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Cerebral aneurysms are the predominant cause of spontaneous subarachnoid hemorrhage (SAH). However, if an aneurismal cause has been excluded, there remains but a short list of meningiomas or metastatic lesions as possible causes. This article details a case of neoplasm that presented exclusively with SAH. A 31-year-old male presented with a SAH with normal cerebral angiography. The initial magnetic resonance image (MRI) revealed a lesion in the left uncus thought to be recovering hemorrhage. Subsequent MRI, however revealed the mass to be expanding. A neuroendoscopical biopsy of the lesion established a diagnosis of glioblastoma. An affirmation is made that patients experiencing "angiographically-negative" SAH should undergo MRI, occasionally on a serial basis, to exclude other etiologies for hemorrhage, including neoplasma.

The diagnosis of thoracic outlet syndrome (TOS) remains difficult; therefore, reliable and objective tests are required. We examined the process to diagnose TOS, and assessed the validity of measuring the medial antebrachial cutaneous nerve (MAC), also the ulnar nerve (UN) as a diagnostic tool. Between 2008 and 2011, 86 sides in 73 patients admitted to our hospital for the treatment of TOS were analyzed. In the process for the diagnosis as TOS, the narrow parts of the subclavian artery that was compressed by the anterior scalene muscle were confirmed with a three-dimensional CT angiography. All patients were taken a brachial plexus anesthesiological block to aim at both for diagnosis and treatment of TOS. For the diagnosis of TOS, measurements of latency (LT) and sensory nerve action potential (SNAP) of MAC and UN were analyzed between the TOS side and the non-TOS side and separated into traumatic type or disputed type. In our research, the LT of MAC and UN did not differ much between the TOS side and the non-TOS side; however, the amplitude of SNAP of MAC and UN were lower on the TOS side, especially in traumatic TOS. We concluded that comparison of the amplitude of SNAP of MAC on the injured or non-injured side was comparatively helpful for the diagnosis of TOS.

Cerebral venous thrombosis is an uncommon disease characterized by expansive cerebral edema, venous infarction and massive intracerebral hemorrhage. Magnetic resonance imaging and angiography are useful for diagnosis of cerebral venous thrombosis. A 54-year-old man was admitted with headache, vomiting and right hemiparesis. Computed tomography (CT) revealed subcortical hematoma in the left parietal lobe. Digital subtraction angiography (DSA) demonstrated occlusion of the left Labbé vein with dilation of cortical veins and deep cerebral veins. He also suffered from pulmonary embolization and deep vein thrombosis in the lower extremities. Anticoagulant and thrombolytic agents were administered, then respiratory condition and hemiparesis were improved. However, his condition deteriolated 7 months after the initial attack. CT revealed huge subcortical hematoma in the same site. He underwent craniotomy and intracerebral hematoma was evacuated during treatment with vitamin K. His symptom gradually improved and he was discharged with moderate disability 2 months after operation. Dicision of surgical treatment is difficult because there is a risk of rebleeding due to thrombolytic therapy and progressive venous congestion. Since anticoagulant and thrombolytic therapy are inevitable, surgical indication for refractory intracerebral hemorrhage associated with cerebral venous thrombosis should be considered carefully.

The aim of this study was to analyze and compare the epidemiology of injury mechanisms in acute subdural hematoma (ASDH) with those of diffuse brain injury (DBI) in the Japan Neurotrauma Data Bank.Data in the Japan Neurotrauma Data Bank were reviewed for 1,002 patients with severe head injury treated at hospitals between 1998 and 2001 (ASDH, n=246; DBI, n=341). Clinical variables including mechanisms of injury were evaluated.Patients with DBI were significantly younger, with higher incidence of skull fracture, lower Glasgow coma scale score and higher injury severity score than patients with ASDH. Different mechanisms of injury were involved, with ASDH occurring much more commonly in non-vehicular injuries, particularly falls (47.2%), while DBI resulted almost exclusively from vehicular injuries (79.7%). Impact sites on the head with ASDH were more commonly occipital or temporal, while those for DBI were frontal, temporal or facial. Alcohol use was involved in 13.8% of drivers with ASDH and 33.6% of drivers with DBI.The principal mechanical damage in DBI was to the brain itself, while primary damage in ASDH occurred to surface blood vessels. ASDH and DBI remain the two worst and most-important types of traumatic brain injury, although the pathogenesis differs with age and mechanism injury.

The facial nerve schwannoma is a rare tumor and it seldom extends into the middle cranial fossa. The typical clinical presentations are progressive facial paralysis and hearing disturbance. We report here a case of huge facial nere facial nerve schwannoma extending into the middle cranial fossa without facial palsy. A 50-year-old man presented with left hearing disturbance. Neurological examination on admission revealed no deficits except for sensorineural hearing loss. MRI demonstrated a cystic tumor extending into the ddle cral fossa from the petrous bone CT the middle cranial fossa from the petrous bone. CT of the temporal bone showed destruction of the surrounding bone around the geniculate ganglion and invasion of the tumor into the tympanic cavity and internal auditory canal. The intracranial tumor was totally removed and the operative specimen demonstrated that the tumor was a schwannoma. The patient was discharged without neurological deficit. The facial nerve schwannoma extending into the middle cranial fossa without facial palsy is rare and only 4 cases have been reported in the literature. The tumor origin was in the greater superficial petrosal nerve and geniculate ganglion. The symptom is conductive hearing loss caused by the tumor extending into the tympanic cavity. We should bear in mind that there is a also rare type of facial nerve schwannoma manifesting hearing disturbance alone.

Olfactory neuroblastoma is a rare tumor of the nasal cavity. It is a locally aggressive tumor with local recurrence, and distant metastasis occurs in 22-40% of patients. We report a case of olfactory neuroblastoma with cauda equina metastases. A 49-year old male had undergone surgery twice previously; the first for olfactory neuroblastoma in October, 1990, and the second for its intracranial and orbital metastasis in September, 1999. He complained of lumbago in autumn, 2005 and MRI showed two enhanced lesions in the cauda equina. The mass was partially removed and histologically diagnosed as olfactory neuroblastoma metastasis. Whole-spine irradiation of 32 Gy and lumber-spine irradiation of 10 Gy were performed. The mass at L2/3 was disappeared after the irradiation although the mass at L4/5 was not changed in size. The patient was discharged without neurological deficit and is now kept under observation as an outpatient. Olfactory neuroblastoma with spinal metastasis is rare and only 11 cases have been reported in the literature. A very poor prognosis was observed in the patients of olfactory neuroblastoma with spinal metastasis. Olfactory neuroblastoma is a radiosensitive tumor, and radiotherapy for spinal metastasis was reported to be effective. However, effectiveness of chemotherapy was still uncertain. The patient with olfactory neuroblastoma should be observed carefully even though no local recurrence had been detected over 10 years. Radiotherapy and further treatment including chemotherapy should be considered in case of spinal metastasis.

Traumatic acute subdural hematomas (ASDH) in Japan Neurotrauma Data Bank were categorized into focal brain injury (FBI) group and diffuse brain injury (DBI) group, and were analyzed to clarify the pathophysiological and therapeutic aspects of these injuries.Data in Japan Neurotrauma Data Bank were reviewed for 1,002 severely head-injured patients treated at hospitals between 1998 and 2001; 526 of these patients had ASDH. ASDH in this data bank were categorized into FBI group and DBI group on the findings of CT scan. The clinical variables in these injuries were evaluated.Of 526 patients with ASDH, 246 (46.8%) were categorized into FBI group, 280, (53.2%) were DBI group. The patients with DBI group were younger, injured in traffic accident, lower Glasgow Coma Scale (GCS), higher Injury Severity Score, poorer outcome, compared to those with FBI group. The patients in DBI group, who underwent decompressive craniectomy and craniotomy, had a significantly better outcome than those who underwent hematoma evacuation via burr hole. There were no relationship between the time from injury to operation and outcome in the patients with DBI group, whereas patients with early surgery in FBI group showed significantly poorer outcome. Hypothermia and the placement of intracranial pressure monitor improved outcome only in patients of DBI group.It seems that the pathophysiological and therapeutic aspects of ASDH associated with DBI might differ from that with FBI alone.

A 87-year old male was admitted to our hospital due to generalized convulsion with loss of consiousness. He was afebrile and his blood sampling was not infectious. Computed tomography scan suspected left chronic subdural hematoma. Burr hole drainage was performed to remove the hematoma, but the abscess was aspirated in the subdural space. Infected subdural hematoma is rare. We discuss the clinical presentation, diagnosis and. treatment, and also briefly review the literature.

The fluorescence-guided resection using 5-aminolevulinic acid (5-ALA) is a well established method for the treatment of brain tumor, especially malignant glioma. However, there is no report on photodynamic diagnosis (PDD) for spinal tumor. In the present study, we evaluated the usefulness of PDD for spinal ependymoma using 5-ALA.Three patients with spinal ependymoma received oral doses of 5-ALA (20 mg/kg body weight) 2 hours before anesthesia induction. Intraoperatively, fluorescence was observed with a 420 nm sharp cut filter after excitation with a violet semiconductor laser (405 nm) and was verified by analysis of fluorescent spectra. Residual fluorescent samples taken from the tumor cavity were examined histologicallyFluorescence peaked at 636nm in the removed tumors in all cases. Fluorescent tissue tended to exist at the cranial and caudal portion in the tumor cavity or around the anterior median fissure. The residual fluorescent tissue was not detected after removal of the tumor in case 1. The residual fluorescent tissue was composed of tumor cells and ependymal lining in case 2 or the infiltrated inflammatory cells and vascular endothelial cells in case 3. Postoperative magnetic resonance (MR) imaging showed no residual tumor in any of the cases.The results of this study indicate the usefulness of 5-ALA-induced tumor fluorescence in guiding resection of spinal ependymoma. 5-ALA-induced porphyrin fluorescence may label spinal ependymomas easily and clearly enough to enhance the completeness of tumor removal.

Aneurysms of the petrous internal carotid artery are rare, and surgical treatment of the aneurysm in the petrous bone carries high risk with procedure. We report a case of large petrous internal carotid artery aneurysm associated with otitis media. A 58-year-old female was admitted to our institution with left hearing loss and facial palsy. She had 4-year history of left exudative otitis media. Imaging studies demonstrated a 17 mm left petrous internal carotid artery aneurysm, destroying osseous partition between carotid canal and Eustachian tube, and protruding into left middle cranial fossa. Endosaccular coil embolization with balloon assist technique was performed successfully without neurological deficit. Follow up magnetic resonance angiogram demonstrated complete obliteration of the aneurysm without parent artery occlusion. Traumatic, mycotic, radiation, and congenital origin have been implicated for petrous internal carotid artery aneurysm. In a review of the literature, 11 cases of mycotic aneurysms in this location were reported and all of them were complicated with chronic otitis media. Because of its close proximity of middle ear and Eustachian tube, adventitial infection of the artery weakens the arterial wall, and gives rise to formation of aneurysm. We conclude that our case is of mycotic origin, and endosaccular coil embolization is effective and less invasive treatment.

The aim of this study was to investigate S-100B protein and NSE as a serum marker of brain cell damage after traumatic brain injury.Forty-one patients with traumatic brain injury were included in this prospective study. Venous blood samples for S-100B protein and NSE were taken after admission and on the next day. Serum levels of S-100 protein and NSE were compared with Glasgow Coma Scale score, computed tomographic findings and outcome after 3 months.Serum S-100B protein and NSE were significantly correlated with Glasgow Coma Scale score and outcome after 3 months. The significant correlation was found between the initial S-100B and NSE (P0.001). In patients without parenchymal injuries on computed tomographic scan such as epidural hematoma and concussion, the elevation of S-100B protein and NSE was observed. The initial values of S-100B and NSE in acute subdural hematomas with unfavorable outcome were significantly higher than in those with favorable outcome. Secondary increase of serum markers was associated with the presence of secondary insult such as hypoxia or hypotension, and was found to have an unfavorable outcome.Serum concentration and kinetics of S-100B protein and NSE provide the clinical assessment of the primary brain damage and have a predictive value for outcome after traumatic brain injury.

We report, with serial angiograms, a case worsening of dural arteriovenous fistulae (DAVFs) located at the hypoplastic right cavernous sinus and draining into the left superior ophthalmic vein across the inter-cavernous sinus. The patient presented with sudden onset of external ophthalmoplegia and deterioration of visual acuity on the left. An imaging work-up at the day of admission included contrast-enhanced computed tomography and conventional catheter angiography, which demonstrated complete thrombosis of the left cavernous sinus. There was no strong evidence to suggest DAVFs other than small faint opacification of the posterior cavernous sinus on the right at the late arterial phase. For this reason a diagnosis of left cavernous sinus thrombosis was made, followed by aggressive anticoagulation therapy with intravenous administration of antibiotics. Although the patient's eye symptoms improved significantly after the anticoagulation therapy, the follow-up angiogram obtained 5 days after admission demonstrated small right cavernous sinus DAVFs, which drained into the left superior ophthalmic vein. The patient was followed up conservatively at the out-patient clinic. Three-month follow up angiograms demonstrated spontaneous cure of the DAVF. Also noted was a complete recovery of external ophthalmoplegia with significant improvement of left visual acuity. The alternation of clinical and angiographic findings in this case may help to understand the etiology of paradoxical worsening of cavernous sinus DAVF. In selected cases, anticoagulation therapy may help to improve the prognosis of paradoxical worsening.

A very rare case of non-functional pituitary adenoma associated with Rathke's cleft cyst is reported. A 42-year-old male suffering from visual disturbance and headache was admitted. Visual acuity was 1.2 on the right and 0.5 on the left, and visual field examination showed bitemporal hemianopsia. Endocrinological study disclosed that the basal serum level of prolactin was elevated slightly to 52.6 ng/ml, whereas those of other hormones were within normal limits. MRI showed a dumbbell-shaped cystic sellar mass extending to the suprasellar region beyond the diaphragm sellae, which consisted of two isolated components around the sellar turcica. At the middle of May, the tumor was partially removed by bifrontal craniotomy. The suprasellar tumor tightly adhered to the frontal lobe and the optic nerve, the tumor was grayish cyst and cyst fluid from the suprasellar mass had the appearance of motor oil and the intrasellar tumor contained old hematoma. Histological findings revealed that the suprasellar mass was Rathke's cleft cyst and the intrasellar mass was diagnosed as pituitary adenoma (non-functional). Visual acuity was improved following surgical operation. So far twenty-three cases of pituitary adenoma associated with Rathke's cleft cysts have been reported in the literature, but there was only one case reported of a non-functional pituitary adenoma associated with a Rathke's cleft cyst. Etiology and pathogenesis of the coexistence of non-functional pituitary adenoma and Rathke's cleft cyst in the present case were not elucidated.

Acute subdural hematoma is usually associated with cerebral contusion or laceration of the bridging veins following a head injury. However, several cases of acute subdural hematoma without head injury (acute spontaneous subdural hematoma) have been reported.Among 162 cases of acute subdural hematoma admitted to our departments between 1996 and 2003, we repoort eight cases of acute spontaneous subdural hematoma. These cases fulfilled the following criteria. 1) Head injury was either trivial or absent. 2) Neither aneurysm nor arteriovenous malformation was apparent. 3) CT scan revealed neither brain contusion nor traumatic subarachnoid hemorrhage. 4) At operation, laceration of the cortical artery was observed. In this article, we describe the clinical feature (age, sex, Glasgow Coma Scale [GCS] Score on admission, past history, CT appearance, and outcome) associated with this condition.Patients ranged in age from 68 to 85 years (average 74.8 years), and were comprised of 3 males and 5 females. Previous medical history included cerebral infarction in 6 of the 8 patients and myocardial infarction in 1 patient. These seven patients were taking antiplatelet manifestation. GCS on admission ranged from 4 to 13. Five of the 7 patients on antiplatelet medication had secondary insults, such as hypoxia. On CT, hematoma thickness ranged from 13.2mm to 42.5mm (average 22.6mm), and midline shift ranged from 10.0mm to 24.0mm (average 16.5mm). Neurological outcome evaluated using the Glasgow Outcome Scale was as follows, good recovery n = 2, moderate disability n = 2, severe disability n = 3, persistent vegetative state n = 1.The mechanism of acute spontaneous subdural hematoma is influenced by the presence of pre-existing cerebrovascular disease and by the use of antiplatelet agents. In such cases, the possibility of cortical arterial bleeding should be taken into account, and craniotomy should be performed.

We reported a case of severe spasticity of the bilateral upper and lower limbs which was improved by cervical spinal cord stimulation (SCS). A 53-year-old man was suffering from sudden cardiopulmonary arrest while walking. After receiving cardiopulmonary resuscitation for 40 minutes, his cardiopulmonary function re-started, but he failed to regain consciousness. MRI revealed a hypoxic brain in his bilateral basal ganglia and occipital lobes. After 2 months, his consciousness advanced to a vegetative state and the muscle tone of his bilateral upper and lower limbs deteriorated to severe spasticity. SCS was performed in the expectation of improving his consciousness. Contrary to this anticipated result, his vegetative state continued but the severe spasticity of his upper and lower limbs improved during the SCS. Single photon emission computed tomography (SPECT) during the period of stimulation revealed a high blood flow, especially in the area of the basal ganglia, thalamus, brain stem and cerebellum, compared with off-stimulation blood flow. The neurophysiologic mechanisms of these abnormal fields and the underlying aberrant afferent nerve impulses from the posterior funiculus in the cervical cord to the cerebral sensory cortex, which may indeed be secondary to ischemic brain, may be regulated by SCS, also adding the effect of increased blood flow to the brain.

A rare case of primary central nervous system lymphoma that regressed spontaneously as shown on serial cranial magnetic resonance imagings (MRI) is described. A 60-year-old woman was admitted to our hospital with a well-enhanced mass lesion in the cerebellum although MRI had demonstrated no abnormal findings 4 months before admission. On admission, She complained of headache, but no neurological deficits were observed. The patient underwent exploratory craniotomy and the tumor was partially removed on February 14. Pathologic examination suspected B-cell type of malignant lymphoma. Postoperative MRI performed on February 23, 2001 showed disappearance of the mass lesion without further treatment. Different polymerase chain reaction (PCR) assays detected clonal immunoglobulin heavy chain gene rearrangements in paraffin-embedded tissues diagnosed as B-cell lymphoma. The patient was discharged without any neurological deficits for two weeks and was followed up on MRI. One year after operation, MRI revealed an abnormal finding in the cerebellum without apparent neurological deterioration. Radiation therapy of the whole brain and the local site was carried out with a total dose of 50Gy. MRI demonstrated complete remission of the tumor following radiation therapy. She was admitted again to our hospital with right hemiparesis on May, 2003. Subsequently, systemic chemotherapy was carried out. The patient died 2 years and 10 months after her initial presentation.

We report a multicentric glioma case which revealed different pathological appearances. A 45-year-old male had been admitted to our hospital complaining of an attack of transient sudden aphasia. On magnetic resonance imaging (MRI), T1-weighted images revealed a low intensity and T2-weighted images demonstrated a homogeneous high intensity abnormal mass in the frontal lobe, which was not enhanced with gadolinium. Removal of the tumor was performed through a right frontal transcortical approach in March, 2002. Histological diagnosis was gemistocytic astrocytoma. The patient's condition was uneventful and postoperative MRI revealed a marked decrease in the volume of the tumor. A total of 54 Gy radiation to the brain in the locality was performed. Four months after the initial surgery, the patient suffered from incomplete right hemiparesis. MRI showed a left parietal abnormal mass which had a ring formation enhancement after gadolinium administration. This Neuro-radiological examination demonstrated complete independence from the initial right frontal tumor. A second surgery which was concerned with cyst aspiration was carried out on August 10, 2002. During the next month, a third operation for partial removal of a left parietal abnormal mass was performed. Histological diagnosis was anaplastic astrocytoma. The right frontal and left parietal tumors revealed neither continuous relation suggesting intracerebral invasion, nor dissemination through the subarachnoid space nor intracerebral metastasis. Our case was diagnosed as multicentric glioma with different pathological appearances, of which only 9 cases have been reported previously.

Growth hormone-secreting pituitary adenoma is usually benign, and distant metastases are extremely rare. A case of growth hormone-secreting pituitary adenoma with multiple dural metastases is reported. A 53-year-old male was initially admitted to our hospital complaining of visual loss, presenting a pituitary abnormal mass with suprasellar extension. At the initial surgery, transsphenoidal surgery was selected, and the histological finding was benign pituitary adenoma. Seven and 16 months after the initial surgery, second and third surgeries via a transcranium route were performed for recurrence of the pituitary tumor. Histological findings revealed an appearance similar to the initial tumor in both surgical specimens. After the third operation, radiation therapy (local irradiation: total; 44 Gy) was performed. Six years after the first surgery, three tumors were located in the right frontal, parietal convexity and cerebellar tentorium. The tumors were totally removed by 4th and 5th surgeries. Histological examination showed malignant transformation from the primary benign growth hormone-secreting pituitary adenoma, with dural metastasis. Immunohistochemical staining with MIB-1 antibody demonstrated a high index of 7%. The patient is still alive after more than one year since the diagnosis of distant metastasis. According to previous reviews, few patients have survived more than one year. We conclude patients with benign pituitary adenoma should be carefully followed up for fear of malignant transformation or dural metastasis.

We report two cases of lymphocytic infundibuloneurohypophysitis (LIH). A 32-year-old male and a 13-year-old male were admitted to our hospital because of a sudden occurrence of the diabetes insipidus (DI). MRI of both patients showed the disappearance of hyperintensity of the posterior pituitary in T1WI, pituitary stalk swelling and enlargement of the pituitary gland, with homogeneous enhancement by gadolinium. We thereby diagnosed LIH, so neither patient was operated on, but both were followed-up conservatively. We reviewed 51 cases of LIH. The patient's ages ranged from 4 to 74 years (mean 45.4 years). Based on the initial symptoms, DI was found in all cases. Almost all these cases revealed characteristic MRI findings similar to those in our cases. The mean follow-up period was 3.1 years. The rate of disappearance of radiological abnormalities was 56.2%, but only 13.7% of DI improved. If we encounter a patient presenting with idiopathic DI whose MRI is strongly suggestive of LIH, and barring the necessity of an urgent operation, careful conservative treatment is advised.

The aim of this study was to evaluate the clinical manifestations and prognostic factors of progressive brain injury following trauma. We reviewed the records of 779 patients with head injury who had an admission Glasgow Coma Scale of 9 or more; 70 (7.0%) developed progressive brain injury as evidenced on serial CT scans. Of these 70 patients, 19 (27.1%) had a subdural hematoma, 19 (27.1%) an epidural hematoma, 16 (22.9%) a cerebral contusion, 13 (18.6%) an intracerebral hematoma, and 3 (4.3%) a diffuse brain swelling. Three months after injury, 36 (51.4%) patients died, 2 (2.9%) were left in a vegetative state and 23 (32.9%) had a favorable outcome. The appearance of progressive brain injury was associated with patient age, admission Glasgow Coma Scale, injury mechanisms, skull fracture and hemorrhagic lesions on the initial CT scan. Patients with the extracerebral lesions deteriorated 4 hours after injury, whereas those with intracerebral lesions deteriorated 8 hours after injury. The outcome based on Glasgow Outcome Scale was significantly associated with age, type of intracranial lesion, Glasgow Coma Scale following deterioration, the mechanism of injury and surgical treatment. It is concluded that early repeated CT scan is indicated in patients with risk factors of developing progressive brain injury.

A rare case of solitary fibrous tumor, located wholly within the fourth ventricle, is reported. A 57-year-old male presented with headache and nausea. The preoperative magnetic resonance images revealed a well circumscribed mass in the fourth ventricle that exhibited a low intensity on T1-weighted images and homogeneously enhanced with gadolinium. Vertebral angiogram revealed a tumor stain supplied from the choroidal branches of the posterior inferior cerebellar artery. The tumor was totally resected through a midline suboccipital approach. Histologically, the tumor was composed of spindle-shaped cells growing in fascicles within a collagenous matrix. Immunohistochemical staining demonstrated vimentin and the CD34 positivity of tumor cells. Solitary fibrous tumor is a newly described entity, which should be considered in the differential diagnosis for dural-based lesions.

We presented a case of neurofibromatosis type I (NF-1) associated with an extracranial arteriovenous fistula (AVF) fed by the occipital and vertebral artery. A 20-year-old man was referred to our hospital because of an occipital subcutaneous pulsatile mass. A CT scan showed a huge subcutaneous enhanced mass. Angiography revealed that the occipital AVF was fed by bilateral occipital arteries, the left ascending pharyngeal artery, the left middle cerebral artery, and the left vertebral artery with-abundant communication with the subcutaneous veins. Endovascular treatment by using both coil and glue (Eudragid) embolization via the occipital artery successfully obliterated the AVF. Subsequently surgical operation was performed. Postoperative angiography showed the disappearance of the AVF. Combination of intravascular surgery and surgical operation should be considered as an effective treatment for NF-1 associated with AVF.