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

Imaging of skull base pathologies: Role of advanced magnetic resonance imaging techniques

Imaging plays a vital role in evaluation of skull base pathologies as this region is not directly accessible for clinical evaluation. Computerized tomography (CT) and magnetic resonance imaging (MRI) have played complementary roles in the diagnosis of the various neoplastic and non-neoplastic lesions of the skull base. However, CT and conventional MRI may at times be insufficient to correctly pinpoint the accurate diagnosis. Advanced MRI techniques, though difficult to apply in the skull base region, in conjunction with CT and conventional MRI can however help in improving the diagnostic accuracy. This article aims to highlight the importance of advanced MRI techniques like diffusion-weighted imaging, susceptibility-weighted imaging, perfusion-weighted imaging, and MR spectroscopy in differentiation of various lesions involving the skull base.

Adjuvant Stereotactic Radiosurgery and Radiation Therapy for the Treatment of Intracranial Chordomas

Objective Chordomas are locally aggressive, highly recurrent tumors requiring adjuvant radiotherapy following resection for successful management. We retrospectively reviewed patients treated for intracranial chordomas with adjuvant stereotactic radiosurgery (SRS) and stereotactic radiation therapy (SRT). Methods A total of 57 patients underwent 83 treatments at the UCLA Medical Center between February 1990 and August 2011. Mean follow-up was 57.8 months. Mean tumor diameter was 3.36 cm. Overall, 8 and 34 patients received adjuvant SRS and SRT, and the mean maximal dose of radiation therapy was 1783.3 cGy and 6339 cGy, respectively. Results Overall rate of recurrence was 51.8%, and 1- and 5-year progression-free survival (PFS) was 88.2% and 35.2%, respectively. Gross total resection was achieved in 30.9% of patients. Adjuvant radiotherapy improved outcomes following subtotal resection (5-year PFS 62.5% versus 20.1%; p = 0.036). SRS and SRT produced comparable rates of tumor control (p = 0.28). Higher dose SRT (> 6,000 cGy) (p = 0.013) and younger age (< 45 years) (p = 0.03) was associated with improved rates of tumor control. Conclusion Adjuvant radiotherapy is critical following subtotal resection of intracranial chordomas. Adjuvant SRT and SRS were safe and improved PFS following subtotal resection. Higher total doses of SRT and younger patient age were associated with improved rates of tumor control.

Genetic characterization of skull base chondrosarcomas

OBJECT

Although chondrosarcomas rarely arise in the skull base, chondrosarcomas and chordomas are the 2 major malignant bone neoplasms occurring at this location. The distinction of these 2 tumors is important, but this distinction is occasionally problematic because of radiological and histological overlap. Unlike chordoma and extracranial chondrosarcoma, no case series presenting a whole-genome analysis of skull base chondrosarcomas (SBCSs) has been reported. The goal of this study is to clarify the genetic characteristics of SBCSs and contrast them with those of chordomas.

METHODS

The authors analyzed 7 SBCS specimens for chromosomal copy number alterations (CNAs) using comparative genomic hybridization (CGH). They also examined IDH1 and IDH2 mutations and brachyury expression.

RESULTS

In CGH analyses, the authors detected CNAs in 6 of the 7 cases, including chromosomal gains of 8q21.1, 19, 2q22-q32, 5qcen-q14, 8q21-q22, and 15qcen-q14. Mutation of IDH1 was found with a high frequency (5 of 7 cases, 71.4%), of which R132S was most frequently mutated. No IDH2 mutations were found, and immunohistochemical staining for brachyury was negative in all cases.

CONCLUSIONS

To the best of the authors' knowledge, this is the first whole-genome study of an SBSC case series. Their findings suggest that these tumors are molecularly consistent with a subset of conventional central chondrosarcomas and different from skull base chordomas.

Endoscopic endonasal surgical management of chondrosarcomas with cerebellopontine angle extension

OBJECT

Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions.

METHODS

Analysis of the authors' database yielded 19 cases of skull base chondrosarcomas; among these were 5 cases with predominant CPA involvement. The electronic medical records of the 5 patients were retrospectively reviewed for age, sex, presentation, pre- and postoperative imaging, surgical technique, pathology, and follow-up. These cases were used to illustrate the surgical nuances involved in the endonasal resection of CPA chondrosarcomas.

RESULTS

The male/female ratio was 1:4, and the patients' mean age was 55.2 ±11.2 years. All cases involved petrous bone and apex, with variable extensions to the posterior fossa and parapharyngeal space. The main clinical scenario was cranial nerve (CN) palsy, evidenced by diplopia (20%), ptosis (20%), CN VI palsy (20%), dysphagia (40%), impaired phonation (40%), hearing loss (20%), tinnitus (20%), and vertigo/dizziness (40%). Gross-total resection of the CPA component of the tumor was achieved in 4 cases (80%); near-total resection of the CPA component was performed in 1 case (20%). Two patients (40%) harbored high-grade chondrosarcomas. No patient experienced worsening neurological symptoms postoperatively. In 2 cases (40%), the symptoms were completely normalized after surgery.

CONCLUSIONS

Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.

Intracranial chordoma presenting as acute hemorrhage in a child: Case report and literature review

Background:

Chordomas are rare, slow-growing malignant neoplasms derived from remnants of the embryological notochord. Pediatric cases comprise only 5% of all chordomas, but more than half of the reported pediatric chordomas are intracranial. For patients of all ages, intracranial chordomas typically present with symptoms such as headaches and progressive neurological deficits occurring over several weeks to many years as they compress or invade local structures. There are only reports of these tumors presenting acutely with intracranial hemorrhage in adult patients.

Case Description:

A 10-year-old boy presented with acute onset of headache, emesis, and diplopia. Head computed tomography and magnetic resonance imaging of brain were suspicious for a hemorrhagic mass located in the left petroclival region, compressing the ventral pons. The mass was surgically resected and demonstrated acute intratumoral hemorrhage. Pathologic examination was consistent with chordoma.

Conclusion:

There are few previous reports of petroclival chordomas causing acute intracranial hemorrhage. To the authors’ knowledge, this is the first case of a petroclival chordoma presenting as acute intracranial hemorrhage in a pediatric patient. Although uncommon, it is important to consider chordoma when evaluating a patient of any age presenting with a hemorrhagic lesion of the clivus.

Chordoma and chondrosarcoma

Chordoma and chondrosarcoma represent 2 fundamentally different and challenging central skull base pathologies. Both are largely surgical diseases with varying outcomes based on completeness of resection. Adjuvant therapy is controversial, although radiation therapy is commonly employed postoperatively, and stereotactic radiosurgery is used either in primary management or treatment of local progression.

Bilateral chondrosarcoma of the jugular foramen: literature review and personal experience

Chondrosarcomas (CS) are slow-growing malignant cartilaginous tumors with locally invasive behavior. They account for only 0.15% head and neck neoplasia. There have been no reports in the management of bilateral skull base CS in the literature to date. The synchronous presentation of bilateral CS of the jugular foramen (JF) was diagnosed in a 22-year-old woman with right abducens nerve palsy. Once evaluated the collateral intracranial venous discharge, the lesions were removed in two surgical stages through a bilateral petro-occipital trans-sigmoid (POTS) approach performing a bilateral closure of sigmoid sinus. The patient is disease free 15 years after surgery. No complications occurred. Diplopia improved after excision of the tumor on the right side. A review of relevant English literature was performed. The POTS approach to the JF proved to be safe and effective. Staged radical surgery alone, assessing intracranial venous flow at all stages of surgery, was a valid strategy for bilateral CS, achieving long-term disease control, avoiding early adjuvant radiotherapy, and carrying no complications.

Sarcoma excision and pattern of complicating sensory neuropathy

A potential complication of sarcoma excision surgery is a sensory neurological dysfunction around the surgical scar. This study utilised both objective and subjective sensation assessment modalities, to evaluate 22 patients after sarcoma surgery, for a sensory deficit. 93% had an objective sensory deficit. Light touch is less likely to be damaged than pinprick sensation, and two-point discrimination is significantly reduced around the scar. Results also show that an increased scar size leads to an increased light touch and pinprick deficit and that two-point discriminatory ability around the scar improves as time after surgery elapses. 91% had a subjective deficit, most likely tingling or pain, and numbness was most probable with lower limb sarcomas. Results also demonstrated that there were no significant relationships between any specific subjective and objective deficits. In conclusion, sensory disturbance after sarcoma surgery is common and debilitating. Efforts to minimize scar length are paramount in the prevention of sensory deficit. Sensation may also recover to an extent; thus, sensory reeducation techniques must become an integral aspect of management plans. Finally to obtain a comprehensive assessment of sensory function, both objective and subjective assessment techniques must be utilised.

Skull base chordoma and chondrosarcoma: influence of clinical and demographic factors on prognosis: a SEER analysis

OBJECTIVE

Chordomas and chondrosarcomas are rare skull base tumors, with similar radiographic and clinical presentations. We investigated factors influencing long-term survival in these 2 tumors using the Surveillance Epidemiology and End Results (SEER) database.

METHODS

Patients with chordoma (n = 416) and chondrosarcoma (n = 269) within the skull base from 1983 to 2009 were identified within the SEER database. Kaplan-Meier curves and Cox proportional hazards models were used to test associations with survival. t tests and χ(2) tests were used to compare groups.

RESULTS

Chordoma and chondrosarcoma patients were similar demographically. Survival at 5 years was 65% for chordomas and 81.8% (P < 0.0001) for chondrosarcomas and at 10 years was 32.3% and 49.5% (P = 0.004). Multivariate analysis demonstrated chordomas had a worse prognosis even when we controlled for age and tumor size (hazard ratio 3.0, 95% confidence interval 1.9-4.7, P < 0.0001). For chordomas, multivariate analysis demonstrated increasing age and tumor size were significantly associated with reduced survival. For chondrosarcomas, multivariate analysis demonstrated older age, earlier decade of diagnosis, and mesenchymal subtype were significantly associated with reduced survival. Postoperative radiation was given to 42% and 41% of patients with chordomas and chondrosarcomas, respectively. The addition of radiation did not improve survival.

CONCLUSION

Consistent with previous case series, skull base chordomas have significantly worse prognosis than chondrosarcomas. Patients in the SEER database had worse survival overall compared with existing case series for both chordomas and chondrosarcomas, suggesting selection bias in the existing literature.

Male sex as a risk factor for the clinical course of skull base chordomas

Object

Chordomas of the skull base are rare and locally invasive and have a poor prognosis. The aim of this retrospective multicenter study was to evaluate the current pattern of care and clinical course and to identify prognostic factors.

Methods

A total of 47 patients (26 men; mean age 48.5 years) treated in 5 centers were included. Histology was centrally reviewed; additionally, semiquantitative N- and E-cadherin expression analysis was performed. Prognostic factors were obtained from multivariate regression models. For survival analysis the Kaplan-Meier method was used.

Results

The median follow-up period was 5.2 years. Complete resection, incomplete resection, and extended biopsy were performed in 14.9%, 80.9%, and 4.3% of patients, respectively. Surgical morbidity was not associated with extent of resection. Adjuvant radiation therapy was performed in 30 (63.8%) of 47 patients. The median progression-free survival (PFS) was 7.3 years. Complete resection prolonged median overall survival (OS) (p = 0.04). Male patients presented with worse PFS (4.8 years vs 9.8 years; p = 0.04) and OS (8.3 years vs not reached; p = 0.03) even though complete resection was exclusively achieved in the male subpopulation. Multivariate analysis confirmed male sex as the most important risk factor for tumor progression (p = 0.04) and death (p = 0.02). Age, duration of symptoms, initial Karnofsky Performance Scale score, brainstem compression, involvement of the petrous bone, infiltration of the dura mater, modality and dose of radiation therapy, and the E- and N-cadherin expression patterns did not gain prognostic relevance.

Conclusions

In skull base chordomas, male patients bear a higher risk of progressive disease and death. Male patients might benefit from more aggressive adjuvant therapy and/or from a closer follow-up schedule.

[Chordoma]

PURPOSES

To review in the literature, all the epidemiological, clinical, radiological, histological and therapeutic data regarding chordomas as well as various notochordal entities: ecchordosis physaliphora, intradural and intraparenchymatous chordomas, benign notochordal cell tumors, parachordomas and extra-axial chordomas. To identify different types of chordomas, including familial forms, associations with tuberous sclerosis, Ollier's disease and Maffucci's syndrome, forms with metastasis and seeding. To assess the recent data regarding molecular biology and progress in targeted therapy. To compare the different types of radiotherapy, especially protontherapy and their therapeutic effects. To review the largest series of chordomas in their different localizations (skull base, sacrum and mobile spine) from the literature.

MATERIALS

The series of 136 chordomas treated and followed up over 20 years (1972-2012) in the department of neurosurgery at Lariboisière hospital is reviewed. It includes: 58 chordomas of the skull base, 47 of the craniocervical junction, 23 of the cervical spine and 8 from the lombosacral region. Similarly, 31 chordomas in children (less than 18 years of age), observed in the departments of neurosurgery of les Enfants-Malades and Lariboisière hospitals, are presented. They were observed between 1976 and 2010 and were located intracranially (n=22 including 13 with cervical extension), 4 at the craniocervical junction level and 5 in the cervical spine.

METHODS

In the entire Lariboisière series and in the different groups of localization, different parameters were analyzed: the delay of diagnosis, of follow-up, of occurrence of metastasis, recurrence and death, the number of primary patients and patients referred to us after progression or recurrence and the number of deaths, recurrences and metastases. The influence of the quality of resection (total, subtotal and partial) on the prognosis is also presented. Kaplan-Meier actuarial curves of overall survival and disease free survival were performed in the entire series, including the different groups of localization based on the following 4 parameters: age, primary and secondary patients, quality of resection and protontherapy. In the pediatric series, a similar analysis was carried-out but was limited by the small number of patients in the subgroups.

RESULTS

In the Lariboisière series, the mean delay of diagnosis is 10 months and the mean follow-up is 80 months in each group. The delay before recurrence, metastasis and death is always better for the skull base chordomas and worse for those of the craniocervical junction, which have similar results to those of the cervical spine. Similar figures were observed as regards the number of deaths, metastases and recurrences. Quality of resection is the major factor of prognosis with 20.5 % of deaths and 28 % of recurrences after total resection as compared to 52.5 % and 47.5 % after subtotal resection. This is still more obvious in the group of skull base chordomas. Adding protontherapy to a total resection can still improve the results but there is no change after subtotal resection. The actuarial curve of overall survival shows a clear cut in the slope with some chordomas having a fast evolution towards recurrence and death in less than 4 years and others having a long survival of sometimes more than 20 years. Also, age has no influence on the prognosis. In primary patients, disease free survival is better than in secondary patients but not in overall survival. Protontherapy only improves the overall survival in the entire series and in the skull base group. Total resection improves both the overall and disease free survival in each group. Finally, the adjunct of protontherapy after total resection is clearly demonstrated. In the pediatric series, the median follow-up is 5.7 years. Overall survival and disease free survival are respectively 63 % and 54.3 %. Factors of prognosis are the histological type (atypical forms), localization (worse for the cervical spine and better for the clivus) and again it will depend on the quality of resection.

CONCLUSIONS

Many different pathologies derived from the notochord can be observed: some are remnants, some may be precursors of chordomas and some have similar features but are probably not genuine chordomas. To-day, immuno-histological studies should permit to differentiate them from real chordomas. Improving knowledge of molecular biology raises hopes for complementary treatments but to date the quality of surgical resection is still the main factor of prognosis. Complementary protontherapy seems useful, especially in skull base chordomas, which have better overall results than those of the craniocervical junction and of the cervical spine. However, we are still lacking an intrinsic marker of evolution to differentiate the slow growing chordomas with an indolent evolution from aggressive types leading rapidly to recurrence and death on which more aggressive treatments should be applied.

Skull base chondrosarcomas: surgical treatment and results

OBJECTIVES

We describe our experience in the management of patients with skull base chondrosarcoma, an uncommon neoplasm of the skull base.

METHODS

Thirteen cases of surgically treated skull base chondrosarcomas were identified. The patients' follow-ups ranged from 7 to 86 months (mean, 47 months).

RESULTS

The most common tumor locations were the jugular foramen (5 cases), the petrous apex (3 cases), and the petroclival region (3 cases). An infratemporal fossa type A approach was performed in 2 cases, and 2 patients underwent an infratemporal fossa type B approach. Two patients underwent a transotic approach, 1 patient underwent a petro-occipital transsigmoid approach, and a petro-occipital transsigmoid approach combined with a transotic approach was chosen in 1 case. One patient underwent an infratemporal fossa type C approach combined with a transotic approach, and 2 patients underwent an infratemporal fossa type B approach combined with a transotic approach. One patient underwent an infratemporal fossa type B approach combined with a transzygomatic approach, and the last patient underwent a transmastoid approach. Gross total tumor removal was achieved in all patients. Postoperative radiotherapy was performed in 7 cases. The most common complications were lower cranial nerve deficits. Two patients experienced recurrences, 36 months and 6 years after surgical removal.

CONCLUSIONS

We believe that the primary treatment for chondrosarcomas of the skull base is gross total surgical resection. We usually do not recommend radiotherapy as the primary treatment for patients with skull base chondrosarcomas; however, radiotherapy may be considered as an alternative primary treatment in selected cases in which there are serious medical contraindications to surgery, as well as in elderly patients. We reserve postoperative radiotherapy for patients with histologically aggressive tumors (grade II or III), as well as for cases of subtotal resection or recurrent tumors.

Chemotherapy of skull base chordoma tailored on responsiveness of patient-derived tumor cells to rapamycin

Skull base chordomas are challenging tumors due to their deep surgical location and resistance to conventional radiotherapy. Chemotherapy plays a marginal role in the treatment of chordoma resulting from lack of preclinical models due to the difficulty in establishing tumor cell lines and valuable in vivo models. Here, we established a cell line from a recurrent clival chordoma. Cells were cultured for more than 30 passages and the expression of the chordoma cell marker brachyury was monitored using both immunohistochemistry and Western blot. Sensitivity of chordoma cells to the inhibition of specific signaling pathways was assessed through testing of a commercially available small molecule kinase inhibitor library. In vivo tumorigenicity was evaluated by grafting chordoma cells onto immunocompromised mice and established tumor xenografts were treated with rapamycin. Rapamycin was administered to the donor patient and its efficacy was assessed on follow-up neuroimaging. Chordoma cells maintained brachyury expression at late passages and generated xenografts closely mimicking the histology and phenotype of the parental tumor. Rapamycin was identified as an inhibitor of chordoma cell proliferation. Molecular analyses on tumor cells showed activation of the mammalian target of rapamycin signaling pathway and mutation of KRAS gene. Rapamycin was also effective in reducing the growth of chordoma xenografts. On the basis of these results, our patient received rapamycin therapy with about six-fold reduction of the tumor growth rate upon 10-month follow-up neuroimaging. This is the first case of chordoma in whom chemotherapy was tailored on the basis of the sensitivity of patient-derived tumor cells.

Endoscopic endonasal technique: treatment of paranasal and anterior skull base malignancies

Objective

Method

Conclusion

MicroRNA expression profiling reveals the potential function of microRNA-31 in chordomas

Chordomas are rare bone tumors arising from remnants of the notochord. Molecular studies to determine the pathways involved in their pathogenesis and develop better treatments are limited. Alterations in microRNAs (miRNAs) play important roles in cancer. miRNAs are small RNA sequences that affect transcriptional and post-transcriptional regulation of gene expression in most eukaryotic organisms. Studies show that miRNA dysregulation is important for tumor initiation and progression. We compared the expression profile of miRNAs in chordomas to that of healthy nucleus pulposus samples to gain insight into the molecular pathogenesis of chordomas. Results of functional studies on one of the altered miRNAs, miR-31, are presented. The comparison between the miRNA profile of chordoma samples and the profile of normal nucleus pulposus samples suggests dysregulation of 53 miRNAs. Thirty miRNAs were upregulated in our tumor samples, while 23 were downregulated. Notably, hsa-miR-140-3p and hsa-miR-148a were upregulated in most chordomas relative to levels in nucleus pulposus cells. Two other miRNAs, hsa-miR-31 and hsa-miR-222, were downregulated in chordomas compared with the control group. Quantification with real-time polymerase chain reaction confirmed up or downregulation of these miRNAs among all samples. Functional analyses showed that hsa-miR-31 has an apoptotic effect on chordoma cells and downregulates the expression of c-MET and radixin. miRNA profiling showed that hsa-miR-31, hsa-miR-222, hsa-miR-140-3p and hsa-miR-148a are differentially expressed in chordomas compared with healthy nucleus pulposus. Our profiling may be the first step toward delineating the differential regulation of cancer-related genes in chordomas, helping to reveal the mechanisms of initiation and progression.

Myxoid chondrosarcoma of sphenoid bone

The myxoid variant of chondrosarcoma is usually seen in soft tissues where it is known as chordoid sarcoma or parachordoma. Rarely, it involves bone and when it does, cranial bones are the preferred location. This tumor is frequently amalgamated with the chondroid variant of chordoma, especially when the lesion occurs in the sphenoid bone/spheno-occipital region, because of their similar clinical presentations, anatomical locations, radiological findings, and mistaken histopathological features. It is essential to distinguish myxoid chondrosarcoma from the chondroid variant of chordoma, because of the different treatment protocol and prognostic importance. We present such a location-based diagnostic dilemma, solved successfully with ancillary immunohistochemistry.

Diffusion-weighted MRI: distinction of skull base chordoma from chondrosarcoma

BACKGROUND AND PURPOSE

Chordoma and chondrosarcoma of the skull base are rare tumors with overlapping presentations and anatomic imaging features but different prognoses. We hypothesized that these tumors might be distinguished by using diffusion-weighted MR imaging.

MATERIALS AND METHODS

We retrospectively reviewed 19 patients with pathologically confirmed chordoma or chondrosarcoma who underwent both conventional and diffusion-weighted MR imaging. Differences in distributions of ADC were assessed by the Kruskal-Wallis test. Associations between histopathologic diagnosis and conventional MR imaging features (T2 signal intensity, contrast enhancement, and tumor location) were assessed with the Fisher exact test.

RESULTS

Chondrosarcoma was associated with the highest mean ADC value (2051 ± 261 × 10(-6) mm(2)/s) and was significantly different from classic chordoma (1474 ± 117 × 10(-6) mm(2)/s) and poorly differentiated chordoma (875 ± 100 × 10(-6) mm(2)/s) (P < .001). Poorly differentiated chordoma was characterized by low T2 signal intensity (P = .001), but other conventional MR imaging features of enhancement and/or lesion location did not reliably distinguish these tumor types.

CONCLUSIONS

Diffusion-weighted MR imaging may be useful in assessing clival tumors, particularly in differentiating chordoma from chondrosarcoma. A prospective study of a larger cohort will be required to determine the value of ADC in predicting histopathologic diagnosis.

Chondroid chordoma and nasal adenocarcinoma: an exceptional association

Collision tumors are exceptional, associating two independent tumoral contingents. We report a case of an association of two rare tumors: sinonasal adenocarcinoma and chondroid chordoma. Initially, only adenocarcinoma was diagnosed. The treatment consisted of endoscopic endonasal surgery followed by conventional radiotherapy. After 18 months, a local recurrence was diagnosed after a facial trauma, but the true histology was difficult to assess. The tumor was dual, associating adenocarcinoma and chondroid chordoma, with atypical localization in the ethmoid. Further evolution was particularly aggressive. We discuss the key points of this observation.

Extraskeletal cartilaginous, osseous, and chordoid tumors in children and adolescents

Extraskeletal cartilaginous, osseous, and chordoid tumors are extraordinarily rare in children and adolescents. These lesions are diagnostically challenging due to their rarity and their overlap with metastatic osteosarcoma, reactive or metabolic calcifying and bone-forming masses, various pseudosarcomatous proliferations such as myositis ossificans, and other rare genetic or metabolic disorders. This article reviews the clinicopathologic features and differential diagnosis of extraskeletal cartilaginous, osseous, and chordoid neoplasms in the first two decades of life and highlights the use of diagnostic adjuncts.

Frequent IDH1/2 mutations in intracranial chondrosarcoma: a possible diagnostic clue for its differentiation from chordoma

Mutations in the genes encoding isocitrate dehydrogenase (IDH) 1/2 have been detected in a significant proportion of diffuse gliomas and in a small fraction of acute myeloid leukemia (AML) cases. Recently, in an examination of various types of mesenchymal tumor, IDH1/2 mutations were only found in cartilaginous tumors including central conventional and periosteal enchondromas/chondrosarcomas. The frequency of IDH1/2 mutations was 56%, and the IDH1 R132C mutation, which is not common in diffuse gliomas or AML, accounted for 40% of these mutations. In this study, we investigated the IDH1/2 mutation status of intracranial chondrosarcomas and chordomas, which are morphologically similar and affect similar regions of the cranial cavity. Of the 13 chondrosarcomas analyzed, six (46.1%) displayed IDH1/2 mutations (the predominant type was IDH1 R132C). Also, an IDH2 mutation (R172S) was observed in one case. Conversely, none of the ten chordomas analyzed displayed any IDH1 or IDH2 mutations. Our data suggest that the IDH1/2 mutation status could be valuable for distinguishing intracranial chondrosarcomas from chordomas.

Characterization of cancer stem-like cells in chordoma

OBJECT

Chordomas are locally aggressive bone tumors known to arise from the remnants of the notochord. Because chordomas are rare, molecular studies aimed at developing new therapies are scarce and new approaches are needed. Chordoma cells and cancer stem-like cells share similar characteristics, including self-renewal, differentiation, and resistance to chemotherapy. Therefore, it seems possible that chordomas might contain a subpopulation of cancer stem-like cells. The aim of this study is to determine whether cancer stem-like cells might be present in chordomas.

METHODS

In this study, the authors used gene expression analysis for common cancer stem-like cellmarkers, including c-myc, SSEA-1, oct4, klf4, sox2, nanog, and brachyury, and compared chordoma cells and tissues with nucleus pulposus tissues (disc degenerated nontumorigenic tissues). Differentiation through agents such as all-trans retinoic acid and osteogenic differentiation medium was induced to the chordoma cells. Additionally, U-CH1 cells were sorted via magnetic cell sorting for stem cell markers CD133 and CD15. After separation, positive and negative cells for these markers were grown in a nonadherent environment, soft agar, to determine whether the presence of these cancer stem-like cells might be responsible for initiating chordoma. The results were compared with those of untreated cells in terms of migration, proliferation, and gene expression by using reverse transcriptase polymerase chain reaction.

RESULTS

The results indicate that chordoma cells might be differentiating and committing into an osteogenic lineage when induced with the osteogenic differentiation agent. Chordoma cells that are induced with retinoic acid showed slower migration and proliferation rates when compared with the untreated cells. Chordoma cells that were found to be enriched by cancer stem-like cell markers, namely CD133 and CD15, were able to live in a nonadherent soft agar medium, demonstrating a self-renewal capability. To the authors' knowledge, this is the first time that cancer stem-like cell markers were also found to be expressed in chordoma cells and tissues.

CONCLUSIONS

Cancer stem-like cell detection might be an important step in determining the recurrent and metastatic characteristics of chordoma. This finding may lead to the development of new approaches toward treatments of chordomas.

Establishment and characterization of a primary human chordoma xenograft model

OBJECT

Chordomas are rare tumors arising from remnants of the notochord. Because of the challenges in achieving a complete resection, the radioresistant nature of these tumors, and the lack of effective chemotherapeutics, the median survival for patients with chordomas is approximately 6 years. Reproducible preclinical model systems that closely mimic the original patient's tumor are essential for the development and evaluation of effective therapeutics. Currently, there are only a few established chordoma cell lines and no primary xenograft model. In this study, the authors aimed to develop a primary chordoma xenograft model.

METHODS

The authors implanted independent tumor samples from 2 patients into athymic nude mice. The resulting xenograft line was characterized by histopathological analysis and immunohistochemical staining. The patient's tumor and serial passages of the xenograft were genomically analyzed using a 660,000 single-nucleotide polymorphism array.

RESULTS

A serially transplantable xenograft was established from one of the 2 patient samples. Histopathological analysis and immunohistochemical staining for S100 protein, epithelial membrane antigen, and cytokeratin AE1/AE3 of the primary patient sample and the xenografts confirmed that the xenografts were identical to the original chordoma obtained from the patient. Immunohistochemical staining and western blot analysis confirmed the presence of brachyury, a recently described marker of chordomas, in the tumor from the patient and each of the xenografts. Genome-wide variation was assessed between the patient's tumor and the xenografts and was found to be more than 99.9% concordant.

CONCLUSIONS

To the best of their knowledge, the authors have established the first primary chordoma xenograft that will provide a useful preclinical model for this disease and a platform for therapeutic development.

Current Surgical Outcomes for Cranial Base Chordomas

BACKGROUND:

Chordomas of the skull base are locally aggressive neoplasms for which maximal surgical resection confers prolonged survival.

OBJECTIVE:

To present the largest consecutive surgical series of cranial base chordomas to date, including complications, functional outcome, and overall (OS) and recurrence-free survival (RFS) in early and late eras of our experience.

METHODS:

From 1988 to 2011, 95 patients with cranial base chordomas were treated, including 56 patients from 1988 to 1999 and 39 from 2000 to 2011. Mean age and average follow-up were 42.6 ± 16.8 years and 38.3 ± 38.5 months, respectively. A historically controlled study design was implemented comparing both eras with respect to 5-year OS, RFS, Karnofsky performance scale at last-follow-up, and complications.

RESULTS:

Mean 5-year OS and RFS for the entire cohort was 74% ± 6% and 56% ± 8%, respectively. Complete resection rates were similar between groups (68% and 74%, respectively; P = .494). In the 2000 to 2011 era, overall (26%), cranial nerve (10%), vascular (3%), and systemic (0%) complications were less frequent than in the 1988 to 1999 era. Patients in the 2000 to 2011 era were 1.50 times more likely to have a Karnofsky performance scale ≥70 than in the 1988 to 1999 era (95% confidence interval 1.15-1.94; P = .003). There was no significant difference in 5-year RFS between the 1988 to 1999 and 2000 to 2011 eras. Five-year OS was higher in the 2000 to 2011 era (93% ± 6% vs 64% ± 8% for the 1988-1999 era; P = .012).

CONCLUSION:

Aggressive surgical resection implementing contemporary skull base approaches can be performed with an acceptable complication profile with preservation of functional status, while conferring a similar OS and RFS.

Challenges in linear accelerator radiotherapy for chordomas and chondrosarcomas of the skull base: focus on complications

PURPOSE

Intracranial chordomas and chondrosarcomas are histologically low-grade, locally invasive tumors that infiltrate the skull base. Currently, consensus therapy includes surgical resection and adjuvant radiotherapy. Radiation delivery is typically limited by the proximity of these tumors to critical skull base structures.

METHODS

This is a retrospective review of 13 cases of chordomas and 2 cases of chondroid chondrosarcomas of the skull based treated with linear accelerator stereotactic radiotherapy (SRT, n = 10) or stereotactic radiosurgery (SRS, n = 5). The average time to the most recent follow-up visit was 4.5 years. The tumor characteristics, treatment details, and outcomes were recorded. Each radiation plan was reviewed, and the dosage received by the brainstem, optic apparatus, and pituitary was calculated.

RESULTS

Of the 10 patients treated with SRT, 6 were found to have unchanged or decreased tumor size as determined from radiographic follow-up. Of the 5 patients treated with SRS, 3 were found to have stable or unchanged tumors at follow-up. The complications included 1 SRT patient who developed endocrinopathy, 2 patients (1 treated with SRS and the other with SRT), who developed cranial neuropathy, and 1 SRS patient who developed visual deficits. Additionally, 1 patient who received both SRS and SRT within 2 years for recurrence experienced transient medial temporal lobe radiation changes that resolved.

CONCLUSIONS

Where proton beam therapy is unavailable, linear accelerator-based SRT or radiosurgery remains a safe option for adjuvant therapy of chordomas and chondrosarcomas of the skull base. The exposure of the optic apparatus, pituitary stalk, and brainstem must be considered during planning to minimize complications. If the optic apparatus is included in the 80% isodose line, it might be best to fractionate therapy. Exposure of the pituitary stalk should be kept to <30 Gy to minimize endocrine dysfunction. Brainstem exposure should be limited to <60 Gy in fractions.

Chordomas of the skull base and cervical spine: clinical outcomes associated with a multimodal surgical resection combined with proton-beam radiation in 40 patients

Previous studies of chordoma have focused on either surgery, radiotherapy, or particular tumor locations. This paper reviewed the outcomes of surgery and proton radiotherapy with various tumor locations. Between 2001 and 2008, 40 patients with chordomas of the skull base and cervical spine had surgery at our hospital. Most patients received proton therapy. Their clinical course was reviewed. Age, sex, tumor location, timing of surgery, extent of resection, and chondroid appearance were evaluated in regard to the progression-free survival (PFS) and overall survival (OS). The primary surgery (PS) group was analyzed independently. The extensive resection rate was 42.5%. Permanent neurological morbidity was seen in 3.8%. Radiotherapy was performed in 75% and the mean dose was 68.9 cobalt gray equivalents. The median follow-up was 56.5 months. The 5-year PFS and OS rates were 70% and 83.4%, respectively. Metastasis was seen in 12.5%. The tumor location at the cranio-cervical junction (CCJ) was associated with a lower PFS (P = 0.007). In the PS group, a younger age and the CCJ location were related to a lower PFS (P = 0.008 and P < 0.001, respectively). The CCJ location was also related to a lower OS (P = 0.043) and it was more common in young patients (P = 0.002). Among the survivors, the median of the last Karnofsky Performance Scale score was 80 with 25.7% of patients experiencing an increase and 11.4% experiencing a decrease. Multimodal surgery and proton therapy thus improved the chordoma treatment. The CCJ location and a younger age are risks for disease progression.

Current comprehensive management of cranial base chordomas: 10-year meta-analysis of observational studies

OBJECT

The role of surgery and adjuvant radiation therapy for cranial base chordomas is not well established. This meta-analysis measures the relationship of complete resection and type of adjuvant radiation therapy to 5-year progression-free survival (PFS) and overall survival (OS) of cranial base chordomas.

METHODS

A systematic MEDLINE search (1999-present) yielded 23 observational studies and 807 patients who fit inclusion criteria. The following analyses were performed: 1) Kaplan-Meier 5-year PFS and OS compared based on the extent of resection and type of adjuvant radiation therapy using the log-rank method; 2) a random-effects model comparing 5-year PFS with complete or incomplete resection; and 3) paired z-test comparisons of weighted average 5-year OS and PFS grouped by type of adjuvant radiation therapy.

RESULTS

The weighted average follow-up was 53.6 months. The weighted average 5-year PFS and OS were 50.8% and 78.4%, respectively. Complete resection conferred a higher 5-year PFS than incomplete resection from the random effects model (mean difference in PFS 20.7%; 95% CI 6.57%-34.91%). Patients with incomplete resection were 3.83 times more likely to experience a recurrence (95% CI 1.63-9.00) and 5.85 times more likely to die (95% CI 1.40-24.5) at 5 years versus patients with complete resection. There was no difference in 5-year OS by type of adjuvant radiation, although 5-year PFS was lower in patients receiving Gamma Knife surgery relative to carbon ion radiotherapy (p = 0.042) on paired z-test. No survival difference occurred between radiation therapy techniques on Kaplan-Meier analysis of compiled patient data.

CONCLUSIONS

Patients with complete resection of cranial base chordomas have a prolonged 5-year PFS and OS. Adjuvant proton-beam, carbon ion, and modern fractionated photon radiation therapy techniques offered a similar rate of PFS and OS at 5 years.

The biological basis for modern treatment of chordoma

Chordomas are rare malignant tumors arising in bone of the spheno-occiput, sacrum, and vertebral column which can cause neurological deficit. Current management of chordoma involves safe resection followed by radiation therapy. However, surgical resection is often subtotal and chordoma often recurs despite optimal therapy. Despite years of effort, effective adjuvant therapy for denovo, recurrent and metastatic chordoma are absent and 5-year survival is at best 65%. While no chemotherapeutic agent has been demonstrated to be effective against chordoma in vivo, a greater understanding of the genetics and molecular biology of chordoma is opening up avenues of investigation towards the rational development of targeted therapies. Although enthusiasm for the use of already established or new investigational agents will increase with greater understanding of chordoma biology, laboratory studies of these agents are important prior to incorporation into clinical human trials. The authors review the current state of knowledge regarding chordoma and offer insight into potential new therapies for this rare and challenging tumor.

Technical notes on endoscopic transnasal transsphenoidal approach for clival chondrosarcoma

Although there are various operative approaches for clival tumors, a transsphenoidal approach is one of choices when the main tumor extention is in an anterior-posterior direction with a slight lateral extension. However, this approach sometimes provides only narrow and deep operative field. Recently, endoscopic transnasal transsphenoidal approach is quite an effective approach for clival tumors because of the improvement of surgical instruments, image guidance systems, and techniques and materials of wound closure. In this paper, we describe the effectiveness, technical problems, and solution of this approach based on our experiences with two clival chondrosarcomas that was removed by endoscopic transnasal transsphenoidal approach.

Defining the “edge of the envelope”: patient selection in treating complex sellar-based neoplasms via transsphenoidal versus open craniotomy

Object

Endonasal approaches have become the gold standard intervention for many anterior and middle skull base tumors. The authors aimed to define some of the existing limitations of these approaches by reviewing their experience with complex sellar region tumors that were initially considered for both transsphenoidal and open skull base approaches and were thus deemed tumors at “the edge of the envelope.”

Methods

Between April 2008 and April 2010, 250 transsphenoidal operations were performed at Brigham and Women's Hospital. All cases were retrospectively reviewed to identify patients with complex sellar region tumors that were initially considered for, or soon thereafter required, an open craniotomy as the definitive treatment. The anatomical tumor characteristics that posed limitations to performing safe and effective endonasal skull base operations were reviewed.

Results

Thirteen cases exemplifying some of the existing limitations to achieving optimal surgical outcomes via transsphenoidal-based approaches are presented. The following 8 factors are separately discussed that repeatedly limited the extent of resection, increased the risk of the operation, and contributed to perioperative complications: significant suprasellar extension, lateral extension, retrosellar extension, brain invasion with edema, firm tumor consistency, involvement or vasospasm of the arteries of the circle of Willis, and encasement of the optic apparatus or invasion of the optic foramina.

Conclusions

Although the ability to approach and resect complex tumors using endonasal skull base techniques has evolved dramatically in recent years, several inherent tumor characteristics mandate extensive preoperative consideration. In selected cases these characteristics may lend support to selecting an open craniotomy as the initial operation.

A systematic review of proton therapy in the treatment of chondrosarcoma of the skull base

Chondrosarcoma (CSA) of the skull base (SB) is an uncommon, slowly growing, neoplasm comprising approximately 0.1% of all intracranial tumors and 6% of SB lesions. Even though its growth is slow, CSA is a potentially lethal tumor. The therapeutic approach to CSA of the SB is still controversial and clinical experience is limited because of the relative rarity of this tumor. The use of proton therapy (PT) after maximal surgery is widely accepted, but there are no controlled studies demonstrating the need of PT and its superiority in comparison to radiotherapy with photons. We conducted a systematic review of the scientific literature published during the period between January 1980 and June 2008 on data regarding irradiation of CSA of the SB with PT and a series of inclusion criteria. During August 2008, two independent reviewers (M.A. and D.A.), by applying the key words "skull base", "chondrosarcoma", and "proton therapy" selected those studies from the PubMed database in which a minimum of ten patients received palliative, radical, or postoperative irradiation with protons and which furnished a minimum of 24 months of follow-up. Forty nine reports were retrieved. There were no prospective trials (randomized or nonrandomized) but just nine uncontrolled single-arm studies for PT mainly related to advanced and frequently incompletely resected tumors. According to the inclusion criteria, only four articles, reporting the most recent updated results of the publishing institution, were included in the analysis providing clinical outcomes for 254 patients in total. Therapeutic approach to CSA of the SB has traditionally relied on surgical control. Radiation therapy has demonstrated to be a valuable modality for local control in the postoperative setting or in advanced/inoperable cases treated with definitive intent. The use of PT following maximal surgical resection shows a very high probability of medium- and long-term cure with a relatively low risk of significant complications.

[CT and MRI of intrinsic space-occupying lesions of the bony skull base]

Intrinsic bony lesions of the skull base are diseases which arise within the bones forming the skull base. Mainly they are bone tumours and tumour-like lesions. With the exception of osteomas of the paranasal sinuses and exostoses of the external auditory canal, these lesions occur rarely. This article gives an overview of the appearance of the most common primary bony skull base masses in CT and MRI. From the authors' point of view these are fibrous dysplasia, chordomas, chondrosarcomas, Langerhans cell histiocytosis and multiple myelomas, which must be differentiated from pseudolesions. The possibilities of CT and MRI in making a specific diagnosis, differential diagnosis and the kind of making the final diagnosis are described.

[Chondrosarcomas of skull base treatment]

BACKGROUND AND PURPOSE

Skull base chondrosarcomas are rare. Gross total removal is the treatment of choice, but can be difficult depending on the closeness of noble structures. Proton beam therapy can be associated in most cases.

METHODS

Retrospective study of five cases treated in 13 years and study of the literature.

RESULTS

Median age of patients was 34 years [28-46]. Cranial nerve palsy was the common clinical presentation. Tumor location was variable but always off midline. Treatment was surgical in all patients with a maximal resection and proton beam therapy associated for two cases. Surgical complications were rare with cranial nerve palsy as the main side effect. Outcomes were good with a median follow-up of 12.4 years [4.3-16.2].

DISCUSSION

The review of the literature showed that chondrosarcomas of skull base are rare. The best outcome is achieved with total surgical resection. Medical imaging can only give clues to the diagnosis. Pathology is required to obtain a precise immunohistochemistry diagnosis. Multidisciplinary treatment using proton beam therapy and surgical removal enables a good local control (90-100%) at 5 years with good quality-of-life. It is difficult to determine how many cases have been published (around 220 cases in the literature) since many surgical or radiotherapy series included the same patients.

Impact of cytogenetic abnormalities on the management of skull base chordomas

Object

Cytogenetic studies of chordomas are scarce and show multiple changes involving different chromosomes. These abnormalities are implicated in the pathogenesis of chordoma, but the clinical significance of these changes is yet to be determined. In this study, the authors discuss the cytogenetic changes in a large series of skull base chordomas with long-term follow-up and focus on the impact of these changes on the prognosis, progression, and management of the disease.

Methods

The karyotypes of chordomas in 64 patients (36 men and 28 women) were studied in relation to survival and recurrence or progression over a mean follow-up period of 48 ± 37.5 months. The standard G-banding technique was used for karyotype analysis. Statistical analysis was performed with the Fisher exact test and ORs, and Kaplan-Meier curves were generated for survival and recurrence/progression of disease.

Results

Seventy-four percent of de novo chordomas had normal karyotypes and a 3% recurrence rate; there was a 45% recurrence rate in de novo tumors with abnormal karyotypes (p < 0.01). Recurrent tumors were associated with a high incidence of abnormal karyotype (75%). The OR for recurrence in lesions with an abnormal versus a normal karyotype was 12. Aberrations in chromosomes 3, 4, 12, 13, and 14 were associated with frequent recurrence and decreased survival time. Ninety-five percent of cases with progression involved chromosome 3 and/or 13. The median survival time was 4 months when both of these chromosomes had aberrations (p = 0.02).

Conclusions

Chordomas with normal karyotypes were associated with a low rate of recurrence and a long patient survival, and recurrent chordomas were associated with an abnormal karyotype, disease progression, and poor survival. De novo chordomas with normal karyotypes may be amenable to radical resection and adjunctive proton beam therapy. Recurrent and de novo chordomas with abnormal karyotypes were associated with complex cytogenetic abnormalities and a poor prognosis, particularly in the presence of aberrations underlying tumor progression in chromosomes 3, 4, 12, 13, and 14.

Radiotherapy of other sellar lesions

Radiotherapy has been used as primary or adjuvant treatment in a number of non-adenomatous masses arising from within the sella. It is particularly important in the therapeutic algorithm of craniopharyngiomas and meningiomas and has also been used in chordomas/chordosarcomas and less commonly, in other lesions. This review describes the place of irradiation in the management of these masses.

Brachyury, SOX-9, and podoplanin, new markers in the skull base chordoma vs chondrosarcoma differential: a tissue microarray-based comparative analysis

The distinction between chondrosarcoma and chordoma of the skull base/head and neck is prognostically important; however, both have sufficient morphologic overlap to make delineation difficult. As a result of gene expression studies, additional candidate markers have been proposed to help in separating those entities. We sought to evaluate the performance of new markers: brachyury, SOX-9, and podoplanin alongside the more traditional markers glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen. Paraffin blocks from 103 skull base/head and neck chondroid tumors from 70 patients were retrieved (1969-2007). Diagnoses were made based on morphology and/or whole-section immunohistochemistry for cytokeratin and S100 protein yielding 79 chordomas (comprising 45 chondroid chordomas and 34 conventional chordomas), and 24 chondrosarcomas. A tissue microarray containing 0.6 mm cores of each tumor in triplicate was constructed using a manual array (MTA-1; Beecher Instruments). For visualization of staining, the ImmPRESS detection system (Vector Laboratories) with 2-diaminobenzidine substrate was used. Sensitivities and specificities were calculated for each marker. Core loss from the microarray ranged from 25 to 29% yielding 66-78 viable cases per stain. The classic marker, cytokeratin, still has the best performance characteristics. When combined with brachyury, accuracy improves slightly (sensitivity and specificity for detection of chordoma 98 and 100%, respectively). Positivity for both epithelial membrane antigen and AE1/AE3 had a sensitivity of 90% and a specificity of 100% for detecting chordoma in this study. SOX-9 is apparently common to both notochordal and cartilaginous differentiation, and is not useful in the chordoma-chondrosarcoma differential diagnosis. Glial fibrillary acid protein, carcinoembryonic antigen, CD24, and epithelial membrane antigen did not outperform other markers, and are less useful in the diagnosis of chordoma vs chondrosarcoma. Podoplanin still remains the only positive marker for chondrosarcoma, though its accuracy is less than previously reported.