CHRNA6 RNA In Situ Hybridization Is a Useful Tool for the Diagnosis of Extraskeletal Myxoid Chondrosarcoma.

Extraskeletal myxoid chondrosarcoma (EMC) is an uncommon mesenchymal neoplasm characteristically composed of uniform-appearing round to spindle-shaped cells with eosinophilic cytoplasm and abundant myxoid extracellular matrix. Although the majority of cases harbor a pathognomonic t(9;22) translocation that fuses EWSR1 with the orphan nuclear receptor NR4A3, there are less common variants that partner NR4A3 with TAF15, TCF12, or TFG. By immunohistochemistry, EMC has features of both cartilaginous and neuroendocrine differentiation, as evidenced by inconsistent expression of S100 protein and synaptophysin or INSM1, respectively, in a subset of cases. Given the limitations of available immunohistochemical stains for the diagnosis of EMC, we analyzed genome-wide gene expression microarray data to identify candidate biomarkers based on differential expression in EMC in comparison with other mesenchymal neoplasms. This analysis pointed to CHRNA6 as the gene with the highest relative expression in EMC (96-fold; P = 8.2 × 10-26) and the only gene with >50-fold increased expression in EMC compared with other tumors. Using RNA chromogenic in situ hybridization, we observed strong and diffuse expression of CHRNA6 in 25 cases of EMC, including both EWSR1-rearranged and TAF15-rearranged variants. All examined cases of histologic mimics were negative for CHRNA6 overexpression; however, limited CHRNA6 expression, not reaching a threshold of >5 puncta or 1 aggregate of chromogen in >25% of cells, was observed in 69 of 685 mimics (10.1%), spanning an array of mesenchymal tumors. Taken together, these findings suggest that, with careful interpretation and the use of appropriate thresholds, CHRNA6 RNA chromogenic in situ hybridization is a potentially useful ancillary histologic tool for the diagnosis of EMC.

Clinical, imaging and pathological features of extraskeletal myxoid chondrosarcoma.

OBJECTIVE: To evaluate clinical and radiological features of extraskeletal myxoid chondrosarcomas (EMC). MATERIAL AND METHODS: Our pathology database was queried for cases of EMCs. Tumor location, size, imaging appearance, presence of metastases, disease recurrence, and clinical outcome were documented. Imaging studies were evaluated in consensus by a musculoskeletal radiologist and an orthopedic oncologist. RESULTS: Thirty subjects met the inclusion criteria (mean age 52.7 ± 16.2 years; 19 male, 11 female), 17 (56.7%) of which had pre-operative imaging. Tumors occurred most often in the lower extremities (20/30; 66.7%). All cases presented as a soft-tissue mass without mineralization on XR or CT. On MRI, tumors were typically hyperintense on T2-weighted sequences (14/14; 100%) and had a chondroid matrix appearance (12/14; 85.7%). Tumor invasion was observed in 11 out of 16 (68.9%) patients and necrosis in 2 out of 11 subjects (18.2%). All subjects had their tumors examined by pathology, and 20 (66.7%) subjects also had descriptive information in addition to the diagnosis (tumor invasion, mitotic rate, and necrosis) noted in the pathology reports. The mean duration of follow-up was 9.4 ± 7.5 (1.0 - 29.6) years. At the last follow-up, 14 out of 28 (50%) subjects were disease-free, 6 out of 28 had persistent metastatic disease and 8 out of 28 had died. CONCLUSIONS: EMC is a rare sarcoma that commonly presents as lower extremity soft tissue mass with chondroid appearance on MRI. Unlike conventional chondrosarcomas, EMC do not demonstrate mineralization on XR or CT.

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.

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 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.

Extraskeletal myxoid chondrosarcoma: Clinicopathological features and outcomes from the United States sarcoma collaborative database.

BACKGROUNDS AND OBJECTIVES: This investigation described clinicopathological features and outcomes of extraskeletal myxoid chondrosarcoma (EMC) patients. METHODS: EMC patients were identified from the United States Sarcoma Collaborative database between 2000 and 2016. Overall survival (OS) and recurrence-free survival (RFS) were calculated, and prognostic factors were analyzed. RESULTS: Sixty individuals with a mean age of 55 years were included, and 65.0% (n = 39) were male. 73.3% (n = 44) had a primary tumor. A total of 41.6% (n = 25) developed tumor relapse following resection. The locoregional recurrence rate was 30.0% (n = 18/60), and mean follow-up was 42.7 months. The 5-year OS was 71.0%, while the 5-year RFS was 41.4%. On multivariate analysis for all EMC, chemotherapy (hazard ratio [HR], 6.054; 95% confidence interval [CI], 1.33-27.7; p = 0.020) and radiation (HR, 5.07, 95% CI, 1.3-20.1; p = 0.021) were independently predictive of a worse RFS. Among patients with primary EMC only, the 5-year OS was 85.3%, with a 30.0% (n = 12) locoregional recurrence rate, though no significant prognostic factors were identified. CONCLUSIONS: Long-term survival with EMC is probable, however there exists a high incidence of locoregional recurrence. While chemotherapy and radiation were associated with a worse RFS, these findings were likely confounded by recurrent disease as significance was lost in the primary EMC-only subset.

SMARCA2-NR4A3 is a novel fusion gene of extraskeletal myxoid chondrosarcoma identified by RNA next-generation sequencing.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare sarcoma of uncertain differentiation, characterized by recurrent chromosomal translocation involving NR4A3 (9q22.33) in more than 90% of cases. Five fusion partners for NR4A3 have been described including: EWSR1 (22q12.2), TAF15 (17q12), FUS (16p11.2), TCF12 (15q21), and TFG (3q12.2). This report describes a patient with an EMC at the dorsum of the right foot. The tumor showed a cord-like and reticular pattern in a background of myxoid matrix. The tumor cells demonstrated an epithelioid morphology with prominent nucleoli. The tumor cells were positive for synaptophysin, GFAP, with focal positivity for CD117, S100, Cam5.2, and NSE, and negative for AE1/3, desmin, and SMA. An RNA next-generation sequencing test showed a SMARCA2-NR4A3 gene fusion which has not been previously reported. The exon 3 of SMARCA2 was fused to exon 3 of NR4A3. This fusion was confirmed by NR4A3 break-apart FISH, although both SMARCA2 (9p24.3) and NR4A3 (9q22.33) are located on chromosome 9. The tumor cells showed retained expression of INI1 and SMARCA2 by immunohistochemistry.

Primary extraskeletal myxoid chondrosarcoma of the breast: report of a case and literature review.

Primary extraskeletal myxoid chondrosarcoma (pEMC) of the breast is rare and only a few cases have been reported to date. Herein, we report a case of primary EMC of the breast in a 45-year-old female. The patient presented with a left breast mass for 1 month. Mammogram revealed a fairly circumscribed mass with spicules of calcifications. The core biopsy and resection specimen showed a myxoid soft tissue neoplasm with histologic features of a myxoid chondrosarcoma. Necrosis, hemorrhage, and brisk mitotic activity were present. No malignant epithelial element was identified even after extensive sampling. The tumor cells exhibited immunoreactivity for vimentin, S100, neuron specific enolase, CD99, and synaptophysin, while the epithelial, myoepithelial, and mammary lineage-associated markers were negative. As up to 81% of EMC cases harbor t(9;22)(q22;q12), this results in a fusion of EWS RNA-binding protein 1 gene (EWSR1) at 22q12 to the nuclear receptor subfamily 4, group A, member 3 gene at 9q22. A rearrangement involving the EWSR1 locus was detected in our case. Whole body PET-CT did not reveal any other mass. A diagnosis of pEMC was rendered. The patient received six cycles of 5-Fluorouracil, Cyclophosphamide, and Adriamycin. The patient was in clinical and radiologic remission at the last follow-up (18 months post surgery). PET-CT and brain MRI were negative. In conclusion, surgical pathologists should include EMC in their differential while dealing with a myxoid soft tissue lesion of the breast, particularly in the core needle biopsies. An expeditious diagnosis of EMC of the breast would allow the surgeon to carry out conservative breast surgery instead of more radical approaches taken in cases of other primary malignant mammary neoplasms.

Relevance of the combination of external beam radiotherapy with the hypoxia-activated prodrug ICF05016 in an experimental model of extraskeletal myxoid chondrosarcoma.

Currently, there is no gold standard treatment for Extraskeletal Myxoid Chondrosarcomas (EMC) making wide margin surgical resection the most effective alternative treatment. Nevertheless, in previous preclinical studies our lab demonstrated the potential of the hypoxia-activated prodrug (HAP) ICF05016 on EMC murine model inoculated with the H-EMC-SS human cell line. The aim of this study was to assess, in vivo, the relevance of the combination of this HAP with External Beam Radiotherapy (EBR). Firstly EMC-bearing mice were treated with 6 Gy or 12 Gy of EBR (single 6 MV photon). Then for combination of HAP and EBR, animals received 6 doses of ICF05016 (46.8 µmol/kg, intravenously) at 4-day intervals, with 6 Gy EBR performed 24 h after the 3rd dose of HAP. Animals were monitored throughout the study for clinical observations (tumour growth, side effects) and survival studies were performed. From tumour samples, PCNA, Ki-67 and p21 expressions were used as markers of proliferation and cell cycle arrest. Statistical significances were determined using Kruskall-Wallis and log rank tests. The radiosensitivity of the EMC model was demonstrated at 12 Gy with significant inhibition of tumour growth. Then, the HAP strategy potentiated EBR efficacy at a lower dose (6 Gy) by improving survival without generating side effects. Thus, results of this study showed the potential interest of ICF05016 for the combination with EBR in the management of EMC.

Systemic manifestations of extraskeletal myxoid chondrosarcoma associated with a novel t(2;22)(q34;q12) EWS translocation in a child and a review of the literature.

Extraskeletal myxoid chondrosarcoma (EMC), a soft-tissue sarcoma with unique clinicopathologic features and characteristic chromosomal translocations, is extremely rare in the pediatric population. We, herein, present the case of a 7-year-old boy with profound microcytic hypochromic anemia, poor weight gain and a mid-thoracic paraspinal mass that was identified as EMC. Systemic manifestations of localized, nonmetastatic EMC have never been described in the pediatric population, yet our patient's anemia and poor weight gain resolved after successful surgical resection of the tumor, suggesting that localized EMC can present with systemic manifestations. The tumor also contained a novel t(2;22)(q34;q12) translocation involving the EWSR1 gene, which is consistent with additional reports suggesting that a growing list of translocations can drive formation of, and potential new management strategies for, EMC.

Identification of an Actionable Mutation of KIT in a Case of Extraskeletal Myxoid Chondrosarcoma.

Extraskeletal myxoid chondrosarcoma (EMC) is an extremely rare soft tissue sarcoma, marked by a translocation involving the NR4A3 gene. EMC is usually indolent and moderately sensitive to anthracycline-based chemotherapy. Recently, we reported on the therapeutic activity of sunitinib in a series of EMC cases, however the molecular target of sunitinib in EMC is unknown. Moreover, there is still the need to identify alternative therapeutic strategies. To better characterize this disease, we performed whole transcriptome sequencing in five EMC cases. Peculiarly, in one sample, an in-frame deletion (c.1735_1737delGAT p.D579del) was identified in exon 11 of KIT. The deletion was somatic and heterozygous and was validated both at DNA and mRNA level. This sample showed a marked high expression of KIT at the mRNA level and a mild phosphorylation of the receptor. Sanger sequencing of KIT in additional 15 Formalin Fixed Paraffin Embedded (FFPE) EMC did not show any other mutated cases. In conclusion, exon 11 KIT mutation was detected only in one out of 20 EMC cases analyzed, indicating that KIT alteration is not a recurrent event in these tumors and cannot explain the EMC sensitivity to sunitinib, although it is an actionable mutation in the individual case in which it has been identified.

The TFG-TEC oncoprotein induces transcriptional activation of the human ß-enolase gene via chromatin modification of the promoter region.

Recurrent chromosome translocations are the hallmark of many human cancers. A proportion of human extraskeletal myxoid chondrosarcomas (EMCs) are associated with the characteristic chromosomal translocation t(3;9)(q11-12;q22), which results in the formation of a chimeric protein in which the N-terminal domain of the TRK-fused gene (TFG) is fused to the translocated in extraskeletal chondrosarcoma (TEC; also called CHN, CSMF, MINOR, NOR1, and NR4A3) gene. The oncogenic effect of this translocation may be due to the higher transactivation ability of the TFG-TEC chimeric protein; however, downstream target genes of TFG-TEC have not yet been identified. The results presented here, demonstrate that TFG-TEC activates the human ß-enolase promoter. EMSAs, ChIP assays, and luciferase reporter assays revealed that TFG-TEC upregulates ß-enolase transcription by binding to two NGFI-B response element motifs located upstream of the putative transcription start site. In addition, northern blot, quantitative real-time PCR, and Western blot analyses showed that overexpression of TFG-TEC up-regulated ß-enolase mRNA and protein expression in cultured cell lines. Finally, ChIP analyses revealed that TFG-TEC controls the activity of the endogenous ß-enolase promoter by promoting histone H3 acetylation. Overall, the results presented here indicate that TFG-TEC triggers a regulatory gene hierarchy implicated in cancer cell metabolism. This finding may aid the development of new therapeutic strategies for the treatment of human EMCs. © 2015 Wiley Periodicals, Inc.

Results of sub-analysis of a phase 2 study on trabectedin treatment for extraskeletal myxoid chondrosarcoma and mesenchymal chondrosarcoma.

BACKGROUND: Trabectedin is reported to be particularly effective against translocation-related sarcoma. Recently, a randomized phase 2 study in patients with translocation-related sarcomas unresponsive or intolerable to standard chemotherapy was conducted, which showed clinical benefit of trabectedin compared with best supportive care (BSC). Extraskeletal myxoid chondrosarcoma (EMCS) and Mesenchymal chondrosarcoma (MCS) are very rare malignant soft tissue sarcomas, and are associated with translocations resulting in fusion genes. In addition, the previous in vivo data showed that trabectedin affect tumor necrosis and reduction in vascularization in a xenograft model of a human high-grade chondrosarcoma. The aim of the present analysis was to clarify the efficacy of trabectedin for EMCS and MCS subjects in the randomized phase 2 study. METHODS: Five subjects with EMCS and MCS received trabectedin treatment in the randomized phase 2 study. Three MCS subjects were allocated to the BSC group. Objective response and progression-free survival (PFS) were assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 by central radiology imaging review. RESULTS: The median follow-up time of the randomized phase 2 study was 22.7 months, and one subject with MCS was still receiving trabectedin treatment at the final data cutoff. The median PFS was 12.5 months (95 % CI: 7.4-not reached) in the trabectedin group, while 1.0 months (95 % CI: 0.3-1.0 months) in MCS subjects of the BSC group. The six-month progression-free rate was 100 % in the trabectedin group. One subject with MCS showed partial response, and the others in the trabectedin group showed stable disease. Overall survival of EMCS and MCS subjects was 26.4 months (range, 10.4-26.4 months) in the trabectedin group. At the final data cutoff, two of five subjects were still alive. CONCLUSIONS: This sub-analysis shows that trabectedin is effective for patients with EMCS and MCS compared with BSC. The efficacy results were better than previously reported data of TRS. These facts suggest that trabectedin become an important choice of treatment for patients with advanced EMCS or MCS who failed or were intolerable to standard chemotherapy. TRIAL REGISTRATION: The randomized phase 2 study is registered with the Japan Pharmaceutical Information Center, number JapicCTI-121850 (May 31, 2012).

Clinicopathologic and radiologic features of extraskeletal myxoid chondrosarcoma: a retrospective study of 40 Chinese cases with literature review.

The aim of this study is to describe the clinicopathologic and radiologic features of 40 cases of extraskeletal myxoid chondrosarcoma (EMC) from China. There were 25 males and 15 females (sex ratio, 1.7:1). Apart from an adolescent, all patients were adults with a median age of 49years. Twenty-four tumors (60%) occurred in the lower limb and limb girdles, especially the thigh, followed by the upper limb and limb girdles (20%) and trunk (10%). Other less commonly involved locations included the head and neck, sacrococcygeal region, and perineum. Tumors ranged in size from 1.5 to 19cm (mean, 7cm). By radiology, they appeared as hypoattenuated or isoattenuated masses on computed tomography with hyperintense signal on T2-weighted magnetic resonance imaging. Intralesional hypointense septa were present in most cases. Of the 40 tumors, 30 belonged to the classic subtype, whereas 9 cases were cellular, and 1 case had a rhabdoid phenotype. Tumor cells showed variable expression of synaptophysin (36%), S-100 protein (29%), epithelial membrane antigen (11%), and neuron-specific enolase (7%). Ki-67 index was remarkably higher in the cellular variant (mean, 30%). EWSR1-related rearrangement was detected in 12 of 14 cases tested by fluorescence in situ hybridization using break-apart probes. The overall 5- and 7-year survival was 71% and 60%, respectively. Awareness of the imaging features may help pathologists in the diagnosis of EMC. Fluorescence in situ hybridization also serves as a useful diagnostic tool for EMC, especially in the distinction from its mimics.

[Myxoid tumors of deep soft tissues]. / Les tumeurs myxoïdes des tissus mous profonds.

Myxoid soft tissue tumors form a heterogeneous group. Their biological potential encompasses the whole spectrum from benign to highly malignant. The present article focuses on myxoid tumors of the deep soft tissues: myxofibrosarcoma, low-grade fibromyxoid sarcoma, myxoma, myxoid liposarcoma, extraskeletal myxoid chondrosarcoma and nodular fasciitis. The last two decades have brought into practice multiple powerful tools that support pathologists in making precise diagnoses, even on small incisional biopsies: detection of fusion transcripts by rt-PCR, detection of chromosomal fusion or breakpoint by FISH, detection of point mutations by PCR and expression of specific markers by immunohistochemistry. Conventional morphology remains the mainstay of diagnosis, and it is essential to obtain adequate clinical and radiological information before interpreting small incisional biopsies. The present article is a summary of morphologic features used to diagnose the most common tumors of the deep soft tissues.

Clinical and radiologic features of extraskeletal myxoid chondrosarcoma including initial presentation, local recurrence, and metastases.

BACKGROUND: The aim of the study was to evaluate the clinical and imaging features of extraskeletal myxoid chondrosarcoma (EMC) including initial presentation, recurrence, and metastases. PATIENTS AND METHODS: In this institutional review board-approved retrospective study, imaging features of 13 patients with pathologically proven EMC seen from August 1995 to December 2011 were analyzed. The group included 3 women and 10 men and the mean age was 54 years (range 29-73 years). Imaging studies were evaluated by two radiologists in consensus. Location, size, and imaging features of primary tumors were recorded as well as the presence of recurrent disease and location of metastases. RESULTS: Among 13 patients, 3 died during the timeframe of this study. Nine patients had primary tumor in the lower extremity, and average tumor size was 9.3 cm (range 3.3-18 cm). On MRI, primary tumors were hyperintense on T2, isointense to muscle on T1, and demonstrated peripheral/septal enhancement. Three patients had local recurrence and 12 had metastatic disease, with lung involvement being the most common. Tumor density on contrast enhanced CT ranged from 8.2 to 82.9 Hounsfield unit (HU). FDG-PET/CT imaging was performed in 3 patients. One patient had no FDG avid disease and 2 patients had metastatic disease with standard uptake values (SUV) of 2.8 and 7.4. The patient with intense FDG uptake demonstrated more solid appearing tumor burden and had the shortest survival. CONCLUSIONS: EMC is a rare tumor that often occurs in the lower extremities and frequently metastasizes to the lungs. Increased tumor density and increased FDG uptake may be related to more aggressive disease.

Juxta-articular extraskeletal myxoid chondrosarcoma mistaken for a benign cyst presenting with multiple lung metastases.

Extraskeletal myxoid chondrosarcoma (EMC) is a malignant cartilage neoplasm usually encountered in the proximal extremities. We report the case of a 58-year-old male who presented initially with a 3-month history of cough. Initial staging demonstrated a right upper lobe mass with bilateral pulmonary nodules and moderate tracer uptake in the right lung mass and right groin on positron emission tomography imaging. Endobronchial ultrasound biopsy confirmed a histological diagnosis of EMC for which the patient underwent right upper lobe wedge resection. Pelvic MRI revealed a peripherally enhancing juxta-articular lesion within the region of the right obturator externus bursa, which was thought initially to represent either a ganglion or paralabral cyst. However, ultrasound-guided biopsy yielded identical histology to the resected lung mass leading to the diagnosis of primary EMC in the right groin with pulmonary metastases. The patient underwent surgical excision of the right groin mass with no local recurrence on the surveillance computed tomography at 5, 12, and 18 months but eventual disease recurrence in the right groin and further progression of the pulmonary metastases at 29 months. We emphasize that the contrast enhancement pattern of EMC can mimic a benign cystic lesion, in particular, when in a juxta-articular location, which has the potential to mislead radiologists and delay diagnosis and definitive treatment.

Extraskeletal Myxoid Chondrosarcoma of Floor of Mouth-A Rare Case Report and Review of Literature.

Introduction: Chondrosarcomas are rare malignancies of the cartilage and myxoid chondrosarcoma is its variant which commonly occurs in soft tissue of extremities. Extraskeletal chondrosarcoma is a rare malignant neoplasm of bone or soft tissue origin and is characterized by the presence of spindle cells admixed with well differentiated cartilage or chondroid stroma. They are mostly radioresistant tumours and surgical resections with adequate margins is considered as the ideal treatment modality with adjuvant radiotherapy in high grade tumours and add on chemotherapy, in case of presence of poor prognostic factors. Case Report: A 51-year-old diabetic, hypertensive female patient presented to our outpatient department with difficulty in chewing food for a duration of 6 months. On clinical examination, she had an ulceroproliferative growth involving right lower alveolus and floor of mouth. MRI face and neck with contrast showed a 4.1 × 2.9 × 4.5 cm lesion involving right lower alveolus extending to floor of mouth. Biopsy showed features of extraskeletal myxoid chondrosarcoma. She was planned for upfront surgery (Right composite resection with modified radical neck dissection with free fibula flap). Patient was stable post-surgery and was discharged in stable condition. Final histopathology report was high grade myxoid chondrosarcoma. The case was presented in tumour board and the patient was planned for adjuvant radiotherapy. She has been on regular follow up for the past 2 years and shows no signs of recurrence. Conclusion: Extraskeletal myxoid chondrosarcoma of oral cavity is a rare entity and very few cases are reported. It is a malignant neoplasm which is diagnosed with the help of immunohistochemistry. Surgery is the ideal modality of treatment accompanied by adjuvant radiotherapy in cases of high-grade tumours.

Extraskeletal Myxoid Chondrosarcoma Identified in a Traumatic Fracture of the Toe: A Case Report.

Introduction: Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft-tissue sarcoma that typically presents in the proximal lower extremity and limb-girdle. It can be easily misdiagnosed, especially when located in atypical locations like the foot. Case Report: We present the case of an 80-year-old Caucasian female with a left 3rd toe pain and swelling that was initially misdiagnosed as a traumatic fracture on radiographs but later determined to be an indolent EMC based on histology. She was successfully treated with amputation of the toe. Conclusion: EMC should be considered in the differential of osseous and soft-tissue abnormalities on radiographic imaging of the extremities. As reported in the literature, it can present in atypical locations with minimal symptoms and successful treatments include resection. Future cases presenting similarly should be evaluated for EMC and, if present, reported along with their applied treatment protocols to allow for further assessment of current therapeutic guidelines.

Extraskeletal Myxoid Chondrosarcoma of the Vulva: A Case Report.

Extraskeletal myxoid chondrosarcoma (EMC) of the vulva is extremely rare. We report our experience with a case of disease control by radiation therapy to a localized lesion of EMC. A 41-year-old woman presented to our clinic with a vulvar mass. Magnetic resonance imaging showed a 15 cm mass between the perineum and the medial thigh muscle. It was the "adductor magnus muscle." After the needle biopsy, a histopathological diagnosis of EMC was made. Tissue genomic analysis detected the EWSR1-NR4A3 fusion gene. A joint operation by the Department of Orthopedics, Gynecology, and Plastic Surgery was performed, which included a wide excision of the perineum, partial excision of the medial thigh muscle, and rectus abdominis valvuloplasty. Intraoperatively, pubic infiltration was detected. Postoperative pelvic radiotherapy was administered as adjuvant therapy. Recurrent common iliac lymph node metastases outside the irradiation field and multiple lung metastases were observed. Pazopanib was administered as adjuvant therapy. Pulmonary metastases were controlled, but the pelvic tumor had spread, so the patient underwent radiation therapy. After second-line chemotherapy with doxorubicin, left pleural effusion and mediastinal lymph node metastasis appeared, and third-line chemotherapy with eribulin mesylate was administered. The pleural effusion improved, but the patient developed cough again, and trabectedin was administered as the fourth chemotherapy. In this case, there was no local recurrence for three years after radiotherapy, suggesting the effectiveness of radiotherapy in local control.