Primary paraganglioma in the facial nerve canal.

OBJECTIVE: To describe primary paraganglioma in the facial nerve canal and discuss the characteristics of facial nerve paraganglioma in contrast with other tumors. CASE REPORT: A 23-year-old man developed gradually progressive right facial palsy as the initial symptom. One year later, he exhibited hearing loss without tinnitus in his right ear. CT demonstrated an enlarged facial nerve canal with irregular bony erosion of the circumference. MRI showed a well-enhanced heterogeneous mass with hypo-intensity spots inside it. During surgery, a blood-rich tumor was observed along the facial nerve: however, extensive bleeding interfered with tumor removal. The surgical specimen demonstrated paraganglioma. The tumor was completely removed in the second surgery in combination with arterial embolization. Facial nerve function was reconstructed with a free muscle flap more than one year following resection. CONCLUSION: Because paraganglioma is a blood-rich tumor, it is important to perform angiography and embolization. If preoperative facial nerve palsy is demonstrated, careful management of facial nerve function is needed. Paraganglioma must be considered in the differential diagnosis of a facial nerve tumor.

Assessment of antiangiogenic effect of imatinib mesylate on vestibular schwannoma tumors using in vivo corneal angiogenesis assay.

OBJECT: Angiogenesis and the platelet-derived growth factor (PDGF) pathway are active in the pathogenesis of vestibular schwannomas (VSs). The purpose of this study was to test whether imatinib mesylate (Gleevec), a PDGF receptor (PDGFR) blocker, reduces angiogenic capacity in sporadic VS and in VS associated with neurofibromatosis Type 2 (NF2) using a corneal angiogenesis assay. METHODS: From 121 VS tissue samples stored in the tumor bank at the Marmara University Institute of Neurological Sciences, 10 samples (6 from sporadic cases, 4 from NF2-associated cases) were selected at random for use in this study. Expression of PDGF-A and PDGF-B and their receptors was evaluated in sporadic and NF2-associated VS as well as in glioblastoma (GBM) and normal brain tissue by means of immunohistochemistry and Western blot analysis. Corneal angiogenesis assay was then used to evaluate the angiogenic capacity of tissue specimens from sporadic and NF2-associated VS with and without imatinib treatment as well as positive and negative controls (GBM and normal brain tissue). RESULTS: The angiogenic potential of the sporadic and NF2-associated VS tumor tissue differed significantly from that of the positive and negative control tissues (p <0.05). Furthermore, NF2-associated VS showed significantly lower angiogenic potential than sporadic VS (p <0.05). Imatinib treatment significantly reduced the angiogenic potential in both the sporadic VS and the NF2-associated VS groups. The level of PDGF-A and PDGFR-α as well as PDGF-B and PDGFR-ß expression in sporadic VS and NF2-associated VS also differed significantly (p <0.05) from the levels in controls. Additionally the level of PDGFR-ß was significantly higher in sporadic VS than in NF2-associated VS (p <0.05). CONCLUSIONS: The findings of this study indicate that NF2-associated VS has significantly more angiogenic potential than sporadic VS and normal brain tissue. Additionally, imatinib reduces the angiogenic activity of both sporadic and NF2-associated VS. The authors conclude that imatinib may be a potential treatment for VS, especially for NF2-associated lesions that cannot be cured with resection or radiosurgery.

[A case of combined glossopharyngeal and trigeminal neuralgia].

It is well-known that idiopathic neuralgias of the trigeminal and glossopharyngeal nerves are caused by vascular compression at the root entry zone of the cranial nerves. Because they are functional diseases, initial treatment is medical, especially with carbamazepine. However, if medical therapy fails to adequately manage the pain, microvascular decompression (MVD) is prescribed. Glossopharyngeal neuralgia is rare, and combined trigeminal and glossopharyngeal neuralgia is an extremely rare disorder. A 70-year-old woman presented herself to Hokkaido Neurosurgical Memorial Hospital because of paroxysms of lancinating pain in her left pharynx and another lancinating pain in her left cheek. Carbamazepine, which was prescribed at another hospital, favorably relieved the pain; however, drug eruption compelled her to discontinue the medication. The multi-volume method revealed that a root entry zone of the left glossopharyngeal nerve was compressed by the left posterior inferior cerebellar artery, and the left trigeminal artery was compressed by the left superior cerebellar artery. MVD for both nerves was performed employing a left lateral suboccipital craniotomy. She experienced complete relief of pain immediately after MVD. Combined trigeminal and glossopharyngeal neuralgia is extremely rare, but some groups noted a relatively high incidence of concurrent trigeminal neuralgia in patients with glossopharyngeal neuralgia up until the 1970's. Glossopharyngeal neuralgia includes pain near the gonion; therefore, there is an overlap of symptoms between glossopharyngeal and trigeminal neuralgias. By virtue of recent progress in imaging technology, minute preoperative evaluations of microvascular compression are possible. Until the 1970's, there might have been some misunderstanding regarding the overlap of symptoms because of lack of the concept of microvascular compression as a cause of neuralgia and rudimentary imaging technology. Minute evaluations of both symptoms and imaging are very important.

A comparative review of multidetector CT angiography and MRI in the diagnosis of jugular foramen lesions.

AIM: To compare the efficiency of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the diagnosis of jugular foramen lesions. MATERIALS AND METHODS: The imaging of 15 patients with tumours predominantly occurring at the jugular foramen was retrospectively reviewed, with postoperative pathology data available for 11 patients. MDCT was performed at arterial phase and MRI with standard sequences and contrast enhancement. All imaging was blindly re-reported by an experienced neuroradiologist. RESULTS: Pathology reported six glomus jugulare tumours and five neuromas, which were all correctly diagnosed using MDCT. A confident diagnosis was also made in the remaining four cases based on the pattern of enhancement. Only glomus tumours enhanced in the arterial phase. Overall, MRI was used to make a confident diagnosis in eight patients. One showed no enhancement and was correctly diagnosed as a neuroma, and seven demonstrated the tumour flow voids characteristic of a glomus tumour. The remaining seven cases all showed a similar enhancement pattern and could not be confidently differentiated between a neuroma or a glomus tumour. MDCT angiography enabled a confident assessment of the jugular vein in all cases, but MRI was inconclusive in a third of cases. Also, in the nine cases of glomus tumour diagnosed using MDCT, an enlarged feeding artery was identified in eight patients. CONCLUSION: MDCT is more accurate than MRI in diagnosing glomus tumours, and in particular, neuromas. It also offers valuable preoperative vascular information to the surgeon.

Intraoperative monitoring of intraarterial paraganglioma embolization by indocyaningreen fluorescence angiography.

Preoperative arterial embolization (AE) of paraganglioma (PG) is widely used to diminish intraoperative blood loss. Thereby conditions for a resection of the tumor shall be improved and risks for facial, vagal or hypoglossus nerve injuries are reduced. The vascularization of jugular and tympanic PGs is particularly complex due to collaterals with the vertebral and internal carotid arteries. Thus AE is often not complete and intraoperative blood loss may still be considerable. The postinterventional perfusion is of interest for the surgeon. We evaluated the arterial perfusion after AE using indocyaningreen (ICG) angiography. Six patients with PG, two carotid PGs, two jugular PGs, one vagal PG and one tympanic PG underwent surgery 1 day after AE. After tumor was exposed, ICG was intravenously applied followed by fluorescence angiography. Residual perfusion was assessed on the video clip and the perfusion index was automatically calculated by the IC-CALC software. This index was compared with the radiologist's assessment of arteriographic control after AE. Two of the six patients showed only marginal residual perfusion. These were patients with carotid PGs. The patient with the vagal PG showed 20%, the patients with jugular PGs 80 and 60% and the patient with the tympanic PG had 70% residual blood flow. The preoperative AE is rarely complete in PGs of the petrous bone. Intraoperative fluorescence angiography is a reliable procedure to evaluate the efficiency of preoperative embolization and can help the surgeon to estimate intraoperative bleeding favouring risks.

Solitary fibrous tumor arising from Cranial Nerve VI in the prepontine cistern: case report and review of a tumor subpopulation mimicking schwannoma.

OBJECTIVE: The authors present a report of a solitary fibrous tumor (SFT) arising from the intradural component of the VIth cranial nerve as it travels through the prepontine cistern. SFTs of the central nervous system are extremely rare entities that clinically masquerade as dural-based lesions, such as meningiomas or hemangiopericytomas. Because of their infrequency and clinical similarity to other central nervous system (CNS) lesions, diagnosis is largely dependent on pathological features. In this study, the authors define a subpopulation of SFTs that seem to arise directly from nerve, rather than meninges, and clinically mimic the appearance of a schwannoma. CLINICAL PRESENTATION: The patient was a 29-year-old woman with a several-month history of progressive right arm and leg numbness and mild hemiparesis, with the development of diplopia 2 weeks before admission. Outside imaging revealed a 3.9-cm mass in the prepontine cistern with extension into Meckel's cave and the cavernous sinus, resulting in significant brainstem compression. INTERVENTION: The patient underwent preoperative angiography with embolization of feeding vessels off of the left meningohypophyseal trunk. The patient was then taken to the operating room by a combined neurosurgical and ear, nose, and throat team, where the patient underwent a retrolabyrinthine/subtemporal craniotomy for tumor resection. During resection of the prepontine component, the tumor was identified as originating from the left Cranial Nerve VI as it traversed through the prepontine cistern. Resection of the tumor component involving the cavernous sinus and Meckel's cave was deferred for follow-up treatment with intensity-modulated radiation therapy. Pathological examination revealed tissue consistent with the diagnosis of SFT. CONCLUSION: SFTs involving the CNS are rare entities that are almost always diagnosed after tissue is obtained because of their clinical and radiographic similarity to meningiomas. This patient had an SFT masquerading as a VIth cranial nerve schwannoma. Although the natural history of SFTs in the CNS is not completely understood, correct diagnosis is important, given the rate of recurrence found in the more common pleural-based SFT and examples of CNS SFTs with malignant features.

Hypervascular acoustic neuroma.

The authors present a patient with a large acoustic neuroma that exhibited an unusual vascular architecture. Magnetic resonance imaging demonstrated multiple flow voids in and around the mass. At surgery, intra- and extratumoral vascularity was arterialized due to luxurious shunting. Two attempts at removal produced severe engorgement and pulsatility of the surrounding brain, dramatically narrowing the operative exposure. Piecemeal resection of the tumor seemed to redistribute blood flow resulting in engorgement of the surrounding brain, analogous to perfusion breakthrough following AVM resection. Treatment strategies similar to those used for AVM resection may be indicated when encountering a hypervascular tumor.

Effect of Gamma Knife radiosurgery on acoustic neurinomas. Assessment by 99mTc-DTPA-human serum albumin- and 201TlCl-single photon emission computed tomography.

Single photon emission computed tomography (SPECT) was performed on 16 patients with acoustic neurinoma before and 1 and 2 years after Gamma Knife surgery. 201TICI-SPECT was used to determine tumor viability. Early and delayed images of 99mTc-DTPA-human serum albumin (99mTc-HSA-D)-SPECT were used to assess tumor vascularity and permeability, respectively. There was a statistically significant decrease in the 99mTc-HSA-D index of the early image at 1 year (p = 0.013) and at 2 years (p = 0.018) after Gamma Knife surgery. On the other hand, the 201Tl index and the 99mTc-HSA-D index of the delayed image were not significantly different from their pretreatment values. These observations demonstrate that a reduction in tumor vascularity without a decrease in tumor viability may be one of the effects of Gamma Knife surgery on acoustic neurinomas.

Vascular malformation with radiation vasculopathy after treatment of chiasmatic/hypothalamic glioma.

Chiasmatic/hypothalamic gliomas usually are histologically benign astrocytomas that may recur many years after diagnosis and treatment. Three children with chiasmatic/hypothalamic gliomas who were treated at the authors' institution returned 9.5, 11.5, and 2 years, respectively, after radiation therapy (RT) because visual and neurologic deterioration developed. Neuroradiographic studies, including arteriography in two of the patients, showed large mass lesions. These were presumed to be recurrence of tumor, and chemotherapy was administered. Pathologic examination of two children who died and of the third who had a biopsy revealed only a minimal amount of residual, histologically benign astrocytoma, whereas the bulk of the specimen consisted of numerous vessels of variable size. These probably represented incorporation of the rich vasculature in the chiasmal region into the tumor, which underwent degeneration secondary to RT. Radiographic methods did not distinguish progressive tumor growth from the vasculopathy and led to inappropriate clinical diagnoses and treatment.

Histopathological evaluation of polymethyl methacrylate as an embolic agent.

Polymethyl methacrylate (PMMA) microspheres were used as an embolic agent to reduce the vascularity in eight patients with intracranial vascular tumours. Post embolization angiograms showed 30-60% reduction in the vascularity of the tumours. No patient developed any neurological complications in the immediate post-embolization period. These eight patients subsequently underwent surgery for the removal of their tumours. During surgery there was minimal blood loss and a good plane of cleavage was obtained between the tumour and the adjacent brain. The surgical specimens were examined histopathologically for the effects of PMMA. PMMA microspheres, in contrast to other cyanoacrylates--isobutyl-2-cyanoacrylate (IBCA)--did not elicit either inflammatory reaction or mural angionecrosis within the wall of the embolised vessels. The histopathological studies suggest that PMMA microspheres are an inert material and can be used as an adjunct in the management of intracranial vascular tumours.

[Glossopharyngeal neurinoma causing symptomatic hemorrhage: case report].

A 86-year-old man was admitted to our hospital because of swallowing disturbance and deterioration of consciousness. He had been aware of hearing disturbance on the right side for twelve months. Computed tomography (CT) scan demonstrated an inhomogeneous hyperdense mass lesion, 3.2 X 2.3 cm in size, at the right cerebello-pontine angle, and ventricular enlargement with intraventricular hemorrhage. Skull tomogram revealed destructive enlargement of the right jugular foramen. The angiogram showed avascular mass with elevation of anterior inferior cerebellar artery, and downward shift of posterior inferior cerebellar artery. Operative and histological findings were compatible with glossopharyngeal neurinoma of Antoni type A dominance. This tumor had numerous abnormal vessels probably causing massive hemorrhage. Only fifteen cases of intracranial neurinoma with symptomatic hemorrhage have been reported in the world literature. This case is reported as the sixteenth one and the first glossopharyngeal neurinoma among them. Possible etiology of such hemorrhage is discussed.

Hematoma of optic nerve glioma--a cause for sudden proptosis. Magnetic resonance imaging findings.

Optic nerve glioma in patients with neurofibromatosis is a relatively benign neoplasm. It is slow growing and considered by some to be a hamartoma. Clinical presentation usually includes loss of vision and gradual, painless proptosis. We report a case in which abrupt proptosis of the right eye was shown on magnetic resonance imaging to be due to a hemorrhage into the tumor.

Glomus intravagale tumour: aspects of management.

Glomus intravagale tumours are relatively rare tumours. A case is described and some aspects of its management are discussed with emphasis on the pre-operative investigation and diagnosis of this condition. Selective embolization of the lesion before operation is an important adjunct in treatment to reduce the vascularity of the tumour during operation. Intra-operative cardiac arrest due to traction of the vagus nerve was encountered. The methods to avoid this complication are discussed.