IMP3, CDK4, MDM2 and ß-catenin expression in Enchondroma and Central Chondrosarcoma: Diagnostic and prognostic utility.

INTRODUCTION: The role of IMP3, CDK4, MDM2 and ß-catenin proteins in Enchondroma and Central Chondrosarcoma is not totally understood. The aim of this study is to evaluate the immunoexpression of these proteins, associating histological grade, clinical data and prognosis to these tumors. METHODS: This is a retrospective-analytical study of 32 Enchondroma and 70 Central Chondrosarcoma. RESULTS: IMP3, CDK4, MDM2 and ß-catenin expression was observed in 22.82 %, 13.82 %, 17.17 % and in 8.8 % of cases, respectively. All Enchondromas positive for these immunomarkers were located in short tubular bones. The positivity for these antibodies is directly proportional to Chondrosarcoma's histological grade increase. No difference was found between Enchondroma and Chondrosarcoma, Grade 1 for IMP3, CDK4 and ß-catenin positivity. Significant metastasis outcome was observed for IMP3, CDK4, MDM2 and death for MDM2 expression. CONCLUSION: IMP3, CDK4, MDM2 and ß-catenin expression in Enchondromas of short bones phenotypically characterizes these tumors. Their expression has not proven to be useful either as diagnostic markers of these neoplasms or in distinguishing between Enchondroma and Chondrosarcoma, Grade 1. The significant immunoexpression of IMP3, CDK4 and MDM2 in metastatic Chondrosarcoma and the lower survival in those with positivity for MDM2 suggest a possible association of these proteins with tumor aggressiveness.

Osteochondroma versus Chondrosarcoma a Diagnostic Dilemma - a Case Report.

Introduction: Osteochondroma is a benign bone tumor, commonly seen as a bony outgrowth from the metaphysis of long bones, having a stalk and cartilage cap. They may be sessile or multiple and usually arise before 20 years of age with no growth beyond puberty. Malignant transformation is a rare complication seen in 1% of solitary cases and 3-5% in the hereditary multiple enchondromatosis variety. Here, we report a rare case of atypical benign osteochondroma with clinical and radiological features suggestive of a malignant transformation. Case Report: A 17-year-old boy presented to us with a complaint of swelling in his right thigh for 12 years. Radiological features were suggestive of malignant transformation, with bony outgrowth exhibiting heterogeneous calcification, local invasion, and a cartilage cap of size 2.5 cm. Bilateral lung nodules were detected on high-resolution computed tomography. Positron emission tomography scan showed no evidence of metastasis. The patient underwent a wide excision of the tumor and the histopathology revealed it to be a benign osteochondroma. It is an atypical presentation of osteochondroma in which we had a discrepancy in radio-histopathological correlation. Conclusion: In instances of diagnostic uncertainty concerning atypical osteochondroma, opting for an excisional biopsy serves as a prudent next step for the planning of subsequent management. The patient needs to be followed up regularly to look for recurrence or any other signs of metastasis.

Chondrosarcoma of Temporomandibular Joint: Report of Two Cases.

Chondrosarcoma of the head and neck region is a rare malignant tumor which occurs from 1 to 12% of all of chondrosarcomas. There are only a few case reports of chondrosarcoma in the temporomandibular joint region. This report describes two cases of chondrosarcoma of the temporomandibular joint (TMJ) in a 27-year-old man and a 35-year-old woman. In both cases signs of temporal bone resorption were noticed, and in the first case tumor had intracranial spread. In both cases the tumor was resected in a single block with peritumoral tissues. The aim of this paper is to emphasize the diagnostic and therapeutic difficulty in this pathology.

Rare presentation of primary synovial chondrosarcoma arising in the shoulder: a case report.

Synovial chondrosarcoma (CHS) is a rare malignant tumor arising from the synovial tissue and is often associated with synovial chondromatosis. Herein, we present a unique case of primary synovial CHS in the shoulder joint without evidence of synovial chondromatosis. A 60-year-old man presented to our hospital with a complain of left shoulder pain that persisted for 6 years, which was initially misdiagnosed as synovitis. Radiography revealed an osteolytic lesion involving the humerus and the scapula. Histologically, the tumor exhibited features of grade 2 synovial CHS, infiltrating the trabecular bones and intra-articular space. Wide resection led to a 9-year recurrence-free survival. This case underscores the challenges in diagnosing and managing synovial CHS, particularly in cases with atypical presentations lacking synovial chondromatosis, necessitating careful follow-up and adequate surgical intervention.

Spinal chordoma and chondrosarcoma treatment experiences - a 20-year retrospective study from databases of two medical centers.

The research retrospectively analyzed cases of spinal chordoma and chondrosarcoma involving patients who received treatment at the two hospitals between 2001 and 2023. Among the 48 patients studied (39 chordoma and 9 chondrosarcoma cases), the average age was 53.9 ± 15.8 years, with a range of 17 to 86 years. Out of these patients, 43 underwent excision surgery and were categorized based on tumor margin into negative (R0) or microscopically positive (R1) margin (n = 14) and macroscopically positive (R2) margin (n = 29) groups. The mean overall survival (OS) for R0/R1 and R2 groups was 156.5 ± 19.3 and 79.2 ± 11.9 months, respectively (p value = 0.012). The mean progression-free survival (PFS) for R0/R1 and R2 was 112.9 ± 24.4 and 25.5 ± 5.5 months (p value < 0.001). The study showed that regardless of whether patients in the R0/R1 or R2 groups received radiation therapy (RT) or not, there was no significant improvement in OS or PFS. Specifically, the OS and PFS for the RT only group were 75.9 ± 16.6 and 73.3 ± 18.0 months. In conclusion, the recommended treatment approach for spinal chordoma and chondrosarcoma remains en bloc resection surgery with an appropriate margin. Patients who are unsuitable for or decline surgery may find a beneficial disease control rate with traditional external beam photon/proton therapy.

The clinical outcomes and prognostic factors of dedifferentiated central chondrosarcoma in extremities.

OBJECTIVE: This study was to analyze the clinical outcomes and prognostic factors of dedifferentiated central chondrosarcomas (DCCS) in extremities. METHODS: A retrospective study was conducted on 49 patients (27 males, 22 females) who underwent surgical treatment between January 2001 and March 2023 in our institution. All patients were diagnosed with dedifferentiated central chondrosarcomas by needle biopsy or postoperative histopathological examination. The general characters, treatment and clinical outcomes were recorded in the follow-up and all surgical-related complications that occurred were recorded in this study. Overall, these data were used to analyse the prognostic factors of DCCS. RESULTS: 49 patients were included in this retrospective study and there were no patients lost in the follow-up period. The median diagnosis age of all patients was 57 years old (ranging from 17 to 87) and the median follow-up time was 34 months (range, 1-289). The average tumor size was 9.6 ± 2.4 cm (3.0-15.5). Median overall survival (OS) and progression-free survival (PFS) were 34 and 23 months, respectively. The 1-year, 2-year, 5-year, and 10-year OS were 87.8% (95% CI 77.6%-98.0%), 71.4% (35/49), 28.6% (14/49) and 18.4% (9/49). And the 1-year, 2-year, 5-year, and 10-year PFS were 75.5% (95% CI 63.6%-87.4%), 49.0% (35/49), 26.5% (14/49) and 16.3% (9/49). Multiple variate analyses indicated metastasis, pathological fracture, Enneking staging and surgical margin were independent prognostic factors in extremity dedifferentiated central chondrosarcomas. CONCLUSIONS: Dedifferentiated central chondrosarcomas in extremities still had a grave prognosis. Metastasis, pathological fracture, Enneking staging, and surgical margin were independent risk factors for prognosis. EVIDENCE LEVEL: IV Therapic.

A total en bloc spondylectomy and reconstruction of vertebra thoracal IV-VI in primary large chondrosarcoma: A rare surgical case report.

INTRODUCTION AND IMPORTANCE: Chondrosarcomas are rare malignant cartilaginous neoplasms, account for the second most common primary bone tumor. Several surgical approaches for achieving en bloc resection have been mentioned in previous studies. This study aimed to present a rare case of chondrosarcoma involving T4-T6 vertebrae that underwent total spondylectomy. PRESENTATION OF CASE: A 36-year-old male was presented with signs and symptoms of thoracal foraminal stenosis due to mass effect of primary chondrosarcoma arising from the 5th thoracal vertebrae. The plain radiograph and MRI showed the characteristic features of chondrosarcoma. Biopsy result was a grade I chondrosarcoma. The patient underwent total spondylectomy of T4-T6 vertebrae, along with posterior stabilization, tubular cage insertion, thoracotomy, and bilateral chest tube insertion. CLINICAL DISCUSSION: Most complaints of spinal chondrosarcomas are localized back pain, swelling, and neurological deficits. The radiological features vary significantly, starts with lysis, to a moth-eaten destruction and interrupted periosteal reaction. Biopsy may classify the disease into conventional and variant types. The former one can further classified as primary and secondary tumor, both are graded as relation to prognosis and metastases. The primary treatment is surgical excision, while radiotherapy and chemotherapy are resistant in many cases. Recurrence commonly appears within 3-5 years postoperatively. THE CONCLUSION: As the primary modality for chondrosarcoma, surgery should aim at preserving or even improving functionality, relieving pain, and controlling local tumor recurrence, promising a prolonged survival. Besides the tumor grade, a successful operation, in terms of complete tumor excision with disease-free margins is a major independent prognostic predictor of the disease, affecting critically both local tumor control and patient survival. Spondylectomy enables wide or marginal resection of malignant lesions of the spine in most cases with acceptable morbidity. However, it induces a significant surgical challenge. The proximity of neurovascular and visceral structures combined with complex spinal anatomy makes the goal of wide margins difficult.

Dedifferentiated Chondrosarcoma: A Report of a Rare and Intriguing Case.

Dedifferentiated chondrosarcomas (DDCS) are highly aggressive tumors with poor outcomes. Chondrosarcoma (CS) can be categorized based on localization (periosteal, central, and peripheral) or histology, with conventional CS being the most common subtype. However, rarer histological types, such as clear-cell CS, DDCS, and mesenchymal CS, also exist. We present a unique case of DDCS in a 28-year-old male who presented with swelling on the proximal phalanx of the fourth finger. Radiographs showed sclerotic margins and a central diaphyseal lytic lesion. Immunohistochemical analysis using S-100 and Ki67 markers confirmed the diagnosis of DDCS. Treatment involved a multidisciplinary approach, including surgical resection, adjuvant chemotherapy, and radiation therapy. This case underscores the importance of early identification of DDCS and the need for tailored management strategies to address its specific characteristics.

Comparisons of clinical characteristics, treatments, and outcomes among different pathological subtypes of chondrosarcoma in the spine.

INTRODUCTION: Spinal chondrosarcoma exhibits higher invasiveness and a worse prognosis compared to chondrosarcoma in the extremities. The prognosis and therapeutic plan vary greatly among different pathological subtypes of chondrosarcoma. This study aimed to analyze the differences in clinical characteristics, molecular features, therapeutic effects, and prognostic factors among the subtypes of chondrosarcoma in the spine. METHODS: A retrospective review was conducted on 205 patients with spinal chondrosarcoma. The clinical features and immunohistochemical (IHC) markers were compared among the pathological subtypes of chondrosarcoma grade 1, grade 2, grade 3, mesenchymal chondrosarcoma (MCS), dedifferentiated chondrosarcoma (DCS), and clear cell chondrosarcoma (CCCS). Chondrosarcoma grade 1/2/3 are collectively referred to as conventional chondrosarcoma (CCS) for multivariate survival analysis. Univariate and multivariate analyses were performed to investigate independent prognostic factors for overall survival (OS) and recurrence-free survival (RFS) in patients with spinal chondrosarcoma. Furthermore, independent prognostic factors for OS and RFS were identified in CCS and MCS. RESULTS: MCS patients were younger than the other subtypes. Patients with chondrosarcoma grade 1/2 had better OS than those with chondrosarcoma grade 3, MCS and DCS, while only chondrosarcoma grade 1 patients showed better RFS than chondrosarcoma grade 2/3, MCS and DCS patients. Ki-67 index was higher in chondrosarcoma grade 3, MCS and DCS than chondrosarcoma grade 1/2. The comparison of IHC markers further highlighted the overexpression of P53/MDM2 in MCS and DCS. Gross total resection, including en-bloc and piecemeal resection, significantly improved OS and RFS for CCS patients, while only en-bloc resection significantly improved the prognosis of MCS patients. Chemotherapy appeared to be important for the OS of MCS patients. CONCLUSION: P53/MDM2 pathway was upregulated in MCS and DCS compared to chondrosarcoma grade 1/2. Radical tumor resection is crucial for the treatment of spinal chondrosarcoma, while MCS patients require further comprehensive treatments perioperatively.

Acute peritumoral brainstem hemorrhage of a clival chondrosarcoma successfully treated via endoscopic endonasal surgery: illustrative case.

BACKGROUND: Chondrosarcoma is typically a slow-growing tumor, and intratumoral hemorrhage is rare. Acute brainstem hemorrhage due to chondrosarcoma has rarely been reported. OBSERVATIONS: A 77-year-old man presented with the sudden onset of headache and vomiting followed by a declining level of consciousness, progressive right hemiparesis, and left ophthalmoplegia. Magnetic resonance imaging showed pontine hemorrhage and a mass in the retroclival space compressing the brainstem. Emergency endoscopic endonasal surgery was performed. Intraoperative observation revealed that a hematoma was located in the pons and subdural space around the tumor mass, suggesting that the hematoma had likely been caused by the rupture of small vessels around the pons, not by intratumoral hemorrhage. The pathological diagnosis was chondrosarcoma. The patient recovered well and underwent radiotherapy. LESSONS: This report describes a case of sudden neurological deterioration due to hemorrhage in a patient with chondrosarcoma of the skull base. An emergency endoscopic endonasal approach for mass reduction and hematoma removal was effective in the acute setting. This approach revealed the suspected etiology of peritumoral hemorrhage, not intratumoral hemorrhage. https://thejns.org/doi/10.3171/CASE2460.

Radiosensitizing Effect of PARP Inhibition on Chondrosarcoma and Chondrocyte Cells Is Dependent on Radiation LET.

Chondrosarcoma is a rare malignant tumor that forms in bone and cartilage. The primary treatment involves surgical removal of the tumor with a margin of healthy tissue. Especially if complete surgical removal is not possible, radiation therapy and chemotherapy are used in conjunction with surgery, but with a generally low efficiency. Ongoing researches are focused on understanding the genetic and molecular basis of chondrosarcoma following high linear energy transfer (LET) irradiation, which may lead to treatments that are more effective. The goal of this study is to evaluate the differential effects of DNA damage repair inhibitors and high LET irradiation on chondrosarcoma versus chondrocyte cells and the LET-dependency of the effects. Two chondrosarcoma cell lines with different IDH mutation status and one chondrocyte cell line were exposed to low LET (X-ray) and high LET (carbon ion) irradiation in combination with an Olaparib PARP inhibitor. Cell survival and DNA repair mechanisms were investigated. High LET irradiation drastically reduced cell survival, with a biological efficiency three times that of low LET. Olaparib significantly inhibited PARylation in all the tested cells. A significant reduction in cell survival of both chondrosarcoma and chondrocyte cells was observed following the treatment combining Olaparib and X-ray. PARP inhibition induced an increase in PARP-1 expression and a reduced effect on the cell survival of WT IDH chondrosarcoma cells. No radiosensitizing effect was observed in cells exposed to Olaparib paired with high LET irradiation. NHEJ was activated in response to high LET irradiation, neutralizing the PARP inhibition effect in both chondrosarcoma cell lines. When high LET irradiation is not available, PARP inhibition could be used in combination with low LET irradiation, with significant radiosensitizing effects on chondrosarcoma cells. Chondrocytes may be affected by the treatment combination too, showing the need to preserve normal tissues from radiation fields when this kind of treatment is suggested.

Combined Endoscopic Endonasal and Contralateral Transmaxillary Approach for Resection of an Anterior Petrous Chondrosarcoma: A 2-dimensional Operative Video.

The contralateral transmaxillary corridor improves access to anterior petrous apex lesions back to the level of the internal auditory canal without the need to mobilize the paraclival internal carotid artery. In this Video 1, we present the case of 31-year-old female patient who presented with new left abducens palsy during pregnancy. Imaging revealed a heterogeneous enhancing extradural mass within the left petrous apex region extending posterior to the horizontal segment of the petrous internal carotid artery, consistent with chondrosarcoma. Chondrosarcomas are the second most common osseous malignancy but only consist of 0.2% of all intracranial tumors.1,2 They are thought to derive from persistent cartilaginous rests retained after endochondral ossification.3 Given that surgery is a mainstay of treatment,4-6 a combined endoscopic endonasal and contralateral transmaxillary approach was selected to achieve maximal resection. The patient consented to the procedure. A complete resection of the mass was performed with pathology demonstrating a grade 2 chondrosarcoma. The patient tolerated the procedure without any complications, the left abducens palsy resolved in follow-up by 3 weeks, and a multidisciplinary tumor board recommended postoperative observation without adjuvant therapy.7 An endoscopic endonasal and contralateral transmaxillary approach is a feasible option for petrous apex lesions such as chondrosarcoma.

Laryngeal chondrosarcoma, a 30-year series.

INTRODUCTION AND OBJECTIVES: Laryngeal chondrosarcoma is a rare laryngeal pathology arising from cartilaginous structures and is predominantly found in the cricoid cartilage. This study investigates its presentation, treatment modalities and patient outcomes. PATIENTS OR MATERIALS AND METHODS: Retrospective study of laryngeal chondrosarcoma cases followed from 1992 to 2022 in the Otorhinolaryngology department of a cancer center - Instituto Português de Oncologia de Lisboa. Statistical analysis was made with Microsoft Excel® and SPSS®. RESULTS: We identified 16 cases, of which two-thirds were male, with an average age of 59.6 years, and only 24% of them had a history of smoking. The commonest presentation was indolent dysphonia and/or dyspnea, and the posterior arch of the cricoid cartilage was the most affected place. Although histopathological studies after biopsy were often inconclusive, surgery emerged as the first-line of treatment for all patients. Larynx microsurgery with lesion debulking was the most frequent surgical approach (47%) followed by partial laryngectomy (24%). Neither adjuvant radiotherapy (RT) nor chemotherapy was administered in any of the cases. There was residual tumor in 23% of the cases so half of these patients were in watchful waiting while the other part underwent further microsurgery or total laryngectomy. Only one patient with recurrence received RT. Disease-specific survival rate at 1 and 5 years was 97% and 91%, respectively. CONCLUSION: Laryngeal chondrosarcoma etiology is still unknown and is effectively treated with surgery, with a generally favorable prognosis. The main concern lies in its propensity to relapse, highlighting the importance of watchful follow-up.

Orthopedic manifestations of Li-Fraumeni syndrome: Prevention and treatment of a polymorphic spectrum of malignancies.

Li-Fraumeni syndrome (LFS) is a rare hereditary cancer predisposition syndrome characterized by a heightened risk of developing various malignancies at an early age. Emerging evidence suggests a correlation between LFS and orthopedic manifestations, underscoring the importance of orthopedic screening in individuals with this syndrome. Pediatric cancer is rare. It is estimated that more than 10%-15% of tumors are secondary to a pathogenic variant in a cancer predisposition gene. More than 100 cancer predisposition genes and their association with syndromes or isolated tumors have been identified. LFS is one of those who have been most widely described. Patients with this syndrome present a high risk of developing one or more tumors. Its knowledge enables the establishment of a follow-up protocol for the patient and affected family members, facilitating early detection of new tumors and reducing tumor and treatment-related morbidity and mortality. The primary objective of this invited editorial article is to provide a thorough review of the existing knowledge of LFS and its polymorphic spectrum of related malignancies, with a focus on aspects directly linked to orthopedic manifestations. Another objective is to offer an update on the most modern prevention, treatment and follow up guidelines that could be useful for the physicians dealing with this cohort of patients.

LINC00665 aggravates the malignant phenotypes in chondrosarcoma cells through miR-665/FGF9 pathway.

Long non-coding RNAs (lncRNAs) have been demonstrated to participate in a variety of physiological and pathological processes, including tumor initiation and development. Nevertheless, few of them have been investigated in chondrosarcoma. Here, we were intended to unveil the role of long intergenic non-protein coding RNA 665 (LINC00665) in chondrosarcoma. RT-qPCR was adopted for gene expression detection. The biological processes in chondrosarcoma cells were detected by CCK-8, EdU, TUNEL, Transwell and wound healing assays. The relationships between genes in chondrosarcoma cells were evaluated by a series of mechanism experiments including RIP, luciferase reporter assays and so on.LINC00665 expressed at a high level in chondrosarcoma cell lines. LINC00665 interference suppressed cell proliferation, migration and invasion in chondrosarcoma. Besides, LINC00665 interacted with microRNA-665 (miR-665), which was then verified to be down-regulated in chondrosarcoma cells. Additionally, LINC00665 and miR-665 were mutually inhibited by each other in chondrosarcoma cells. Importantly, LINC00665 stimulated fibroblast growth factor 9 (FGF9) expression in chondrosarcoma cells via sponging miR-665. Furthermore, FGF9 participated in the regulation of LINC00665-promoted chondrosarcoma development. CONCLUSION: LINC00665 facilitates chondrosarcoma progression via miR-665/FGF9 axis, which might indicate a new path for the treatment of chondrosarcoma.

Can the preoperative CT-based deep learning radiomics model predict histologic grade and prognosis of chondrosarcoma?

BACKGROUND AND PURPOSE: Computed tomography (CT) and biopsy may be insufficient for preoperative evaluation of the grade and outcome of patients with chondrosarcoma. The aim of this study was to develop and validate a CT-based deep learning radiomics model (DLRM) for predicting histologic grade and prognosis in chondrosarcoma (CS). METHODS: A multicenter 211 (training cohort/ test cohort, 127/84) CS patients were enrolled. Radiomics signature (RS), deep learning signature (DLS), and DLRM incorporating radiomics and deep learning features were developed for predicting the grade. Kaplan-Meier survival analysis was used to assess the association of the model-predicted grade with recurrence-free survival (RFS). Model performance was evaluated with the area under the receiver operating characteristic curve (AUC) and the Harrell's concordance index (C-index). RESULTS: The DLRM (AUC, 0.879; 95 % confidence interval [CI], 0.802-0.956) outperformed (z = 2.773, P=0.006) the RS (AUC, 0.715;95 % CI, 0.606-0.825) in predicting grade in the test cohort. RFS showed significant differences (log-rank test, P<0.05) between low-grade and high-grade patients stratified by DLRM. The DLRM achieved a higher C-index (0.805; 95 % CI, 0.694-0.916) than the RS (0.692, 95 % CI, 0.540-0.844) did in predicting RFS for CS patients in the test cohort. CONCLUSION: The DLRM can accurately predict the histologic grade and prognosis in CS.

Case report of large solitary skull base metastasis from renal cell carcinoma as initial clinical presentation: Radiological findings and differentials.

A 58-year-old male with good past health presented with headache and visual disturbance for 1 month. Computed tomography (CT) and magnetic resonance imaging (MRI) were performed, showing a large aggressive midline mass with epicenter at the skull base and sellar-suprasellar region. There was marked heterogenous enhancement and intratumoral calcifications. It demonstrated clivus erosion, sphenoid sinus invasion, cavernous sinus invasion and optic chiasm compression. The imaging features were considered to be consistent with clival chordoma and the patent underwent emergent endoscopic transsphenoidal surgical excision. The difficult operation found an unexpected highly vascularized tumor and histopathology of the excision showed clear cell renal cell carcinoma metastasis. Subsequent work up of the patient with positron emission tomography-computed tomography (PET-CT) confirmed suspicion of the primary tumor, arising from left kidney. This case demonstrates an underestimated differential diagnosis of a large aggressive skull base mass as the first initial clinical presentation of metastatic disease.

Chondrosarcoma From Floating and Nonfloating Ribs Presenting as a Floating Abdominal Tumor: A Case Report on a Rare Medical Condition.

Chondrosarcoma is a soft tissue tumor that develops in cartilage cells. It can exhibit an aggressive growth tendency when compared to the chondrosarcomas developing in other regions of the body. Clinical presentation of these tumors can also vary depending on the site of presentation. We aim to present the case of a 69-year-old male with a swelling in the chest extending into the abdomen. It is a rare condition that is treated surgically by wide local excision of the tumor.

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.