Chondrosarcoma of the temporal bone. Diagnosis and treatment of 13 cases and review of the literature

Endoscopic transsphenoidal approach in resection of intracranial clivus chondrosarcoma: A case report

Intracranial primary chondrosarcomas are rare, accounting for <0.15% of all intracranial tumors, but exhibit a high risk of recurrence. Due to the rarity of this condition, it has proven difficult to establish efficacy-based treatment guidelines. The present study details a case of clivus chondrosarcoma exhibiting no recurrence following surgical resection using an endoscopic transsphenoidal approach and postoperative adjuvant radiotherapy. A 41-year-old female presented with primary symptoms of left eye esotropia, scotoma of the left nasal visual field and double vision. Preoperative cranial magnetic resonance imaging revealed a lesion on the clivus, which was initially diagnosed as chordoma. However, clivus chondrosarcoma was ultimately diagnosed based on intraoperative findings and postoperative histopathology. The tumor was totally resected and 25 doses of adjuvant radiotherapy with planning gross tumor volume (60 Gy) and planning clinical target volume (50 Gy) were administered for 5 weeks. The patient was discharged at 12 days post-surgery with no obvious postoperative complications. Over the 28-month follow-up period, there was no evidence of recurrence, which may be due to the successful use of combined gross total resection and adjuvant radiotherapy. Therefore, surgical resection using an endoscopic transsphenoidal approach and postoperative adjuvant radiotherapy is an effective method for treating intracranial clivus chondrosarcoma.

Rare Diseases of the Middle Ear and Lateral Skull Base

Otalgia, otorrhea and hearing loss are the most common ear-related symptoms that lead to the consultation of an otolaryngologist. Furthermore, balance disorders and affections of the cranial nerve function may play a role in the consultation. In large academic centres, but also in primary care, the identification of rare diseases of the middle ear and the lateral skull base is essential, as these diseases often require interdisciplinary approaches to establish the correct diagnosis and to initiate safe and adequate treatments. This review provides an overview of rare bone, neoplastic, haematological, autoimmunological and infectious disorders as well as malformations that may manifest in the middle ear and the lateral skull base. Knowledge of rare disorders is an essential factor ensuring the quality of patient care, in particular surgical procedures. Notably, in untypical, complicated, and prolonged disease courses, rare differential diagnoses need to be considered.

[Falcine chondrosarcoma (case report and literature review)]

Chondrosarcoma is a rare malignancy composed of transformed cells of cartilage. This cancer is characterized by slow growth. Almost 75% of intracranial chondrosarcomas are observed on the skull base and grow from bone synchondrosis. Other rarer localizations of tumor are cerebral falx, tentorium cerebelli, vascular plexuses of the ventricles, fourth ventricle, convexital surface of the brain, etc. In this manuscript, we report treatment of patient with falcine chondrosarcoma.

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.

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.

Chondrosarcoma of the skull base: report of six cases

Five patients with chondrosarcoma, grade I or II, and one with mesenchymal chondrosarcoma of the skull base were treated at our clinic between 1967 and 1991. The patients were three men and three women who ranged in age from 21 to 39 years. The presenting symptoms were diplopia, decreased visual acuity, or symptoms of involvement of VIIIth and lower cranial nerves. The duration of the symptoms ranged from 18 months to 14 years. A plain skull x-ray and tomography of the skull, computed tomographic (CT) scans, and magnetic resonance images (MRI) revealed a calcified mass. Angiograms showed an occlusion of the arteries or venous sinuses, or both, in four patients, and a distinct tumor stain in one. The tumors were subtotally removed in all six cases. Two patients received postoperative irradiation for the residual tumor. In one patient, extraocular movement was compromised postoperatively, although in the other five patients there was no aggravation of the neurologic signs. Follow-up CT scans and MRI demonstrated no recurrent tumors nor any enlargement of residual tumors. Based on these findings, we advocate aggressive surgical removal of these tumors, which should be augmented by radiation therapy if the postoperative CT scans or MRI reveal residual tumors.

Cranial chondrosarcoma and recurrence

The literature regarding recurrences in patients with cranial chondrosarcoma is limited to small series performed at single institutions, raising the question if these data precisely reflect the true recurrence of this tumor for guiding the clinician in the management of these patients. An extensive systematic review of the English literature was performed. The patients were stratified according to treatment modality, treatment history, histological subtype, and histological grade, and the recurrence rates were analyzed. A total of 560 patients treated for cranial chondrosarcoma were included. Five-year recurrence rate among all patients was 22% with median follow-up of 60 months and median disease-free interval of 16 months. Tumor recurrence was more common in patients who only received surgery or had mesenchymal subtype tumors. Our systematic review closely reflects the actuarial recurrence rate and provides predictive factors in the recurrence of cranial chondrosarcoma.

Pathobiology of selected tumors of the base of the skull

Skull base surgery is a new subspeciality, and, up to this point, most articles on this subject have focused on innovative operative-reconstructive approaches to tumors in this region. It is now important that we embark on a new era, the era of tumor biology, and concentrate on new ways of evaluating these neoplasms from a pathologic viewpoint. The hematoxylin-cosin section is no longer an end point, but just a beginning. This is the age of molecular biology. It is important that these tumors be evaluated, either prospectively or retrospectively, employing immunohistochemical staining, flow cytometry, oncogene expression, cytogenetics, or other techniques in order to identify important prognostic features. Data from these additional studies may then be used to develop new treatment strategies. Skull base societies should develop protocols for one or more of these tumors to ensure that they are indeed evaluated uniformly. In this article I emphasize the importance of accurate histologic classification or subclassification of these neoplasms and focus on contemporary parameters that may or may not impact on prognosis.

Malignant clival chordoma with postoperative cutaneous metastases

The authors report the case of a chordoma with malignant cytologic features, presenting as a mass lesion in the clival and infratemporal region at the level of the craniocervical junction in an 8-year-old female. Following gross resection of the mass, the patient subsequently developed distant subcutaneous and peritoneal metastases from the lesion. The rare histologic features, the surgical approach to the lesion, and the follow-up management of this unique case are discussed.

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.

A systematic review of intracranial chondrosarcoma and survival

Most data regarding survival in patients with chondrosarcoma are limited to case studies and small series performed at single institutions. A systematic review was performed to study the relationship between potential prognostic factors and survival. The survival rates were analyzed according to modality of treatment, treatment history, histological subtype, and histological grade. A total of 560 patients with intracranial chondrosarcoma were analyzed. Median follow-up time was 60 months. The 5-year mortality among all patients was 11.5% with median survival of 24 months. Mortality at 5 years was significantly greater for patients with tumors of higher grade, or of the mesenchymal subtype, or who had received surgical resection alone. The results of our systematic review provide useful data in predicting survival among intracranial chondrosarcoma patients.

[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.

Unusual presentation of petro-clival chondrosarcoma: short report

Skull base chondrosarcoma is a rare neoplasm. Our patient presented with acute onset of diplopia along with symptoms of lower cranial nerve palsies in 1997. She showed complete resolution of symptoms following a short course of antibiotics and remained quiescent for three years. However, remission of symptoms in chondrosarcoma is unusual. An unusual case of a patient with petroclival low grade chondrosarcoma, who presented with relapse of symptoms after three years and was treated with surgery and radiotherapy, is presented.

Chondrosarcoma of the temporal bone

Chondrosarcoma of the temporal bone is a rare disease, with only 36 cases of this tumor having been reported in the English language literature. We report the case of a 52-year-old woman with myxoid chondrosarcoma of the temporal bone whose only symptom was progressive hearing loss. The tumor was removed using aspiration, mastoidectomy and tympanotomy, with retention of the jugular bulb. No recurrence has been noted 45 months after the operation. Diagnosis was established from histological examination of the surgical specimens. The clinical characteristics and management of this rare lesion are discussed.

Chondrosarcomas of the skull base and temporal bone

OBJECTIVE

To evaluate the clinical presentation and outcomes of treatment for patients with chondrosarcomas involving the skull base and temporal bone.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary medical centre.

PATIENTS

Cases of histologically confirmed chondrosarcoma involving the skull base and temporal bones.

INTERVENTION

Surgery.

MAIN OUTCOME MEASURES

Demographic features of presenting patients; presenting symptoms and signs; surgical approach employed; use of post-operative radiation therapy; histological grade of tumour; and interval of post-operative follow up.

RESULTS

Twelve patients were identified with chondrosarcomas involving the skull base, with post-operative follow up ranging from three to 33 years. The average age at presentation was 42 years. The most common presenting symptoms were diplopia, decreased visual acuity and headaches. Five of the 12 patients required multiple surgical procedures.

CONCLUSIONS

Patients with chondrosarcoma involving the skull base and temporal bone may present in a variety of ways. Surgical resection, even subtotal, in combination with radiation therapy, can often provide good tumour control over many years for these rare tumours.

The challenges of revision skull base surgery

Because the skull base is an anatomically complex structure, skull base tumors can hide easily in the crevices that interconnect the intra- and extracranial spaces and intermingle with important neurovascular structures. Often, total surgical resection of these tumors is not possible, and even with postoperative adjuvant radiotherapy, some recurrences after treatment are inevitable. Early detection of recurrent skull base tumors requires clinical vigilance and periodic imaging studies. The management of recurrent skull base tumors presents many challenges beyond those associated with primary procedures. A multidisciplinary setting that includes modern microsurgery and stereotactic radiation therapy provides patients with optimal care.

Skull base chondrosarcoma originating from the petroclival junction

OBJECTIVE

To define the presentation of patients with skull base chondrosarcoma, to elucidate surgical strategies, and to identify the role of postoperative radiotherapy.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

All patients (n = 33) with skull base chondrosarcoma managed at our institution. The average follow-up time was 7.7 years (range, 0-20 years).

MAIN OUTCOME MEASURES

Tumor location, presenting symptoms, presence of residual or recurrent tumor, and mortality.

RESULTS

The most common tumor location was the petroclival junction (n = 29). Common presenting symptoms were diplopia (48%) and headache (45%). Surgical approaches included retrosigmoid, transtemporal, transfacial, and frontotemporal craniotomies. Biopsy only was performed in four patients, subtotal resection in 19 patients, and total resection in nine patients. Most patients received postoperative radiotherapy (82%). Follow-up revealed residual, stable disease in 28% of patients and recurrent disease in 24% of patients. The mean time to recurrence was 3.0 +/- 2.8 years. The lack of postoperative radiation was significantly correlated with an increased risk of recurrence (odds ratio, 28; p = 0.007) but incomplete tumor resection was not (p = 0.6). Life-table analysis revealed that the 5-year survival rate was 85% and the 10-year survival rate was 77%. Five patients died; four of the deaths attributable to recurrent disease.

CONCLUSION

The characteristic growth pattern of skull base chondrosarcoma is tumor eroding the petroclival junction. Current therapeutic strategy is resection through an extradural subtemporal craniotomy with removal of the petrous apex and clivus. Radical resection of uninvolved structures is often not necessary. Nonetheless, gross total removal is often achievable. Postoperative radiotherapy reduces the chance of tumor recurrence.

Differentiating imaging findings in primary and secondary tumors of the jugular foramen

The preoperative diagnosis of a jugular foramen tumor may be challenging, since a large variety of unusual lesions may be located in this region. These tumors may be classified as primary lesions (which are located in the jugular foramen or extend from the jugular foramen into the surrounding structures) and as secondary lesions (that extend from the surrounding structures into the jugular foramen). Primary tumors include glomus jugulare tumors, schwannomas, meningiomas and peripheral primitive neuroectodermal tumors, while secondary tumors comprise chordomas, chondrosarcomas, chondroblastomas, giant-cell tumors, cholesterol granulomas, giant cholesterol cyst, endolymphatic sac tumors, reactive myofibroblastic tumors, temporal bone carcinomas and metastases. Accurate preoperative radiological suspicion is of great value for preoperative patient counseling and has a direct impact on the surgical planning in these cases. The present study describes and discusses the main differentiating imaging features of lesions involving the jugular foramen, whose accurate preoperative radiological evaluation is essential for proper surgical planning.

[Skull base chondrosarcoma. An interdisciplinary challenge]

BACKGROUND

Chondrosarcoma is a rare differential diagnosis of malignant tumours of the skull base. The prognosis was rated as unfavourable in articles for many years. It has, however, improved considerably in recent years. The objective of this study was to evaluate and current, new optimised treatment strategies.

PATIENTS AND METHODS

We retrospectively analysed the case histories and course of four patients whom we treated for chondrosarcoma of the skull base over the past 5 years at the Freiburg Skull Base Centre.

RESULTS

Because of initially mild symptoms, the patients first came for examination at an advanced stage of the tumour. All patients underwent surgery, whereby an R0-resection was barely or only questionably present. Three patients underwent radiation therapy postoperatively. All patients are currently tumour free.

CONCLUSIONS

Surgical treatment with curative intent is basically the therapy of choice. Due to the usually large size of the tumour and its close relationship to relevant structures, complete resection is, however, not always possible despite advances in surgical procedures. Taking the possibility of modern adjuvant radiotherapeutic procedures into account, an incomplete, function-preserving resection is preferred to a radical and mutilating resection.

Mesenchymal chondrosarcoma of the temporal bone

A 64-year-old patient with mesenchymal chondrosarcoma of the temporal bone is described. CT and MRI showed an extensive mass with calcification involving the temporal bone and extending into the middle cranial fossa and nasopharynx. The tumor was ill-defined from surrounding normal bone, and a subtotal petrosectomy was carried out. The nasopharyngeal extension was removed secondarily using an endoscope. The clinical and diagnostic aspects and management of this rare lesion are discussed.

Chondrosarcoma of the skull base

OBJECTIVES

Sarcomas of the skull base are challenging, potentially lethal tumors. Prognosis is considered poor. The present report reviews treatment options and presents a case of treatment with en bloc resection of the temporal bone and adjacent skull base.

STUDY DESIGN

Single case report and literature review.

RESULTS

Extensive skull base resection for chondrosarcoma can be performed successfully and may be curative.

CONCLUSION

There is a role for en bloc resection of large areas of the skull base for treatment of chondrosarcoma. It appears that treatment combining surgery and radiation therapy is most likely to be effective.

National cancer database report on chondrosarcoma of the head and neck

BACKGROUND

Management of chondrosarcoma of the head and neck is largely based on single-institution reports with small numbers accrued over several decades.

METHODS

The American College of Surgeons' National Cancer Data Base included 400 cases of chondrosarcoma of the head and neck diagnosed between 1985 and 1995. Chi square analyses of selected contingency tables and Wilcoxon regression analyses of selected survival stratifications were performed.

RESULTS

Histologic types included conventional (80.8%), myxoid (10.5%), and mesenchymal (8.8%). The mesenchymal and myxoid subtypes were rare among white patients (17.1%) and more common among African-American (31.8%) and Hispanic patients (44.9%). Treatment was most commonly surgery alone (59.5%) and surgery with irradiation (21.0%). Disease-specific survival was 87.2% at 5 years and 70.6% at 10 years. Worse 5-year survival was associated with higher grade (67.3%), regional or distant spread (71.0%), and the myxoid (45.0%) or mesenchymal (53.2%) subtypes.

CONCLUSIONS

Chondrosarcoma of the head and neck encompasses a variety of lesions that differ substantially by demographic and tumor characteristics. Individual tumors can be classified further according to site of origin, histologic subtype, and tumor grade, which can be used to predict biologic behavior and prognosis.

Recurrent chondrosarcoma of the cranial base: a durable response to ifosfamide-doxorubicin chemotherapy

The case of a 46-year old woman with recurrent chondrosarcoma of the cranial base, refractory to neurosurgical intervention and external radiotherapy is reported. She received five cycles of systemic chemotherapy utilizing ifosfamide and doxorubicin which resulted in a durable clinical and radiographic response lasting 52+ months. A review of the management options for recurrent chondrosarcoma of the cranial base is also presented.

Intracranial chondrosarcoma: review of the literature and report of 15 cases

The available data in the literature (177 cases), two current clinical patients, and cases which occurred in The Netherlands (13) were reviewed concerning the clinical presentation, pathological features, radiological data, and treatment options of chondrosarcoma of the cranial base. The mean age of patients was 37 years, the male/female ratio 1:1.1. The most frequent complaints were diplopia with oculomotor disorders (51%), headache (31%), and decreased hearing, dizziness, and tinnitus with statoacusticus dysfunction (21%). The mean duration of symptoms before diagnosis was 27 months. The chondrosarcomas were located in the petrosal bone in 37% (47 cases), in the occipital bone and clivus in 23% (30 cases), in the sphenoid bone in 20% (25 cases) and to a lesser extent in frontal, ethmoidal, and parietal bones (14%). In 6% (eight cases) the primary location was in dural tissue. Radiological examinations showed bone destruction and variable calcification (CT), involvement of neuronal and vascular structures (MRI), and mostly hypovascularity on angiography. On histological examination 51% of tumours were classified as grade I, 11% grade II, 30% mesenchymal, and 8% myxoid. The mesenchymal type was the most malignant as illustrated by a strong tendency to intradural and cerebral growth and possibly occurrence in younger age groups. The treatment of choice until recently was surgery because of the critical location and local aggressive nature. Regrowth of tumour after surgery occurred in 53% of the patients (average after 32 months). Charged particle irradiation gave a five year survival of 83-94% and a local control rate of 78%-91%. Both in surgery and radiotherapy there is treatment related morbidity and mortality that should be considered when offering these therapies. Recent promising results imply that charged particle radiotherapy, in combination with surgery, may be the therapeutical choice of the future.

Chondrosarcoma of the petrous apex. Dilemmas in diagnosis and treatment

A case of chrondrosarcoma of the petrous temporal bone is presented. Chondrosarcomas rarely occur intracranially and typically present apex mass. The dilemmas faced in the diagnosis and treatment of petrous apex chondrosarcomas are discussed. This case also gives interesting insight into the natural history of this tumour.

Loss of heterozygosity in the retinoblastoma tumor suppressor gene in skull base chordomas and chondrosarcomas

BACKGROUND

The retinoblastoma (Rb) gene is a well characterized tumor suppressor gene in which loss of heterozygosity has been implicated in a number of malignancies including osteosarcoma and breast carcinoma. Chordomas and chondrosarcomas are rare skull base neoplasms with a propensity for local recurrences, resistance to conventional radiotherapy, and a 5%-30% incidence of metastases. Except for the so called "chondroid chordoma," histologic features do not correlate with the clinical behavior or growth patterns of these tumors. No study to date has investigated what role tumor suppressor genes or oncogenes play in the development and continued growth of these rare neoplasms.

METHODS

In order to evaluate the role of the retinoblastoma tumor suppressor gene in chordomas and chondrosarcomas we screened seven chordomas and two chondrosarcomas located at the skull base for loss of heterozygosity (LOH) of the Rb gene. Genomic DNA was extracted from tumor specimens as well as matched control tissue and utilizing a polymerase chain reaction technique, intron 17 and 20 were amplified from each specimen. The intron 17 product was then digested with the restriction endonuclease X ba1 followed by electrophoresis on a 1% agrose gel. The intron 20 amplified products were electrophoresed on a nondenaturing 6% polyacrylamide gel.

RESULTS

We demonstrated LOH at intron 17 of the retinoblastoma gene in 2/7 chordomas and in 0/2 chondrosarcomas. The two chordomas possessing LOH were particularly aggressive tumors demonstrating extensive involvement of the skull base and rapid recurrences following radical resections.

CONCLUSIONS

Alterations of the Rb gene may play a role in the growth of skull base chordomas with LOH of the Rb gene serving as a marker for more aggressive tumors. This report represents the first study evaluating the Rb gene in chordomas or chondrosarcomas and is the first report of allelic loss of the Rb gene in skull base chordomas.

Chondrosarcoma of the temporal bone

Eight patients with a chondrosarcoma of the temporal bone have been treated at the National Hospital for Neurology and Neurosurgery over a 16-year-period. Patients usually presented with symptoms and signs of lower cranial nerve palsies, though in most cases these resolved after surgery. This result, combined with the fact long-term survival can be achieved, makes surgical treatment of these tumours the best option, as the response to primary radiotherapy is uncertain. Surgical access is difficult, but an infratemporal approach is probably the most satisfactory. The use of post-operative adjuvant radiotherapy may provide some benefit. Long-term follow-up is necessary, and for this magnetic resonance imaging (MRI) is preferable to computed tomography (CT) scanning.

Chondroid chordoma versus low-grade chondrosarcoma of the base of the skull: can immunohistochemistry resolve the controversy?

The classification of cartilaginous tumors of the skull base, including chondroid chordoma and chondrosarcoma remains the subject of controversy. Critical review of the literature and our own experience of chordomas and cartilaginous tumors of the skull base led to the following conclusions: 1) Chondrosarcoma of the skull base is a distinct clinicopathological entity. The immunohistochemical staining pattern (cytokeratin negative, epithelial membrane antigen (EMA) negative) can be helpful in distinguishing it from chordoma with chondroid differentiation (cytokeratin positive, EMA positive). 2) The chondroid chordomas originally described by Heffelfinger et al. may have included some true chondrosarcomas with focal areas of myxoid chordomalike appearance. 3) Focal chondroid differentiation in chordoma is not such a rare phenomenon. Further study is needed to define whether chordoma with chondroid foci should be separated out from conventional chordoma as a distinct entity with a better prognosis.

Chondrosarcoma of the skull base: a series of eight cases

Chondrosarcomas of the skull base are indolent, locally invasive tumors with a marked tendency to recur. Surgery is the mainstay of treatment because these tumors are generally resistant to other forms of treatment. A surgical approach with wide access to the skull base and one that is easily repeatable is required, because recurrence is common. We have used the LeFort I maxillotomy or mobilization of the zygoma at the time of craniotomy to obtain wide access to the skull base in eight cases of chondrosarcoma. Three patients have undergone subsequent procedures by us for recurrent disease. One patient died 30 days after the operation, and one has required an open repair of a cerebrospinal fluid leak. Good palliation of symptoms has been achieved in all survivors. These approaches fulfill the criteria for the surgical management of these difficult tumors by allowing excellent exposure, safe repetition if required, satisfactory palliation, and acceptable morbidity.

Neuro-ophthalmologic findings in chordoma and chondrosarcoma of the skull base

Review of the clinical features of 48 patients with chordoma and 49 patients with low-grade chondrosarcoma of the skull base disclosed overlapping clinical profiles but distinctive features. Both tumors occurred at all ages but chondrosarcoma tended to occur in the third and fourth decades. Twenty-five (52%) of the patients with chordoma and 24 (49%) of the patients with chondrosarcoma had ocular symptoms (diplopia or visual impairment) as the initial manifestation of the disease. Of the 59 patients (both groups) with diplopia, the diplopia was initially intermittent in 25 (42%). Headache and diplopia from an insidious abducens nerve palsy was most common in both groups. Abducens nerve palsy occurred in 22 (46%) of the patients with chordoma and 23 (47%) of the patients with chondrosarcoma. Normal examination results were more common in patients with chordoma, whereas visual loss, facial numbness, and multiple cranial neuropathies were more common in patients with chondrosarcoma. The similarities in the clinical features of these tumors reflect their common origin at the central skull base and the vulnerability of the abducens nerves at that site. The differences reflect the tendency of chordomas to originate from the clivus and chondrosarcomas to originate from the temporal bone.

Chondroblastoma of the temporal bone. Case report and literature review

Chondroblastoma is a rare tumor of bone that represents approximately 1% of all primary bone tumors. In the temporal bone, only 33 have been reported. We present a case of chondroblastoma of the temporal bone, followed by a literature review and analysis of reported cases. We conclude that the best chance for a prolonged disease-free interval is total excision using a combined otolaryngologic and neurosurgical approach.

Chondrosarcomas of the petrous apex

From 1974 to 1988, four patients with chondrosarcomas of the petrous apex were followed. Average age was 46 years (range, 30 to 61), one man and three women. The mean delay between the first patient's symptoms and the visit was 18 months (range, 15 to 24). The surgical treatment consisted of two infratemporal approaches (type A), one transcochlear approach, and one partial excision by retrofacial route. For the four patients, the surgery was followed by cobalt therapy. Three of four patients are alive and one patient died 5 years later of a cerebrovascular lesion and bilateral acute parotiditis. None presented with a recurrent disease.