Secondary Chiari malformation due to enlarged spinal arachnoid villi-like structure: illustrative case.

BACKGROUND: Secondary Chiari malformation can be caused by various disorders associated with cerebrospinal fluid (CSF) leakage at the spinal level. In this report, the authors describe a rare case of secondary Chiari malformation caused by excessive CSF absorption through the enlarged spinal arachnoid villi-like structure. OBSERVATIONS: A 20-year-old woman presented with progressive severe headache and posterior neck pain. Magnetic resonance imaging showed tonsillar herniation and decreased subarachnoid space around the spinal cord. A hypointense signal area was observed in the ventral spinal canal on a T2-weighted image. An axial image revealed multiple small, arachnoid cyst-like structures at the right T1 nerve root sleeve. Direct surgery revealed that the cyst-like structures were continuous with the arachnoid membrane and protruded into the abnormally large epidural venous sinus. The cyst-like structures were resected, and the dural sleeve was repaired using fascia. The patient showed good improvement of symptoms after surgery. LESSONS: Excessive CSF absorption through the enlarged spinal arachnoid villi-like structure can cause secondary Chiari malformation. Neurosurgeons should be aware of this unusual mechanism of CSF leakage. Simple posterior fossa decompression will be ineffective or even harmful.

Pathophysiology and surgical treatment of spinal adhesive arachnoid pathology: patient series.

BACKGROUND: Spinal adhesive arachnoid pathology is a rare cause of myelopathy. Because of rarity and variability, mechanisms of myelopathy are unknown. The authors retrospectively analyzed patients to understand pathophysiology and provide implications for surgical treatment. OBSERVATIONS: Nineteen consecutive patients were studied. Thirteen patients had a secondary pathology due to etiological disorders such as spinal surgery or hemorrhagic events. They received arachnoid lysis (4 patients), syringo-subarachnoid (S-S) shunt (8 patients) with or without lysis, or anterior decompression. Three of them developed motor deterioration after lysis, and 6 patients needed further 8 surgeries. Another 6 patients had idiopathic pathology showing dorsal arachnoid cyst formation at the thoracic level that was surgically resected. With mean follow-up of 44.3 months, only 4 patients with the secondary pathology showed improved neurological grade, whereas all patients with idiopathic pathology showed improvement. LESSONS: The idiopathic pathology was the localized dorsal arachnoid adhesion that responded to surgical treatment. The secondary pathology produced disturbed venous circulation of the spinal cord by extensive adhesions. Lysis of the thickened fibrous membrane with preservation of thin arachnoid over the spinal veins may provide safe decompression. S-S shunt was effective if the syrinx extended to the level of normal subarachnoid space.

Immunohistochemical Analysis of Cerebral Intraparenchymal Choroid Plexus Tumor: Case Report.

BACKGROUND: It is very rare for a choroid plexus tumor to occur intraparenchymally in the absence of a relation to the choroid plexus. CLINICAL PRESENTATION: A case of cerebral intraparenchymal choroid plexus tumor in a 30-year-old woman presenting with left hemiparesis is described. Brain magnetic resonance imaging depicted a large cystic mass in the right frontal lobe. Tumor resection was performed by right frontal craniotomy. No connection with the choroid plexus was observed during the operation. Histologically, the tumor exhibited a glandular structure with a papillary pattern suggesting a neoplasm of epithelial origin. Immunohistochemical analyses revealed the tumor as an atypical choroid plexus papilloma. CONCLUSION: Immunohistochemical findings, especially regarding Kir7.1, are very important for the differential diagnosis of cerebral intraparenchymal choroid plexus tumors from metastatic tumors. The present case reveals that an atypical choroid plexus papilloma can occur intraparenchymally without an association with the choroid plexus. Intraparenchymal atypical choroid plexus papillomas may have previously been diagnosed incorrectly as metastatic adenocarcinomas of unknown origin.

Localized reversible high signal intensities on diffusion-weighted MRI in hypoglycemia: A study of 70 cases.

INTRODUCTION: It is well-known that localized reversible high signal intensities in the splenium of the corpus callosum or the basal ganglia appear on diffusion-weighted MRI in the presence of hypoglycemia. The aim of this study was to clarify the incidence and significance of such high signal intensity lesions. RESULTS: We analyzed 70 cases of hypoglycemia with consciousness disturbance referred to our outpatient office. Localized reversible high signal intensities on diffusion-weighted MRI were noted in 6 cases (8.6%). They were at the splenium of the corpus callosum in four cases (5.7%), and right frontal cortex and bilateral frontal white matter in one each. Convulsions were noted in five cases, and right hemiparesis was noted in three. None of the three cases of hemiparesis showed localized reversible high signal intensities on diffusion-weighted MRI. These lesions are reversible if the patients undergo treatment without delay. CONCLUSION: The significance of these lesions is still unclear. However, when a high signal intensity lesion that is not reasonable for the symptom is detected on diffusion-weighted MRI, an immediate check of the blood sugar level is mandatory.

Measurement of human blood viscosity by an electromagnetic spinning sphere viscometer.

We herein applied an electromagnetic spinning sphere (EMS) viscometer to the measurement of human blood viscosity for the first time. We collected blood samples from 100 healthy outpatient volunteers in order to analyse viscosity dependence on blood cell parameters and on the shear rate with a simple approximation formula [ηi (γ)\, = Ai γ(- pi) + η0]. Viscosity dependence on blood cell parameters was relatively high at a high shear rate, but became lower as the shear rate decreased. The approximation formula with appropriate parameters of Ai and pi nearly faithfully reproduced actual blood rheological behaviour with a standard deviation of 1.5%. The distributions of Ai and pi values were broad, suggesting that the pattern of viscosity dependence on the shear rate varied with individual differences. The results obtained using the EMS viscometer suggest that blood viscosity values are individual-specific and actual individual measurements are important for understanding rheological conditions.

Utility of early post-treatment single-photon emission computed tomography imaging to predict outcome in stroke patients treated with intravenous tissue plasminogen activator.

It is important to predict the outcome of tissue plasminogen activator (tPA)-treated patients early after the treatment for considering the post-tPA treatment option. We assessed cerebral blood flow (CBF) of tPA-treated patients with single-photon emission computed tomography (SPECT) 1 hour after tPA infusion to predict the patient outcome. Technetium-99m-hexamethylpropyleneamine oxime SPECT was performed in 35 consecutive tPA-treated patients. Asymmetry index, a contralateral-to-ipsilateral ratio of CBF, was calculated to analyze CBF quantitatively. Hypoperfusion or hyperperfusion was defined as a decrease of 25% or more or a increase of 25% or more in asymmetry index, respectively. Of all 35 patients, 23 had only hypoperfusion, 8 had both hypoperfusion and hyperperfusion, 2 had only hyperperfusion, and 2 had no perfusion abnormality. When evaluating the association between hypoperfusion and outcome, hypoperfusion volumes were significantly correlated with the modified Rankin Scale at 3 months (r = .634, P < .001). Hyperperfusion was observed in 10 patients (28.6%) and they showed a marked National Institutes of Health Stroke Scale score improvement in the first 24-hour period, which were significantly greater than those of 25 patients without hyperperfusion (P = .033). Eight patients (22.9%) with intracerebral hemorrhage (ICH) were all asymptomatic. Most ICHs were located in hypoperfusion areas, and no ICH was related to hyperperfusion. The results of the present study demonstrated that hypoperfusion volume was associated with poor outcome, whereas the presence of hyperperfusion seemed to be predictive of symptom improvement but not of development of ICH. Taken together, early post-treatment SPECT imaging seems to be a useful biomarker of outcome in tPA-treated patients.

[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.

Spontaneous regression of an anterior skull base mass.

Spontaneous regression of an intracranial mass is rare. We report a 77-year-old man with spontaneous regression of an anterior skull base mass suspected to be an inflammatory pseudotumor. The patient attended our outpatient department approximately once per month for a regular check-up following a brain stem infarction. A small mass was detected at the anterior skull base by MRI. The mass gradually grew to about 3 cm over a period of 5 years and then remained stable for 3 years. Thereafter, the mass showed spontaneous regression 8 years after it was first visible on MRI. 'Inflammatory pseudotumor' is a broad category and the natural history of these lesions is highly variable. Although the definition does include some types of malignant lesion, most masses are benign lesions that can regress spontaneously, as in our patient. A 'wait-and-see' policy is appropriate for such patients.

[A case of subarachnoid hemorrhage presenting with supplementary motor aphasia as an initial symptom].

Supplementary motor aphasia results from impairment of the supplementary motor area in the left mesial frontal cortex. We report a rare case of subarachnoid hemorrhage presenting with supplementary motor aphasia as an initial symptom. A 52-year-old woman was brought to our hospital by ambulance due to sudden severe headache and supplementary motor aphasia. CT demonstrated subarachnoid hemorrhage that appeared to be particularly thick in the pericallosal cistern. She had undergone neck clipping of a left vertebral artery aneurysm for subarachnoid hemorrhage 14 years earlier. At that time, she underwent neck clipping of a de novo anterior communicating artery aneurysm. The postoperative course was uneventful and supplementary motor aphasia had disappeared in 4 weeks. To our knowledge, this is the first reported case of subarachnoid hemorrhage presenting with supplementary motor aphasia as an initial symptom. In this case, adhesion of the arachnoid membrane resulting from old subarachnoid hemorrhage might have prevented new subarachnoid hemorrhage from spreading diffusely. Hematomas spread mainly into the pericallosal cistern from ruptured aneurysm of the anterior communicating artery. Therefore, thick hematoma in this cistern might have compressed the supplementary motor area, resulting in supplementary motor aphasia. Aphasia disappeared as pressure from the hematoma dissipated. Neurosurgeons may be likely to encounter a patient showing a transient consciousness disturbance after the use of the anterior interhemispheric approach or within a period of vascular spasm. Supplementary motor aphasia might also be included in such consciousness disturbance. Supplementary motor aphasia might be a reversible symptom if there is no irreversible damage to the supplementary motor area by infarction or intraparenchymal hemorrhage.

A restricted subarachnoid hemorrhage in the cortical sulcus in cerebral amyloid angiopathy: could it be a warning sign?

BACKGROUND: Cerebral amyloid angiopathy is a well-known disease that is predominantly recognized in elderly people and repeatedly causes large subcortical hemorrhages. These hemorrhages may be derived from vessel wall weakness because of Abeta depositions in the wall of the cortical and leptomeningeal arteries. Although vessel ruptures in CAA have been thought to occur in cortical arteries, it was recently demonstrated that the primary hemorrhage occurs in the subarachnoid space, particularly the cerebral sulci, as a result of multiple ruptures of meningeal arteries in some cases of subcortical hematoma caused by CAA. CASE DESCRIPTION: Case patient 1 was a 74-year-old woman who presented with epileptic seizure. A restricted SAH in the right frontal lobe was observed on MRI. Thirty-three days later, left hemiparesis occurred suddenly and a huge subcortical hematoma was observed in the right frontal lobe on CT. The hematoma was removed, and the patient was pathologically diagnosed with amyloid angiopathy. Case patient 2 was a 73-year-old man who presented with epileptic seizure. A restricted SAH in the right frontal lobe was observed on MRI. Twenty days later, left hemiparesis occurred suddenly and a huge subcortical hematoma was observed in the right frontoparietal area on CT. Hematoma removal was performed on both patients, and they were diagnosed pathologically with amyloid angiopathy. CONCLUSIONS: We report on the cases of 2 patients with CAA who presented with epileptic seizure and were found to have a restricted subarachnoid hematoma in the cerebral sulcus on MRI before their subcortical hemorrhages occurred. Both cases were diagnosed pathologically. This demonstrated that vessel ruptures in CAA can occur in the subarachnoid space, particularly the cerebral sulci, as a result of ruptures of meningeal arteries. A restricted SAH on CT/MRI could be a warning sign of a huge subcortical hemorrhage in CAA.

Calcified vestibular schwannoma in the cerebellopontine angle.

Although vestibular schwannoma is a common tumor in the cerebellopontine angle, calcified vestibular schwannoma is rare. A 59-year-old woman with sudden onset epileptic seizures, was referred to Hokkaido Neurosurgical Memorial Hospital. Neurological examination revealed left Bruns nystagmus, left deafness and left cerebellar ataxia. Brain MRI revealed a mass, about 3cm in diameter, in the left cerebellopontine angle. The mass showed heterogeneous intensity on T1- and T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. Hydrocephalus was seen. On CT scan, the tumor was calcified. Preoperatively, vestibular schwannoma, meningioma, cavernous hemangioma, or thrombosed giant aneurysm were considered as differential diagnoses. The pathological diagnosis was schwannoma. For a calcified mass in the cerebellopontine angle, vestibular schwannoma should be considered in the differential diagnosis to plan appropriate treatment strategies.