Dedifferentiated chondrosarcoma: Radiological features, prognostic factors and survival statistics in 23 patients

Ensemble learning guided survival prediction and chemotherapy benefit analysis in high-grade chondrosarcoma: A study based on the surveillance, epidemiology, and end results (SEER) database

Purpose: The chemotherapy benefit for high-grade chondrosarcoma remains controversial. Ensemble learning has better overall performance than single computational approaches for clinical decision. The primary objective was to select prognostic variables and develop optimal ensemble learning algorithms for survival prediction and analyzing chemotherapy benefit in high-grade chondrosarcoma. The secondary objective included identifying specific patient groups with estimated survival benefit for guidance in chemotherapy strategies. Methods: The data of 1931 patients with chondrosarcoma from 2000 to 2019 were obtained from the Surveillance, Epidemiology, and End Results database to conduct the retrospective analysis. Among 468 patients with high-grade chondrosarcoma, cox proportional hazards models and random survival forests were used for feature selection. Ensemble learning and survival support vector machine with different kernel methods were developed and compared for their prognostic performance. Results: Ensemble learning outperformed the single models, with the concordance index reaching 0.764 (based on inverse probability of censoring weights) and the mean area under time-dependent receiver operating characteristic curve of 0.851. According to the ensemble model, overall survival generally improved in younger patients after chemotherapy. Age-stratified analysis revealed differential chemotherapy benefits across various clinical subgroups. Survival benefits were observed in: Age ≤ 10 with dedifferentiated chondrosarcoma, amputation, local surgical treatment, absence of distant metastasis, or grade III tumor; Age ≤ 20 who were male with clear cell chondrosarcoma, non-axial primary sites, or no radiotherapy; Age ≤ 30 who were female with primary site at pelvis/limb, received radiotherapy, extension beyond periosteum, further extension, or distant metastasis; Age≤40 with chondrosarcoma NOS (including mesenchymal, juxtacortical and classical chondrosarcoma); Age ≤ 50 with grade IV tumor or no surgery received. Conclusion: Ensemble learning algorithms demonstrate outstanding overall performance in prognostic assessment of high-grade chondrosarcoma and identification of age-specific factors associated with chemotherapy benefit for tailored chemotherapy strategy.

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.

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.

Dedifferentiation in bone and soft tissue sarcomas: How do we define it? What is prognostically relevant?

Dedifferentiation traditionally is defined by descriptive criteria as a tumor showing an abrupt change in histology from a conventional, classic, low-grade appearing neoplasm to a tumor that is more cellular, pleomorphic and "high grade", with grading typically being performed by subjective criteria. The dedifferentiated areas range from areas with recognizable histologic differentiation which differs from the primary tumor (such as an osteosarcoma arising from a low-grade chondrosarcoma) to areas containing sarcomas without specific histologic differentiation (such as pleomorphic or spindle cell sarcoma). Many, but not all, dedifferentiated tumors are aggressive and associated with significantly shorter survival than their conventional counterparts, even grade 3 conventional tumors. As a result, dedifferentiated tumors are generally considered to be clinically aggressive and as a result, more aggressive surgery or the addition of (neo)adjuvant chemotherapy is often considered. However, long-term (greater than 20 year) survivors are reported in the most common dedifferentiated bone and soft tissue sarcomas. Moreover, use of mitotic criterion for defining dedifferentiation in dedifferentiated liposarcoma as well as grading (by the French system) have been found to be associated with survival. This paper reviews the literature on dedifferentiated chondrosarcoma, dedifferentiated liposarcoma, dedifferentiated chordoma and dedifferentiated parosteal osteosarcoma. As a result of that review, recommendations are advocated to identify evidence-based, objective diagnostic and grading criteria for dedifferentiation that are appropriate for each tumor type. Adding such criteria will improve consistency in diagnosis worldwide, allow easier comparison of clinical research performed on dedifferentiated tumors and help communicate (to patients and clinicians) the tumors with highest risk of clinically aggressive behavior, to allow appropriate and personalized treatment planning.

FGF23 Expression Is a Promising Immunohistochemical Diagnostic Marker for Undifferentiated Pleomorphic Sarcoma of Bone (UPSb)

Background: Undifferentiated pleomorphic sarcoma of bone (UPSb) is a rare primary bone sarcoma that lacks a specific line of differentiation. Distinguishing between UPSb and other malignant bone sarcomas, including dedifferentiated chondrosarcoma and osteosarcoma, is challenging due to their overlapping features. We have previously identified that UPSb tumours have elevated mRNA levels of Fibroblast Growth Factor 23 (FGF23) transcripts compared to other sarcomas including osteosarcoma. In the present study, we evaluated the specificity and practicality of FGF23 immunoreactivity as a specific diagnostic tool to differentiate UPSb tumours from osteosarcomas and dedifferentiated chondrosarcomas. Methods: A total of 10 UPSb, 10 osteosarcoma, and 10 dedifferentiated chondrosarcoma cases (all high-grade), were retrieved and immunohistochemistry for FGF23 was performed. Results: FGF23 protein was expressed at high levels in 80-90% of undifferentiated pleomorphic sarcoma of the bone cases, whereas it was expressed at significantly lower levels in dedifferentiated chondrosarcoma and osteosarcoma cases. A semiquantitative analysis, considering the intensity of immunoreactivity, confirmed significantly elevated FGF23 expression levels in UPSb tissues compared to those observed in osteosarcoma and dedifferentiated chondrosarcoma tissues. Conclusions: The results we present here suggest that FGF23 immunohistochemistry may be a useful tool to aid in differentiating UPSb from morphologically similar malignant bone sarcomas, especially in situations where sampling is restricted and there is limited clinical information available.

A Systematic Review of Adjuvant Chemotherapy in Localized Dedifferentiated Chondrosarcoma

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype of chondrosarcoma with the bimorphic histological appearance of a conventional chondrosarcoma component with abrupt transition to a high-grade, non-cartilaginous sarcoma. DDCS can be radiographically divided into central and peripheral types. Wide resection is currently the main therapeutic option for localized DDCS. Moreover, the effectiveness of adjuvant chemotherapy remains controversial. Therefore, we performed a systematic review of available evidence to evaluate the effect of adjuvant chemotherapy on localized DDCS. The purpose was to compare the 5-year survival rate among patients treated with surgery plus adjuvant chemotherapy or surgery alone for localized DDCS. The search was conducted in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Of the 217 studies shortlisted, 11 retrospective non-randomized studies (comprising 556 patients with localized DDCS) were selected. The 5-year survival rates were similar between the two treatment groups (28.2% (51/181) vs. 24.0% (90/375), respectively). The overall pooled odds ratio was 1.25 (95% confidence interval: 0.80-1.94; p = 0.324), and heterogeneity I2 was 2%. However, when limited to peripheral DDCS, adjuvant chemotherapy was associated with prolonged survival (p = 0.03). Due to the paucity of included studies and the absence of prospective comparative studies, no conclusions can be drawn regarding the effectiveness or ineffectiveness of adjuvant chemotherapy for localized DDCS.

Intratumoral and peritumoral CT radiomics in predicting prognosis in patients with chondrosarcoma: a multicenter study

OBJECTIVE

To evaluate the efficacy of the CT-based intratumoral, peritumoral, and combined radiomics signatures in predicting progression-free survival (PFS) of patients with chondrosarcoma (CS).

METHODS

In this study, patients diagnosed with CS between January 2009 and January 2022 were retrospectively screened, and 214 patients with CS from two centers were respectively enrolled into the training cohorts (institution 1, n = 113) and test cohorts (institution 2, n = 101). The intratumoral and peritumoral radiomics features were extracted from CT images. The intratumoral, peritumoral, and combined radiomics signatures were constructed respectively, and their radiomics scores (Rad-score) were calculated. The performance of intratumoral, peritumoral, and combined radiomics signatures in PFS prediction in patients with CS was evaluated by C-index, time-dependent area under the receiver operating characteristics curve (time-AUC), and time-dependent C-index (time C-index).

RESULTS

Eleven, 7, and 16 features were used to construct the intratumoral, peritumoral, and combined radiomics signatures, respectively. The combined radiomics signature showed the best prediction ability in the training cohort (C-index, 0.835; 95%; confidence interval [CI], 0.764-0.905) and the test cohort (C-index, 0.800; 95% CI, 0.681-0.920). Time-AUC and time C-index showed that the combined signature outperformed the intratumoral and peritumoral radiomics signatures in the prediction of PFS.

CONCLUSION

The CT-based combined signature incorporating intratumoral and peritumoral radiomics features can predict PFS in patients with CS, which might assist clinicians in selecting individualized surveillance and treatment plans for CS patients.

CRITICAL RELEVANCE STATEMENT

Develop and validate CT-based intratumoral, peritumoral, and combined radiomics signatures to evaluate the efficacy in predicting prognosis of patients with CS.

KEY POINTS

• Reliable prognostic models for preoperative chondrosarcoma are lacking. • Combined radiomics signature incorporating intratumoral and peritumoral features can predict progression-free survival in patients with chondrosarcoma. • Combined radiomics signature may facilitate individualized stratification and management of patients with chondrosarcoma.

Dedifferentiated Chondrosarcoma: Diagnostic Controversies and Emerging Therapeutic Targets

PURPOSE OF REVIEW

The pathogenesis of dedifferentiated chondrosarcoma is controversial, and no genetic abnormality has consistently been identified in the disease. Focusing on the diagnostic challenges encountered in dedifferentiated chondrosarcoma, the following review aims at summarizing the tumor's active neoplastic pathways while highlighting therapeutic modalities that could potentially be explored to enhance patient survivorship.

RECENT FINDINGS

Owing to the challenging examination of small needle biopsy sampling as well as the disease's overlapping morphological and immunohistochemical features with other bone and soft-tissue sarcomas, the diagnosis of dedifferentiated chondrosarcoma can be problematic. While combined doxorubicin- and cisplatin-based regimens remain the first-line systemic chemotherapy in the disease, ~50% of tumors carry EXT1/2 or IDH1/2 mutations, advancing EXT or IDH inhibitors as potential alternative therapies, respectively. Despite systemic chemotherapy, dedifferentiated chondrosarcoma remains an aggressive tumor with dismal prognosis and limited survival. A multidisciplinary collaboration across multiple cancer centers is warranted to yield an accurate diagnosis, understand the disease's underlying pathogenesis, develop adequate treatment, and improve patient survivorship.

Chondrosarcoma of the spine-a case report

CASE

A 73-year-old male patient presented with a 3-month history of back pain. In bone scintigraphy and the FDG PET-CT scan (fluorodeoxyglucose positron-emission computed tomography), highly suspect uptake levels were found in TH12-L1. Accordingly, an osteodestructive process was found on MRI (magnetic resonance imaging). Following a successfully performed biopsy of TH12, histologic analysis of the bone material revealed a chondrosarcoma (G1; T4N2M0). Complete resection of the tumor was successfully performed, since chondrosarcoma are resistant to radiation and chemotherapy.

CONCLUSION

As chondrosarcoma is a rare bone neoplasm, it must be considered in the differential diagnosis of lower back pain to initiate adequate treatment.

Clinical characteristic-assisted surgical benefit stratification for resection of primary tumor in patients with advanced primary malignant bone neoplasms: a population-based propensity score-matched analysis

Background

Primary tumor resection (PTR) is the standard treatment for patients with primary malignant bone neoplasms (PMBNs). However, it remains unclear whether patients with advanced PMBNs still benefit from PTR. This study aimed to develop a prediction model to estimate the beneficial probability of PTR for this population.

Methods

This study extracted data from patients diagnosed with advanced PMBNs, as recorded in the Surveillance, Epidemiology, and End Results (SEER) database, with the period from 2004 to 2015. The patient cohort was then bifurcated into two groups: those who underwent surgical procedures and the non-surgery group. Propensity score matching (PSM) was utilized to mitigate any confounding factors in the study. The survival rates of patients from both the surgical and non-surgery groups were evaluated using Kaplan-Meier (K-M) curves analysis. Moreover, the study used this method to assess the capacity of the nomogram to distinguish patients likely to derive benefits from surgical intervention. The study was grounded in the hypothesis that patients who underwent PTR and survived beyond the median overall survival (OS) time would potentially benefit from the surgery. Subsequently, logistic regression analysis was performed to ascertain significant predictors, facilitating the development of a nomogram. This nomogram was subjected to both internal and external validation using receiver operating characteristic curves, area under the curve analysis, calibration plots, and decision curve analysis.

Results

The SEER database provided a total of 839 eligible patients for the study, among which 536 (63.9%) underwent PTR. Following a 2:1 PSM analysis, patients were classified into two groups: 364 patients in the surgery group and 182 patients in the non-surgery group. Both K-M curves and multivariate Cox regression analysis revealed that patients who received PTR had a longer survival duration, observed both before and after PSM. Crucial factors such as age, M stage, and tumor size were identified to be significantly correlated with surgical benefits in patients with advanced PMBNs. Subsequently, a nomogram was developed that uses these independent predictors. The validation of this predictive model confirmed its high accuracy and excellent discrimination ability of the nomogram to distinguish patients who would most likely benefit from surgical intervention.

Conclusion

In this study, we devised a user-friendly nomogram to forecast the likehood of surgical benefits for patients diagnosed with advanced PMBNs. This tool facilitates the identification of the most suitable candidates for PTR, thus promoting more discerning and effective use of surgical intervention in this patient population.

Dedifferentiated Chondrosarcoma from Molecular Pathology to Current Treatment and Clinical Trials

Dedifferentiated chondrosarcoma (DDCS) is a rare subtype of chondrosarcoma, a primary cartilaginous malignant neoplasm. It accounts for up to 1-2% of all chondrosarcomas and is generally associated with one of the poorest prognoses among all chondrosarcomas with the highest risk of metastasis. The 5-year survival rates range from 7% to 24%. DDCS may develop at any age, but the average presentation age is over 50. The most common locations are the femur, pelvis humerus, scapula, rib, and tibia. The standard treatment for localised disease is surgical resection. Most patients are diagnosed in unresectable and advanced stages, and chemotherapy for localised and metastatic dedifferentiated DDCS follows protocols used for osteosarcoma.

Case report: Treatment of metastatic dedifferentiated chondrosarcoma with pembrolizumab yields sustained complete response

Dedifferentiated chondrosarcomas (DDCS) are aggressive tumors with poor outcomes. Treatment of localized DDCS is primarily surgical, though most patients present with unresectable or metastatic disease. Systemic treatment options for advanced DDCS are limited, and the benefits of chemotherapy in this patient population remain controversial. Among other systemic therapy options, there is emerging clinical evidence to support the use of immunotherapy in patients with advanced DDCS. However, studies regarding the efficacy of immunotherapy in advanced DDCS are limited. Here, we present the case of a patient with metastatic, programmed death-ligand 1 (PD-L1)-positive DDCS treated with pembrolizumab who showed a sustained complete response for 24 months after initiation of therapy. To our knowledge, this case represents one of few documented cases of metastatic chondrosarcoma with sustained response to immunotherapy. The impressive response seen with PD-L1 inhibition in our patient indicates that immunotherapy is a successful treatment option in a subset of DDCS patients, and further investigation is needed to identify potential responders to immunotherapy.

Dedifferentiated chondrosarcoma with minimal or small dedifferentiated component

Dedifferentiated chondrosarcoma (DDCS) is an aggressive bone sarcoma characterized by low-intermediate grade cartilage component with abrupt transition to a high-grade non-chondrosarcomatous component. Generally, the dedifferentiated (DD) component is large. However, rare cases have minimal (<1 cm) or small (1-2 cm) areas of DD. We describe the clinicopathologic features of such tumors and evaluate the prognostic significance of this finding compared to cases with large DD (>2 cm). Available slides were re-reviewed for assessment of histologic features. The medical record was reviewed for imaging studies and clinical characteristics. Thirty-five cases were included. Six patients had minimal DD, four had small DD and 25 had large DD. None of the minimal DD showed definitive imaging evidence of DD. Two minimal DD (33%) locally recurred and 2 (33%) developed distant metastases. None of the small DD cases showed definitive imaging evidence of DD. None of the small DD locally recurred and at least 1 (25%) developed distant metastases. There was no significant difference in age, gender, pelvic site, tumor size >8 cm, tumor necrosis or undifferentiated pleomorphic sarcoma-like morphology between minimal or small DD compared to large DD, though osteosarcomatous differentiation was significantly more common in large DD. There was no significant difference in overall survival between minimal or small DD compared to large DD (p = 0.81 and p = 0.17, respectively), or in progression-free survival (p = 0.47 and 0.29, respectively), or metastasis-free survival (p = 0.06 and 0.62, respectively). DDCS with minimal or small DD show similar demographic distribution, anatomic localization and histologic features to large DD. DD in these cases is unlikely to be detected on imaging. Furthermore, at least a subset of these tumors is extremely aggressive despite the limited extent of DD. This highlights the need for thorough gross and histologic examination and sampling.

Dedifferentiated Chondrosarcoma: A Case Series and Review of the Literature

BACKGROUND

Dedifferentiated chondrosarcoma (DCS) is a rare and aggressive malignancy with a poor prognosis. The purpose of this investigation was to describe our treatment and outcomes of 16 DCS patients at our institution and provide a review of the current literature.

METHODS

This study was a retrospective review over a consecutive twenty-year period. Data including treatment details and outcomes were recorded.

RESULTS

A total of 16 cases from 2000 to 2018 were identified. The median age (IQR) was 62 years (52; 69) and the majority of DCS arose in the femur (50%, n=8) and pelvis (25%, n=4). Fourteen (88%) cases underwent limb salvage/wide margin resection (n=13) or intralesional surgery (n=1). For all DCS, the median survival (IQR) was 46 months (12; 140), with both a five and ten-year probability of 32.1% (95% CI, 7.3% to 57.0%). At study conclusion, 81.3% (n=13) were deceased and 18.7% (n=3) were alive.

CONCLUSIONS

Our findings confirm the poor prognosis of DCS patients, with a five-year estimate of 32%. Together with existing literature, our data might help enable future strategic recommendation of these patients.

Clinical features and treatment outcomes of dedifferentiated and grade 3 chondrosarcoma: A multi-institutional study

Chondrosarcoma is the second most common primary malignant bone tumor. In this multicenter study, we sought to evaluate the (i) disease-specific survival (DSS) and disease-free survival (DFS), and (ii) prognostic factors in patients with dedifferentiated chondrosarcoma (DDCS) and grade 3 chondrosarcoma (G3CS) in Japan. We retrospectively investigated the treatment outcomes and prognostic factors in 62 patients with DDCS and 19 patients with G3CS at 15 institutions participating in the Japanese Musculoskeletal Oncology Group. We also clarified significant clinico-pathological factors for oncological outcomes. In surgery for primary lesions aimed at cure, a histologically negative margin (R0) was obtained in 93% (14/15) of patients with G3CS and 100% (49/49) of patients with DDCS. The 5-year DSS was 18.5% in patients with DDCS and 41.7% in patients with G3CS (P = 0.13). Local control was obtained in 80% (12/15) and 79.6% (39/49) of patients with G3CS and DDCS in the primary lesion after surgery with a wide surgical margin, respectively. In multivariate analysis, stage and no treatment/palliative treatment for the primary lesion were independent prognostic factors for DSS of DDCS, age and no treatment/palliative treatment for DSS of G3CS. The 5-year DFS rate was 22.8% in 26 patients with DDCS who did not receive adjuvant chemotherapy, and 21.4% in 14 patients who received adjuvant chemotherapy. The prognosis of DDCS remains poor, although R0 resection was performed in most cases. Effective and/or intensive chemotherapeutic regimens or agents should be considered or developed for patients with high-grade chondrosarcoma, particularly for those with DDCS.

Dedifferentiated chondrosarcoma of the middle finger arising from a solitary enchondroma: A case report

BACKGROUND

Dedifferentiated chondrosarcoma (DDCS) accounts for 10% of all chondrosarcomas and has the poorest outcome, with a 5-year survival rate of 7%-25%. DDCS commonly occurs in the femur and pelvis, whereas DDCS of the finger is extremely rare. Furthermore, the histological findings of preexisting solitary enchondroma samples are important and valuable for diagnosing malignant transformations.

CASE SUMMARY

We report our experience with DDCS in the proximal phalanx of the left middle finger of an 87-year-old woman. She had undergone surgery for enchondroma, with curettage and artificial bone grafting, 11 years ago, in the same location. Several years after the primary surgery, the left middle finger gradually started to enlarge, and the growth speed increased in the past year. Plain radiographs showed an expansive osteolytic lesion with calcifications and residual grafting material. Owing to the suspicion of malignancy, we performed ray amputation. Histological findings revealed an abrupt transition between the low-grade chondrosarcoma and dedifferentiated sarcoma components. The dedifferentiated components showed the features of a high-grade undifferentiated pleomorphic sarcoma. The patient was diagnosed with DDCS arising from a preexisting enchondroma. She had no local recurrence or distant metastasis and died of pneumonia 6 years and 10 months after the second surgery.

CONCLUSION

The histological findings of a precursor lesion showed a typical enchondroma, suggesting that DDCS can arise from enchondroma.

Dedifferentiated chondrosarcoma: current standards of care

Dedifferentiated chondrosarcomas are aggressive variants of chondrosarcoma, associated with poor outcomes. Tumor biphasism is the norm. The majority of these tumors are symptomatic at presentation. Radiologically, large soft tissue masses with bony destruction predominate. Treatment protocols of these tumors are not well defined. Surgical resection forms the standard of care for localized disease. (Neo)adjuvant therapies remain controversial as the results from multiple (mainly retrospective) studies remain conflicting. Age at presentation, stage and ability to obtain negative resection margins are important prognostic factors. The overall prognosis is dismal. Newer and novel therapies targeting the complex genetic makeup of these tumors have renewed interest in the adjuvant setting that could hold promise in the near future.

Metastatic Dedifferentiated Chondrosarcoma to Thyroid Gland: A Case Report

A 54-year-old man presented with a pathologic hip fracture secondary to a right femur tumor. A reaming biopsy showed the diagnosis of dedifferentiated chondrosarcoma (DDC). In addition, the patient had a thyroid mass. Fine needle aspirate from the thyroid mass revealed numerous large fragments of cohesive spindle cells with moderate nuclear atypia and brisk mitosis, identical to the femur tumor. Immunohistochemical staining on cell blocks of thyroid aspirate showed positivity for mesenchymal markers and negativity for epithelial and thyroid markers. The metastasis of DDC to the thyroid gland is a very rare incident and has previously been described once in the literature. In this report, we describe the clinical and pathologic findings of this case.

Pathological fracture does not affect prognosis in dedifferentiated chondrosarcoma of the limbs

BACKGROUND

The aim of this retrospective study is to analyze history and treatment outcomes of pathological fracture (PF) in dedifferentiated chondrosarcoma (DdChS) of the limbs..

METHODS

We retrospectively reviewed 175 adult patients with primary DdChS of the limbs.Disease-specific survival (OS) and local recurrence (LR) were analyzed.

RESULTS

Median age was 66 years (range, 29-91). Most DdChS (121, 69.1%) were localized in the femur. Forty-nine (28.0%) had metastasis at diagnosis; thirty-nine DdChS (22.3%) had a PF.OS rate was lower in patients with metastasis at diagnosis (8.6% Vs 41.0% at 10 years, p < 0.001). A similar OS was observed among patients with localized disease, whether with/without PF (p = 0.638), with/without chemotherapy (p = 0.543) and independently from the type of surgery (resection/amputation) (p = 0.877). Amputation reduces the risk of LR (80.0% vs 63.1% at 5 years, p = 0.039), particularly in the PF group..

CONCLUSION

Patients with metastases have a particularly poor prognosis in DdChS, but pathological fracture does not influence prognosis in terms of survival and local control. Initial curative resection is essential in order to reduce the chance of recurrences. Amputation might be an option in patients with localized disease and a PF to reduce the risk of LR..

GATA-3 expression in a de-differentiated chondrosarcoma with cutaneous iatrogenic implantation: a diagnostic pitfall with important clinical implications

De-differentiated chondrosarcoma (DDCS) is an extremely aggressive tumor of the bone characterized by a high-grade, non-chondroid sarcoma adjacent to a low- or intermediate-grade chondrosarcoma. Adequate tumor sampling demonstrating the biphasic features is necessary to make an accurate diagnosis. The diagnosis may be challenging as histopathology may mimic other neoplasms. We present a case of a 76-year-old woman with a history of breast cancer who presented with a pathologic non-displaced fracture. A bone biopsy demonstrated a high-grade neoplasm composed of pleomorphic spindled and epithelioid cells with focal expression of AE1/3 and GATA3, most likely consistent with metastatic breast carcinoma. After a difficult clinical course, the tumor was resected demonstrating a similar morphology to her prior biopsy, as well as an area of a low-grade cartilaginous neoplasm consistent with chondrosarcoma. The biphasic tumor alongside a low-grade chondrosarcoma allowed for a diagnosis of DDCS. Several days after her procedure, the patient developed violaceous nodules overlying and surrounding the surgical site. Skin biopsy demonstrated a malignant epithelioid neoplasm with identical histomorphologic features identical to her prior bone resection. Given the location of the skin lesions directly within the surgical site right after resection, the clinical-pathological picture was that of sarcomatosis cutis by iatrogenic cutaneous implantation.

Dedifferentiated chondrsarcoma: a clinicopathologic analysis of 25 cases

Background

To investigate the clinical, imaging and pathological features of dedifferentiated chondrosarcoma for better diagnosis.

Methods

Patients who had been confirmed to have dedifferentiated chondrosarcoma were enrolled in this study and analyzed in the clinical, imaging and pathological data.

Results

Twenty-five patients had pathologically confirmed dedifferentiated chondrosarcoma including 15 males and 10 females with an age range of 24–74 (median 58, interquartile range 49–65). Ten patients had the tumor at the femur, four at the ilium, two at the humerus, two at the tibia, two at cotyle, and one at each of the following locations: scapula, sacrum, rib, pubic branch, and calcaneus. Twenty-one patients had local pain and a soft tissue mass while the other four patients had only local pain without a soft tissue mass. Four patients had pathological fractures. Imaging showed extensive bone destruction with calcification inside the lesion and possible pathological fractures. On gross observation of the specimen, the chondrosarcoma components were usually located inside the bone, and the dedifferentiated sarcoma components were mainly located outside the bone. Microscopy showed the dedifferentiated tumor had two components: well-differentiated chondrosarcoma and poorly differentiated non-chondral sarcoma including malignant fibrous histiocytoma in eleven cases, osteosarcoma in ten cases, fibrosarcoma in two, liomyosarcoma in one, and lipoblastoma in the remaining one.. Followed up from 3 moths to 60 months (mean 15.6), eight patients died with a survival time of 10–23 months (mean 16), and the other 17 patients survived with the survival duration from three to 60 months (15).

Conclusion

Dedifferentiated chondrosarcoma is a fatal disease with multiple components, and most of the cases have dual morphological and imaging features of chondrosarcoma and non-chondrosarcoma. The imaging presentations are primarily of common central chondrosarcoma, combined with cortical destruction, soft tissue mass, and pathological fractures.

The role of imaging in differentiating low-grade and high-grade central chondral tumours

Chondrosarcoma is a malignant cartilage matrix-producing tumour. Those arising de novo are called primary chondrosarcomas and are the second commonest primary malignant bone tumours. Numerous types of primary chondrosarcoma exist, namely conventional central (intramedullary), periosteal (juxta-cortical), clear cell, mesenchymal, and dedifferentiated. The biologic aggressiveness, prognosis and thus management of chondrosarcoma are dependent on the histological sub-type and grade. Accurate pre-operative diagnosis is therefore essential in determining management and outcome which requires a multidisciplinary approach taking into account clinical features, imaging findings and histopathology. In this review, we present the pertinent multimodality imaging features which aid in the differentiation of low-grade and high-grade conventional central chondrosarcoma.

Unrecognized Chondrosarcoma as a Cause of Total Hip Arthroplasty Failure

Background

Total hip arthroplasty (THA) is one of the most successful procedures in orthopedic surgery. The most frequent THA indications are osteoarthritis and avascular necrosis, whereas symptomatic aseptic loosening is the most common indication to revision surgery. Chondrosarcoma (CS) is the most frequent bone sarcoma in adults, and proximal femur is the most prevalent location. Wide resection is the treatment of choice.We report 3 cases of unrecognized high-grade CS in the setting of primary or revision THA and reviewed the literature on this rare clinical presentation.

Methods

A systematic literature review on CS in the setting of THA, published between 1980 and 2020, was performed on PubMed, Embase, Medline, Ovid SP, and Web of Science, using the guidelines set in the Preferred Reporting Items for Systematic Reviews and Mata-analyses (PRISMA).

Results

Case series: Three patients were referred to our sarcoma center after failure of THA due to unrecognized high-grade CS. All 3 had rapid fatal outcome. Literature review: Fifty-nine articles were identified, of which 8 were included in the study. They confirmed that primary or revision THA failure due to unrecognized CS is extremely rare, with only few cases reported in the literature.

Conclusions

Before proceeding to primary or revision arthroplasty, diagnosis must be ascertained. Atypical presentation of a common pathology, such as osteoarthritis, avascular necrosis, or aseptic loosening of an endoprosthesis, should raise suspicion for another cause to symptoms, and additional workup be performed. As our cases demonstrated, unrecognized or inadequately managed bone sarcoma may lead to poor or even fatal outcome.

A review of imaging of surface sarcomas of bone

Surface lesions of bone are uncommon. Although their imaging features generally mirror those of their intramedullary counterparts, surface lesions may demonstrate distinct characteristics which along with their unusual location present a diagnostic challenge. Surface sarcomas are usually of a lower grade compared with intramedullary variants, leading to differences in management. Osteosarcoma arising from the cortical surface of the bone is termed juxtacortical or surface osteosarcoma and includes three distinct entities: parosteal, periosteal, and high-grade surface osteosarcoma. We also review the features intracortical osteosarcoma, which some authors include under the umbrella term surface osteosarcoma. These lesions exhibit biologic features distinct from those of conventional intramedullary osteosarcoma, which underlines the importance of accurate imaging diagnosis. Periosteal chondrosarcoma and periosteal Ewing sarcoma also have distinctive imaging appearances. The purpose of this article is to review surface sarcomas of bone with regard to their clinical and radiological features and to discuss the differential diagnosis for each condition.

Magnetic Resonance Imaging Role in the Differentiation Between Atypical Cartilaginous Tumors and High-Grade Chondrosarcoma: An Updated Systematic Review

Chondrosarcoma (CS) is a malignant tumor affecting the bones while atypical cartilaginous tumors (ACTs) are chondral tumors with moderate cellularity, mild atypia, and with myxoid changes and mild metastatic ability. Both can have one of the worst prognoses if not identified early enough. Magnetic resonance imaging (MRI) has been one of the modalities to detect such tumors and we aim to determine the common characteristic and features to be seen while screening for CS or ACTs. We conducted a systematic review of the previously published reports that investigated the diagnostic ability of MRI and the reported characteristics that can differentiate between ACTs and high-grade chondrosarcomas (HGCS). A comprehensive relevant database search was performed to include all the relevant studies. Among these studies, seven studies investigated the overall accuracy in the classification of the different chondroma types. Additionally, many studies reported the characteristic findings of each tumor according to the MRI results. These characteristics mainly included trapped fat, bone marrow edema, cortical damage, and soft-tissue expansion. Therefore, further attention should be given to these criteria for better assessment, differentiation, and favorable outcomes. MRI can efficiently identify some of the characteristics of both ACTs and HGCS. However, combining it with other radiological modalities may lead to a better differentiation. The detection of ACTs and HGCS lesions with MRI solely has been doubted before in the literature.

Can MRI differentiate between atypical cartilaginous tumors and high-grade chondrosarcoma? A systematic review

Background and purpose - Adequate staging of chondroid tumors at diagnosis is important as it determines both treatment and outcome. This systematic review provides an overview of MRI criteria used to differentiate between atypical cartilaginous tumors (ACT) and high-grade chondrosarcoma (HGCS).Patients and methods - For this systematic review PubMed and Embase were searched, from inception of the databases to July 12, 2018. All original articles describing MRI characteristics of pathologically proven primary central chondrosarcoma and ACT were included. A quality appraisal of the included papers was performed. Data on MRI characteristics and histological grade were extracted by 2 reviewers. Meta-analysis was performed if possible. The study is registered with PROSPERO, CRD42018067959.Results - Our search identified 2,132 unique records, of which 14 studies were included. 239 ACT and 140 HGCS were identified. The quality assessment showed great variability in consensus criteria used for both pathologic and radiologic diagnosis. Due to substantial heterogeneity we refrained from pooling the results in a meta-analysis and reported non-statistical syntheses. Loss of entrapped fatty marrow, cortical breakthrough, and extraosseous soft tissue expansion appeared to be present more often in HGCS compared with ACT.Interpretation - This systematic review provides an overview of MRI characteristics used to differentiate between ACT and HGCS. Future studies are needed to develop and assess more reliable imaging methods and/or features to differentiate ACT from HGCS.

The incidence of skip metastases on whole bone MRI in high-grade bone sarcomas

INTRODUCTION

Skip metastases have been described with osteosarcoma, Ewing sarcoma and rarely chondrosarcoma. The aim of this study was to determine the incidence of skip metastases on whole bone MRI in all primary high-grade sarcomas of the major long bones.

MATERIALS AND METHOD

Retrospective review of patients from April 2007 to April 2019 with high-grade primary bone sarcomas of the humerus, radius, ulna, femur, tibia or fibula who had whole bone MRI at initial staging. Data collected included age, sex, tumour type, presence and location of skip metastases based on whole bone MRI and presence of distant metastases (the skeleton and lung).

RESULTS

The study included 216 males and 171 females with mean age 30.6 years (range 4-92 years). Tumour types were as follows: High-grade osteosarcoma n = 202, Ewing sarcoma n = 68, high-grade chondrosarcoma n = 44, dedifferentiated chondrosarcoma n = 37, high-grade spindle cell sarcoma n = 29 and angiosarcoma n = 7. Skip lesions were identified in 63 (16.3%). However, after taking into account the presence of distant skeletal (n = 11) and pulmonary (n = 33) metastases, the overall incidence of skip metastases was 6.5%, occurring in 15 (7.5%) high-grade osteosarcomas, 3 (4.5%) Ewing sarcoma, 1 (2.8%) high-grade chondrosarcoma, 4 (10.8%) dedifferentiated chondrosarcomas, and 2 (6.9%) high-grade spindle cell sarcomas. A false positive MRI diagnosis of skip metastasis was made in 4 cases, 3 enchondromata and one focal nodular marrow hyperplasia.

CONCLUSION

The current study has documented the incidence of skip metastases in common types of high-grade primary bone sarcoma. The possibility of false positive skip metastases has also been highlighted.

Prognostic Factors in Dedifferentiated Chondrosarcoma: A Retrospective Analysis of a Large Series Treated at a Single Institution

Background

Dedifferentiated chondrosarcomas (DDCSs) are highly malignant tumors with a dismal prognosis and present a significant challenge in clinical management.

Methods

In an IRB approved retrospective protocol, we identified 72 patients with DDCS treated at our institution between 1993 and 2017 and reviewed clinicopathological characteristics, treatment modalities, and outcomes to analyze prognostic factors.

Results

Femur (44.4%), pelvis (22.2%), and humerus (12.5%) were most commonly involved sites. Twenty-three patients (31.9%) presented with distant metastasis, and 3 (4.2%) of them also had regional lymph node involvement. The median overall survival (OS) was 13.9 months. On multivariate analysis, pathological fracture, larger tumor size, lymph node involvement, metastasis at diagnosis, extraosseous extension, and undifferentiated pleomorphic sarcoma component correlated with worse OS, whereas surgical resection and chemotherapy were associated with improved OS. For progression-free survival (PFS), pathological fracture and metastasis at diagnosis showed increased risk, while chemotherapy was associated with decreased risk. Among patients who received chemotherapy, doxorubicin and cisplatin were significantly associated with improved PFS but not OS. Among patients without metastasis at diagnosis, 17 (34.7%) developed local recurrence. Thirty-one (63.3%) developed distant metastases at a median interval of 18.1 months. On multivariate analysis, R1/R2 resection was related with local recurrence, while macroscopic dedifferentiated component was associated with distant metastasis.

Conclusions

The prognosis of DDCS is poor. Complete resection remains a significant prognostic factor for local control. Chemotherapy with doxorubicin and cisplatin seems to have better PFS. More prognostic, multicenter trials are warranted to further explore the effectiveness of chemotherapy in selected DDCS patients.

Prognostic Factors and Treatment Options for Patients with High-Grade Chondrosarcoma

Background

The goal of this study was to determine the prognostic factors exclusive for high-grade chondrosarcoma and whether adjuvant radiotherapy could achieve better overall survival (OS) or cancer-specific survival (CSS) for patients with high-grade chondrosarcoma.

Material/Methods

Surveillance, Epidemiology, and End Results (SEER) cancer registry database was utilized to extract the chondrosarcoma cases diagnosed between 1973 and 2014. Among these cases, the histological grades of poorly differentiated (grade 3) and undifferentiated (grade 4) were categorized as high-grade and included in this study. Chondrosarcoma OS and CSS were the primary outcomes in the present study. The log-rank test was performed for univariate analysis, and the Cox regression model was conducted for multivariate analysis.

Results

A total of 743 patients with high-grade chondrosarcoma were identified in this study (430 cases were poorly differentiated tumors, and 313 cases were undifferentiated tumors). Age at diagnosis, pathological grade, histo-type, SEER stage, tumor size and surgical resection were identified as independent predictors in both OS and CSS analysis of high-grade chondrosarcoma. When stratified by histological grade, surgical resection remained the effective treatment. Strikingly, radiotherapy was determined as an independent protective factor in both OS and CSS analysis of undifferentiated (grade 4) dedifferentiated chondrosarcoma, and adjuvant radiotherapy combined surgical resection could improve both the OS and CSS of patients with undifferentiated myxoid and dedifferentiated chondrosarcoma compared with other treatment regimens.

Conclusions

Our study first demonstrated that adjuvant radiotherapy combined surgery could improve the survival of patients with undifferentiated myxoid and dedifferentiated chondrosarcoma. These results encourage the application of adjuvant radiotherapy for patients with high-grade chondrosarcoma and maximize the patients’ outcome.

H3K27me3 deficiency defines a subset of dedifferentiated chondrosarcomas with characteristic clinicopathological features

Dedifferentiated chondrosarcoma is a rare bone sarcoma, whose genetic background remains incompletely understood. Mutations in SUZ12 or EED, which encode polycomb repressive complex 2 (PRC2) components, and resulting deficiency in H3K27me3 are characteristic features of the majority of malignant peripheral nerve sheath tumors. Here, we investigated H3K27me3 and PRC2 status in dedifferentiated chondrosarcoma. Among 19 evaluable dedifferentiated chondrosarcoma cases, six (32%) showed immunohistochemical loss of H3K27me3 only in the dedifferentiated component, whereas the well-differentiated component retained H3K27me3. H3K27me3-deficient dedifferentiated chondrosarcoma occurred in two men and four women with a median age of 66. All of these tumors affected bones of the upper half of the body, with the ribs being preferentially involved, which represented a significantly different distribution compared to that in the 13 H3K27me3-intact dedifferentiated chondrosarcomas. H3K27me3-deficient dedifferentiated chondrosarcomas were histologically different from H3K27me3-intact dedifferentiated chondrosarcomas, as the former invariably demonstrated dedifferentiated histology with a striking similarity to classic malignant peripheral nerve sheath tumor, comprising sweeping to swirling fascicles of relatively uniform spindle cells. Heterologous rhabdomyoblastic differentiation, the focal presence of grade 3 chondrosarcoma histology, and a cartilaginous component in the metastatic sites were exclusively seen in some cases of H3K27me3-deficient dedifferentiated chondrosarcoma. In all three H3K27me3-deficient dedifferentiated chondrosarcomas that contained focal grade 3 histology, dedifferentiated components did not juxtapose to the grade 3 areas but transitioned abruptly from the grade 1-2 components. Targeted next generation sequencing, which was successfully performed on four H3K27me3-deficient dedifferentiated chondrosarcomas, identified an IDH2 mutation in one case and COL2A1 truncations in three cases. The dedifferentiated areas of three cases harbored SUZ12 or EED alterations, which were absent in the well-differentiated component, suggesting a role for PRC2 aberrations in dedifferentiation. H3K27me3 deficiency defines a novel subset of dedifferentiated chondrosarcoma that requires recognition because of its diagnostic and potential clinical implications.

Dedifferentiated chondrosarcoma of the pelvis: clinical outcomes and current treatment

Background

Dedifferentiated chondrosarcomas (CS) are a high-grade variant of CS that confers a 5-year survival of around 10–24%. Dedifferentiated CS arising from the pelvis confers an even worse prognosis.

Questions

(1) What is the prognosis of patients with dedifferentiated CS of the pelvis? (2) Do wide margins or type of surgical intervention influence outcome? (3) Does the use of adjuvant therapy affect outcome?

Methods

Patients were retrospectively reviewed from a prospectively collated musculoskeletal oncology database from 1995 to 2016. Thirty-one cases of dedifferentiated CS arising from the pelvis were included. Wide margins were defined as greater than 4 mm. The mean age was 55.6 years (range 33 to 76 years) and there were 19 males (61.3%) and 12 females (38.7%).

Results

The disease presented at a locally or systemically advanced stage in 13 patients (41.9%). Eighteen patients (58.1%) underwent surgery with curative intent. Overall survival at 12 months was 15.4% for patients treated with palliative intent and 50% for those treated with surgery. In the surgical group, there were higher rates of disease-free survival in patients who underwent hindquarter amputation and those who received wide surgical margins (p = 0.047 and p = 0.019, respectively). Those who underwent hindquarter amputation were more likely to achieve wide margins (p = 0.05). Time to recurrent disease (local or systemic) was always less than 24 months. No hindquarter amputation for recurrent disease resulted in disease-free survival. No patient who received adjuvant therapy for palliative or recurrent disease had disease control.

Conclusions

Pelvic dedifferentiated CS often presents at an advanced local or systemic stage and confers a poor prognosis. Achieving wide surgical margins (> 4 mm) provided the highest rate of long-term disease-free survival. Failing to achieve wide margins results in rapid disease recurrence, conferring deleterious consequences.

C-reactive protein: An independent predictor for dedifferentiated chondrosarcoma

Dedifferentiated chondrosarcoma is a rare primary bone malignancy with a very poor prognosis. The aim of the study was to identify pretreatment serum markers as prognostic factors for the overall survival (OS) of patients with dedifferentiated chondrosarcoma. We retrospectively reviewed 33 patients with histologically confirmed dedifferentiated chondrosarcoma treated at our department from 1977 to 2015. Kaplan-Meier estimation, uni- and multivariable Cox proportional hazard model were performed to evaluate the association between serum markers such as the C-reactive protein and OS. In univariable analysis, CRP was strongly associated with OS (HR 1.35; 95%CI 1.13-1.61; p = 0.001). This association prevailed after adjustment for AJCC tumor stage (HR 1.31; 95%CI 1.02-1.57; p = 0.031) in multivariable analysis. In conclusion, our data gave evidence that baseline CRP is an independent predictor for OS in patients with dedifferentiated chondrosarcoma. CRP could be exploited for the clinical prediction of this disease in the future. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:2797-2801, 2018.

Prognostic factors for patients with chondrosarcoma: A survival analysis based on the Surveillance, Epidemiology, and End Results (SEER) database (1973-2012)

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First, it is a population-based study which can provide big sample size.

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Second, similar articles about chondrosarcoma using big data are lacking.

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Third, the relationship between treatment type and survival outcomes was analyzed in detail.

Current reports on prognostic factors for chondrosarcoma mainly involve patients in treatment centers. Few are based on multicenter or multi-eras. We analyzed existing data from the Surveillance, Epidemiology, and End Results (SEER) database to investigate the risk factors for survival outcomes. All patients with chondrosarcoma from 1973 to 2012 were identified. 3737 patients were eligible and included. In survival analysis, patient had good survival outcome if the patient was female, young, with localized stage, well grade, small tumor size, treated with surgery, while patient was male, old, with distant stage, undifferentiated grade, tumor size <50 mm, located in vertebral or pelvic bones, underwent radiation had bad survival outcome. Surgery types from having best survival outcomes to worst were local excision, radical excision, amputation, no surgery. ‘Well’ and ‘moderately’ grade seems to be suitable for local excision, but ‘poorly’ and ‘undifferentiated’ grade suitable for wide local excision. Multivariate COX regression analysis showed year of diagnosis, sex, age of diagnosis, stage, grade, tumor site, surgery, radiation were independent risk factors. Year of diagnosis, sex, age of diagnosis, stage, grade, tumor site, surgery, radiation were independent risk factors. Excision is a better treatment than amputation. Doctors can use wide local excision to treat chondrosarcoma, especially when encountering high grade chondrosarcoma or pelvic chondrosarcoma.