An institutional review of clear cell chondrosarcoma

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.

Three-Dimensional CT and 3D MRI of Hip- Important Aids to Hip Preservation Surgery

Common hip internal derangements include femoroacetabular impingement (FAI), developmental dysplasia of hip (DDH) dysplasia, and avascular necrosis (AVN) of the femoral head. These are initially screened by radiographs. For preoperative planning of hip preservation, 3-dimensional (3D) CT is commonly performed to assess bony anatomy and its alterations. Magnetic resonance imaging (MRI) is used to evaluate labrum, hyaline cartilage, tendons, synovium, and loose bodies, and provides vital information for surgical decision-making. However, conventional 2D MRI techniques are limited by lack of isotropic multiplanar reconstructions and partial volume artifacts. With advancements in hardware and software, novel isotropic 3D MR Proton Density images are acquired with acceptable acquisition times leading to improved visualization of soft tissue and osseous structures for various hip conditions. Three-Dimensional MRI allows multiplanar non-gap reconstructions along the structures of interest. It results in detection of small, otherwise inconspicuous labral tears without the need for MR arthrogram, which can be subsequently measured. In addition, radial reconstructions of the femoral head can be performed from original 3D volume MR imaging and CT imaging without the need for individual different plane acquisitions. Three-Dimensional MRI thus impacts surgical decision-making for the important common hip derangement conditions. For example, femoral head hyaline cartilage loss may make hip preservation difficult or impossible. In this review, we discuss the advantages and technical details of 3D CT and MRI and their significant role in aiding hip preservation surgery for common hip conditions. The conditions discussed in this article include FAI, DDH, AVN, synovial disorders, cartilaginous tumors, and hip fractures.

The Epidemiology of Chondrosarcoma in Iran Based on Iran National Cancer Registry

Background: Chondrosarcoma is regarded as the second most common primary bone malignancy following osteosarcoma. Objectives: The present study aimed at determining the epidemiology, incidence, and survival rate of chondrosarcoma in the Iranian population, according to the Iran National Cancer Registry (INCR). Methods: In an epidemiological study, patients with limb chondrosarcoma were evaluated based on INCR data between 2008 and 2015. Data included patients’ demographic characteristics, date of diagnosis, location of the tumor, patient’s survival, and type of tumor based on the International Classification of Diseases for Oncology (ICD-O-3; first revision, third edition) were collected and analyzed. Results: Out of 732 enrolled patients, 425 patients (58.06%) were male and 307 (41.94%) were female with a mean age of 44.08 (SD = 19.31) and 45.06 (SD = 18.72), respectively. Age-standardized incidence rates (ASIR) were 1.73 and 1.27 per 1 million person-years for males and females, respectively. Conventional chondrosarcoma was the most common subtype with ASIR 1.28 and constituted 84.7% of patients with chondrosarcoma. About 71.03% of all Chondrosarcoma patients (70.35% of males and 71.99% of females) were between 20 to 59 years old. The 1-, 3-, 5-, and 7-year survival rates of patients were 0.87, 0.73, 0.57, and 0.47, respectively. Also, the mean survival time was 6.12 years (95% CI: 5.85 - 7.39). Conclusions: The incidence of chondrosarcoma in Iran is not as high as in other countries, but as patients are younger in Iran, the survival rate is worse compared to other countries. Therefore, better case findings and better care are needed to improve the patients' outcomes in Iran.

Conventional Chondrosarcoma with Clear Cell Features in the Rib: Report of Two Cases and Review of the Literature

A subset of clear cell chondrosarcomas may contain focal areas of low-grade conventional chondrosarcoma; however, it is rare to find foci resembling clear cell chondrosarcoma admixed with areas otherwise typical conventional chondrosarcoma. We report two patients with conventional chondrosarcoma with clear cell features occurring in the rib, one in the setting of multiple hereditary exostoses (MHE) and the other without MHE. Both patients were found to have a destructive rib mass with a soft tissue component and underwent en bloc resection. Histologic examination revealed predominantly grade 2 conventional chondrosarcomas; however, multiple foci containing large cells with pale eosinophilic to clear cytoplasm, distinct cell borders, centrally located nuclei, and conspicuous nucleoli, resembling clear cell chondrosarcoma were identified throughout the specimen. The significance of clear cell features in an otherwise typical conventional chondrosarcoma, to our knowledge, is unknown and deserves recognition. Finally, these tumors highlight the need for careful histologic examination and proper classification as unexpected findings may impact management.

Successful en bloc resection for femoral head clear cell chondrosarcoma without biopsy: A case report

Clear cell chondrosarcoma (CCCS) is a rare, low-grade, malignant chondrogenic bone tumour. This tumour commonly affects the epiphysis of long bones, particularly in the proximal femur. The present study reported on the case of a 58-year-old male with right hip pain of five months duration. Plain radiography, magnetic resonance imaging and computed tomography scan revealed the characteristic appearance of chondroid mineralisation in the right femoral head, suggesting typical CCCS. Although biopsy is the gold standard for definite diagnosis prior to treatment, wide resection with removal of the biopsy tract is thought to negatively affect the surgical margin and postoperative hip function. Therefore, en bloc resection without any biopsy and a hip hemiarthroplasty were performed. The pathological diagnosis was CCCS and an adequate surgical margin was obtained. No local recurrence or distant metastases were detected and postoperative function was excellent at the final follow-up. The femoral head is a typical location of CCCS. Wide resection with adequate margins is the main treatment strategy for CCCS and when radiological features are typical, en bloc resection without a biopsy is an acceptable treatment option to improve patient outcomes.

Late Lung Metastasis in a Patient with a Clear Cell Chondrosarcoma: An Indication for a Life-Long Follow-Up?

Background

Clear cell chondrosarcoma (CCCS) is a rare subtype of chondrosarcoma and comprises between 1.6% and 2.5% of all chondrosarcoma. They are known to be chemo- and radiotherapy resistant; surgical resection is therefore the therapy of choice.

Methods

We present a 63-year-old woman with a progressive lung nodule 20 years after initial diagnosis and treatment of a clear cell chondrosarcoma of the right os naviculare.

Results

On serial CT scans of the chest, an asymptomatic, slowly growing nodule in the left upper lung lobe was detected. CT-guided transthoracic biopsy of this nodule confirmed the diagnosis of a chondrosarcoma lung metastasis. Video-assisted thoracoscopic wedge resection was performed with complete removal of the nodule. The patient recovered well from surgery and remains in good health during further follow-up.

Conclusion

Given the tendency of clear cell chondrosarcoma to recur and metastasize after extended periods of time, a long-term, possibly life-long follow-up and clinical surveillance is advisable in these patients.

Malignant Cartilage-Forming Tumors

Chondrosarcomas are heterogeneous matrix-producing cartilaginous neoplasms with variable clinical behavior. Subtypes include conventional (75%), dedifferentiated (10%), clear cell (2%), mesenchymal (2%), and periosteal chondrosarcoma (<1%). Tumor location and primary vs secondary also play a role. In conventional chondrosarcoma, histologic grading (I, II, and III) remains the gold standard for predicting recurrence and metastases. Due to the locally aggressive but overall nonmetastatic behavior, grade I chondrosarcomas (primary and secondary) of long and short tubular bones have been reclassified as atypical cartilaginous tumor. In this review, the pathologic features of malignant cartilage tumors are discussed with updates on recent genetic findings.

Condrosarcoma de células claras en tibia proximal. Reporte de caso

Introducción. El condrosarcoma de células claras es un subtipo de tumor poco frecuente del grupo de los condrosarcomas de bajo grado. A diferencia de los condrosarcomas convencionales, estos tumores se presentan principalmente en epífisis de huesos largos. Dadas sus características líticas de aspecto quístico, pueden confundirse con quistes óseos, por lo que su diagnóstico debe hacerse por histopatología e inmunohistoquímica mediante biopsia. Igualmente, la negatividad para citoqueratinas y anticuerpos antiendomisio es una herramienta para descartar el diagnóstico diferencial de metástasis. Su tratamiento es quirúrgico, bien sea con manejo intralesional o resección completa con márgenes libres. Presentación del caso. Mujer de 46 años quien consultó al servicio de ortopedia oncológica de una institución de IV nivel de atención por un cuadro clínico de 8 meses de evolución consistente en dolor en la cara medial de la rodilla izquierda a nivel de la tibia proximaluna. Se practicaron imágenes diagnósticas que mostraron una lesión quística en el platillo tibial lateral; se ordenó biopsia de la lesión, y mediante histopatología e inmunohistoquímica se diagnosticó condrosarcoma de células claras. Se realizó un manejo quirúrgico con resección de la lesión con márgenes libres y una reconstrucción del defecto óseo con un aloinjerto estructural de tibia proximal, con lo cual se obtuvo una evolución satisfactoria. Conclusiones. Se presenta el caso de una paciente con un subtipo de condrosarcoma de bajo grado infrecuente en su presentación y localización, quien fue diagnosticada mediante inmunohistoquímica y tratada quirúrgicamente para lograr un salvamento exitoso de su extremidad.

Conventional Cartilaginous Tumors: Evaluation and Treatment

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Enchondromas are benign cartilaginous lesions that rarely require surgical intervention.

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Atypical cartilaginous tumors (ACTs), also referred to as grade-1 chondrosarcomas, may be managed without any intervention or with extended intralesional curettage and bone-void filling.

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High-grade chondrosarcomas, or grade-2 and 3 chondrosarcomas, should be managed aggressively with wide resection.

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Chemotherapy and radiation do not currently play a role in the treatment of chondrosarcomas.

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Differentiating an enchondroma from an ACT and an ACT from a high-grade chondrosarcoma can be difficult and requires clinical experience, radiographic and advanced imaging, and possibly a biopsy. Ultimately, a multidisciplinary team that includes a musculoskeletal oncologist, a radiologist, and a pathologist is needed to make the most appropriate diagnosis and treatment plan for each patient.

Clear Cell Chondrosarcoma with Rib Cage Metastasis: Case Report

Clear cell chondrosarcoma is a rare histological subtype of chondrosarcoma, usually with a relatively non-aggressive clinical course. However, infrequently they may relapse and metastasize. We describe a case of a male patient, 53 years old, with rib cage metastases of a clear cell chondrosarcoma 11 years after the first surgical intervention, and review the literature.

Clear Cell Chondrosarcoma: Clinical Characteristics and Outcomes in 15 Patients

Background. Clear cell chondrosarcoma (CCC) represents less than 6% of all chondrosarcomas, and thus, our understanding of this rare entity is limited. Analyzing clinical characteristics and treatment patterns, thus increasing our knowledge, may improve treatment strategy. We review our institutional experience with 15 patients, including one case with dedifferentiation. Methods. A retrospective review was conducted in CCC patients treated at our institution from 1996 to 2015, with at least 2-year follow-up. Descriptive statistics and Kaplan–Meier survival analyses were performed. Results. Of 19 patients identified, 15 patients had at least 2-year follow-up and were included. The median age at diagnosis was 43 years. 80% were male. The most common presenting signs were pain (12 patients; 80%) and fracture (2 patients; 13.3%). The most common site was proximal femur (8 patients; 53%). All patients had MSTS Stage I disease. Primary treatment included wide resection in 10 patients (67%) and intralesional or marginal resection in 5 patients (33%). Three patients died of disease during the study period, 1 with dedifferentiation of recurrent CCC. The median time to death from disease was 15.3 years (95% CI: (14.2; NA)). The median time to either recurrence or death was 7.73 years for patients who had intralesional/marginal resection and 16.44 years for patients with wide resection (HR (wide vs. intralesional/marginal) = 0.21, 95% CI: (0.04; 1.18), $p=0.053$ ). The median time to recurrence or death was significantly shorter for patients not initially treated at a sarcoma center ( $p=0.01$ ). Conclusions. CCC is a rare entity, and our understanding of it is still evolving. We observed a higher recurrence rate for intralesional or marginal resection, and wide resection alone remains the mainstay of treatment. Better outcomes were observed in patients initially treated by trained musculoskeletal oncologists. Due to the propensity of CCC to recur decades after initial resection, lifelong surveillance is recommended.

What Factors Are Associated with Treatment Outcomes of Japanese Patients with Clear Cell Chondrosarcoma?

BACKGROUND

Clear cell chondrosarcoma is an extremely rare chondrosarcoma subtype; thus, its treatment outcomes and associated factors have not been widely studied. Knowing more about it is potentially important because clear cell chondrosarcomas are often misdiagnosed as other benign lesions and subsequently treated and followed inappropriately.

QUESTIONS/PURPOSES

(1) What are the patient- and tumor-related characteristics of clear cell chondrosarcoma? (2) What proportion of patients with clear cell chondrosarcoma initially had a misdiagnosis or a misleading initial biopsy result? (3) What is the survivorship of patients with clear cell chondrosarcoma free from death, local recurrence, and distant metastasis, and what factors are associated with greater survivorship or a reduced risk of local recurrence?

METHODS

Between 1985 and 2018, 12 Japanese Musculoskeletal Oncology Group (JMOG) hospitals treated 42 patients with a diagnosis of clear cell chondrosarcoma. All 42 patients had complete medical records at a minimum of 1 year or death, and were included in this multicenter, retrospective, observational study. No patients were lost to follow-up within 5 years of treatment but four were lost to follow-up greater than 5 years after treatment because their physicians thought their follow-up was sufficient. Clinical data were collected by chart review. The median (range) follow-up period was 69 months (2 to 392). In general, when a possibly malignant bone tumor was found on imaging studies, the histological diagnosis was made by biopsy before initiating treatment. Once the diagnosis had been made, the patients were treated by surgery only, complete resection if technically possible, because chondrosarcomas are known to be resistant to chemotherapy and radiotherapy. Unresectable tumors were treated with particle-beam radiation therapy. When patients with chondrosarcoma were referred after unplanned surgical procedures with inadequate surgical margins, immediate additional wide resection was considered before local recurrence developed. This diagnostic and treatment strategy is common to all JMOG hospitals and did not change during the study period. Primary wide resection was performed in 79% (33 of 42) patients, additional wide resection after initial inadequate surgery in 12% (five of 42), curettage and bone grafting in 5% (two of 42) patients, and radiotherapy was administered to 5% (two of 42). Surgical margins among the 40 patients who underwent surgery at JMOG hospitals were no residual tumor in 93% (37 of 42) of patients, microscopic residual tumor in 2% (one of 42), and macroscopic residual tumor or state after curettage or intralesional excision in 5% (two of 42). The oncological endpoints of interest were 5- and 10- year overall survival, disease-free survival, survival free of local recurrence, and survival free of distant metastases; these were calculated using the Kaplan-Meier method and compared using the log-rank test. Risk ratios with their respective 95% confidence intervals (CIs) were estimated in a Cox regression model. The Bonferroni adjustment was used for multiple testing correction.

RESULTS

The sex distribution was 74% men and 26% women (31 and 11 of 42, respectively), with a mean age of 47 ± 17 years. Eighty one percent (34 of 42) of tumors occurred at the ends of long bones, and the proximal femur was the most common site accounting for 60% (25 of 42). The mean size of the primary tumors was 6.3 ± 2.7 cm. Definite pathologic fractures were present in 26% (10 of 42) and another 26% (10 of 42) had extraskeletal involvement. None had metastases at presentation. Twenty four percent (six of 25) tumors in the proximal femur were misdiagnosed as benign lesions and treated inadequately without biopsy. Twenty nine percent (10 of 35) patients had initial misdiagnoses by biopsy and core needle biopsies had a greater risk of resulting in inaccurate histological diagnoses. The study patients' 5- and 10-year overall survival rates were 89% (95% CI 74 to 96) and 89% (95% CI 74 to 96), respectively; 5- and 10- year disease-free survival rates 77% (95% CI 58 to 89) and 57% (95% CI 36 to 75), respectively; 5- and 10-year local recurrence-free survival rates 86% (95% CI 68 to 95) and 71% (95% CI 49 to 86), respectively; and 5- and 10-year distant metastasis-free survival rates 84% (95% CI 67 to 93) and 74% (95% CI 53 to 88), respectively. Notably, bone metastases (17%, seven of 42) were as common as pulmonary metastases (14%, six of 42); four patients developed both bone and pulmonary metastases. The difference between 10-year overall survival rates and 10-year disease-free survival indicated very late recurrence more than 5 years after the initial treatment. After controlling for multiple comparisons, the only factor we found that was associated with local recurrence-free survival was initial treatment (positive margin versus primary wide resection) (risk ratio 8.83 [95% CI 1.47 to 53.1]; p = 0.022 after the Bonferroni adjustment). Additional wide resection reduced the risk of local recurrence.

CONCLUSIONS

The femoral head was the most common location of clear cell chondrosarcoma and had a high risk of misdiagnosis as common benign lesions that resulted in initial inadequate surgery and a consequent high risk of local recurrence. Immediate additional wide resection should be considered in patients who had initial inadequate surgery to reduce the risk of local recurrence. Because clear cell chondrosarcoma can recur locally or distantly in the bones and lungs in the long term, patients should be informed of the risk of very late recurrence and the necessity of decades-long with surveillance for local recurrence and lung and bone metastases.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Clear cell chondrosarcoma of proximal femur: a rare entity with diagnostic dilemma

Clear cell chondrosarcoma is an extremely rare malignant neoplasm. The rarity and slow-growing nature of this tumour often lead to prolonged symptoms and also initial misdiagnosis with benign lesions such as chondroblastoma. It can also be confused with avascular necrosis of the femoral head when the lesion is located in the femoral head, as was in the case we report. The patient was kept on observation and conservative treatment for almost 9 years before the correct diagnosis and appropriate treatment. Wide local resection with negative margins forms the mainstay of treatment since intralesional procedures predispose to high local recurrence rate. A prolonged follow-up is recommended since late local recurrences and metastases are common.

Clear-cell chondrosarcomas: Fine-needle aspiration cytology, radiological findings, and patient demographics of a rare entity

BACKGROUND

Clear-cell chondrosarcomas (CCCSs) constitute a very rare subtype of chondrosarcoma. CCCS may radiologically mimic chondroblastoma, and given the difference in surgical approach, it is important to distinguish these two entities preoperatively.

DESIGN

Using the institutional digital records, we identified histologically verified CCCS between 1996 and 2013, where preoperative fine-needle aspiration (FNA) cytology was available. Clinical characteristics were categorized and described, and FNAs were reviewed by a panel of senior cytopathologists. In addition, corresponding radiological imaging was reviewed by senior radiologists, and a literature review on CCCS and chondroblastoma was conducted.

RESULTS

A total of seven CCCS FNAs were identified from six patients. The cytomorphology showed low to intermediate cellular smears of clusters and single round or oval tumor cells. Tumor cells had rounded (sometimes binucleated) nuclei with limited pleomorphism and rich vacuolated cytoplasm. Chondroid background matrix was always found. While CCCS patients had a significantly higher age at diagnosis compared to chondroblastoma, no age cut-off would distinctly separate the two.

CONCLUSIONS

CCCS has distinguished cytomorphological features on FNA smears. CCCS should be considered as a possible differential diagnosis in adults (>25 years) with a radiological suspicion of chondroblastoma. Since radiology and patient age cannot conclusively distinguish CCCS from chondroblastoma, FNA may prove an important tool for correct preoperative diagnosis of CCCS.

Clear cell chondrosarcoma is an underestimated tumor: Report of 7 cases and meta-analysis of the literature

Introduction

Clear cell chondrosarcoma (CCC) is a rare subtype of chondrosarcoma and it is commonly considered a low-grade tumor and less aggressive than atypical cartilaginous tumor (grade 1 central chondrosarcoma). However, the experience even of musculoskeletal tumor centres with this rare entity is limited. The aim of this study is to analyse our own treatment results and those of the literature regarding the therapy and outcome of this lesion.

Material and Methods

7 cases of CCC have been treated in our department between 2003 and 2015. Their follow-up data were collected retrospectively. 187 literature cases with histopathological and clinical characteristics were retrieved by means of a PubMed search with the key word “clear cell chondrosarcoma”. The data pertaining to treatment and follow up were extracted. We analysed the survival of patient and the risk factors for local recurrence (LR) as well as metastatic disease (MD).

Results

The mean age at the time of diagnosis was 40 years. Two thirds of the patients were male. The mean follow-up time was 109 months. To our surprise, there was a high rate of LR (30%) and of MD (20%) when compared to low-grade conventional chondrosarcomas. 15% of LR and 20% of metastatic disease were observed after more than 10 years follow-up. Uncommon locations of MD such as in the spine is a unique observation in chondrosarcomas and underlines the high aggressiveness of this tumor. 10-year overall survival was almost 80%, 10-years disease free survival 60%. Positive margins (p = 0.038) and metastases (p = 0.006) impaired the overall survival significantly. The rate of local recurrence was significantly dependent on resection margin (p < 0.001); however there was no correlation with the grade of differentiation of the tumor. The development of MD was affected by local recurrence (p = 0.006), but we could not detect a significant association with margin status (p = 0.184).

Conclusions

A wide resection is the advocated treatment option. Long term follow-up for at least 10 years is necessary in order to not overlook late LR or MD. This work demonstrates for the first time the apparent aggressiveness of the CCC.

Delayed Reconstruction by Total Calcaneal Allograft following Calcanectomy: Is It an Option?

Many options are available in literature for the management of delayed reconstruction following calcanectomy. In cases of low-grade tumor lesions, conservative surgery can be considered. We describe a case of delayed reconstruction by calcaneal allograft after calcanectomy for low-grade chondrosarcoma. At 12-month follow-up, the patient had no pain; MSTS score and AOFAS score were satisfactory. Subtalar nonunion was observed with no secondary displacement or graft necrosis. The aim of conservative treatment for this patient was to restore normal gait with plantigrade locomotion and function of the Achilles tendon. Calcaneal reconstruction by total allograft is an alternative approach following calcanectomy for calcaneal tumors. We also discussed other options of calcaneal reconstruction.

The biology and management of cartilaginous tumors: a role for targeting isocitrate dehydrogenase

Chondrosarcomas are rare mesenchymal neoplasms defined by the production of abnormal cartilaginous matrix. Conventional chondrosarcoma is the most common histology. The management of primary conventional chondrosarcoma generally is surgical with the possible addition of radiation therapy. Treatment of conventional chondrosarcoma is problematic in unresectable or metastatic disease because the tumors tend to be resistant to standard sarcoma chemotherapy regimens. Previous attempts at targeted therapy, including inhibitors of Hedgehog signaling, the mTOR pathway, and platelet-derived growth factor receptor (PDGFR) have been largely disappointing. However, heterozygous mutations in isocitrate dehydrogenase (IDH) enzymes recently have been identified in chondrogenic neoplasms, with mutations reported in approximately 87% of benign enchondromas, 70% of conventional chondrosarcomas, and 54% of dedifferentiated chondrosarcomas. The normal IDH protein continues to produce alpha-ketoglutarate (alpha-KG) whereas the mutant IDH protein converts KG to the oncometabolite 2-hydroxyglutarate (2-HG). Clinical trials of novel IDH inhibitors are ongoing, with evidence of early activity in IDH-mutant leukemias. IDH inhibitors show antitumor effects against IDH-mutant chondrosarcoma cell lines, supporting the inclusion of patients with chondrosarcoma with IDH mutations on IDH inhibitor clinical trials for solid tumors. Targeting IDH mutations may offer hope of a novel antineoplastic strategy not only for patients with chondrosarcomas, but also for other solid tumors with aberrant IDH activity.

An unusual case of clear cell chondrosarcoma with very late recurrence and lung metastases, 29 years after primary surgery

Clear cell chondrosarcoma is a rare bone neoplasm with low-grade clinical course and the potential to metastasize to the skeleton and lungs. The aim of this report is to present a case that is extremely rare, but in accordance with the literature where the clear cell chondrosarcoma reportedly has a tendency for late metastases. In our patient the primary surgery was intralesional, since it was mistakenly interpreted as a benign tumour in the early 80s. The local recurrence and lung metastases occurred, however, 29 years after the initial treatment. The local recurrence was resected with wide margins, no additional surgery or oncological treatments were given, and two and half years postoperatively patient is doing well and there is no progression in the disease. In conclusion, it is important to have a long follow-up to the clear cell chondrosarcoma patients even for decades or lifelong, because the malignancy tends to metastasize or recur after an extended period. The course of metastasized disease may be unusually slow, so relatively aggressive treatment in metastasized and recurring cases is justified.

Chondrosarcoma of bone

Chondrosarcoma is a cartilage forming neoplasm, which is the second most common primary malignancy of bone. Clinicians who treat chondrosarcoma patients must determine the grade of the tumor, and must ascertain the likelihood of metastasis. Acral lesions are unlikely to metastasize, regardless of grade, whereas axial, or more proximal lesions are much more likely to metastasize than tumors found in the distal extremities with equivalent histology. Chondrosarcoma is resistant to both chemotherapy and radiation, making wide local excision the only treatment. Local recurrence is frequently seen after intralesional excision, thus wide local excision is sometimes employed despite significant morbidity, even in low-grade lesions. Chondrosarcoma is difficult to treat. The surgeon must balance the risk of significant morbidity with the ability to minimize the chance of local recurrence and maximize the likelihood of long-term survival.

The imaging of cartilaginous bone tumours. II. Chondrosarcoma

Chondrosarcoma is the third most common primary malignant bone tumour. There are various histological subtypes of chondrosarcomas, of which conventional intramedullary chondrosarcoma is by far the most common. Rarer sub-types include clear cell chondrosarcoma, myxoid chondrosarcoma, mesenchymal chondrosarcoma and dedifferentiated chondrosarcoma. Chondrosarcoma is also classified into central, peripheral and periosteal, dependent upon the lesion site, and into primary chondrosarcoma if the lesion arises de novo and secondary chondrosarcoma if the tumour arises in a pre-existing lesion. The various subtypes of chondrosarcoma have characteristic imaging features that may aid diagnosis and may guide biopsy, therefore potentially preventing misdiagnosis. The aim of this article is to provide an overview of the pertinent clinical and imaging findings of the different forms of chondrosarcoma.

Clear cell chondrosarcoma of the head and neck

Clear cell chondrosarcoma is a rare variant of chondrosarcoma that mostly involves the end of long bones. However, nine cases have been reported in the head and neck: four in larynx, two in nasal septum, two in maxilla and one in the skull. These cases form the basis of this review. Head and neck cases accounts for less than 5% of Clear cell chondrosarcomas in the whole body and the larynx is the most common place. The histological findings of head and neck cases are consistent with general features of this entity in the whole body and nearly all tumors in this case series had a component of conventional chondrosarcoma. Clear cell chondrosarcoma is an intracompartmental tumor and retains "Grenz zone" just beneath the epithelium. Therefore, the overlying mucosa remained intact in all laryngeal cases. Nasal tumor caused ballooning of the septum and the maxillary lesion did not involve the oral mucosa. This tumor presents various radiographic features in the head and neck area. Chondroblastoma, chondroma, osteoblastoma, osteosarcoma and metastatic renal cell carcinoma are included in the histologic differential diagnoses. Differentiation from chondroblastic osteosarcoma is important in the maxilla. A wide resection is adequate in most cases. However, some laryngeal cases show tendency to recur. Clear cell chondrosarcoma is a slow growing tumor and this necessitates a long time follow-up of patients. Due to the extreme rarity in the head and neck, diagnosis of Clear cell chondrosarcoma in this area, must be confirmed by histochemical and immunohistochemical studies.

Chondrosarcomas revisited

Chondrosarcomas are malignant bone tumors with pure hyaline cartilage differentiation; myxoid changes, calcification, or ossification may be present. Several subtypes of chondrosarcomas exist. Behavior patterns vary, ranging from slow-growing nonmetastasizing lesions to aggressive metastasizing sarcomas. Symptoms are usually mild, with duration ranging from several months to years, and usually consist of persistent, dull, aching pain or palpable masses. Radiographic findings include bone expansion with cortical thickening, radiolucent areas with variably distributed punctate or ring-like matrix calcifications, cortical erosion or destruction, endosteal scalloping, and scant or absent periosteal reaction; extension into the soft tissue may be present. Histological differential diagnosis from benign cartilaginous lesions can be achieved by increased cellularity, enlarged plump nuclei, binucleated cells, hyperchromatic nuclear pleomorphism, and permeation of cortical or medullary bone. Atypia is usually mild to moderate; necrosis and mitoses can be seen, particularly in high-grade lesions. Adequate surgery is the mainstay of treatment. High-grade and pelvic chondrosarcomas are best managed with wide resection. Because of the low metastatic potential and low local recurrence rate noted with intralesional surgery, low-grade chondrosarcomas can be treated with curettage (with or without treatment of the defect cavity) with a local adjuvant, such as phenol or cryotherapy. Adjuvant chemotherapy may be considered for mesenchymal and dedifferentiated chondrosarcomas. Radiation therapy can be considered after incomplete resection or if resection is not feasible or would cause unacceptable morbidity.

Chondrosarcoma Variants

This article presents a review of chondrosarcoma variants, with a focus on the extraordinarily rare variants of chondrosarcoma in which hyaline cartilage is not the dominant feature. Discussed are the differential diagnoses for these neoplasms, radiologic studies, gross and microscopic features, and prognosis. Summaries are provided of the key features for the major variants.

Clear cell chondrosarcoma of bone: long time follow-up of 18 cases

INTRODUCTION

Clear cell chondrosarcoma is a variant of conventional chondrosarcoma behaving as low grade malignant bone tumor. We reviewed our cases of clear cell chondrosarcoma with the aim to assess the best diagnostic and curative approach to this rare tumor.

MATERIALS AND METHODS

We report 18 cases of clear cell chondrosarcoma treated at the authors' institution. Pertinent clinical information, pre and postoperative serum alkaline phosphatase (SAP) level were obtained from the patients charts. Available imaging studies including plain roentgenograms, computed tomography (CT) images (in 6 patients) and magnetic resonance imaging (MRI) images (in 2 patients).

RESULTS

Eight cases were firstly treated in other institutions, seven with one or more curettage, while one, presented with pathologic fracture, was treated with repeated osteosynthesis. Of the seven patients treated with curettage, five were referred with local recurrence, the mean time between surgical treatment and local recurrence was 52.2 months (from 12 to 132). The other two patients were curetted out 4 and 1 month before, respectively, and were then referred to us to decide about further treatment after incidental diagnosis. Of these cases, three (37.5%) recurred again after our treatment and two of them presented with late bone metastases. Eight patients were originally treated with wide (six) or marginal (two) surgical margins by us. Among them only one proximal humerus (wide margins) had local recurrence 26 months from the first operation. Two patients underwent curettage in our institution, and one of them had a local recurrence. Pre-operative SAP level were obtained in 17 patients. Among them, 11 patients had high pre-operative SAP level (64.7%) and 6 cases were normal. Post-operative SAP levels were obtained in nine patients. After removal of the tumors; SAP levels decreased to normality in seven of the nine patients with high pre-operative SAP. In the other two patients, although the SAP levels were normal, post-operative SAP levels were decreased.

CONCLUSION

Serum alkaline phosphatase can be used as a good tumor marker in diagnosis and follow-up. Due to the occurrence of local recurrences and distant metastasis after curettage, we suggest surgical treatment with "en bloc" resection from the first presentation.

Update on chondrosarcomas

PURPOSE OF REVIEW

This paper reviews recent molecular, biologic, developmental therapeutic, and clinical findings in conventional and variant chondrosarcomas.

RECENT FINDINGS

The prognosis of chondrosarcomas traditionally correlates with histologic grade and adequacy of surgery. Newer markers of cell differentiation, activation, genetics, and cell signaling may offer important prognostic information. Translational research has validated platelet-derived growth factor receptor, estrogen signaling, matrix metalloproteinase-1, histone deacetylase, methylthioadenosine phosphorylase, and vascular endothelial growth factor-A as potential therapeutic targets. Bisphosphonates may also possess important antitumoral effects. Molecular studies have established that extraskeletal myxoid chondrosarcoma is a unique entity defined by the presence of a fusion gene between the orphan nuclear receptor, CHN/NOR1, and a promiscuous partner, most commonly EWSR1. Clinical studies have shown that development of second malignancies is an uncommon but real risk for chondrosarcoma survivors; the benefit of chemotherapy for dedifferentiated chondrosarcomas remains questionable; and late recurrences of clear cell chondrosarcomas emphasize the need for long-term follow up.

SUMMARY

Chondrosarcomas are a heterogeneous group of bone and soft tissue tumors. Recent advances in molecular diagnostics, pathobiology, and developmental therapeutics will aid both scientists and clinicians in improving the classification and therapy of this diverse family of cartilaginous tumors.

Chordoma and chondrosarcoma: Similar, but quite different, skull base tumors

BACKGROUND

Chordoma and chondrosarcoma of the skull base are frequently amalgamated because of similar anatomic location, clinical presentation, and radiologic findings. The chondroid chordoma variant has been reported to carry a better prognosis. The objective of the current study was to investigate the distinctions between these 3 entities.

METHODS

The data concerning 109 patients with chordoma, chondroid chordoma, and chondrosarcoma who were treated by a single surgeon with maximum surgical resection and frequently by adjunct proton beam radiotherapy between 1990 and 2006 were analyzed retrospectively. Pathologic distinction was established by cytokeratin and epithelial membrane antigen staining. Clinical, radiologic, pathologic, and cytogenetic studies were analyzed in relation to disease recurrence and death.

RESULTS

The average follow-up was 48+/-37.5 months (range, 1-191 months). There were no reliable distinguishing clinical or radiologic features noted between the groups. Chondrosarcoma patients had a significantly better outcome compared with chordoma patients with regard to survival and recurrence-free survival (P=.028 and P<.001, respectively), whereas patients with chondroid chordoma had a poor outcome similar to chordoma patients with regard to survival and recurrence-free survival (P=.337 and P=.906, respectively).

CONCLUSIONS

Chordoma and chondrosarcoma differ with regard to their origin and histology, and differ markedly with regard to outcome. Chondroid chordomas behave in a manner that is clinically similar to chordomas, with the same prognosis. Both chordoma types demonstrate an aggressive clinical course and poor outcome after disease recurrence. The optimal treatment for all groups of patients involves radical surgical resection followed by high-dose radiotherapy in patients with chordomas. Radiotherapy may not be necessary in patients with low-grade chondrosarcoma.

Aggressive clear cell chondrosarcomas: do distinctive characteristics exist?: a report of 4 cases

CONTEXT

Clear cell chondrosarcoma (CCC) is commonly considered to be a low-grade subtype of chondrosarcoma. However, a few cases of CCC behave as high-grade lesions (with early metastases or multiple/synchronous locations).

OBJECTIVE

To investigate morphologic features that can help predict the aggressiveness of these CCCs.

DESIGN

To investigate possible hallmarks of this aggressiveness, we are presenting the clinicopathologic features of 6 cases of CCC, 4 of which presented aggressive features and 2 low-grade behavior. The patients were 5 men and 1 woman; their ages ranged from 22 to 47 years. Histologic appearance, ultrastructure, and immunohistochemical expression of metalloproteinase 1 and 2 and their inhibitors were evaluated in all 6 cases.

RESULTS

Pain was the most common symptom; the lesions were located in the femur (4), humerus (2), and vertebral body (1), with 1 patient presenting a double/synchronous lesion. Although no major differences were detected using conventional light microscopy, an ultrastructural analysis--at variance with usual cases--showed a lack of superficial microvilli in more than 50% of neoplastic cells in the aggressive cases, therefore suggesting a less differentiated phenotype. In addition, metalloproteinase 2 was more diffusely expressed in the aggressive tumors than in the conventional CCCs, whereas p53 labeling was always negative.

CONCLUSIONS

The aggressive behavior of some CCCs may be, at least in part, correlated to a lesser degree of cell differentiation and to the expression of tumor cell proteins, such as metalloproteinase 2, which are able to favor neoplastic spreading.