Complications and local recurrence of chondrosarcoma and chordoma treated by total tumor resection in thoracic and lumbar spine.

BACKGROUND: En bloc resection of spinal tumors is challenging and associated with a high incidence of complications; however, it offers the potential to reduce the risk of recurrence when a wide margin is achieved. This research aims to investigate the safety and efficacy of en bloc resection in treating thoracic and lumbar chondrosarcoma/chordoma. METHODS: Data from patients diagnosed with chondrosarcoma and chordoma in the thoracic or lumbar region, who underwent total en bloc or piecemeal resection at our institution over a 7-year period, were collected and regularly followed up. The study analyzed overall perioperative complications and compared differences in complications and local tumor recurrence between the two surgical methods. RESULTS: Seventeen patients were included, comprising 12 with chondrosarcoma and 5 with chordoma. Among them, 5 cases underwent intralesional piecemeal resection, while the remaining 12 underwent planned en bloc resection. The average surgical time was 684 min (sd = 287), and the mean estimated blood loss was 2300 ml (sd = 1599). Thirty-five complications were recorded, with an average of 2.06 perioperative complications per patient. 82% of patients (14/17) experienced at least one perioperative complication, and major complications occurred in 64.7% (11/17). Five patients had local recurrence during the follow-up, with a mean recurrence time of 16.2 months (sd = 7.2) and a median recurrence time of 20 months (IQR = 12.5). Hospital stays, operation time, blood loss, and complication rates did not significantly differ between the two surgical methods. The local recurrence rate after en bloc resection was lower than piecemeal resection, although not statistically significant (P = 0.067). CONCLUSIONS: The complication rates between the two surgical procedures were similar. Considering safety and local tumor control, en bloc resection is recommended as the primary choice for patients with chondrosarcoma/chordoma in the thoracic and lumbar regions who are eligible for this treatment.

X-rays radiomics-based machine learning classification of atypical cartilaginous tumour and high-grade chondrosarcoma of long bones.

BACKGROUND: Atypical cartilaginous tumour (ACT) and high-grade chondrosarcoma (CS) of long bones are respectively managed with active surveillance or curettage and wide resection. Our aim was to determine diagnostic performance of X-rays radiomics-based machine learning for classification of ACT and high-grade CS of long bones. METHODS: This retrospective, IRB-approved study included 150 patients with surgically treated and histology-proven lesions at two tertiary bone sarcoma centres. At centre 1, the dataset was split into training (n = 71 ACT, n = 24 high-grade CS) and internal test (n = 19 ACT, n = 6 high-grade CS) cohorts, respectively, based on the date of surgery. At centre 2, the dataset constituted the external test cohort (n = 12 ACT, n = 18 high-grade CS). Manual segmentation was performed on frontal view X-rays, using MRI or CT for preliminary identification of lesion margins. After image pre-processing, radiomic features were extracted. Dimensionality reduction included stability, coefficient of variation, and mutual information analyses. In the training cohort, after class balancing, a machine learning classifier (Support Vector Machine) was automatically tuned using nested 10-fold cross-validation. Then, it was tested on both the test cohorts and compared to two musculoskeletal radiologists' performance using McNemar's test. FINDINGS: Five radiomic features (3 morphology, 2 texture) passed dimensionality reduction. After tuning on the training cohort (AUC = 0.75), the classifier had 80%, 83%, 79% and 80%, 89%, 67% accuracy, sensitivity, and specificity in the internal (temporally independent) and external (geographically independent) test cohorts, respectively, with no difference compared to the radiologists (p ≥ 0.617). INTERPRETATION: X-rays radiomics-based machine learning accurately differentiates between ACT and high-grade CS of long bones. FUNDING: AIRC Investigator Grant.

The application of three-dimensional custom-made prostheses in chest wall reconstruction after oncologic sternal resection.

BACKGROUND AND OBJECTIVES: As one of the cutting-edge advances in the field of reconstruction, three-dimensional (3D) printing technology has been constantly being attempted to assist in the reconstruction of complicated large chest wall defects. However, there is little literature assessing the treatment outcomes of 3D printed prostheses for chest wall reconstruction. This study aimed to analyze the surgical outcomes of 3D custom-made prostheses for the reconstruction of oncologic sternal defects and to share our experience in the surgical management of these rare and complex cases. METHODS: We summarized the clinical features of the sternal tumor in our center, described the surgical techniques of the application of 3D customized prosthesis for chest wall reconstruction, and analyzed the perioperative characteristics, complications, overall survival (OS), and recurrence-free survival of patients. RESULTS: Thirty-two patients with the sternal tumor who underwent chest wall resection were identified, among which 13 patients used 3D custom-made titanium implants and 13 patients used titanium mesh for sternal reconstruction. 22 cases were malignant, and chondrosarcoma is the most common type. The mean age was 46.9 years, and 53% (17/32) of the patients were male. The average size of tumor was 6.4 cm, and the mean defect area was 76.4 cm2. 97% (31/32) patients received R0 resection. Complications were observed in 29% (9/32) of patients, of which wound infection (22%, 7/32) was the most common. The OS of the patients was 72% at 5 years. CONCLUSION: We demonstrated that with careful preoperative assessment, 3D customized prostheses could be a viable alternative for complex sternal reconstruction.

Update of cartilaginous tumours according to the WHO classification 2020.

Cartilaginous tumours are a large and heterogeneous group of neoplasms characterised by the presence of a chondroid matrix, with lobular growth and arcuate, ring-like or popcorn-like calcification patterns. MRI shows hyperintensity in T2-weighted sequences and a lobulated or septal relief in postcontrast images. In the WHO 2020 classification, chondral tumours are classified as benign, intermediate or malignant. Despite technological advances, they continue to pose a challenge for both the radiologist and the pathologist, being the main difficulty the differentiation between benign and malignant tumours, which is why they require a multidisciplinary approach. This paper describes the main changes introduced in the 2020 update, describes the imaging characteristics of the main cartilaginous tumours and provides the radiological keys to differentiate between benign and malignant tumours.

Secondary peripheral chondrosarcoma in multiple osteochondromas: a retrospective single-institution case series.

BACKGROUND: Multiple osteochondromas is genetic disorder characterized by the formation of multiple benign cartilage-capped bone tumors, named osteochondromas, during skeletal development. The most feared complication is the secondary peripheral chondrosarcoma, a malignant cartilaginous neoplasm that arises from the chondroid cap of pre-existent osteochondromas. We conducted a retrospective cohort study on patients diagnosed and followed up from 1960 to 2019 to describe the clinical and pathological features of individuals affected by peripheral chondrosarcoma in multiple osteochondromas, to evaluate follow up information and individual outcome and to compare the results with literature. Data, including age, gender, site, histological grade, cartilage cap thickness, surgical treatments, surgical margins, genotype mutational status as well as treatment details were captured from the hospital electronic health records and from Registry of Multiple Osteochondromas. In addition, a complete histological review of all hematoxylin and eosin (H&E)-stained sections has been performed by expert pathologists. RESULTS: One hundred five of the screened cases were included in the present study. The age at diagnosis of SPC ranges from 13 to 63, with median age at diagnosis of 34 years. The site most frequently affected by malignant degeneration was the pelvis (46 patients, 44%) with higher incidence in male patients (32 males vs.14 females). The second one was lower limbs (including femur, fibula, or tibia), identified in 35 patients. Histological information - available for 103 patients - showed: 59 patients with grade 1; 40 patients had a grade 2 and 4 patients had a grade 3. The most common surgical treatment was the complete resection, followed by debulking, amputation and partial resection. Most of cases did not have recurrence of the disease. Outcome in disease-free survival highlights that a worse course of the disease was associated with histological grade 2 or 3, and partial resection surgery. In most of analyzed cases (94%) a pathogenic variant was identified. CONCLUSIONS: In conclusion, the present study gives an overview of the secondary peripheral chondrosarcomas, confirming that this disease represents an impacting complication for multiple osteochondromas patients and suggests that malignant transformation can occur also in younger patient, in a not irrelevant number of cases.

Functional or radical surgical treatment of laryngeal chondrosarcoma, analysis of survival and prognostic factors: A REFCOR and NetSarc-ResOs multicenter study of 74 cases.

INTRODUCTION: Laryngeal chondrosarcoma (LCS) is a rare tumor of slow evolution whose treatment is poorly codified. For a long time, a radical treatment by total laryngectomy (TL) was proposed. More recent studies tend to propose a conservative surgical approach of the larynx. The objective of this study was to compare the overall survival (OS) of total laryngectomized patients (TL+) versus non-laryngectomized patients (TL-). The secondary objectives were to analyse the reoperation free survival (RFS), the total laryngectomy free survival (TLFS) and to identify the preoperative factors leading surgeons to propose TL. MATERIALS AND METHODS: A retrospective analysis of prospectively collected incident cases from the REFCOR and NetSarc-ResOs multicenter databases between March 1997 and June 2021 was conducted. A propensity score matching analysis was performed to compare the OS of TL+ and TL-patients. RESULTS: 74 patients were included. After propensity score, the 5-year OS of TL+ and TL-patients was comparable (100 %, p = 1). The 5-year RFS rate was 69.2 % (95 % CI [57.5-83.4]) and the 5-year TLFS was 61.7 % (95 % CI [50.4-75.5]). Cricoid involvement greater than 50 % (HR 3.58; IC 95 % [1.61-7.92] p < 0.001), an ASA score of 3 or 4 (HR 5.07; IC 95 % [1.64-15.67] p = 0.009) and involvement of several cartilages (HR 5.26; IC 95 % [1.17-23.6] p = 0.04) are prognostic factors for TL. Dyspnea caused by the tumour is a prognostic factor for reoperation (HR 2.59; IC 95 % [1.04-6.45] p = 0.03). CONCLUSION: These results demonstrate that conservative treatment should be considered as first-line treatment for laryngeal chondrosarcoma.

Cytopathology of Chondromyxoid Fibroma: Report of 2 Cases with Immunocytochemical Expression of GRM1.

INTRODUCTION: Chondromyxoid fibroma (CMF) is a rare, benign bone tumor that occurs predominantly in the second and third decades of life, more frequently in males. Overexpression of GRM1 as a consequence of tumor-specific gene rearrangement of GRM1 has recently been reported as a useful immunohistochemical marker for histopathological diagnosis of CMF. However, the usefulness of GRM1 staining of cytology specimens has not yet been evaluated. In this report, the cytological findings and GRM1 immunocytochemistry of two cases of CMF are described. CASE PRESENTATIONS: Case 1 was a 15-year-old girl with a rib tumor. Imaging findings suggested a benign neurogenic tumor such as schwannoma. The tumor had increased in size over a 2-year period and was resected. Case 2 was a 14-year-old boy with a metatarsal tumor involving his left first toe. Imaging findings were suspicious of a benign neoplastic lesion. Biopsy findings suggested a benign tumor, and the patient underwent tumor resection. Cytologically, in both cases the tumor cells were predominantly spindle-shaped or stellate, with a myxoid to chondromyxoid background matrix and multinucleated giant cells, and these matrices were metachromatic with Giemsa staining. Cellular atypia was more accentuated in case 2 than in case 1. Immunocytochemical staining for GRM1 was positive in both cases. CONCLUSION: Due to the overlap in cytological findings, it is often difficult to differentiate CMF from chondroblastoma and chondrosarcoma grade 2. Immunocytochemical staining for GRM1 may support the diagnosis of CMF, and the reuse of Papanicolaou-stained specimens is applicable. The present cases further demonstrated the difficulty of differentiating CMF from other mimicking tumors such as chondroblastoma and chondrosarcoma grade 2. In such instances, immunocytochemistry for GRM1 is applicable to the diagnostic process, the value of which is strengthened by reusing Papanicolaou-stained specimens.

Carcinosarcoma of the parotid gland: a case report and review of the literature.

BACKGROUND: Carcinosarcoma of the parotid gland is an extremely rare malignancy comprising of 0.04-0.16% of all salivary gland tumors. This is the first case of an adenoid cystic carcinoma with chondrosarcoma to the best of our knowledge. They consist of distinct carcinomatous and sarcomatous components and may arise de novo or from a preexisting pleomorphic adenoma. CASE PRESENTATION: Herein we present a case of an 80-year-old white female who presented with progressively increasing left facial swelling over 6 weeks. Magnetic Resonance Imagining revealed a mass (3.4 cm) in the parotid gland with a predominant cystic/necrotic component. The cytology was atypical (Milan3) and a total parotidectomy and selective lymph node dissection was done. The resection showed extensive necrosis with high grade sarcomatous (chondrosarcoma) areas. The epithelial component was adenoid cystic carcinoma with perineural invasion. The patient is currently undergoing radiotherapy of the tumor bed and skull base due to propensity of perineural invasion of the adenoid cystic component. The most common carcinomas in carcinosarcomas of salivary glands are adenocarcinoma and squamous cell carcinoma. CONCLUSION: Carcinosarcoma is a high-grade aggressive lesion with a poor prognosis and should be treated aggressively. More studies are needed to understand the origin of these tumors.

Racial disparities in the management and outcomes of primary osseous neoplasms of the spine: a SEER analysis.

PURPOSE: Primary osseous neoplasms of the spine, including Ewing's sarcoma, osteosarcoma, chondrosarcoma, and chordoma, are rare tumors with significant morbidity and mortality. The present study aims to identify the prevalence and impact of racial disparities on management and outcomes of patients with these malignancies. METHODS: The 2000 to 2020 Surveillance, Epidemiology, and End Results (SEER) Registry, a cancer registry, was retrospectively reviewed to identify patients with Ewing's sarcoma, osteosarcoma, chondrosarcoma, or chordoma of the vertebral column or sacrum/pelvis. Study patients were divided into race-based cohorts: White, Black, Hispanic, and Other. Demographics, tumor characteristics, treatment variables, and mortality were assessed. RESULTS: 2,415 patients were identified, of which 69.8% were White, 5.8% Black, 16.1% Hispanic, and 8.4% classified as "Other". Tumor type varied significantly between cohorts, with osteosarcoma affecting a greater proportion of Black patients compared to the others (p < 0.001). A lower proportion of Black and Other race patients received surgery compared to White and Hispanic patients (p < 0.001). Utilization of chemotherapy was highest in the Hispanic cohort (p < 0.001), though use of radiotherapy was similar across cohorts (p = 0.123). Five-year survival (p < 0.001) and median survival were greatest in White patients (p < 0.001). Compared to non-Hispanic Whites, Hispanic (p < 0.001) and "Other" patients (p < 0.001) were associated with reduced survival. CONCLUSION: Race may be associated with tumor characteristics at diagnosis (including subtype, size, and site), treatment utilization, and mortality, with non-White patients having lower survival compared to White patients. Further studies are necessary to identify underlying causes of these disparities and solutions for eliminating them.

Rare Dedifferentiated Periosteal Chondrosarcoma with 11-Year Metastatic Relapse: A Case Report.

A 50-year-old man presented for evaluation of a periscapular mass. Biopsy suggested a low-grade chondrosarcoma; however, the resected specimen revealed a grade 2 chondrosarcoma with a low-grade dedifferentiated mesenchymal component. The mass multiply recurred as chondrosarcoma without a dedifferentiated component before the patient developed lung metastases of chondrosarcoma without a dedifferentiated component 11 years after the initial diagnosis and died of disease. This is one of the first reported cases of a dedifferentiated chondrosarcoma with low-grade dedifferentiated component. While overall prognosis may be better than in typical dedifferentiated chondrosarcoma, this tumor demonstrated numerous local recurrences as well as metastasis.

SMARCB1/INI1-deficient epithelioid and myxoid neoplasms in paratesticular region: Expanding the clinicopathologic and molecular spectrum.

SMARCB1/INI1-deficient soft tissue tumors with epithelioid and myxoid features are diverse and mainly include soft tissue myoepithelial tumor, extraskeletal myxoid chondrosarcoma, and the recently described myoepithelioma-like tumor of the vulvar region and myxoepithelioid tumor with chordoid features. Because of their overlapping features, the accurate diagnosis and classification of these tumors are often challenging. Herein, we report two unique cases of SMARCB1/INI1-deficient soft tissue neoplasm with epithelioid and myxoid features occurring in male paratesticular region. The first case was a 52-year-old man presented with an intermittent painful left paratesticular mass for 1 year. The second case was a 41-year-old man presented with a painless paratesticular mass on the right side for 3 months. Both patients underwent an orchiectomy. After 6 and 26 months of follow-up, both were alive with no evidence of recurrence or metastasis. In both cases, the tumor was relatively well-demarcated and showed monomorphic round to epithelioid cells arranged in a nested, trabecular, reticular, and corded pattern, setting in a myxohyalinized and vascularized matrix. The tumor cells showed relatively uniform round nuclei with vesicular chromatin and variably prominent nucleoli. No rhabdoid cells were identified. Mitoses numbered 3 and 2 per 10 high-power fields. Tumor necrosis or lymphovascular invasion was absent. Immunohistochemically, both tumors expressed epithelial membrane antigen (focal), calponin (focal), and CD99. SMARCB1/INI1 expression was deficient in both cases. In addition, case 1 diffusely expressed pan-cytokeratin, and case 2 diffusely expressed CD34 and synaptophysin. Molecular genetically, case 1 showed SMARCB1 homozygous deletion as detected by fluorescence in-situ hybridization (FISH), and case 2 demonstrated SMARCB1 copy number deletions by next-generation sequencing and SMARCB1 monoallelic deletion by FISH. Both cases lacked EWSR1 rearrangements by FISH. The overall clinicopathologic profiles of the two cases made it difficult to classify them as one of the established categories of SMARCB1/INI1-deficient mesenchymal tumors. Our study further expands the clinicopathologic and molecular spectrum of SMARCB1/INI1-deficient epithelioid and myxoid neoplasms and highlights the challenges to diagnose these tumors.

Decoupling NAD+ metabolic dependency in chondrosarcoma by targeting the SIRT1-HIF-2α axis.

Chondrosarcomas represent the second most common primary bone malignancy. Despite the vulnerability of chondrosarcoma cells to nicotinamide adenine dinucleotide (NAD+) depletion, targeting the NAD+ synthesis pathway remains challenging due to broad implications in biological processes. Here, we establish SIRT1 as a central mediator reinforcing the dependency of chondrosarcoma cells on NAD+ metabolism via HIF-2α-mediated transcriptional reprogramming. SIRT1 knockdown abolishes aggressive phenotypes of chondrosarcomas in orthotopically transplanted tumors in mice. Chondrosarcoma cells thrive under glucose starvation by accumulating NAD+ and subsequently activating the SIRT1-HIF-2α axis. Decoupling this link via SIRT1 inhibition unleashes apoptosis and suppresses tumor progression in conjunction with chemotherapy. Unsupervised clustering analysis identifies a high-risk chondrosarcoma patient subgroup characterized by the upregulation of NAD+ biosynthesis genes. Finally, SIRT1 inhibition abolishes HIF-2α transcriptional activity and sensitizes chondrosarcoma cells to doxorubicin-induced cytotoxicity, irrespective of underlying pathways to accumulate intracellular NAD+. We provide system-level guidelines to develop therapeutic strategies for chondrosarcomas.

CT and MR imaging findings of head and neck chondrosarcoma.

OBJECTIVES: This study investigated the imaging features of head and neck chondrosarcoma (HNCS) according to its origin and pathologic subtype. METHODS: Patients who were pathologically diagnosed with HNCS between January 2000 and April 2022 were retrospectively reviewed. Lesions were classified based on their origin and pathologic subtype. The size and margin were evaluated on the image. Internal calcification and the effects on adjacent bone were assessed using computed tomography (CT) images, while signal intensity and contrast enhancement patterns were analyzed using magnetic resonance (MR) imaging. RESULTS: Thirteen HNCSs were included in this study: 8 bone tumors (61.5%) and 5 soft tissue tumors (38.5%). The bone tumors were pathologically diagnosed as conventional (n = 5) and mesenchymal type (n = 3). Soft tissue tumors were defined as myxoid type. The main symptoms were swelling (90.9%) and pain (72.7%). The lesions measured 4.5 cm on average. The margins showed benign and well-defined except for the mesenchymal type. On CT, most bone tumors (75%) showed internal calcification with remodeling or destruction of the adjacent bone. No soft tissue tumors, except one case, showed internal calcification or destruction of the adjacent bone. MR imaging features were non-specific (T2 high signal intensity and contrast enhancement). CONCLUSIONS: HCNS showed various imaging findings according to their origin and pathologic subtype. HNCS should be differentiated if a bone tumor shows internal calcification and affects the adjacent bone. When diagnosing slow-growing soft tissue tumors, even if low possibility, HNCS should be considered.

Role of Apparent Diffusion Coefficient Map-Based First- and High-Order Radiomic Features for the Discrimination of Sacral Chordomas and Chondrosarcomas With Overlapping Conventional Imaging Features.

PURPOSE: Chondrosarcomas arise from the lateral pelvis; however, midline chondrosarcomas (10%) display similar imaging features to chordoma, causing a diagnostic challenge. This study aims to determine the diagnostic accuracy of apparent diffusion coefficient (ADC)-based radiomic features and two novel diffusion indices for differentiating sacral chordomas and chondrosarcomas. METHODS: A retrospective, multireader review was performed of 82 pelvic MRIs (42 chordomas and 40 chondrosarcomas) between December 2014 and September 2021, split into training (n = 69) and validation (n = 13) data sets. Lesions were segmented on a single slice from ADC maps. Eight first-order features (minimum, mean, median, and maximum ADC, standard deviation, skewness, kurtosis, and entropy) and two novel indices: restriction index (RI, proportion of lesions with restricted diffusion) and facilitation index (FI, proportion of lesions with facilitated diffusion) were estimated. One hundred seven radiomic features comparing patients with chondrosarcoma versus chordoma were sorted based on mean group differences. RESULTS: There was good to excellent interobserver reliability for eight of the 10 ADC metrics on the training data set. Significant differences were observed (P < .005) for RI, FI, median, mean, and skewness using the training data set. Optimal cutpoints for diagnosis of chordoma were RI > 0.015; FI < 0.25; mean ADC < 1.7 × 10-3 mm2/s; and skewness >0.177. The optimal decision tree relied on FI. In a secondary analysis, significant differences (P < .00047) in chondrosarcoma versus chordoma were found in 18 of 107 radiomic features, including six first-order and 12 high-order features. CONCLUSION: The novel ADC index, FI, in addition to ADC mean, skewness, and 12 high-order radiomic features, could help differentiate sacral chordomas from chondrosarcomas.

A machine learning-based model for clinical prediction of distal metastasis in chondrosarcoma: a multicenter, retrospective study.

Background: The occurrence of distant metastases (DM) limits the overall survival (OS) of patients with chondrosarcoma (CS). Early diagnosis and treatment of CS remains a great challenge in clinical practice. The aim of this study was to investigate metastatic factors and develop a risk stratification model for clinicians' decision-making. Methods: Six machine learning (ML) algorithms, including logistic regression (LR), plain Bayesian classifier (NBC), decision tree (DT), random forest (RF), gradient boosting machine (GBM) and extreme gradient boosting (XGBoost). A 10-fold cross-validation was performed for each model separately, multicenter data was used as external validation, and the best (highest AUC) model was selected to build the network calculator. Results: A total of 1,385 patients met the inclusion criteria, including 82 (5.9%) patients with metastatic CS. Multivariate logistic regression analysis showed that the risk of DM was significantly higher in patients with higher pathologic grades, T-stage, N-stage, and non-left primary lesions, as well as those who did not receive surgery and chemotherapy. The AUC of the six ML algorithms for predicting DM ranged from 0.911-0.985, with the extreme gradient enhancement algorithm (XGBoost) having the highest AUC. Therefore, we used the XGB model and uploaded the results to an online risk calculator for estimating DM risk. Conclusions: In this study, combined with adequate SEER case database and external validation with data from multicenter institutions in different geographic regions, we confirmed that CS, T, N, laterality, and grading of surgery and chemotherapy were independent risk factors for DM. Based on the easily available clinical risk factors, machine learning algorithms built the XGB model that predicts the best outcome for DM. An online risk calculator helps simplify the patient assessment process and provides decision guidance for precision medicine and long-term cancer surveillance, which contributes to the interpretability of the model.

Does primary tumor resection improve survival for patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at diagnosis ?

BACKGROUND: Recent studies demonstrated that primary tumor resection (PTR) improves survival of patients with metastatic bone sarcomas. However, it remains quite unclear regarding the role of PTR in the treatment of sarcomas of pelvic bones with synchronous metastasis at diagnosis. METHODS: Using the Surveillance, Epidemiology, and End Results Program, we enrolled a total of 385 patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at initial diagnosis, including 139 patients with osteosarcoma, 176 with Ewing sarcoma, and 70 with chondrosarcoma. Association between PTR and disease-specific survival (DSS) were investigated using the univariable and multivariable Cox regression models. Hazard ratio (HR) and 95% confidence interval (CI) were reported. Representative institutional PTR strategies and clinical outcomes for patients with metastatic pelvic sarcomas from our cancer center were displayed. RESULTS: The usage rate of PTR was 28.1% (39/139) in osteosarcoma, 13.6% (24/176) in Ewing sarcoma, and 41.4% (29/70) in chondrosarcoma with synchronous metastatic lesions. PTR was not associated with an improved DSS for metastatic pelvic osteosarcoma (HR = 0.686, 95% CI = 0.430 ~ 1.094, P = 0.113) and Ewing sarcoma (HR = 0.580, 95% CI = 0.291 ~ 1.154, P = 0.121). The use of PTR was associated with an improved DSS for metastatic pelvic chondrosarcoma (HR = 0.464, 95% CI = 0.225 ~ 0.954, P = 0.037). CONCLUSION: Primary lesion resection may provide a survival benefit for metastatic chondrosarcoma, but not for osteosarcoma and Ewing sarcoma of pelvic bones, sacrum, and coccyx. This population-based study recommends an active surgical intervention for metastatic chondrosarcoma while non-surgical treatment for metastatic osteosarcoma and Ewing sarcoma of the pelvis in terms of survival improvement.

SPECT/CT Radiomics for Differentiating between Enchondroma and Grade I Chondrosarcoma.

This study was performed to assess the value of SPECT/CT radiomics parameters in differentiating enchondroma and atypical cartilaginous tumors (ACTs) located in the long bones. Quantitative HDP SPECT/CT data of 49 patients with enchondromas or ACTs in the long bones were retrospectively reviewed. Patients were randomly split into training (n = 32) and test (n = 17) data, and SPECT/CT radiomics parameters were extracted. In training data, LASSO was employed for feature reduction. Selected parameters were compared with classic quantitative parameters for the prediction of diagnosis. Significant parameters from training data were again tested in the test data. A total of 12 (37.5%) and 6 (35.2%) patients were diagnosed as ACTs in training and test data, respectively. LASSO regression selected two radiomics features, zone-length non-uniformity for zone (ZLNUGLZLM) and coarseness for neighborhood grey-level difference (CoarsenessNGLDM). Multivariate analysis revealed higher ZLNUGLZLM as the only significant independent factor for the prediction of ACTs, with sensitivity and specificity of 85.0% and 58.3%, respectively, with a cut-off value of 191.26. In test data, higher ZLNUGLZLM was again associated with the diagnosis of ACTs, with sensitivity and specificity of 83.3% and 90.9%, respectively. HDP SPECT/CT radiomics may provide added value for differentiating between enchondromas and ACTs.

Clear cell chondrosarcoma: a review of clinicopathologic characteristics, differential diagnoses, and patient management.

Clear cell chondrosarcoma (CCC), an extremely rare primary bone tumor, is currently classified by the World Health Organization as a low-grade malignant cartilaginous neoplasm. Clinically, CCC occurs primarily in males with a peak incidence in the third to fifth decades of life, and occasionally, it presents in skeletally immature patients. Unlike conventional chondrosarcoma, CCC has a predilection for the epiphysis of long bones and often displays radiologic features reminiscent of chondroblastoma. The recommended treatment is wide operative resection. CCC has a local recurrence rate of approximately 30%, and nearly 20% cases metastasize mainly to bone and lung often a decade after surgical intervention. Incomplete excision or curettage is associated with a high rate of recurrence. Histologically, the process is characterized by infiltrative lobules and sheets of round to oval cells with abundant cleared cytoplasm and well-defined cell borders associated with trabecula of osteoid and woven bone, scattered osteoclasts, and foci of conventional low-grade chondrosarcoma in about one-half of cases. Correlation with clinical and radiologic characteristics, such as epiphyseal location and young patient age, assists in establishing a correct diagnosis. Pathologic diagnosis of CCC is complicated by the low diagnostic accuracy of core needle biopsy, overlapping histologic features with other matrix-rich primary bone tumors, and a lack of a specific immunohistochemical and molecular profile. DNA methylation-based profiling classifier (sarcoma classifier) is one recent technologic advancement that may help to confirm the histopathological diagnosis of CCC or indicate the need for thorough reassessment in cases where results contradict previous conventional findings.

Management of chordoma and chondrosarcoma with definitive dose-escalated single-fraction spine stereotactic radiosurgery.

PURPOSE: The management of chordoma or chondrosarcoma involving the spine is often challenging due to adjacent critical structures and tumor radioresistance. Spine stereotactic radiosurgery (SSRS) has radiobiologic advantages compared with conventional radiotherapy, though there is limited evidence on SSRS in this population. We sought to characterize the long-term local control (LC) of patients treated with SSRS. METHODS: We retrospectively reviewed patients with chordoma or chondrosarcoma treated with dose-escalated SSRS, defined as 24 Gy in 1 fraction to the gross tumor volume. Overall survival (OS) was calculated by Kaplan-Meier functions. Competing risk analysis using the cause-specific hazard function estimated LC time. RESULTS: Fifteen patients, including 12 with chordoma and 3 with chondrosarcoma, with 22 lesions were included. SSRS intent was definitive, single-modality in 95% of cases (N = 21) and post-operative in 1 case (5%). After a median censored follow-up time of 5 years (IQR 4 to 8 years), median LC time was not reached (IQR 8 years to not reached), with LC rates of 100%, 100%, and 90% at 1 year, 2 years, and 5 years. The median OS was 8 years (IQR 3 years to not reached). Late grade 3 toxicity occurred after 23% of treatments (N = 5, fracture), all of which were managed successfully with stabilization. CONCLUSION: Definitive dose-escalated SSRS to 24 Gy in 1 fraction appears to be a safe and effective treatment for achieving durable local control in chordoma or chondrosarcoma involving the spine, and may hold particular importance as a low-morbidity alternative to surgery in selected cases.