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Invasion of the skull base by carcinomas: histopathologically evidenced findings with CT and MRI.

The depth and extent of the invasion of the skull base by a tumor are the most critical information for successful en bloc resection of the tumor. The only means available for the evaluation of these factors are CT or MRI images. In order to clarify the ability of these imaging modes to delineate the invasion of the skull base, preoperative images of ten patients who underwent en bloc resection of skull base tumors at Kobe University Hospital were compared with the histopathological findings of the resected specimens. CT proved to be superior to MRI for evaluating bone destruction of the skull base. On the other hand, MRI provided more useful information about intracranial invasion than CT. As a hypertrophic linear shadow on Gd-enhanced MRI represented dural invasion or thickened dura mater adjacent to the tumor, this technique should be taken into consideration to determine the dural resection. We concluded that preoperative evaluation of the depth of skull base invasion by both CT and Gd-enhanced MRI is essential for planning complete tumor resection.

Aged↗

Skull base approaches in the pediatric population.

BACKGROUND: This study aimed to examine the surgical, oncologic, and developmental results of infants and children undergoing extirpation of skull base tumors. METHODS: Sixty-seven children aged 0.5 to 18 years (mean, 11 years) who were operated on during a 6-year period made up the study cohort. Eighteen cases (27%) involved malignant tumors, and 49 (73%) involved benign tumors. The most common benign tumors were craniopharyngioma (n = 10) and juvenile nasopharyngeal angiofibroma (n = 8). The most common malignant tumor was sarcoma (n = 5). Thirty-six tumors (55%) involved the anterior skull base, and the rest involved the lateral (n = 24) and posterior (n = 7) skull base. Subcranial, transfacial, and subfrontal approaches were used for extirpation of anterior skull base tumors. Voluminous or malignant tumors were excised by use of combined approaches (subcranial-transfacial, subcranial-degloving, or pterional-degloving). Twenty-two children underwent adjuvant therapy (chemotherapy, radiation, or both). Postoperative follow-up was 3 to 60 months. RESULTS: No severe postoperative complications (ie, meningitis, cerebrospinal fluid leak, tension pneumocephalus) and no perioperative mortality occurred. Two and a half years later, 54 of the children (80%) are alive and well. Five children, two with optic glioma and one each with squamous cell carcinoma, ependymoma, and germinoma, have died of their disease. The subcranial approach had no cosmetic impact on the craniofacial development of the patients. CONCLUSION: The extirpation of skull base tumors by use of conventional surgical techniques is feasible and safe among infants and children. The complication and mortality rates are lower than those in adults. The long-term cosmetic effect of the subcranial approach is negligible.

Adolescent↗

[Skull base metastasis from renal cell carcinoma presenting as abducens nerve paresis: report of two cases].

We report two cases of skull base metastasis from renal cell carcinoma. Case 1: A 55-year-old female presented with a skull base tumor located on the clivus. Partial removal of the tumor was performed via the transsphenoidal approach. Case 2: A 44-year-old male presented with a skull base tumor occupying the orbital, nasal, and paranasal cavities. The first operation, partial removal of the tumor, was performed via the transsphenoidal approach. Thereafter, the tumor regrowth and the patient's symptoms were progressive, so a second operation was performed via Le-Forte I craniotomy to prevent cranial nerve dysfunction and air way obstruction. The initial symptom of these two cases was abducens nerve paresis, which is caused by the tumor extending from the clivus to the cavernous sinus. The neuroradiological features were the destruction of skull base bone and angiographic tumor stain. Histopathological examination of the surgically resected specimens revealed clear cell carcinoma, and thereafter they were diagnosed as skull base metastasis from renal cell carcinoma. We emphasize the necessity of a thorough medical workup to enable speedy diagnosis of renal cell carcinoma in such cases.

Abducens Nerve↗

The safety and effectiveness of the Le Fort I approach to removing central skull base lesions.

The difficulty of gaining access to the central skull base has led to the development of many surgical approaches to this area during the past decade. Yet we believe that the Le Fort I technique, which has been used for almost 140 years in orthognathic surgery, is still an excellent approach to treating anterior skull base lesions. This procedure, which entails the horizontal sectioning of the dentoalveolar maxillary segment, seemed to fall out of favor with otolaryngologists after a few reports of complications surfaced during the past 10 to 15 years. In this article, we report a series of seven patients whom we treated with a Le Fort I approach during a 3-year period for a variety of benign and malignant anterior skull base lesions. We have encountered no significant complications of surgery or recurrence of disease at a maximum postoperative followup of 3 years.

Adult↗

The skull base, paranasal sinuses, and related malignancies.

Tumors of the anterior skull base most commonly originate from the nasal cavity and paranasal sinuses. Such early presenting signs and symptoms as nasal obstruction, epiphora, and epistaxis are frequently thought to have a benign pathology. Proptosis, vision changes, skin fixation, and cervical adenopathy are associated with advanced disease. Treatment of paranasal sinus tumors is complex, involving combined therapy and multidisciplinary teams. The particular method of treatment is determined by multiple factors, including tumor histopathology, age, health of the patient, and extent of disease. In the past several years, numerous approaches to the skull base have evolved, allowing otolaryngologists and head and neck surgeons to extend earlier operative indications and treat cancers that were previously deemed unresectable. This article reviews some of the current surgical and nonsurgical approaches to skull base tumors originating from the paranasal sinuses.

Antineoplastic Agents↗

Radiology of skull base neoplasms.

Computed tomography (CT) and magnetic resonance (MR) imaging are used routinely to stage skull base neoplasms preoperatively, define the extent of the tumor, identify perineural spread, plan surgery and radiation therapy, and evaluate the postoperative patient. Arteriography and interventional radiology also play a role in the identification and treatment of certain skull base neoplasms, particularly juvenile nasopharyngeal angiofibromas and paragangliomas. The skull base can be divided into three parts: anterior, central, and posterior. Pathology differs in each region, and CT and MR imaging often demonstrate characteristic imaging features suggestive of diagnosis.

Humans↗

Retrolabyrinthine craniectomy: the unsung hero of skull base surgery.

Despite being the foundation of, or supplement to, many skull base exposures, the retrolabyrinthine approach has not been adequately illustrated in the skull base literature. As an aid to skull base surgeons in training, this article provides a step-by-step description of the microsurgical anatomy and operative nuances of this important technique.

Journal Article↗

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.

Adult↗

[The maxillary swing approach to resect the tumors in the skull base and the paranasopharyngeal space].

OBJECTIVE: To determine the best approach to resecting the tumors in paranasopharyngeal space and skull base. METHOD: Through a Weber-Ferguson-Longmire incision,the whole maxilla was freed from bony connections and swung laterally while remaining attached to the masseter muscle and the cheek flap. Then the skull base and paranasopharyngeal space was exposed. So the tumor could be resected completely. Two cases of tumor in paranasopharyngeal space, 1 case of tumor in skull base, by the maxillary swing approach, the tumor was resected under sight. The fat of check was used to pack the space. RESULT: One case was vascular smooth muscle tumor and 1 case was adenoid cystic carcinoma in paranasopharyngeal space, 1 case was chordoma in skull base. The last case received post-operation radiotherapy. All the cases healed with no severe dentofacial malformation and dysfunction. In the follow up period, no one recurred postoperatively. CONCLUSION: The maxillary swing approach to resect the tumor in the skull base and the paranasopharyngeal can expose better. The operation is safe with little damage.

Adult↗

Fibrosing inflammatory pseudotumors of the central skull base.

The most important step in the differential diagnosis of mass lesions of the central skull base is to rule out malignant neoplasms. However, nonneoplastic lesions, such as infections or nonspecific inflammatory lesions of the skull base, can mimic malignant processes. In this study, the authors analyzed seven cases of nonneoplastic noninfectious mass-forming lesions involving the central skull base. In most cases, malignant processes were suspected at the initial phase of diagnostic work-up, but subsequent histologic examinations revealed that these lesions consisted of inflammatory cells and fibrosis without neoplastic cells. Common manifestations were pain and other neurological symptoms related to the involved anatomical sites. A variety of neurological dysfunctions of the cranial nerves not including the olfactory and spinal accessory nerves were observed. No patient developed separate lesions outside the head and neck region. After the pathologic diagnosis, most of the patients were treated with oral steroid therapy, with initial doses of prednisolone, 60 to 100 mg/d. It was difficult to relate responsiveness to steroid therapy with the histologic degree of sclerosis, fibrosis, or chronicity of the disease in these cases. Otolaryngologists should be aware of this disease when making treatment decisions for their patients with skull base lesions.

Adult↗

Approach to diagnosis of skull base lesions.

The ability to operate safely on the skull base and yet preserve cranial nerves and leave the patient with minimum neurologic deficit is a fairly new development. The field is expanding rapidly, and lesions that were once deemed unresectable can now be resected. With this in mind, one must maintain an extremely high index of suspicion for lesions in this area. Early diagnosis of skull base lesions is enhanced by a careful neuro-otologic history and physical examination on all patients with complaints of pain, headache, or cranial nerve dysfunction, either motor or sensory. Based on a thorough examination, a tentative lesion localization is made and appropriate special sensory, laboratory, and radiographic tests are used to confirm the abnormality. In addition, it is our responsibility to maintain a knowledge of the state of the art as to treatment possibilities for skull base lesions.

Brain Diseases↗

New developments in the pathology of skull base tumors.

As an anatomical interface between various tissues, the skull base harbors an exceptionally broad variety of neoplasms, some of which pose a major challenge for surgical pathology. The characterization of distinct immunohistochemical expression profiles and the identification of molecular genetic alterations associated with different tumor entities have significantly advanced this field. The new World Health Organization (WHO) classification of tumors of the nervous system lists 15 histopathological variants of meningioma. Of clinical importance are those entities that carry an increased risk of recurrence and a poor prognosis, i.e., the atypical meningioma (WHO grade II), clear-cell meningioma (WHO grade II), chordoid meningioma (WHO grade II), rhabdoid meningioma (WHO grade III), papillary meningioma (WHO grade III), and anaplastic meningioma (WHO grade III). Diagnostic criteria for atypical and anaplastic meningioma variants have now been stringently defined. The differential diagnosis of meningiomas includes hemangiopericytoma, hemangioblastoma, solitary fibrous tumor, sarcomas, and chordoid neoplasms. Recent data highlight the importance of distinguishing chordoma and chondrosarcoma of the skull base since chondrosarcomas show a significantly better clinical outcome. Among the less common, aggressive tumor entities in this anatomical region, infiltrating pituitary adenoma/pituitary carcinoma, superficial malignant gliomas, rhabdomyosarcoma, olfactory neuroblastoma, various sarcomas, and malignant lymphoma must be considered. Profiles of molecular genetic alterations have been established for several of these neoplasms and may facilitate the differential diagnosis. This review summarizes recent developments in the histopathological characterization, classification, and molecular pathology of neoplasms arising at the skull base.

Biomarkers, Tumor↗

Inflammatory pseudotumors of the skull base.

Inflammatory pseudotumor is a rare affliction of the skull base with a propensity for locally aggressive growth. Frequently, the location of involvement does not lend itself to conventional biopsy techniques, resulting in diagnostic and treatment dilemma. A retrospective review of three unusual cases of skull base inflammatory pseudotumors is reported. These lesions illustrate the difficulty of management by virtue of their histopathology and behavior. They are clinically and radiographically indistinguishable from invasive neoplasms. One involved the petrous apex with bony erosion; a second case presented with pain and trigeminal paresthesia secondary to an infiltrative lesion in the clivus and the sphenoid sinus; and the third case involved peritubal soft tissues of the infratemporal fossa, with mandibular paresthesia and middle ear effusion. All three lesions were resected via lateral skull base approaches with no evidence of recurrence. Because of the inherent nature of this lesion and its rarity, inflammatory pseudotumor should remain a diagnosis of exclusion. When suspected, surgical approaches should be designed to allow complete extirpation with limited morbidity.

Journal Article↗

Anterolateral and lateral skull-base approaches for treatment of neoplastic diseases.

PURPOSE: Neoplasms affecting the anterolateral and lateral skull base have different sites of origin and histology, and its resection is technically difficult. The purpose of this study was to describe the surgical outcome and overall and disease-free survival of patients who had anterolateral and lateral skull base procedures for treatment of neoplasms with and without adjuvant therapy. MATERIALS AND METHODS: A retrospective study was performed on 26 patients who underwent anterolateral or lateral skull-base procedures through subcranial approaches such as maxillectomy with ethmoidectomy, osteoplastic maxillotomy, transmandibular, infratemporal, and transtemporal/infratemporal techniques for treatment of neoplastic diseases. Twenty-one cases were malignancies, with no evidence of metastasis. These approaches were combined frequently with a transbasal, pterional, subtemporal, or temporo-occipital craniotomy. Survival and disease-free intervals were evaluated with the Kaplan-Meier product limit method. RESULTS: Nine cases were maxillary antrum malignancies with extension to the middle fossa and/or infratemporal fossa, 7 with nasopharyngeal neoplasms, 3 malignant lesions in the infratemporal fossa, and 3 with auditory canal carcinomas. The rest had miscellaneous diagnosis. Major morbidity occurred in 15% of cases. Perioperative mortality was 0. From 21 cases with malignancies, 4 had recurrences and the overall survival was 78% at 36 months of follow-up. CONCLUSION: Anterolateral and lateral skull-base surgery is done with low morbidity and no operative mortality. The oncologic results are better than those reported in the literature probably because of a stringent selection of cases, although a longer follow-up period is required.

Adolescent↗

[Skull base aspergillosis granuloma originating from the sphenoid sinus: a case report].

A case of skull base Aspergillus granuloma originating from the sphenoid sinus was reported. This 64-year-old man complained of unilateral visual loss and serious facial pain, and was admitted to our department. He had been treated by transnasal sphenoidectomy because of sphenoid sinus aspergillosis. MRI showed a mass lesion located in the sphenoid sinus, cavernous sinus, ethmoid sinus and intraorbit. Angiography showed severe stenosis of the left internal carotid artery at the cavernous portion. As the symptoms gradually aggravated, we felt compelled to perform intracranial surgical treatment using the extradural approach to the skull base lesions. As the fibrous lesion was very hard and strongly adherent to the surrounding tissues, only partial removal of the lesion and resection of the trigeninal nerve were carried out. After surgery, the patient was released from severe facial pain and had an uneventful course. But, two months later, he died due to Aspergillus meningoencephalitis. Aspergillosis originating from the sphenoid sinus is rare, but it is known that some lesions show abrupt invasive extension to the skull base and the prognosis is bad. Early diagnosis and suitable treatment for the skull base or intracranial lesions is required.

Aspergillosis↗

Microvascular reconstruction of the skull base: indications and procedures.

PURPOSE: The aim of the current study was to review the use of free tissue transfer for reconstruction of the skull base and for coverage of intracranial contents. PATIENTS AND METHODS: From 1990 until 1996, revascularized flaps were transferred to the skull and the skull base in 11 patients in whom intracranial/extracranial resection of tumors of the skull base was performed in cooperation with the Department of Neurosurgery. The defects resulted from removal of squamous cell carcinomas (n = 4), basal cell carcinomas (n = 4), malignant melanoma, malignant schwannoma, and malignant meningioma. Defect repair was accomplished by revascularized transfer of latissimus dorsi muscle flaps in seven cases and rectus abdominis flaps and forearm flaps in two cases each. In five patients with extensive intracranial tumor spread, reconstruction was performed for palliative reasons. RESULTS: A safe soft tissue closure of the intracranial and intradural space was achieved in all patients, whereas the contour of the facial skull and the neurocranium was satisfactorily restored at the same time. By using the entire length of the grafted muscle, the vascular pedicle could be positioned next to the external carotid artery and conveniently connected to the cervical vessels. The mean survival time of the patients with palliative treatment was 8.4 months, with an average duration of hospital stay of 24.5 days. CONCLUSIONS: Despite the increased surgical effort of revascularized tissue transfer, microvascular reconstruction of large skull base defects appears to be justified, even as a palliative measure.

Adolescent↗

Anterior skull base surgery for malignant tumors: a multivariate analysis of 27 years of experience.

INTRODUCTION: Few studies have examined prognostic factors that have an impact on outcomes in anterior skull base surgery by multivariate analysis. METHODS: We retrospectively examined our institution's skull base experience from 1973-2000. RESULTS: During this time, 166 patients underwent an anterior skull base resection for malignancy (median age, 53 years; range, 6-92 years). The 5-year relapse-free and disease-specific survival was 41% and 57% (median follow-up, 53 months). Multivariate analysis found that dural invasion, primary histologic diagnosis, and margin status had a significant impact on relapse-free and disease-specific survival. CONCLUSIONS: These data indicate that patients with anterior skull base malignancies are treated successfully with skull base surgery. Patients demonstrating adverse prognostic variables such as dural invasion, adverse histologic findings, and/or positive margins should be considered for the addition of adjuvant therapy or innovative therapies as they become available in the future.

Adenocarcinoma↗

Skull base in trigonocephaly.

The authors present aspects of the skull base in trigonocephalic children. Different patterns on clinical anthropometric investigation, bidimensional computer tomography (CT) scan and three-dimensional (3D) CT scan were studied. We present a series of 27 cases of trigonocephaly operated on in the department of pediatric neurosurgery at the Hôpital des enfants La Timone in Marseille since 1975. The skull base has been studied with CT scan in 12 patients and in 5 a 3D CT reconstruction was performed. A control series of 27 children without synostosis has been studied with the same patterns. We have analyzed in 3D, the volume of the anterior fossa related to the orbital volume, the permeability of basal sutures and the spatial orientation of petrous, sphenoid and zygomatic bones. An analysis of nasoethmoidal complex was performed in relation with hypotelorism. CT scan allows the study of the opening of orbital, nasion-pterional angles and the clinopterional angles, as well as nasion-clinoidal and bipterional distances. A computerized analysis of these data compared with normal skull base permits a new approach to these malformations and the necessity for subdivision of trigonocephaly.

Cephalometry↗