The biology and pathology of selected skull base tumors

Efficacy and safety of carbon ion radiotherapy for chordomas: a systematic review and meta-analysis

OBJECTIVE

Carbon ion radiotherapy (C-ion RT) for chordomas has been gradually performed in several research centres. This study aimed to systematically review the results of clinical reports from these institutions and to evaluate the safety and efficacy of C-ion RT.

METHODS

In accordance with the PRISMA guidelines and set search strategies, we searched four databases for articles from their inception to February 11, 2023. These articles were screened, and data were extracted independently by two researchers. STATA 14.0 was used for statistical analysis of survival results.

RESULTS

A total of 942 related articles were retrieved, 11 of which were included. Regarding lesion location, 57% (n = 552) originated in the sacral region, 41% (n = 398) in the skull base, and 2% (n = 19) in the spine (upper cervical). The local control (LC) rates at 1, 2, 3, 5, 9, and 10 years in these studies were 96%, 93%, 83%, 76%, 71%, and 54%, respectively. The overall survival (OS) rates at 1, 2, 3, 5, 9, and 10 years in these studies were 99%, 100%, 93%, 85%, 76%, and 69%, respectively. Acute and late toxicities were acceptable, acute toxicities were mainly grade 1 to grade 2 and late toxicities were mainly grade 1 to grade 3.

CONCLUSION

C-ion RT has attractive clinical application prospects and is an important local treatment strategy for chordomas. Encouraging results were observed in terms of LC and OS. Meanwhile, the acute and late toxicities were acceptable. PROSPERO registration number: CRD42023398792.

Proton and carbon ion beam treatment with active raster scanning method in 147 patients with skull base chordoma at the Heidelberg Ion Beam Therapy Center-a single-center experience

BACKGROUND

This study aimed to compare the results of irradiation with protons versus irradiation with carbon ions in a raster scan technique in patients with skull base chordomas and to identify risk factors that may compromise treatment results.

METHODS

A total of 147 patients (85 men, 62 women) were irradiated with carbon ions (111 patients) or protons (36 patients) with a median dose of 66 Gy (RBE (Relative biological effectiveness); carbon ions) in 4 weeks or 74 Gy (RBE; protons) in 7 weeks at the Heidelberg Ion Beam Therapy Center (HIT) in Heidelberg, Germany. The median follow-up time was 49.3 months. All patients had gross residual disease at the beginning of RT. Compression of the brainstem was present in 38%, contact without compression in 18%, and no contact but less than 3 mm distance in 16%. Local control and overall survival were evaluated using the Kaplan-Meier Method based on scheduled treatment (protons vs. carbon ions) and compared via the log rank test. Subgroup analyses were performed to identify possible prognostic factors.

RESULTS

During the follow-up, 41 patients (27.9%) developed a local recurrence. The median follow-up time was 49.3 months (95% CI: 40.8-53.8; reverse Kaplan-Meier median follow-up time 56.3 months, 95% CI: 51.9-60.7). No significant differences between protons and carbon ions were observed regarding LC, OS, or overall toxicity. The 1‑year, 3‑year, and 5‑year LC rates were 97%, 80%, and 61% (protons) and 96%, 80%, and 65% (carbon ions), respectively. The corresponding OS rates were 100%, 92%, and 92% (protons) and 99%, 91%, and 83% (carbon ions). No significant prognostic factors for LC or OS could be determined regarding the whole cohort; however, a significantly improved LC could be observed if the tumor was > 3 mm distant from the brainstem in patients presenting in a primary situation.

CONCLUSION

Outcomes of proton and carbon ion treatment of skull base chordomas seem similar regarding tumor control, survival, and toxicity. Close proximity to the brainstem might be a negative prognostic factor, at least in patients presenting in a primary situation.

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.

Gamma Knife Management of Skull Base Chordomas: Is it a Choice?

Background:

Skull base chordomas are locally invasive tumors which able to extend in different directions with skull base invasion. Although they are histologically benign, they have invasive nature makes total resection virtually impossible to achieve in most cases and this lead to residual tumors after surgery. To decrease postoperative surgical resection morbidity of these tumors, gamma knife radiosurgery (GKRS) was performed as alternative management for these residual chordomas to evaluate its safety and efficacy.

Materials and Methods:

A retrospective study was made on eight residual skull base chordomas treated with GKRS between 2011 and 2015. The mean patient age was 49 years (range 30–73 years). Four patients harboring chordoma were male, and four patients were females with 1:1 ratio. All patients had undergone one prior surgery. Patients were treated with peripheral dose ranged between 12–15 gray (Gy) (mean 13.75 Gy) usually at 35% to 50% isodose curve (mean 38.8%). The maximum dose to the adjacent brain stem area ranged between 10 and 12 Gy. All patients were followed up from 8 to 39 months (mean 18 months).

Results:

The tumor control rate was 50% and 25% after 18 and 36 months, respectively, but we found that their wasdeclined in the tumor control rate with long follow-up time. Four tumors were stable in their size just for 18 months, and then there two of these tumors were progressed in their size, the other four patients showed progression in their tumors in their 1^st year of treatment without sign of central tumor necrosis.

Conclusion:

Skull base chordoma patients complained from symptoms due to tumor mass effect which were not prospected to respond to GKRS alone as the aim of this type of treatment was the local tumor control, the tumor control rate declined with long follow-up time and this correlated with radioresistant nature of skull base chordoma. We advise a gross total resection to decrease the tumor volume, and this making gamma knife a reasonable treatment modality.

Pathologic aspects of skull base tumors

Skull base tumors form a highly heterogeneous group. As there are several structures in this anatomical site, a large number of different primary malignancies might develop, as well as a variety of secondary (metastatic) tumors. In this article, the most common malignancies are presented, along with a short histopathologic description. For some entities, an immunohistochemical profile is also given that should be helpful in proper diagnosis. As many pathologic diagnoses nowadays also include genetic studies, the most common genetic abnormalities in skull base tumors are presented.

Intraoperative Navigated Angiosonography for Skull Base Tumor Surgery

BACKGROUND

One of the main challenges during skull base tumor surgery is identifying the relationships between the lesion and the principal intracranial vessels. To this end, neuronavigation systems based on preoperative imaging lack accuracy because of brain shift and brain deformation. Intraoperative navigated B-mode ultrasonography is useful in defining the extent of brain tumor. Doppler imaging adds information regarding flow entity in neighboring vessels. Second-generation ultrasound contrast agents improve the signal-to-noise ratio of B-mode imaging and permit the study of the vessel's course, blood flow, and perfusion characteristics of focal lesions. We report our experience using intraoperative navigated contrast-enhanced ultrasound to perform a navigated angiosonography (N-ASG) for the visualization of vessels in a series of 18 skull base tumors.

METHODS

We performed N-ASG in a series of 18 skull base tumors (10 meningiomas, 3 craniopharyngiomas, 2 giant pituitary adenomas, 1 posterior fossa epidermoid, 2 dermoid cysts). N-ASG was obtained after craniotomy before resecting each lesion and during tumor removal, after intravenous injection of ultrasound contrast agent.

RESULTS

In all 18 cases, major vessels and their branches were simultaneously identified (both high and low flow) using N-ASG, which allowed to visualize the whole length of each vessels. N-ASG was also useful in highlighting the lesion, compared with standard B-mode imaging, and showing its perfusion patterns.

CONCLUSIONS

N-ASG can be applied to skull base tumor surgery, providing helpful information about the relationship between principal intracranial vessels and tumors. This technique could be of assistance in approaching the tumor and avoiding vascular damages.

Clival chordomas: A pathological, surgical, and radiotherapeutic review

BACKGROUND

The purpose of this study was to discuss the optimal management of patients with clival chordomas and provide an up-to-date review of the field.

METHODS

A schematic description of the anatomy of the clivus and its surrounding structures is provided based on the modular classification of the surgical corridors used in endoscopic skull base surgery. Postoperative radiotherapy (RT) techniques are described.

RESULTS

The optimal treatment is gross total resection. Recent advances in endoscopic endonasal skull base surgery have allowed very high rates of macroscopic and radiographic complete tumor resection in spite of the challenging location of these lesions. When the tumor location or extension is too lateral or inferior to be effectively resected with an endoscopic approach, an open approach or a combination of endoscopic and open approaches in stages should be considered. Postoperative RT is usually indicated because the likelihood of recurrence is high in spite of complete surgical resection. The main site of recurrence is local and late recurrences are relatively common. The probability of cure is approximately 50% at 10 years and significantly increases when complete tumor resection has been achieved.

CONCLUSION

The preferred treatment for patients with clival chordoma is gross total resection (via endoscopic endonasal surgery when possible) followed by postoperative RT. Treatment at experienced multidisciplinary cranial base centers is key to minimize complications and to enhance the probability of total removal of the tumors.

Craniofacial approaches to large juvenile angiofibromas

OBJECT

Craniofacial approaches provide excellent exposure to lesions in the anterior and middle cranial fossae. The authors review their experience with craniofacial approaches for resection of large juvenile nasopharyngeal angiofibromas.

METHODS

Between 1992 and 2009, 22 patients (all male, mean age 15 years, range 9-27 years) underwent 30 procedures. These cases were reviewed retrospectively.

RESULTS

Gross-total resection of 17 (77%) of the 22 lesions was achieved. The average duration of hospitalization was 8.2 days (range 3-20 days). The rate of recurrence and/or progression was 4 (18%) of 22, with recurrences occurring a mean of 21 months after the first resection. All patients underwent preoperative embolization. Nine patients (41%) developed complications, the most common of which was CSF leakage (23%). The average follow-up was 27.7 months (range 2-144 months). The surgery-related mortality rate was 0%. Based on their mean preoperative (90) and postoperative (90) Karnofsky Performance Scale scores, 100% of patients improved or remained the same.

CONCLUSIONS

The authors' experience shows that craniofacial approaches provide an excellent avenue for the resection of large juvenile nasopharyngeal angiofibromas, with acceptable rates of morbidity and no deaths.

Commentary: mechanistic considerations for associations between formaldehyde exposure and nasopharyngeal carcinoma

Occupational exposure to formaldehyde has been linked to nasopharyngeal carcinoma. To date, mechanistic explanations for this association have primarily focused on formaldehyde-induced cytotoxicity, regenerative hyperplasia and DNA damage. However, recent studies broaden the potential mechanisms as it is now well established that formaldehyde dehydrogenase, identical to S-nitrosoglutathione reductase, is an important mediator of cGMP-independent nitric oxide signaling pathways. We have previously described mechanisms by which formaldehyde can influence nitrosothiol homeostasis thereby leading to changes in pulmonary physiology. Considering evidences that nitrosothiols govern the Epstein-Barr virus infection cycle, and that the virus is strongly implicated in the etiology of nasopharyngeal carcinoma, studies are needed to examine the potential for formaldehyde to reactivate the Epstein-Barr virus as well as additively or synergistically interact with the virus to potentiate epithelial cell transformation.

Proton therapy in chordoma of the base of the skull: a systematic review

Chordoma is a rare, slow-growing, locally aggressive, primary bone tumor that arises from the skull base region in approximately 25-35% of cases. The therapeutic approach to chordoma has traditionally been surgery, followed by radiation therapy. The advent of charged particle radiotherapy has let us consider protons as the postoperative treatment of choice, but no controlled studies have yet confirmed the superiority of protons over photons. During January 2008, two independent researchers conducted a systematic review of the current data on the treatment of base of the skull chordoma C with proton therapy (PT) and, for comparison, with other irradiation techniques (conventional radiation therapy, ion therapy, fractionated stereotactic radiation therapy, and radiosurgery). Two hundred and ten reports in total were retrieved (81 concerning PT). According to the inclusion criteria, 47 articles were considered in the analysis. There were no prospective trials (randomized or nonrandomized) but just seven uncontrolled single-arm studies for PT, providing clinical outcomes for 416 patients in total; these reports were mainly related to advanced inoperable or incompletely resected tumors. The therapeutic approach to chordoma of the base of the skull has traditionally relied on surgical control. Radiation therapy has demonstrated to be a valuable modality for local control in the postoperative setting, particularly with the advent of charged particle radiotherapy. The use of protons has shown better results in comparison to the use of conventional photon irradiation, resulting in the best long-term (10 years) outcome for this tumor with relatively few significant complications considering the high doses delivered with this therapeutic modality.

Chondrosarcoma of the skull base: long-term follow-up

OBJECTIVE

Chondrosarcoma of the skull base is an uncommon neoplasm comprising 0.15% of all intracranial tumors and 6% of skull base neoplasms. The outcome of treatment is difficult to assess because the slow growth rate means that there is a long interval before detecting the recurrence. We describe the use of lateral skull base techniques for these lesions and examine the long-term outcomes. The pathological features, radiological findings, and radiotherapy options are also discussed.

STUDY DESIGN

Retrospective case review with current follow-up where possible.

SETTING

Tertiary referral neurotologic private practice.

PATIENTS

Eight patients with histologically confirmed skull base chondrosarcoma operated on since 1979. At the time of the surgery, the five women and three men ranged in age from 31 to 63 years, with a mean of 42.9 years. The follow-up ranged from 9 months to 25 years and 5 months.

INTERVENTIONS

All patients underwent surgical removal; the earliest patient underwent surgical removal via transcochlear and retrosigmoid approaches, and seven via an infratemporal fossa approach, with or without exenteration of the otic capsule.

MAIN OUTCOME MEASURES

Number of patients with residual and recurrent tumors.

RESULTS

In the patient who underwent surgery via the transcochlear approach, recurrence was noted within 3 months, and new exploration using the retrosigmoid approach was performed for the removal of the recurrent lesion. This patient showed no signs of recurrence for 25 years since last surgery. Of the seven patients who underwent surgery via the infratemporal fossa approach, one had residual tumor found at 1 year, but remained alive and well for 21 years after the surgery. The other six had gross total resection and showed no signs of recurrence at the last known follow-up. One patient died as a result of an unrelated cause 18 years after surgery for the chondrosarcoma.

CONCLUSION

The gross total resection of these lesions is possible because of the evolution of lateral skull base techniques and can be routinely accomplished with the infratemporal fossa approach. The improved exposure afforded by this approach seems to have resulted in more complete extirpation of the tumor and a decrease in the recurrence rate.

Surgical pathology of the skull base: a 7-year experience

A significant diversity of tissue types interface at the base of the skull and contribute to the diagnostic challenges of skull base surgical pathology. Advances in surgical technique now permit biopsy and resection of lesions previously termed "inoperable." Retrospective review was made of all pathology specimens from skull base surgeries performed at the University of California Davis Medical Center from 1990 to 1996. Surgical biopsies and resections were performed on 186 patients who had 33 distinctive diagnoses. Any preoperative biopsy or tissue from referring institutions was reviewed prior to skull base surgery. One hundred eighteen patients had benign lesions, the most frequent of which were pituitary adenoma (55) and acoustic neuroma (27). Other benign lesions included angiofibroma, meningioma, fibrous dysplasia, and paraganglioma. Sixty-eight patients had malignant tumors, 32 of which were squamous cell earcinoma. Other malignancies included salivary carcinomas, basal cell carcinoma, neuroblastoma, melanoma, and several sarcomas. Unexpected findings were two metastatic carcinomas and five inflammatory lesions. Nearly 1500 intraoperative consultations were performed to establish resection margins and less commonly to confirm the diagnosis. The discrepancy rate between the intraoperative and final diagnosis was 1.8%. Immunohistochemistry and/or electron microscopy was utilized in 44% of the specimens to confirm the diagnosis. Surgical pathology is an essential ingredient to a successful skull base surgery program. Pathologists are involved in both pre- and intraoperative decisions. The diversity of lesions that arise from the skull base often has overlapping histologies that require careful attention to morphology and the use of ancillary studies for accurate diagnosis. The need for frequent intraoperative interpretations contributes to the significant challenge for the surgical pathologist.

Infantile clivus chordoma without clivus involvement: case report and review of the literature

BACKGROUND

We present a giant clival chordoma with disseminated disease but without involvement of the clivus. To our knowledge, this is the youngest child and only the second case, presenting without base of skull involvement, in paediatric literature and the fourth reported case of a chordoma in a patient with tuberous sclerosis.

DISCUSSION

We discuss the subtle presentation, difficulties in diagnosis and management and also review the literature.

Angiofibroma: an outcome review of conventional surgical approaches

Juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor of the nasopharynx, and for its treatment, many surgical approaches have been recommended. However, selecting the appropriate one for the tumor in an advanced stage is still controversial. In this study, we evaluate the rate of recurrence of JNA and its relationship to the preoperative stage as well as various surgical approaches. Thirty-seven patients with pathologically proven JNA were retrospectively analyzed. For each patient, data were obtained regarding the primary extension, various surgical approaches and rate of recurrence. Seven patients were in stage III with intracranial extensions. Two of these patients had symptomatic recurrence that needed surgery. Three of them were disease free, and in two cases residues were demonstrated that were asymptomatic and were chosen only to be observed. Among different surgical approaches used, the transpalatal resulted in 1 recurrence out of 14 patients treated with this approach when the lesion was limited to the nasal cavity, nasopharynx and paranasal sinuses (stage I). No recurrence was observed with the use of this approach with lesions with minimal extension to the pterygopalatine fossa (stage IIA). But among three patients with intracranial extension who were treated with this approach, two resulted in symptomatic recurrence; however, using the Lefort I surgical technique, no evidence of recurrence was observed in the two patients in stage III who were treated with this approach. Involvement of the orbit, middle cranial fossa and base of the pterygoid by the primary JNA results in a higher incident of recurrent tumor. Among different surgical techniques, the lowest recurrence rate is seen either in the transpalatal approach when the tumor is limited to the nasopharynx with extension to the nasal cavity or paranasal sinuses or with the Lefort I approach when skull base invasion is present.

Chordomas of the skull base: manifestations and management

PURPOSE OF REVIEW

Chordomas are rare congenital tumors of the midline skull base. They are slow-growing and usually cause symptoms only when they compress a cranial nerve.

RECENT FINDINGS

The MRI will show the lesion with irregular uptake of gadolinium. The only way to define the diagnosis is with tissue, and there are two primary pathologic forms of the disease. Resection approaches vary with extent of disease, surgeon preference, and critical structures involved.

SUMMARY

There is building evidence that proton beam therapy improves survival and duration of a disease-free state.

Management of malignant tumors of the anterior skull base: experience with 76 patients

As the management of anterior cranial fossa malignancies has undergone significant evolution, decreases in morbidity and mortality rates have occurred. In this article, the authors discuss the clinical presentation, neuroimaging findings, and management options for common anterior skull base malignancies. Also discussed are surgery-related indications and principles.

Tumors of the skull base in children: review of tumor types and management strategies

Although many treatment strategies for skull base tumors in adults have been reported, relatively little has been reported regarding such therapies in the pediatric population. Skull base tumors in children present a therapeutic challenge because of their unique pathological composition, the constraints of the maturing skull and brain, and the small size of the patients. In this review, the authors examine the pediatric skull base lesions that occur in the anterior, middle, and posterior cranial base, focusing on unique pediatric tumors such as encepahalocele, fibrous dysplasia, esthesioneuroblastoma, craniopharyngioma, juvenile nasopharyngeal angiofibroma, cholesteatoma, chordoma, chondrosarcoma, and Ewing sarcoma. They review management strategies that include radio- and chemotherapy, as well as surgical approaches with emphasis on the modifications and complications associated with the procedures as they apply in children. Evidence for the advantages and limitations of radiotherapy, chemotherapy, and surgery as it pertains to the pediatric population will be examined. With a working knowledge of skull base anatomy and special considerations of the developing craniofacial skeleton, neurosurgeons can treat skull base lesions in children with acceptable morbidity and mortality rates. Outcomes in this population may be better than those in adults, in part because of the benign histopathology that frequently affects the pediatric skull base, as well as the plasticity of the maturing nervous system.

Chordoma

Optimal therapy of chordoma is a combined approach of surgical resection followed by proton beam irradiation for residual disease. The goals of surgery are to establish a definitive diagnosis, obtain total or maximal resection, and "shape" any residual disease so that it is favorable for radiation. Given the difficult locations and large sizes of these tumors, potential morbidity from these surgeries is high. Chordomas respond best to high doses of radiation, but nearby neurologic structures limit doses that can be delivered. Proton beam radiation appears to have a distinct advantage over conventional external beam radiation in this disease because of the rapid fall-off of radiation beyond the target. Unfortunately, the data on efficacy and safety of treatments for chordoma is limited because of the rarity of disease. Current reports in the literature are exclusively case series and reports, limiting the strength of the conclusions that can be drawn.

Pathology of skull base tumors

The multidisciplinary requirements of skull base surgery have evolved over the last 25 years. The heterogeneity of tissue types in the cranium base gives rise to a diverse group of benign and malignant neoplasms with vastly different prognoses. This article reviews the distinct clinicopathologic features of some of the unique and problematic neoplasms of this region.

Esthesioneuroblastoma: a meta-analysis and review

Our objective was to review recent developments in diagnosis, staging, and treatment of esthesioneuroblastoma (ENB). A meta-analysis of publications between 1990 and 2000 was carried out, and studies were classified according to their main subject: origin/aetiology of ENB, histopathological diagnosis, and treatment. Data so far point to the basal progenitor cells of the olfactory epithelium as the origin of ENB. Histopathological diagnosis remains difficult and is based on results of antigen expression detected through a panel of antibodies by immunohistochemistry. RT-PCR of HASH expression could be a specific marker of ENB. Overall and disease-free survival at 5 years averaged 45% (SD 22) and 41% (SD 21) in the studies included in the meta-analysis. Survival in Hyams' grades I-II was 56% (SD 20) compared with 25% (SD 20) in grades III-IV (odds ratio 6.2). In patients with metastases in cervical lymph nodes (on average 5% of the total) survival was 29%, compared with 64% for patients with N0 disease (odds ratio 5.1). Survival according to treatment modalities was 65% for surgery plus radiotherapy, 51% for radiotherapy and chemotherapy, 48% for surgery, 47% for surgery plus radiotherapy and chemotherapy, and 37% for radiotherapy alone. The histopathological grading according to Hyams and the presence of cervical lymph-node metastases emerged as prognostic factors. A combination of surgery and radiotherapy seems to be the optimum approach to treatment. The exact role of chemotherapy in treatment protocols is still unclear. The role of elective neck dissection is unclear.

Current Concepts in the Management of Tumors of the Skull Base

BACKGROUND: Due to their involvement with critical neurovascular structures, tumors located in the cranial base present challenges to neurosurgeons and are associated with high morbidity and mortality. METHODS: Rates of tumor control, complications, patient outcomes, and recurrences were extracted and summarized from two decades of our surgical and radiological treatment follow-up and review of the medical literature. RESULTS: Recent advances in surgical techniques involving cranial base approaches have made surgical intervention safer and curative resection more likely. In managing benign tumors, surgical resection is the gold standard for treatment. While immediate complications are still significant, long-term outcomes in most cases are excellent. Focused radiosurgery using a gamma knife or linear accelerator has produced favorable outcomes, and it improves the management of small or minimally symptomatic cranial base tumors. For slow-growing malignant tumors, extensive surgery followed by radiotherapy achieves the best outcome. In managing highly malignant tumors, outcome is determined by the effects of chemotherapy and radiotherapy. On some occasions, surgery is needed to obtain greater control of highly malignant tumors. CONCLUSIONS: Skull base tumors are relatively common, and management of these tumors is rapidly evolving. The combination of surgical excision using cranial base techniques, radiosurgery, fractionated radiotherapy, and chemotherapy should be individually tailored based on the location and pathological aggressiveness of the tumor and the symptomatology of the patient.

Lymphoepithelial carcinoma of the larynx and hypopharynx: study of eight cases with relationship to Epstein-Barr virus and p53 gene alterations, and review of the literature

Eight cases of lymphoepithelial carcinoma (LEC) of the larynx and hypopharynx were evaluated for clinicopathologic features, and the presence of the Epstein-Barr virus (EBV) and p53 alterations. The seven men and one woman, all of non-Asian descent, averaged 64 years of age. Eighty-eight percent had histologically confirmed cervical lymph node metastasis at diagnosis. None had systemic disease. Seven of eight patients available for follow-up (mean, 17.7 months) were alive and free of disease, although one did develop recurrent tumor in the neck. Four tumors were composed, histologically, of pure LEC. Four others had foci of both LEC and conventional squamous cell carcinoma. All eight tumors exhibited alterations in p53 expression, but none was positive for EBV. Combining these 8 cases with the 15 previously published cases in the English literature indicate that LEC in this site is a rare, rather aggressive tumor, primarily of older adults (mean, 62 years) with a propensity for early cervical lymph node metastasis and eventual distant dissemination and death from disease in about one third of patients. Although p53 alterations are common and of no apparent prognostic significance, LEC at this site seems to have little, if any, relationship to the EBV in patients of non-Asian origin.

Cytogenetics of cranial base tumors

Many different tumor types can arise in or invade the skull base. The more common tumors include, but are not limited to, angiofibromas, chondrosarcomas, chordomas, hemangiopericytomas, meningiomas, carcinomas, olfactory neuroblastomas, paragangliomas, pituitary adenomas, and rhabdomyosarcomas. Several of these tumors, including meningiomas, hemangiopericytomas, and rhabdomyosarcomas are characterized by nonrandom cytogenetic abnormalities. In this paper, we review the recognized chromosomal aberrations in cranial base tumors and illustrate the insights that can be gained into the genetic basis of tumor formation using karyotypes from skull base tumors that we have examined. As in tumors in other locations, chromosomal findings may be of diagnostic and prognostic value in cranial base tumors.