Paraganglioma in the frontal skull base--case report.
A 56-year-old female presented with a paraganglioma in the left anterior cranial fossa who manifesting as persistent headache. Computed tomography and magnetic resonance imaging showed a solid, enhanced tumor with a cystic component located medially. The tumor was attached to the left frontal base and the sphenoid ridge. Angiography demonstrated a hypervascular tumor fed mainly by the left middle meningeal artery at the left sphenoid ridge. The preoperative diagnosis was meningioma of the left frontal base. The tumor was totally resected via a left frontotemporal craniotomy. Histological examination revealed the characteristic cellular arrangement of paraganglioma generally designated as the "Zellbaren pattern" on light microscopy. Only 10 patients with supratentorial paraganglioma have been reported, seven located in the parasellar area. The origin of the present tumor may have been the paraganglionic cells which strayed along the middle meningeal artery at differentiation. (+info)
A 38-year-old male presented with an extremely rare primary osteogenic sarcoma, unassociated with Paget's disease or late effects of radiation, involving the sella and sphenoid sinus region. Complete excision of the tumor was achieved through an extended frontobasal approach. Postoperatively, six cycles of combination chemotherapy (adriamycin, ifosphamide, and cisplatin) followed by a total of 55 Gy local radiotherapy in 33 fractions was given. Primary osteogenic sarcoma should be considered in the differential diagnosis of the central skull base tumors. Osteogenic sarcoma, in general, has a bad prognosis, and should be managed aggressively with multimodality treatment including gross total surgical resection, combination chemotherapy, and radiotherapy. (+info)
Cranionavigator combining a high-speed drill and a navigation system for skull base surgery--technical note.
Drilling of the skull base bone without damaging the important inside structures and with the correct orientation is very difficult even with the help of the anatomical landmarks. Monitoring of the location and direction of the drill tip and indications of the removed part of the bone during the drilling procedure enhances safety and achieves less invasive neurosurgery. We have developed a novel cranionavigator by combining a high-speed drill with a neurosurgical navigation system. To reduce the positional error to less than 1.5 mm, the position sensor (magnetic field sensor) must be attached 5 cm from the metallic fan portion of the drill and the sensor kept at least 10 cm away from the operating microscope. Simulation studies with the cranionavigator using two dried skulls and three cadaver heads were performed before clinical application. Clinically, this surgical instrument was used in four patients with the skull base tumor. The cranionavigator helped to safely drill the skull base bone in a shorter time by dynamic and real-time display of the precise operating site and extent of bone drilling on the preoperative computed tomography scans or magnetic resonance images. The cranionavigator is a very helpful instrument for skull base surgery in the hands of neurosurgeons with extensive expertise and anatomical knowledge. (+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)
Recurrence of clival chordoma along the surgical pathway.
Chordomas are locally aggressive malignant tumors of notochordal origin whose metastatic potential is increasingly recognized. Surgical pathway recurrence has been noted only rarely in the literature. We present three patients with clival chordomas whose sole or initial recurrence was along the pathway of prior surgical access. A characteristic mass found along the pathway of prior surgical access for resection of a chordoma should suggest recurrent chordoma. (+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)
Low-stage medulloblastoma: final analysis of trial comparing standard-dose with reduced-dose neuraxis irradiation.
PURPOSE: To evaluate prospectively the effects on survival, relapse-free survival, and patterns of relapse of reduced-dose (23.4 Gy in 13 fractions) compared with standard-dose (36 Gy in 20 fractions) neuraxis irradiation in patients 3 to 21 years of age with low-stage medulloblastoma, minimal postoperative residual disease, and no evidence of neuraxis disease. PATIENTS AND METHODS: The Pediatric Oncology Group and Children's Cancer Group randomized 126 patients to the study. All patients received posterior fossa irradiation to a total dose of 54 Gy in addition to the neuraxis treatment. Patients were staged postoperatively with contrast-enhanced cranial computed tomography, myelography, and CSF cytology. Of the registered patients, 38 were ineligible. RESULTS: The planned interim analysis that resulted in closure of the protocol showed that patients randomized to the reduced neuraxis treatment had increased frequency of relapse. In the final analysis, eligible patients receiving standard-dose neuraxis irradiation had 67% event-free survival (EFS) at 5 years (SE = 7.4%), whereas eligible patients receiving reduced-dose neuraxis irradiation had 52% event-free survival at 5 years (SE = 7.7%) (P =.080). At 8 years, the respective EFS proportions were also 67% (SE = 8.8%) and 52% (SE = 11%) (P =.141). These data confirm the original one-sided conclusions but suggest that differences are less marked with time. CONCLUSION: Reduced-dose neuraxis irradiation (23.4 Gy) is associated with increased risk of early relapse, early isolated neuraxis relapse, and lower 5-year EFS and overall survival than standard irradiation (36 Gy). The 5-year EFS for patients receiving standard-dose irradiation is suboptimal, and improved techniques and/or therapies are needed to improve ultimate outcome. Chemotherapy may contribute to this improvement. (+info)