

Conclusion: In this large retrospective cohort of patients with ECM, location of primary tumor and solitary lung metastases seem to be associated with better survival. Chemotherapy did not impact survival in unselected patients. Further research is necessary in order to identify more active regimens and to provide clinical and molecular factors to select patients that could delay systemic treatment for metastatic disease.