Intra-operative localisation of skull base tumours. A case report using the ISG viewing wand in the management of trigeminal neuroma.
Deep-seated skull base tumours provide as much a challenge to the surgeons' skills of localisation as to his technical abilities during the resection. These lesions are frequently inaccessible and lie adjacent to vital structures requiring extensive cerebral retraction for adequate exposure and direct visualisation. The ISG viewing wand is a newly developed image guidance system to aid direction of the operative approach and localisation of intracerebral pathology. We discuss its use in the management of a trigeminal neuroma. (+info)
Association of lower cranial nerve schwannoma with spinal ependymoma in ? NF2.
A 15 year old male, who had earlier been operated for intraspinal intramedullary ependymoma, subsequently developed a right cerebello pontine (CP) angle mass. A diagnosis of right CP angle ependymoma was considered, in view of established histology of previously operated spinal lesion. Histopathological examination of the well defined extra-axial mass, which was attached with ninth cranial nerve, however revealed a schwannoma. A diagnosis of Neurofibromatosis-2 (NF2) is strongly suspected, because of well established fact, that the spinal ependymomas may have association with lower cranial nerve schwannomas in NF2. Cranial and spinal MRI screening for early diagnosis of associated, asymptomatic lesions, in suspected cases of NF2, particularly in children, is recommended. (+info)
Cavernous angioma of the optic chiasm--case report.
A 31-year-old female presented with cavernous angioma originating from the optic chiasm manifesting as sudden onset of right retroorbital pain and right visual disturbance. She had a psychomotor seizure 10 years ago. Cavernous angioma at the right basal ganglia had been partially removed at that time. After the operation, the patient had left hemiparesis, but gradually improved. Neurological examination revealed decreased right visual acuity, left homonymous hemianopsia, and left hemiparesis. Magnetic resonance imaging revealed a mixed signal intensity mass at the right optic nerve to the optic chiasm with a low signal intensity rim on T2-weighted imaging, situated at the right basal ganglia where the cavernous angioma had been partially resected. Right frontotemporal craniotomy was performed by the pterional approach. A subpial hematoma was situated at the right optic nerve to the optic chiasm. The hematoma with an angiomatous component was completely resected from the surrounding structure. Histological examination of the specimens confirmed cavernous angioma. Postoperatively, her right visual acuity was slightly improved, but the visual field defect was unchanged. We emphasize the importance of correct diagnosis by magnetic resonance imaging and subsequent resection for preserving and improving the visual function of patients with cavernous angiomas of the optic chiasm. (+info)
Isolated metastases of adenocarcinoma in the bilateral internal auditory meatuses mimicking neurofibromatosis type 2--case report.
A 56-year-old male with a history of lung cancer presented with isolated metastases of adenocarcinoma in the bilateral internal auditory meatuses (IAMs), mimicking the bilateral acoustic schwannomas of neurofibromatosis type 2, and manifesting as rapidly worsening tinnitus and bilateral hearing loss. Magnetic resonance imaging showed small tumors in both IAMs with no sign of leptomeningeal metastasis. The preoperative diagnosis was neurofibromatosis type 2. Both tumors were removed and the histological diagnoses were adenocarcinoma. Neuroimaging differentiation of a solitary metastatic IAM tumor from a benign tumor is difficult, although rapidly progressive eighth cranial nerve dysfunction suggests a malignant process. Metastases should be considered as a rare diagnostic possibility in a patient with small tumors in both IAMs. (+info)
Pure extradural approach for skull base lesions.
Lesions in the parasellar and paracavernous regions can be removed by various skull base approaches involving basal osteotomies. A major complication of intradural skull base approaches is CSF leak and associated meningitis. We have managed 5 patients with skull base lesions with a pure extradural approach using wide basal osteotomies. The operative techniques are described. (+info)
Infratemporal fossa approaches to the lateral skull base.
The infra-temporal fossa approach is one of the lateral approaches to the skull base. It is indicated for the treatment of tumors such as glomus tumor, petrous apex cholesteatoma, chondroma, lower cranial nerve neuroma and nasopharyngeal cancer. In the present paper, we described the surgical anatomy of the lateral skull base and the indications for the infra-temporal fossa approach with its variants. We showed the hints and pitfalls in the procedures. Five illustrative cases are also presented. (+info)
Multiple intracranial lipomas, hypogenetic corpus callosum and vestibular schwannoma: an unusual spectrum of MR findings in a patient.
We describe imaging findings of a patient with multiple intracranial lipomas, hypogenetic corpus callosum and a vestibular schwannoma. We did not find association of intracranial lipomas and vestibular schwannoma in English literature. (+info)
Imaging findings in schwannomas of the jugular foramen.
BACKGROUND AND PURPOSE: Tumors of the cranial nerve sheath constitute 5% to 10% of all intracranial neoplasms, yet few articles have described their CT and MR characteristics. We report the imaging findings in a relatively large series of schwannomas of the jugular foramen, contrasting them with other disease entities, especially vestibular schwannomas and tumors of the glomus jugulare. METHODS: CT and/or MR studies of eight patients who underwent surgery for histologically proved schwannomas were reviewed retrospectively. One additional patient with an assumed schwannoma of the jugular foramen, who did not have surgery, was also included. RESULTS: Surgical findings showed schwannomas of the glossopharyngeal nerve in seven patients and tumor involvement of both the glossopharyngeal and vagal nerves in one patient. All tumors were partially located within the jugular foramen. Growth extending within the temporal bone was typical. Tumor extended into the posterior cranial fossa in all nine patients and produced mass effect on the brain stem and/or cerebellum in seven patients; in five patients, tumor extended below the skull base. On unenhanced CT scans, tumors were isodense with brain in six patients and hypodense in two. In seven patients, CT scans with bone algorithm showed an enlarged jugular foramen with sharply rounded bone borders and a sclerotic rim. On MR images, T1 signal from tumor was low and T2 signal was high relative to white matter in all patients. Contrast enhancement on CT and/or MR studies was strong in eight patients and moderate in one. CONCLUSION: Schwannoma of the jugular foramen is characteristically a sharply demarcated, contrast-enhancing tumor, typically centered on or based in an enlarged jugular foramen with sharply rounded bone borders and a sclerotic rim. Intraosseous extension may be marked. (+info)