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

Translational Windows in Chordoma: A Target Appraisal

Chordomas are rare tumors that are notoriously refractory to chemotherapy and radiotherapy when radical surgical resection is not achieved or upon recurrence after maximally aggressive treatment. The study of chordomas has been complicated by small patient cohorts and few available model systems due to the rarity of these tumors. Emerging next-generation sequencing technologies have broadened understanding of this disease by implicating novel pathways for possible targeted therapy. Mutations in cell-cycle regulation and chromatin remodeling genes have been identified in chordomas, but their significance remains unknown. Investigation of the immune microenvironment of these tumors suggests that checkpoint protein expression may influence prognosis, and adjuvant immunotherapy may improve patient outcome. Finally, growing evidence supports aberrant growth factor signaling as potential pathogenic mechanisms in chordoma. In this review, we characterize the impact on treatment opportunities offered by the genomic and immunologic landscape of this tumor.

LncRNA XIST Promotes Growth of Human Chordoma Cells by Regulating miR-124-3p/iASPP Pathway

Introduction

Chordoma is a malignant primary bone tumor that is found in the spine and skull. X-inactive specific transcript (XIST) is a long non-coding RNA (lncRNA) is known to be involved in the development of various cancers, but its precise function and mechanism in human chordoma have not been elucidated. Here, we investigated the role of lncRNA XIST in chordoma progression.

Methods

Quantitative real time-polymerase chain reaction (qRT-PCR) was performed to determine lncRNA XIST expression in human chordoma tissues and matched-noncancerous tissues. Western blot was used to determine protein expression. Silencing and overexpression of lncRNA XIST were carried out by RNA interference (RNAi) and lentiviral transduction, respectively. Cell Counting Kit-8 (CCK-8) assay and flow cytometry were employed to examine the effects of lncRNA XIST on growth of human chordoma cells. Lastly, the role of lncRNA XIST in vivo was explored using a xenograft model.

Results

We found that lncRNA XIST expression was upregulated in chordoma and strongly correlated with poor patient prognosis. Moreover, lncRNA XIST promoted proliferation and inhibited apoptosis of chordoma cells. Mechanistically, upregulation of lncRNA XIST led to a decrease in miR-124-3p expression, thereby promoting the expression of the miR-124-3p target gene, inhibitor of apoptosis-stimulating protein of p53 (iASPP). Addition of miR-124-3p inhibitor or mimic reversed the effects induced by lncRNA XIST silencing or overexpression on chordoma cell proliferation. Lastly, using a xenograft mouse model, we found that silencing of lncRNA XIST decreased tumorigenicity in vivo, as shown by increased tumor cell apoptosis.

Conclusion

Our findings demonstrate a key role for lncRNA XIST in chordoma progression by regulating miR124-3p/iAPSS pathway.

Suprasellar Benign Chondroma: A Case Report and Literature Review

Intracranial chondroma is a rare benign tumor comprising only 0.2% of all intracranial tumors. A 27-year-old woman presented with visual dysfunction and headache. Brain computed tomography and magnetic resonance imaging revealed a suprasellar mass lesion with a calcified component. Gross total removal was achieved via a basal interhemispheric approach. Postoperatively, visual function improved to the normal range, and no recurrence was evident 4 years later. Histopathological examination confirmed the diagnosis of benign chondroma. Preoperative differentiation of chondromas from chordomas is clinically important, because of the different treatment and prognostic implications. The only effective treatment for chondroma is total surgical removal. We present a case of gross total resection of a suprasellar chondroma with reference to the literature.

Carbon ion radiotherapy for skull base chordomas and chondrosarcomas: a systematic review and meta-analysis of local control, survival, and toxicity outcomes

BACKGROUND

Carbon ion radiotherapy (CIRT) is an emerging radiation therapy to treat skull base chordomas and chondrosarcomas. To date, its use is limited to a few centers around the world, and there has been no attempt to systematically evaluate survival and toxicity outcomes reported in the literature. Correspondingly, the aim of this study was to qualitatively and quantitatively assess these outcomes.

METHODS

A systematic search of seven electronic databases from inception to November 2019 was conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. Outcomes were then pooled by random-effects meta-analyses of proportions.

RESULTS

A total of nine studies provided unique metadata for assessment, with six originating from Heidelberg, Germany. The surveyed cohort size was 632 patients, with 389 (62%) chordomas and 243 (38%) chondrosarcomas of the skull base. Across all studies, median cohort age at therapy and female proportion were 46 years and 51% respectively. Estimates of local control incidence at 1-, 5-, and 10-years in chordoma-only studies were 99%, 80%, and 56%, and in chondrosarcoma-only studies were 99%, 89%, and 88%. Estimates of overall survival probability at 1-, 5-, and 10-years in chordoma-only studies were 100%, 94%, and 78%, and in chondrosarcoma-only studies were 99%, 95%, and 79%. The incidence of early and late toxicity (Grade ≥ 3) ranged from 0 to 4% across all study groups.

CONCLUSIONS

The emerging use of CIRT to treat skull base chordomas and chondrosarcomas appear promising with regard to tumor control, overall survival, and risk profile of early and late toxicity. The current literature suffers from the fact only a few centers in the world currently employ this technology.

Soft Tissue Special Issue: Chondroid Neoplasms of the Skull

Clinically, radiologically, and pathologically, chondroid neoplasms of the skull can be diagnostically challenging due to overlapping features in each of these domains. Compounding the problem for the pathologist, there is also significant morphologic, immunophenotypic, and molecular genetic overlap between benign and malignant cartilaginous lesions, and the majority of these lesions are encountered quite rarely in routine surgical pathology practice. Each of these factors contribute to the diagnostic difficulty posed by these lesions, highlighting the importance of radiologic-pathologic correlation in the diagnosis. This review is intended to provide an update for surgical pathologists on some of the most commonly encountered chondroid neoplasms in the skull, and includes the following lesions: chondromyxoid fibroma, synovial chondromatosis, chondrosarcoma and variants, and chordoma and variants. For each of these lesions, the differential diagnosis and useful ancillary tests will be discussed in the context of a broad range of additional primary and secondary lesions.

Low-Grade Chondrosarcoma In The Sellar Area: Case Report And Literature Review

Low-grade chondrosarcoma (LGC) is a very rare intracranial tumor, particularly in the sellar area. Herein, we describe an unusual case of LGC occurring in the sellar area. A 52-year-old man presented with diminution of vision for more than 3 months, but did not exhibit headaches reported in previous cases. MRI showed that the maximum size of the tumor was 7 cm on the left side of the saddle. We characterized the specific pathological characteristics. Histologically, the tumor had polypoid areas and a lobulated growth pattern under low-power examination. At high magnification, the tumor consisted of small cells with hyperchromatic nuclei in the cartilage matrix, with an alternating loose hypocellular zone and rich myxoid area. In our case, LGC needed to be distinguished from chordoma. Immunohistochemically, the tumor cells showed diffuse positivity for S-100 and vimentin, IDH1 was weakly cytoplasm positive. The Ki-67 labeling index was less than 5%. Additionally, AE1/3, EMA, and CK19 were negative, which could be used to exclude chordoma. This case report expands the literature on LGC and will help clinicians and pathologists better understand this entity.

Intra-articular extra-axial chordoma of the wrist: a case report with review of the current literature

Chordomas are rare bone malignancies that are thought to arise from remnants of the notochord and usually are located in the axial skeleton. Immunophenotypical matching neoplasms primarily found in appendicular locations, referred to as extra-axial chordoma, are rarely encountered by radiologists, surgeons, and pathologists. Only a few of these cases have been described in the literature with only one intra-articular case with involvement of the knee joint. We present the first case of an intra-articular extra-axial chordoma of the wrist. Diagnostic imaging patterns were initially ambiguous and histopathological reprocessing was crucial in order to determine the diagnosis of an intra-articular neoplasm with co-expression of cytokeratins, S-100 protein, and brachyury.

Upregulation Of miR-149-3p Suppresses Spinal Chordoma Malignancy By Targeting Smad3

Purpose

Dysregulation of miRNAs plays an important role in the malignancy of different tumors including chordoma. Expression of miR-149-3p was earlier reported to be downregulated in chordoma tissue. However, its biological role remains to be unrevealed in chordoma, especially in spinal chordoma.

Methods

Expression of miR-149-3p and Smad3 was detected by RT-qPCR and Western blot. Chordoma malignancy was evaluated by cell proliferation, migration, invasion, and apoptosis using MTT assay, transwell assay, flow cytometry analyzing apoptosis rate, and Western blot-determined expression of Bcl-2, Bax, and cleaved caspase 3, respectively. The target binding between miR-149-3p and Smad3 was predicted by TargetScan Human website and confirmed by luciferase reporter assay and RNA immunoprecipitation. Xenograft tumors were generated, and expression of miR-149-3p and Smad3 was investigated in vivo.

Results

miR-149-3p was downregulated in spinal chordoma tissues and cells, and its overexpression promoted chordoma cell apoptosis and inhibited proliferation, migration, and invasion in U-CH1 and MUG-Chor1 cells. Unexpectedly, Smad3 was a downstream target of miR-149-3p and negatively correlated with miR-149-3p expression in chordoma tissues. Besides, Smad3 was upregulated in chordoma tissues and its silencing had a similar effect as miR-149-3p overexpression in U-CH1 and MUG-Chor1 cells. Moreover, Smad3 upregulation could partially reverse the tumor-suppressive effect of miR-149-3p in chordoma cells. In vivo, the tumorigenesis of U-CH1 and MUG-Chor1 cells was impaired by upregulated miR-149-3p through decreasing Smad3 expression.

Conclusion

miR-149-3p could serve as a tumor suppressor in spinal chordoma through targeting and downregulating Smad3.

Site-Specific Considerations in the Surgical Management of Skull Base Chondrosarcomas

BACKGROUND

Numerous approaches have been reported in the management of skull base chondrosarcomas. Data are lacking for surgical outcomes by the tumor site of origin.

OBJECTIVE

To provide insight into outcomes by site of origin and factors affecting resection in order to aid in surgical approach selection.

METHODS

A retrospective review was conducted of 49 patients with chondrosarcoma treated at our institution. Charts were reviewed for tumor- and treatment-related factors. Extent of resection was the primary outcome, while neurological function and surgical complications were secondary outcomes. Statistical analyses were performed assessing variables for their impact on the primary outcome.

RESULTS

The gross total resection rate for the overall cohort was 67.3%, and 97.8% of patients were either neurologically stable or improved postoperatively. A petroclival site of origin had lower rates of resection vs all other sites (P < .05). Histology and previous surgery did not predict outcome (P > .05), while previous radiotherapy and cavernous sinus invasion correlated with a subtotal resection (P < .05). In the petroclival cohort, clival, jugular tubercle, and soft tissue involvement correlated with a subtotal resection (P < .05). An endoscopic endonasal transpterygoid approach alone or combined with a transcranial approach yielded the highest resection rates for petroclival tumors (P < .05).

CONCLUSION

Chondrosarcomas pose unique challenges based on the site of origin and pattern of extension. While current surgical strategies appear to yield adequate results at a majority of skull base sites, petroclival tumors represent a particular cohort in which improvement is needed. Based on our analysis, strategies incorporating both endoscopic and transcranial skull base approaches are likely necessary to achieve optimal outcomes.

Endoscopic Endonasal Surgery for Cranial Base Chondrosarcomas

BACKGROUND

Microsurgical resection via open approaches is considered the main treatment modality for cranial base chondrosarcomas (CBCs). The use of endoscopic endonasal approaches (EEAs) has been rarely reported.

OBJECTIVE

To present the endoscopic endonasal experience with CBCs at our institution.

METHODS

Retrospective review of the medical records of 35 consecutive patients who underwent EEA for CBC resection between January 2004 and April 2013. Surgical outcomes and variables that might affect extent of resection, complications, and recurrence were analyzed.

RESULTS

Forty-eight operations were performed (42 EEAs and 6 open approaches). Gross-total resection was achieved in 22 patients (62.9%), near total (≥90% tumor resection) in 11 (31.4%). Larger tumors were associated with incomplete resection in univariate and multivariate analysis ( P = .004, .015, respectively). In univariate analysis, tumors involving the lower clivus and cerebellopontine angle were associated with increased number of complications, especially postoperative cerebrospinal fluid leak ( P = .015) and new cranial neuropathy ( P = .037), respectively. Other major complications included 2 cases of meningitis and deep venous thrombosis, and 1 case of hydrocephalus and carotid injury. Involvement of the lower clivus, parapharyngeal space, and cervical spine required a combination of approaches to maximize tumor resection ( P = .017, .044, .017, respectively). No predictors were significantly associated with increased risk of recurrence. The average follow-up time was 44.6 ± 31 months.

CONCLUSIONS

EEAs may be considered a good option for managing CBCs without significant posterolateral extension beyond the basal foramina and can be used in conjunction with open approaches for maximal resection with acceptable morbidity.

The role of TNF-α in chordoma progression and inflammatory pathways

PURPOSE

Chordomas are highly therapy-resistant primary bone tumors that exhibit high relapse rates and may induce local destruction. Here, we evaluated the effects of tumor necrosis factor-alpha (TNF-α) on chordoma progression and clinical outcome.

METHODS

Chordoma cells were treated with TNF-α after which its short- and long-term effects were evaluated. Functional assays, qRT-PCR and microarray-based expression analyses were carried out to assess the effect of TNF-α on chemo-resistance, epithelial to mesenchymal transition (EMT), migration, invasion and cancer stem cell-like properties. Finally, relationships between TNF-α expression and clinicopathological features were assessed in a chordoma patient cohort.

RESULTS

We found that TNF-α treatment increased the migration and invasion of chordoma cells. Also, NF-κB activation was observed along with increased EMT marker expression. In addition, enhanced tumor sphere formation and soft agar colony formation were observed, concomitantly with increased chemo-resistance and CD338 marker expression. The TNF-α and TNFR1 expression levels were found to be significantly correlated with LIF, PD-L1 and Ki67 expression levels, tumor volume and a short survival time in patients. In addition, a high neutrophil to lymphocyte ratio was found to be associated with recurrence and a decreased overall survival.

CONCLUSIONS

From our data we conclude that TNF-α may serve as a prognostic marker for chordoma progression and that tumor-promoting inflammation may be a major factor in chordoma tumor progression.

Tumour Volume and Dose Influence Outcome after Surgery and High-dose Photon Radiotherapy for Chordoma and Chondrosarcoma of the Skull Base and Spine

AIMS

To evaluate the long-term outcomes of patients with chordoma and low-grade chondrosarcoma after surgery and high-dose radiotherapy.

MATERIALS AND METHODS

High-dose photon radiotherapy was delivered to 28 patients at the Neuro-oncology Unit at Addenbrooke's Hospital (Cambridge, UK) between 1996 and 2016. Twenty-four patients were treated with curative intent, 17 with chordoma, seven with low-grade chondrosarcoma, with a median dose of 65 Gy (range 65-70 Gy). Local control and survival rates were calculated using the Kaplan-Meier method.

RESULTS

The median follow-up was 83 months (range 7-205 months). The 5 year disease-specific survival for chordoma patients treated with radical intent was 85%; the local control rate was 74%. The 5 year disease-specific survival for chondrosarcoma patients treated with radical intent was 100%; the local control rate was 83%. The mean planning target volume (PTV) was 274.6 ml (median 124.7 ml). A PTV of 110 ml or less was a good predictor of local control, with 100% sensitivity and 63% specificity. For patients treated with radical intent, this threshold of 110 ml or less for the PTV revealed a statistically significant difference when comparing local control with disease recurrence (P = 0.019, Fisher's exact test). Our data also suggest that the probability of disease control may be partly related to both target volume and radiotherapy dose.

CONCLUSION

Our results show that refined high-dose photon radiotherapy, following tumour resection by a specialist surgical team, is effective in the long-term control of chordoma and low-grade chondrosarcoma, even in the presence of metal reconstruction. The results presented here will provide a useful source for comparison between high-dose photon therapy and proton beam therapy in a UK setting, in order to establish best practice for the management of chordoma and low-grade chondrosarcoma.

Lessons learned in the evolution of endoscopic skull base surgery

OBJECTIVEEndoscopic skull base surgery (ESBS) is a relatively recent addition to the neurosurgical armamentarium. As with many new approaches, there has been significant controversy regarding its value compared with more traditional approaches to ventral skull base pathology. Although early enthusiasm for new approaches that appear less invasive is usually high, these new techniques require rigorous study to ensure that widespread implementation is in the best interest of patients.METHODSThe authors compared surgical results for ESBS with transcranial surgery (TCS) for several different pathologies over two different time periods (prior to 2012 and 2012-2017) to see how results have evolved over time. Pathologies examined were craniopharyngioma, anterior skull base meningioma, esthesioneuroblastoma, chordoma, and chondrosarcoma.RESULTSESBS offers clear advantages over TCS for most craniopharyngiomas and chordomas. For well-selected cases of planum sphenoidale and tuberculum sellae meningiomas, ESBS has similar rates of resection with higher rates of visual improvement, and more recent results with lower CSF leaks make the complication rates similar between the two approaches. TCS offers a higher rate of resection with fewer complications for olfactory groove meningiomas. ESBS is preferred for lower-grade esthesioneuroblastomas, but higher-grade tumors often still require a craniofacial approach. There are few data on chondrosarcomas, but early results show that ESBS appears to offer clear advantages for minimizing morbidity with similar rates of resection, as long as surgeons are familiar with more complex inferolateral approaches.CONCLUSIONSESBS is maturing into a well-established approach that is clearly in the patients' best interest when applied by experienced surgeons for appropriate pathology. Ongoing critical reevaluation of outcomes is essential for ensuring optimal results.

Gamma knife surgery efficacy in controlling postoperative residual clival chordoma growth

OBJECTIVE

This study primarily aims to evaluate the efficacy of gamma knife surgery in controlling growth progression rate of residual clival chordoma through retrospective outcome analysis of 12 consecutive patients.

PATIENTS AND METHODS

Data for 12 consecutive patients underwent GKS for post-operative residual histologically verified clival chordoma at our institution (IMC - Cairo- Egypt) from 2006 through end of 2017 were retrospectively reviewed and analyzed with mean follow-up period of 45 months (range12-120 months).

RESULTS

In the last follow up MR, tumor growth control was achieved in 33.3% of patients (mean treated tumors volume was 2.7cc with mean peripheral prescription dose of 16 Gy), and 66.7% of patients reported lost tumor growth control (mean treated tumor volume was 9.2 cc with mean peripheral dose was 13.5 Gy). The overall tumor free progression with mean follow up period of 45mos was 33.3%. The Actuarial 2, 3 and 5 year tumor control rates after initial GKS was 35%, 30% and 25% respectively.

CONCLUSION

Without satisfactory maximum tumor reduction and sufficient high peripheral prescription radiation tumor dose, it should not be expected that GKS could efficiently control the progression of residual clival chordoma, especially for long term.

The role of dose escalation and proton therapy in perioperative or definitive treatment of chondrosarcoma and chordoma: An analysis of the National Cancer Data Base

BACKGROUND

Chordomas and chondrosarcomas are a rare but challenging subset of tumors to treat; however, previous studies have shown benefits from proton therapy, which are thought to be primarily driven by prescription conformality permitting homogeneous tumor dosing and the allowance of higher doses. No retrospective studies to date have directly compared the outcomes of conventional and particle therapy or examined the role of high doses (specifically ≥70 Gy) in definitive radiotherapy (DRT) or perioperative radiotherapy (PRT) for both types of malignancies.

METHODS

A total of 863 patients with chondrosarcoma and 715 patients with chordoma treated with nonpalliative proton or conventional radiation therapy with a dose range of 20 to 80 Gy and at least 15 months of follow-up were identified from the National Cancer Data Base for the years 2003-2014. The primary endpoint of overall survival (OS) was evaluated, and clinical features, including age, sex, grade, clinical stage, and Charlson-Deyo comorbidity index, were compared.

RESULTS

Patients receiving DRT were older and had more advanced disease. In DRT for chondrosarcoma, a high dose (40.6% vs 16.9%; P = .006) and proton therapy (75.0% vs 19.1%; P = .046) were associated with improved OS at 5 years in a multivariate analysis. In DRT for chordoma, proton therapy was associated with improved OS at 5 years in a multivariate analysis (100% vs 34.1%; P = .031), and a high dose for chordoma was significant for improved OS in a univariate analysis with both DRT (79.0% vs 54.1%; P = .027) and PRT (83.3% vs 77.4%; P = .007).

CONCLUSIONS

In the largest retrospective series to date, dose escalation and proton radiotherapy were associated with improved OS in patients with chondrosarcoma and chordoma despite limited follow-up and access to particle therapy.

Radiological review of skull lesions

Abstract

Calvarial lesions are often asymptomatic and are usually discovered incidentally during computed tomography or magnetic resonance imaging of the brain. Calvarial lesions can be benign or malignant. Although the majority of skull lesions are benign, it is important to be familiar with their imaging characteristics and to recognise those with malignant features where more aggressive management is needed. Clinical information such as the age of the patient, as well as the patient’s history is fundamental in making the correct diagnosis. In this article, we will review the imaging features of both common and uncommon calvarial lesions, as well as mimics of these lesions found in clinical practice.

Teaching Points

• Skull lesions are usually discovered incidentally; they can be benign or malignant.

• Metastases are the most frequent cause of skull lesions.

• Metastatic lesions are most commonly due to breast cancer in adults and neuroblastoma in children.

• Multiple myeloma presents as the classic “punched out” lytic lesions on radiographs.

• Eosinophilic granuloma is an osteolytic lesion with bevelled edges.

Four-Level Vertebrectomy for En Bloc Resection of a Cervical Chordoma

BACKGROUND

Chordomas are locally aggressive tumors that can involve multiple levels of the spine and are difficult to resect. We present our technique for 4-level en bloc cervical spondylectomy for a locally aggressive chordoma.

CASE DESCRIPTION

A 37-year-old woman presented with a 6-month history of dysphagia and a large indurated cervical mass. Imaging showed an enhancing lesion involving C3-6. Needle biopsy confirmed the diagnosis of chordoma. En bloc resection was chosen to maximize her chances of disease-free survival. A 360° approach was deemed necessary. We posteriorly disconnected the vertebral bodies and skeletonized the bilateral vertebral arteries and nerve roots. The interspinous and yellow ligaments and the spinous processes were spared to maintain a solid posterior tension band, as previously described approaches that had sacrificed these elements had a high rate of instrumentation failure. After posterior instrumentation, a wide anterior approach enabled us to resect the tumor attached to the vertebral bodies of C3-6 as 1 specimen. A 4-level corpectomy cage and plate were used for anterior instrumentation. The patient tolerated the surgery well. She needed a temporary gastrostomy, and she had a right C5 palsy that progressively recovered. Follow-up imaging showed no tumor recurrence and good bony fusion.

CONCLUSIONS

En bloc resection as part of a multidisciplinary team approach remains the mainstay of spinal chordoma treatment. Modern instrumentation and careful dissection can provide good results even in locally advanced cases.

Sellar chondrosarcoma presenting with amenorrhea: A case report

RATIONALE

Intracranial chondrosarcomas are rare entities and most of which arise off the midline. Chondrosarcomas that occur in the sellar region are extremely rare, and to the best of our knowledge, there is no reporting about sellar chondrosarcoma with amenorrhea as the onset symptom.

PATIENT CONCERNS

A 45-year-old woman presented with a 7-month history of amenorrhea and a 3-month history of progressive visual loss in the left eye.

DIAGNOSIS

The patient was diagnosed with recurrent sellar chondrosarcoma arising from intrasellar with extensive tumor invasion into bilateral sphenoid sinuses.

INTERVENTIONS

Twice endonasal transsphenoidal tumorectomies were performed followed with a stereotactic radiotherapy and hormone replacement therapy.

OUTCOMES

The patient's condition was stable and her visual symptoms improved, the hormones returned to normal, and no recurrence was noted on MRI after six months.

LESSONS

Sellar chondrosarcomas with the onset of endocrine dysfunctions are extremely rare, which may be misdiagnosed as pituitary adenoma and the definitive diagnosis depends on histopathological and immunohistochemical evidence. The first choice of treatment is surgery with the goal of complete resection, and postoperative adjuvant radiotherapy should be highlighted.

miR-16-5p inhibits chordoma cell proliferation, invasion and metastasis by targeting Smad3

Aberrantly expressed miRNAs play a crucial role in the development of multiple cancer types, including chordoma. However, the detailed molecular mechanisms are unclear and need to be elucidated. In this study, miRNAs were screened by miRNA array analysis and then confirmed by real-time PCR analysis. We found that miR-16-5p was significantly downregulated in chordoma, and overexpression of miR-16-5p suppressed chordoma cell proliferation, invasion and migration in vitro and in vivo and correlated with the upregulated expression of E-cadherin and downregulated expression of N-cadherin and vimentin. Furthermore, Smad3 was identified as a target of miR-16-5p, and Smad3 was highly expressed in chordoma tissues. Further research showed that knockdown of Smad3 had an effect similar to that of overexpression of miR-16-5p in chordoma cells. Our findings demonstrate that miR-16-5p plays a tumor suppressor role in chordoma progression by targeting Smad3, which could provide a promising prognostic and therapeutic strategy for chordoma treatment.

A cavernous sinus lesion clinically responsive to steroids

Tolosa Hunt syndrome (THS) is characterized by painful ophthalmoplegia secondary to idiopathic granulomatous inflammation of the cavernous sinus. The characteristic finding on MRI is an enhancing T1 isointense and T2 hypo- or hyperintense cavernous sinus mass lesion, which may result in focal narrowing of the ipsilateral internal carotid artery. Although the incidence is quite rare, it is a common diagnostic consideration in cases that present with multiple cranial neuropathies. However, the differential diagnosis for a unilateral cavernous sinus lesion in adults is broad and includes neoplastic, inflammatory (such as sarcoidosis and immunoglobulin G4-related disease [IgG4-RD]), infectious etiologies (such as syphilis and leprosy), as well as vascular lesions. We describe a patient presenting with neurologic symptoms referable to a persistent unilateral cavernous sinus MRI abnormality, initially thought to be consistent with Tolosa-Hunt syndrome, that was clinically but not radiographically responsive to steroids. Following reevaluation due to the presence of new symptoms, pathology revealed that the abnormality was most consistent with chordoma, a rare skull based tumor. In patients with a presumed diagnosis of Tolosa-Hunt syndrome, close clinical and radiographic follow-up is imperative, with early consideration for biopsy in patients that fail to respond to treatment both clinically and radiographically.

[Extended endoscopic endonasal surgery for clival chordoma and chondrosarcoma: Our experience in 14 cases]

OBJECTIVE

To report our experience in the management of chordoma and chondrosarcoma with extended endoscopic endonasal surgery.

METHOD

We performed a retrospective analysis of a series of 14 patients with clival chordoma or chondrosarcoma who had extended endoscopic endonasal surgery from 2008 to 2016 performed by the same multidisciplinary team.

RESULTS

We had fourteen patients (male/female 2:1), with a mean age of 49years for chordoma and 32 for chondrosarcoma. The most common clinical presentation was diplopia in 78.5% of cases, followed by dysphagia in 28.6%. Histologically, 71.4% were chordomas and 28.6% were chondrosarcomas. In addition, invasion of at least two thirds or more of the clivus was found in 81% of the cases; in 57.1% there was intradural invasion, and in 35.7% invasion of the sella turcica. In 42.8% of cases, the degree of resection was total and in 21.5% subtotal. The most common complication was CSF fistula, occurring in 28.6% of the cases, with only one case requiring surgery to repair it. Adjuvant treatment with Proton Beam was performed in 35.7% of cases and with conventional radiotherapy in 21.5%. Mean follow-up was 53.5months and tumour recurrence or progression was found in 21.5% of the cases, two of which had not received adjuvant treatment. There were no deaths.

CONCLUSION

The extended endoscopic endonasal approach (EEEA) performed by an experienced team is a good alternative for the management of these lesions. Intradural invasion may be related to an increased risk of complications and worse clinical presentation, in addition to a lower rate of total resection.

Clinical Application of Multimodal Neuronavigation System in Neuroendoscope-Assisted Skull Base Chordoma Resection

Skull base chordoma is a rare tumor arising from embryonic remnants of the notochord with invasive potential. Due to the destruction of osseous landmarks and invasion of surrounding structures, surgical resection is challenging. The authors explored the clinical value of a multimodal neuronavigation system in skull base chordoma resection using a neuroendoscope. Between January 2012 and January 2016, the authors utilized neuroendoscopy to excise skull base chordoma in 93 patients. The authors performed 45 operations assisted by multimodal neuronavigation (neuronavigation group) and 48 without intraoperative imaging guidance (control group). In the control group, 35 patients (73%) underwent gross total resection. In the neuronavigation group, all patients underwent gross total resection without radiographically identified bleeding. Only 1 patient (2%) in the neuronavigation group showed a temporary reduction in vision, which improved after symptomatic treatment. In contrast, there were 4 patients (8%) with postoperative complication, including 2 patients with intracranial hematoma and 2 with neurological deficits. Complication rates were higher than the neuronavigation group. In the follow-up period, 2 patients in the control group with subtotal resection had recurrence within 24 months, but without extracranial metastases. The multimodal neuronavigation system could contribute intraoperative real-time guidance for spatial relationships between lesions and adjacent neurovascular structures, as well as eroded and distorted anatomical landmarks through multiple image fusion and 3-dimensional reconstruction. It significantly improves surgical outcome and provides a new insight into the management of skull base chordomas.

State-of-the-Art Imaging in Human Chordoma of the Skull Base

Purpose of Review

Chordoma are rare tumours of the axial skeleton which occur most often at the base of the skull and in the sacrum. Although chordoma are generally slow-growing lesions, the recurrence rate is high and the location makes it often difficult to treat. Both computed tomography (CT) and magnetic resonance imaging (MRI) are crucial in the initial diagnosis, treatment planning and post-treatment follow-up.

Recent Findings

Basic MRI and CT characteristics of chordoma were described in the late 1980s and early 1990s. Since then, imaging techniques have evolved with increased resolution and new molecular imaging tools are rapidly evolving. New imaging tools have been developed not only to study anatomy, but also physiologic changes and characterization of tissue and assessment of tumour biology. Recent studies show the uptake of multiple PET tracers in chordoma, which may become an important aspect in the diagnosis, follow-up and personalized therapy.

Summary

This review gives an overview of skull base chordoma histopathology, classic imaging characteristics, radiomics and state-of-the-art imaging techniques that are now emerging in diagnosis, treatment planning and disease monitoring of skull base chordoma.

The identification of H3F3A mutation in giant cell tumour of the clivus and the histological diagnostic algorithm of other clival lesions permit the differential diagnosis in this location

BACKGROUND

Giant Cell Tumour of Bone (GCT) is a locally aggressive primary bone tumour that usually occurs at the epiphyses of the long bones of the appendicular skeleton with a tendency to recurrence. Recurrent somatic H3F3A mutations have been described in 92% of GCT cases. GCTs involving the Clivus are extremely rare lesions and less than 15 cases are described in the literature. They represent a surgery challenge and are easily misdiagnosed. Our aim was to reveal if the genetic bases underlying Clival GCTs were the same of GCTs of long bones to improve the diagnosis and treatment.

METHODS

The targeted somatic sequencing of GCT-related genes (H3F3A, H3F3B, IDH1, IDH2 and ZNF687) was performed on Clival GCT biopsies of two different cases. Histological analyses on the same tissues were used to detect the neoplastic population and its expression profile.

RESULTS

Sanger sequencing revealed that both patients were positive for the p.Gly34Trp mutation in the H3F3A gene. Immunofluorescence assay using monoclonal antibody, specifically detecting the mutant H3.3, highlighted that the mutation only involved the mononuclear cell population and not the multinucleated giant cells. Moreover, immunohistochemistry assay showed that RANKL was highly expressed by the stromal cells within Clival GCT, mimicking what happens in GCT of the long bones. In addition, systematic literature review allowed us to generate a histology-based diagnostic algorithm of the most common clival lesions.

CONCLUSIONS

We conclude that the Clival GCT is genetically defined by somatic mutation in the H3F3A gene, linking it to the GCT of long bones. The similarity with GCTs of long bones let us to hypothesize the utility of Denosumab therapy (already effective for GCTs) in these surgically challenging cases. Moreover, H3F3A genetic screening can be combined to the histological analysis to differentiate GCTs from morphologically similar giant cell-rich sarcomas, while the histological diagnostic algorithm could help the differential diagnosis of other clival lesions.

Impact of early access to multidisciplinary care on treatment outcomes in patients with skull base chordoma

OBJECTIVE

To determine if early access to multidisciplinary surgical care affects outcomes in patients with skull base chordoma.

METHOD

A retrospective chart review of prospectively collected data was performed on 51 patients treated from 1993 to 2014. The cohort was divided into those presenting (1) for initial management (ID, n = 21) or (2) with persistent/progressive disease after prior biopsy/surgery (PD, n = 30) outside of a multidisciplinary setting. The impact of initial surgical management in a multidisciplinary center on progression-free survival (PFS) was assessed with Kaplan-Meier and log-rank analyses.

RESULTS

Mean follow-up, median PFS, median overall survival (OS), and 10-year OS for the entire cohort was 70 months, 47 months, 159 months, and 19%, respectively. Initial management in a multidisciplinary center resulted in a significant improvement in PFS versus initial surgery with or without radiotherapy (XRT) outside of this setting (64 vs 25 months, p = 0.035). Initial surgical resection outside of a multidisciplinary setting increased the risk of recurrence/progression on univariate (HR, 2.276; p = 0.022) and multivariate analysis (HR, 2.831; p = 0.006), respectively.

CONCLUSIONS

The results from this study emphasize the impact that coordinated multidisciplinary surgical care has on patient outcomes for chordomas of the clivus. Biopsy followed by attempted radical resection at a dedicated center does not affect PFS and, therefore, represents a reasonable first step in management for patients presenting outside of multidisciplinary setting.

Surgical Resection and Adjuvant Radiation Therapy in the Treatment of Skull Base Chordomas

OBJECTIVE

Chordomas are rare tumors of notochordal origin that are known to be locally aggressive and are often treated with surgical resection followed by adjuvant radiation therapy (RT). The accepted standard of treatment for chordomas of the mobile spine, which includes en-bloc resection with wide margins, cannot be easily applied to the chordomas of the skull base because of their proximity to critical neurovascular structures. We describe our experience with the role of surgery and adjuvant RT in the treatment of chordomas over 16 years.

METHODS

We performed a retrospective chart review on patients with diagnoses of clival chordoma between the years 2000 and 2015 at Northwestern Memorial Hospital. We reviewed presenting symptoms, tumor location and size, extent of resection, complications, recurrence, adjuvant treatment, and follow-up duration.

RESULTS

A total of 20 patients underwent 32 surgeries. Of the 20 initial surgeries, 80% underwent gross total resection, and 20% had subtotal resection. The mean follow-up time was 60.75 months. Mean tumor volume was 23.07 cm³. Most common presenting signs and symptoms were headaches (70%), cranial nerve palsies (45%), and diplopia (55%). Diplopia was defined as complaints of double vision without any objective evidence of a cranial nerve palsy. Median time to progression was 57 months, and median overall survival was 136 months. Initial tumor volume and the need for a second dose of RT either as sole or as adjuvant treatment of a recurrence had a statistically significant effect on progression-free survival (P = 0.009, 0.009). None of the factors studied had a statistically significant effect on overall survival.

CONCLUSIONS

The treatment of chordomas remain challenging and requires multimodal treatment strategies spanning different specialties. Initial tumor size and need for second dose of RT for recurrence appear to play a significant role in progression-free survival. Adjuvant RT after gross total resection may play a role in improved progression-free and overall survival in patients with clival chordomas.

Presentation, Treatment, and Long-Term Outcome of Intrasellar Chordoma: A Pooled Analysis of Institutional, SEER (Surveillance Epidemiology and End Results), and Published Data

BACKGROUND

Chordoma that occurs primarily in the sella turcica is rare and presents unique treatment challenges.

OBJECTIVE

The purpose of this study was to determine common features, treatment approaches, and survival characteristics of intrasellar chordoma.

METHODS

Institutional databases, the SEER (Surveillance Epidemiology and End Results) database, and PubMed/EMBASE were queried for chordoma with a primarily intrasellar component. The SEER database was also queried for adult skull base chordoma. Patient-level data were extracted where available. Kaplan-Meier survival analyses were conducted.

RESULTS

Among 80 cases, the mean age at presentation was 55.6 (standard deviation, 15.9), with a female predominance (1.16:1.00). Patients experienced symptoms for a mean duration of 19.0 months, including cranial nerve deficits, hypopituitarism, and hyperprolactinemia. Among patients receiving treatment, 77.5% underwent surgery. In addition, less than half of the patients (n = 34, 47.3%) received adjuvant radiation therapy. The 5-year overall survival (OS) of intrasellar chordoma was 60.0% (standard error [SE], 6.9). Patients aged 40 years and younger had a 5-year OS of 80.8% (SE, 12.2), compared with patients older than 40 years, who had an OS of 55.4% (SE, 7.7) (Mantel-Cox, P = 0.044). Males experienced a lower 5-year OS (44.0; SE, 9.7) than did females (76.8; SE, 8.5), (Mantel-Cox, P = 0.003). Median OS was greater in patients with skull base chordoma than in patients with intrasellar chordoma (Mantel-Cox, P = 0.046).

CONCLUSIONS

Intrasellar chordoma presents frequently with visual disturbances and hyperprolactinemia and has a slightly higher incidence in females. Young age predicts a better prognosis. Intrasellar chordoma has a lower overall survival than has skull base chordoma.

Proposed Treatment Paradigm for Intracranial Chondrosarcomas Based on Multidisciplinary Coordination

OBJECTIVES

There was no consensus regarding the treatment of intracranial chondrosarcoma (CSA). The study aimed to evaluate the adverse factors for progression-free survival (PFS) and overall survival (OS) and to propose a treatment strategy for CSA.

METHODS

The clinical chart and radiographic data of 106 consecutive cases (mesenchymal and conventional CSA in 18 and 88 patients, respectively) of surgically treated CSAs were retrospectively reviewed.

RESULTS

Gross total resection was achieved in 43 patients (40.6%), and adjuvant radiotherapy was administered in 45 patients. After a mean follow-up duration of 47.8 months, 38 patients (37.3%) experienced recurrence. PFS and disease-specific OS at 5 years was 57.7% and 74.4%. Independent adverse factors for PFS were previous surgery (hazard ratio [HR] 2.261; P = 0.028), increased lesion size (HR, 1.298; P = 0.026), extent of surgical resection (HR, 3.226; P < 0.001), malignant pathology (HR, 2.018; P = 0.003), and postoperative radiotherapy (HR, 3.246; P = 0.001). The stereotactic radiosurgery subgroup presented best 5-year PFS of 88.9%, and a linear accelerator prolonged the mean PFS time (57.0 months) compared with no radiation (38.1 months). In the incomplete resection subgroup (n = 63), radiotherapy significantly benefited tumor control (HR, 2.101; P = 0.016). Extent of surgical resection (HR, 1.797; P = 0.026) and malignant disease (HR, 1.717; P = 0.030) were associated with OS.

CONCLUSIONS

Intracranial CSAs were not completely amendable by surgery alone. Gross total resection as far as possible plus radiation were necessary for mesenchymal CSA and conventional CSA with active growth or residual tumor. Stereotactic radiosurgery was an alternative if proton therapy was unavailable. A future study with a large cohort is required to verify our findings.

Chordoma of the Head and Neck: A Review

Chordoma is a rare malignant bone tumor that can arise anywhere along the central neural axis and many involve head and neck sites, most commonly the skull base. The relative rarity of these tumors, combined with the complex anatomy of the head and neck, pose diagnostic challenges to pathologists. This article describes the pertinent clinical, pathologic, and molecular features of chordomas and describes how these features can be used to aid in formulating a differential diagnosis. Emphasis is placed on key diagnostic pitfalls and the importance of incorporating immunohistochemical information into the diagnosis.

Clival chordoma: a single-centre outcome analysis

BACKGROUND

The treatment of clival chordomas remains challenging. Total tumour resection is often impossible without hampering adjacent anatomical structures and causing functional sequelae. On the other hand, chordomas show limited response to non-surgical treatment modalities. Up to now, no well-established interdisciplinary treatment algorithms for clival chordomas exist. In this regard, we analysed the data from all patients that underwent interdisciplinary treatment for clival chordoma in our institution over the last 10 years.

METHOD

Retrospective report of all patients treated at the authors' institution from 2005 to 2015.

RESULTS

Thirteen patients underwent 24 surgeries, of which 2 (8%) were gross total resections and 22 (92%) incomplete resections. Neurological deterioration, endocrinological disturbances and other surgical complications were observed in six (25%), three (13%) and nine (38%) cases, respectively. Three surgeries (13%) led to an improvement of the initial preoperative neurological condition. All patients were discussed on the interdisciplinary tumour board and all underwent one type of radiotherapy following initial surgery: proton beam in 11 cases (85%) and photon beam in two (15%) cases. In the course of their recurrent disease, three patients (23%) received systemic therapy (imatinib, pazopanib and nivolumab). One patient received a personalised cellular immunotherapy. One patient (8%) was lost to follow-up. Of the remaining 12 patients, four patients (33%) died in the period of analysis; all deaths were chordoma-related. The 5-year cumulative survival rate was 83% (52-97%, CI 95%), 5-year progression-free survival rate was 53% (26-79%, CI 95%). The eight patients (66%) still alive had favourable outcome (KPS, 90 ± 10.7%). SF36 analysis among the survivors revealed 43 points for the Physical Component Summary (12% above, 38% at and 50% below the general population norm) and 47 points for the Mental Component Summary (25% above, 38% at and 38% below).

CONCLUSIONS

Our patients show a low rate of gross total resection but an outcome well comparable to other published results. This emphasises the importance of interdispiplinary treatment strategies, with surgery supplying maximal safe resection and avoiding severe neurological deficit, allowing patients to undergo adjusted radiotherapy and other treatment options in a good condition.

Multidisciplinary management of clival chordomas; long-term clinical outcome in a single-institution consecutive series

OBJECTIVE

Chordomas of the skull base have high recurrence rates even after radical resection and adjuvant radiotherapy. We evaluate the long-term clinical outcome using multidisciplinary management in the treatment of clival chordomas.

METHODS

Between 1984 and 2015, 22 patients diagnosed with an intracranial chordoma were treated at the Karolinska University Hospital, Stockholm, Sweden. Sixteen of 22 were treated with Gamma Knife radiosurgery (GKRS) for tumour residual or progression during the disease course. Seven of 22 received adjuvant fractionated radiotherapy and 5 of these also received proton beam radiotherapy.

RESULTS

Fifteen of 22 (68%) patients were alive at follow-up after a median of 80 months (range 22-370 months) from the time of diagnosis. Six were considered disease free after >10-year follow-up. The median tumour volume at the time of GKRS was 4.7 cm³, range 0.8-24.3 cm³. Median prescription dose was 16 Gy, range 12-20 Gy to the 40-50% isodose curve. Five patients received a second treatment with GKRS while one received three treatments. After GKRS patients were followed with serial imaging for a median of 34 months (range 6-180 months). Four of 16 patients treated with GKRS were in need of a salvage microsurgical procedure compared to 5/7 treated with conventional or proton therapy.

CONCLUSION

After surgery, 7/22 patients received conventional and/or photon therapy, while 15/22 were treated with GKRS for tumour residual or followed with serial imaging with GKRS as needed upon tumour progression. With this multidisciplinary management, 5- and 10-year survivals of 82% and 50% were achieved, respectively.

Long non-coding RNA LOC554202 modulates chordoma cell proliferation and invasion by recruiting EZH2 and regulating miR-31 expression

OBJECTIVES

Chordoma is a rare malignant bone tumour arising from notochordal remnants. Long non-coding RNA LOC554202, as the host gene of miR-31, contributes to various cancer developments. However, little is known about the biological function of LOC554202 in chordoma. Here, the relationship between LncRNA LOC554202, miR-31 and EZH2 was elucidated in chordoma.

MATERIALS AND METHODS

The levels of LOC554402, miR-31, EZH2, RNF144B, and epithelial-mesenchymal transition (EMT) markers were measured in chordoma tissues and the chordoma cell lines via quantitative real-time PCR (qRT-PCR) or Western blot. FISH assay demonstrated the LOC554402 expression in chordoma tissues. The chordoma cell lines, U-CH1 and JHC7, were transfected with siRNA or miRNA mimics and analysed for cell proliferation ability, apoptosis, cell migration, and invasion. RNA pull down, RIP assay, and Luciferase Reporter Assay were used to analyze the interaction between LOC554202 and EZH2. Animal tumour xenografts were generated, and qRT-PCR was performed to investigate EZH2, miR-31, and RNB144B expression on tumour growth in vivo.

RESULTS

We found elevated expression of LOC554202 was associated with a decreased level of miR-31 in cancer tissues. Knockdown of LOC554202 or overexpression of miR-31 suppressed the proliferation, migration, and invasion of chordoma cells. Unexpectedly, EZH2 as a binding protein of LOC554202, and it was positively regulated by LOC554202, leading to the reduced expression of miR-31. Furthermore, the impaired function of miR-31 restored expression of the oncogene RNF144B and maintained the metastasis-promoting activity in vitro. The results in vivo confirmed the anti-tumour effects of knockdown of LOC554202, which inhibited EZH2/miR-31 to activate the oncogene RNF144B.

CONCLUSION

Our results suggest that LOC554202 may play an important role in the progression of chordoma by the direct upregulation of EZH2 and indirect promotion of RNF144B via miR-31.

Role of endoscopic transnasal surgery for skull base chondrosarcoma: a retrospective analysis of 19 cases at a single institution

OBJECTIVE Skull base chondrosarcoma is one of the most intractable tumors because of its aggressive biological behavior and involvement of the internal carotid artery and cranial nerves (CNs). One of the most accepted treatment strategies for skull base chondrosarcoma has been surgical removal of the tumor in conjunction with proactive extensive radiation therapy (RT) to the original tumor bed. However, the optimal strategy has not been determined. The goal of this study was to evaluate the early results of endoscopic transnasal surgery (ETS). METHODS The authors retrospectively analyzed 19 consecutive patients who underwent ETS at their institution since 2010. Adjuvant stereotactic radiosurgery (SRS) was performed only for the small residual tumors that were not resected to avoid critical neurological complications. Histological confirmation and evaluation of the MIB-1 index was performed in all cases. The Kaplan-Meier method was used to determine the actuarial rate of tumor-free survival. RESULTS The median tumor volume and maximal diameter were 14.5 cm³ (range 1.4-88.4 cm³) and 3.8 cm (range 1.5-6.7 cm), respectively. Nine patients (47%) had intradural extension of the tumor. Gross-total resection was achieved in 15 (78.9%) of the 19 patients, without any disabling complications. In 4 patients, the surgery resulted in subtotal (n = 2, 11%) or partial (n = 2, 11%) resection because the tumors involved critical structures, including the basilar artery or the lower CNs. These 4 patients were additionally treated with SRS. The median follow-up duration was 47, 28, and 27 months after the diagnosis, ETS, and SRS, respectively. In 1 patient with an anterior skull base chondrosarcoma, the tumor relapsed in the optic canal 1 year later and was treated with a second ETS. Favorable tumor control was achieved in all other patients. The actuarial tumor control rate was 93% at 5 years. At the final follow-up, all patients were alive and able to perform independent activities of daily living without continuous neurological sequelae. CONCLUSIONS These preliminary results suggest that ETS can achieve sufficient radical tumor removal, resulting in comparative resection rates with fewer neurological complications to those in previous reports. Although the follow-up periods of these cases were relatively short, elective SRS to the small tumor remnant may be rational, achieving successful tumor control in some cases, instead of using proactive extensive RT. Thus, the addition of RT should be discussed with each patient, after due consideration of histological grading and biological behavior. To determine the efficacy of this strategy, a larger case series with a longer follow-up period is essential. However, this strategy may be able to establish evidence in the management of skull base chondrosarcoma, providing less-invasive and effective options as an initial step of treatment.

Pediatric Clival Chordoma: A Curable Disease that Conforms to Collins' Law

BACKGROUND

Skull base chordomas in children are extremely rare. Their course, management, and outcome have not been defined.

OBJECTIVE

To describe the preeminent clinical and radiological features in a series of pediatric patients with skull base chordomas and analyze the outcome of a cohort who underwent uniform treatment. We emphasize predictors of overall survival and progression-free survival, which aligns with Collins’ law for embryonal tumors.

METHODS

Thirty-one patients with a mean age of 10.7 yr (range 0.8-22) harboring skull base chordomas were evaluated. We retrospectively analyzed the outcomes and prognostic factors for 18 patients treated by the senior author, with uniform management of surgery with the aim of gross total resection and adjuvant proton-beam radiotherapy. Mean follow-up was 119.2 mo (range 8-263).

RESULTS

Abducens nerve palsy was the most common presenting symptom. Imaging disclosed large tumors that often involve multiple anatomical compartments. Patients undergoing gross total resection had significantly increased progression-free survival (P = .02) and overall survival (P = .05) compared with those having subtotal resection. Those who lived through the period of risk for recurrence without disease progression had a higher probability of living entirely free of progression (P = .03; odds ratio = 16.0). Age, sex, and histopathological variant did not yield statistical significance in survival.

CONCLUSION

Long-term overall and progression-free survival in children harboring skull base chordomas can be achieved with gross surgical resection and proton-beam radiotherapy, despite an advanced stage at presentation. Collins’ law does apply to pediatric skull base chordomas, and children with this disease have a high hope for cure.

Genetic aberrations and molecular biology of skull base chordoma and chondrosarcoma

Chordomas and chondrosarcomas are two major malignant bone neoplasms located at the skull base. These tumors are rarely metastatic, but can be locally invasive and resistant to conventional chemotherapies and radiotherapies. Accordingly, therapeutic approaches for the treatment of these tumors can be difficult. Additionally, their location at the skull base makes them problematic. Although accurate diagnosis of these tumors is important because of their distinct prognoses, distinguishing between these tumor types is difficult due to overlapping radiological and histopathological findings. However, recent accumulation of molecular and genetic studies, including extracranial location analysis, has provided us clues for accurate diagnosis. In this report, we review the genetic aberrations and molecular biology of these two tumor types. Among the abundant genetic features of these tumors, brachyury immunohistochemistry and direct sequencing of IDH1/2 are simple and useful techniques that can be used to distinguish between these tumors. Although it is still unclear why these tumors, which have such distinct genetic backgrounds, show similar histopathological findings, comparison of their genetic backgrounds could provide essential information.

Multimodality Treatment of Skull Base Chondrosarcomas: The Role of Histology Specific Treatment Protocols

BACKGROUND: Limited data exist to guide the multimodality management of chondrosarcomas (CSAs) arising in the skull base.

OBJECTIVE: To determine the impact of histological subtype/grade on progression-free survival (PFS) and the indications for surgery, radiation, and chemotherapy based on histology.

METHODS: A retrospective review was performed of 37 patients (conventional type: 81%, mesenchymal: 16.2%, dedifferentiated: 2.7%) treated at The University of Texas M.D. Anderson Cancer Center. Of the conventional subtype, 23% were grade 1, 63% were grade 2, and 14% were grade 3. In addition to surgery, mesenchymal/dedifferentiated CSAs (18% of the cohort) underwent neoadjuvant chemotherapy and 48.6% of the overall cohort received adjuvant radiotherapy. Histological grade/subtype and treatment factors were assessed for impact on median PFS (primary outcome).

RESULTS: Conventional subtype vs mesenchymal/dedifferentiated was positively associated with median PFS (166 vs 24 months, P &lt; .05). Increasing conventional grade inversely correlated with median PFS (P &lt; .05). Gross total resection positively impacted PFS in conventional CSAs (111.8 vs 42.9 months, P = .201) and mesenchymal/dedifferentiated CSAs (58.2 vs 1.0 month, P &lt; .05). Adjuvant radiotherapy significantly impacted PFS in conventional grades 2 and 3 (182 vs 79 months, P &lt; .05) and a positive trend with mesenchymal/dedifferentiated CSAs (43.5 vs 22.0 months). Chemotherapy improved PFS for mesenchymal/dedifferentiated CSAs (50 vs 9 months, P = .089).

CONCLUSION: There is a potential need for histological subtype/grade specific treatment protocols. For conventional CSAs, surgery alone provides optimal results grade 1 CSAs, while resection with adjuvant radiotherapy yields the best outcome for grade 2 and 3 CSAs. Improvements in PFS seen with neoadjuvant therapy in mesenchymal/dedifferentiated CSAs indicate a potential role for systemic therapies. Larger studies are necessary to confirm the proposed treatment protocols.

Distinctive Head and Neck Bone and Soft Tissue Neoplasms

Benign and malignant primary bone and soft tissue lesions of the head and neck are rare. The uncommon nature of these tumors, combined with the complex anatomy of the head and neck, pose diagnostic challenges to pathologists. This article describes the pertinent clinical, radiographic, and pathologic features of selected bone and soft tissue tumors involving the head and neck region, including angiofibroma, glomangiopericytoma, rhabdomyosarcoma, biphenotypic sinonasal sarcoma, chordoma, chondrosarcoma, and osteosarcoma. Emphasis is placed on key diagnostic pitfalls, differential diagnosis, and the importance of correlating clinical and radiographic information, particularly for tumors involving bone.

Leukemia Inhibitory Factor Promotes Aggressiveness of Chordoma

Chordomas are rare tumors of the spine and skull base that are locally destructive and resistant to chemotherapy and radiation therapy, with a poor prognosis and limited therapeutic options. Chordoma patients have a long life expectancy with high mortality from the disease. Cancer stem cells, which are known to exist in chordomas, have extensive proliferative and self-renewal potential and are responsible for maintaining tumor heterogeneity along with chemotherapy and radiotherapy resistance. Leukemia inhibitory factor (LIF) has multiple functions in stem cell biology, the immune response, and cancer, and is potentially a key molecule that allows cancer stem cells to self-renew. The purpose of this study was to determine whether LIF increases the aggressive traits of chordoma cells and leads to a poor prognosis in patients. Chordoma cell lines were treated with LIF, and functional tests were done. Twenty skull base chordoma samples were checked for levels of LIF and a correlation with clinicopathological features. The whole transcriptome microarray was used to observe changes in gene expression. We observed increased migration, invasion, tumorosphere formation, colony formation, epithelial–mesenchymal transition, and chemoresistance accompanied by a dramatic elevation in inflammatory gene networks and pathways in chordomas. The expression of LIF was associated with tumor size and a poorer overall survival. Microarray and quantitative real-time polymerase chain reaction assessments suggest that LIF can facilitate tumor-promoting inflammation. Results indicate that LIF plays a role in maintaining cancer stem cells in chordomas.

Sellar and Parasellar Imaging

The skull base is a complex anatomical region that harbors many important neurovascular structures in a relatively confined space. The pathology that can develop at this site is varied, and many disease processes may present with similar clinical and neuroimaging findings. While computed tomography maintains a role in the evaluation of many entities and can, for instance, delineate osseous erosion with great detail and characterize calcified tumor matrices, magnetic resonance imaging (MRI) is the mainstay in the neuroimaging assessment of most pathology occurring at the skull base. Various MRI sequences have proven to be robust tools for tissue characterization and can provide information on the presence of lipids, paramagnetic and diamagnetic elements, and tumor cellularity, among others. In addition, currently available MRI techniques are able to generate high spatial resolution images that allow visualization of cranial nerves and their involvement by adjacent pathology. The information obtained from such examinations may aid in the distinction of these disease processes and in the accurate delineation of their extent prior to biopsy or treatment planning.

A Prospective Outcomes Study of Proton Therapy for Chordomas and Chondrosarcomas of the Spine

PURPOSE

To evaluate the effectiveness of definitive or adjuvant external beam proton therapy on survival in patients with chordomas and chondrosarcomas of the spine.

METHODS AND MATERIALS

Between March 2007 and May 2013, 51 patients with a median age of 58 years (range, 22-83 years) with chordoma (n=34) or chondrosarcomas (n=17) of the sacrum (n=21), the cervical spine (n=20), and the thoracolumbar spine (n=10) were treated with external beam proton therapy to a median dose of 70.2 Gy(RBE) [range, 64.2-75.6 Gy(RBE)] at our institution. Distant metastases, overall survival, cause-specific survival, local control, and disease-free survival were calculated.

RESULTS

The mean follow-up time was 3.7 years (range, 0.3-7.7 years). Across all time points, 25 patients experienced disease recurrence: 18 local recurrences, 6 local and distant recurrences, and 1 distant metastasis. The 4-year rates of overall survival and cause-specific survival were 72%; disease-free survival was 57%, local control was 58%, and freedom from distant metastases was 86%. The median time to local progression was 1.7 years (range, 0.2-6.0 years), and the median time to distant progression was 1.6 years (range, 0.2-6.0 years). The risk factors for local recurrence were age ≤58 years (62% vs 26%; P=.04) and recurrence after prior surgery (29% vs 81%; P=.01). Secondary cancers developed in 2 patients: B-cell lymphoma 5.5 years after treatment and bladder cancer 2 years after treatment. We observed the following toxicities: sacral soft tissue necrosis requiring surgery (n=2), T1 vertebral fracture requiring fusion surgery (n=1), chronic urinary tract infections (n=1), surgery for necrotic bone cyst (n=1), and grade 2 bilateral radiation nephritis (n=1).

CONCLUSION

High-dose proton therapy controls more than half of spinal chordomas and chondrosarcomas and compares favorably with historic photon data. Local progression is the dominant mode of treatment failure and may be reduced by treating patients at the time of initial diagnosis. The impact of age is a novel finding of this study.

Skull base chordomas: clinical outcome in a consecutive series of 45 patients with long-term follow-up and evaluation of clinical and biological prognostic factors

OBJECTIVE

Skull base chordomas (SBCs) are rare dysembryogenetic invasive tumors with a variable tendency for recurrence. According to previous studies, the recurrence rate seems to be affected by both clinical variables and tumor biological features. The authors present the results of treatment of SBCs in a large series of patients and investigate the role of 1p36 chromosomal region loss of heterozygosity (LOH) as a prognostic factor.

METHODS

Between 1990 and 2011, 45 patients were treated for SBCs. The mean follow-up was 76 months (range 1–240 months). An LOH analysis was performed in 27 cases. Survival analysis was performed to determine clinical and biological parameters correlating with clinical outcome.

RESULTS

The 5- and 10-year overall survival rates were 67% and 57%, respectively. Five- and 10-year progression-free survival rates were 58% and 44%, respectively. Multivariate analysis showed that extent of resection, adjuvant radiation therapy, and absence of rhinopharynx invasion were positive independent predictors of overall survival. The latter 2 variables and a younger patient age were positive independent predictors of progression-free survival. Twenty-one patients showed 1p36 LOH. All events of recurrence and death clustered in the group of patients with 1p36 LOH; however, this biological marker was not statistically significant on multivariate analysis.

CONCLUSIONS

Resection is the treatment of choice in primary and recurrent SBC. Patient age, rhinopharynx invasion at diagnosis, extent of tumor removal, and postoperative radiation therapy influence SBC prognosis. Genetic analysis, even while showing interesting results, did not reveal 1p36 LOH as an independent predictor of clinical outcome.

Surgical management of skull base tumors

AIM

To present a review of the contemporary surgical management of skull base tumors.

BACKGROUND

Over the last two decades, the treatment of skull base tumors has evolved from observation, to partial resection combined with other therapy modalities, to gross total resection and no adjuvant treatment with good surgical results and excellent clinical outcomes.

MATERIALS AND METHODS

The literature review of current surgical strategies and management of skull base tumors was performed and complemented with the experience of Barrow Neurological Institute.

RESULTS

Skull base tumors include meningiomas, pituitary tumors, sellar/parasellar tumors, vestibular and trigeminal schwannomas, esthesioneuroblastomas, chordomas, chondrosarcomas, and metastases. Surgical approaches include the modified orbitozygomatic, pterional, middle fossa, retrosigmoid, far lateral craniotomy, midline suboccipital craniotomy, and a combination of these approaches. The selection of an appropriate surgical approach depends on the characteristics of the patient and the tumor, as well as the experience of the neurosurgeon.

CONCLUSION

Modern microsurgical techniques, diagnostic imaging, intraoperative neuronavigation, and endoscopic technology have remarkably changed the concept of skull base surgery. These refinements have extended the boundaries of tumor resection with minimal morbidity.