Cerebral Infarction Due to Occlusion of Main Trunk of Middle Cerebral Artery in Patient with Accessory Middle Cerebral Artery

The existence of an accessory middle cerebral artery (AMCA) usually has no pathological significance. Three patients developed cerebral infarction due to thromboembolic occlusion of the main trunk of the middle cerebral artery (MCA). In these patients, AMCA originating from the anterior cerebral artery was intact, and ran to the lateral side along the main MCA. Emergency endovascular treatment to remove the thrombus in the main MCA was performed, and MCA was recanalized. In one patient, the main MCA re-occluded and cerebral infarction developed on the next day. The diameter of AMCA is commonly smaller than that of the main MCA. Therefore, volume of ischemic region depends on the collateral blood flow to the left MCA territory by AMCA. Once an anomalous MCA is detected in a patient with cerebral infarction involving the MCA territory, close examinations to assess the anatomy of both the main and anomalous MCA are mandatory.

Carotid artery stenting for spontaneous internal carotid artery dissection presenting with hypoglossal nerve palsy: A case report

Background:

Some studies reported cases of internal carotid artery (ICA) dissection (ICAD) that was treated by carotid artery stenting (CAS). Symptoms of ICAD resulting from the lower cranial nerve palsy are rare and the treatment strategy is not clearly defined. We report a patient with ICAD showing hypoglossal nerve palsy alone that was treated by CAS.

Case Description:

A 47-year-old man presented with headache, dysphagia, dysarthria, and tongue deviation to the left. He had no history of trauma nor any other significant medical history. Axial T2-CUBE MRI and MRA showed dissection of the left ICA accompanied with a false lumen. These findings indicated that direct compression by the false lumen was the cause of hypoglossal nerve palsy. Although medical treatment was continued, symptoms were not improved. Therefore, CAS was performed to thrombose the false lumen and decompress the hypoglossal nerve. His symptoms gradually improved after CAS and angiography performed at month 6 showed well-dilated ICA and disappearance of false lumen.

Conclusion:

CAS may be an effective treatment for the lower cranial nerve palsy caused by compression by a false lumen of ICAD.

Bow hunter’s syndrome treated by anterior decompression with fusion: A case report

Background:

Bow hunter’s syndrome (BHS) is a rare condition induced by occlusion or compression of the vertebral artery (VA) during head movement or rotation. Here, we report a patient with BHS effectively treated with an anterior cervical discectomy and fusion (ACDF).

Case Description:

A 75-year-old male experienced recurrent embolic strokes to the posterior circulation. This was attributed angiographically to transient stenosis of the right VA due to a right-sided C5-C6 osteophyte when the head was rotated to the right; the stenosis was improved when the patient rotated his head to the left. The patient successfully underwent a C5-C6 ACDF for removal of the right-sided lateral osteophyte which resulted in no further transient right-sided VA occlusion.

Conclusion:

Following a C5-C6 ACDF for removal of a right lateral osteophyte, a 75-year-old male’s intermittent right-sided VA occlusion responsible for multiple posterior circulation emboli was relieved.

Pediatric meningioma with rhabdoid features developed at the site of skull fracture: illustrative case

BACKGROUND

Pediatric meningiomas are rare, and only a few cases attributed to trauma and characterized by development at the site of bone fracture have been reported. Both pediatric and traumatic meningiomas have aggressive characteristics.

OBSERVATIONS

An 11-year-old boy who sustained a head injury resulting from a left frontal skull fracture 8 years previously experienced a convulsive attack. Imaging revealed a meningioma in the left frontal convexity. Total removal of the tumor with a hyperostotic section was successfully achieved. Intraoperative investigation showed tumor invasion into the adjacent frontal cortex. Histologically, the surgical specimen revealed a transitional meningioma with brain invasion and a small cluster of rhabdoid cells. This led to a final pathological diagnosis of an atypical meningioma with rhabdoid features. The postoperative course was uneventful, and no recurrence of the tumor was found after 2 years without adjuvant therapy.

LESSONS

This is the first report of a pediatric meningioma with rhabdoid features occurring at the site of a skull fracture. Meningiomas that contain rhabdoid cells without malignant features are not considered to be as aggressive as rhabdoid meningiomas. However, the clinical course must be carefully observed for possible long-term tumor recurrence.

A Case of Suprasellar Papillary Glioneuronal Tumor Mimicking Craniopharyngioma

Papillary glioneuronal tumor (PGNT) is a low-grade biphasic neoplasm with astrocytic and neuronal differentiation. This tumor occurs most commonly in the frontal and temporal lobes, close to the ventricles, and rarely in the cerebellum, brainstem, and pineal gland. However, there has been no report of this tumor in the suprasellar region to date. In this paper, we report a case of PGNT in the suprasellar region in a 16-year-old girl. Magnetic resonance imaging (MRI) revealed a cystic tumor with calcification that progressed from the anterior skull base to the suprasellar and temporal regions. Preoperatively distinguishing this tumor from craniopharyngioma was difficult because of the patient’s age, localization of the tumor, and neuroimaging results. This case showed a backward shift of the chiasma, which is observed in only 4.7% of craniopharyngioma, as well as normal endocrine findings. Endocrinological examination and an MRI evaluation of the chiasmal shift may be useful for discrimination.

Usefulness of MRI Slices Parallel to the Optic Chiasma in a Case with Traumatic Optic Nerve Avulsion after a Bear Attack

Optic nerve avulsion is an exceedingly rare condition. Here, we describe a case of optic nerve avulsion in a 74-year-old man with temporal hemianopia in the contralateral eye after a bear attack. Magnetic resonance imaging (MRI) revealed separation of the optic nerve distal to the optic chiasma, whereas the high signal in diffusion-weighted imaging suggested nerve injury from the left side of the optic chiasma to the left optic tract. MRI slices parallel to the optic chiasma were obtained and used for evaluating the site of optic nerve avulsion and nerve injury, which were responsible for temporal hemianopia in the contralateral eye.

Duplicated middle cerebral artery associated with aneurysm at M1/M2 bifurcation: a case report

BACKGROUND

A duplicated middle cerebral artery arises from the internal carotid artery and supplies blood to the middle cerebral artery territory. A duplicated middle cerebral artery is sometimes associated with an intracranial aneurysm. Most aneurysms associated with duplicated middle cerebral artery are located at the origin of the duplicated middle cerebral artery. An aneurysm located at the distal middle cerebral artery is not common.

CASE PRESENTATION

We encountered a 62-year-old Asian man with duplicated middle cerebral artery associated with aneurysms at the M1/M2 junction of the duplicated middle cerebral artery and top of the internal carotid artery.

CONCLUSIONS

In cases of duplicated middle cerebral artery, association with a distal aneurysm on the duplicated middle cerebral artery is rare. However, the aneurysm may be formed on the thicker middle cerebral artery due to hemodynamic stress.

Thromboembolic complications during endovascular treatment of ruptured cerebral aneurysms

Background In cases of subarachnoid hemorrhage due to aneurysm rupture, the administration of an anticoagulant or antiplatelet agent involves the risk of rebleeding from the aneurysm. There is a possibility of inducing thromboembolic events during the endovascular embolization of ruptured cerebral aneurysms. Patients and methods From April 2006 to March 2017, we treated a total of 70 patients with ruptured cerebral aneurysms with an endovascular technique. Among them, five patients (7.1%) showed intra-arterial thrombus formation. The aneurysms were located at the anterior communicating artery and basilar artery in two patients each, and on the internal carotid artery at the bifurcation of the anterior choroidal artery (AChoA) in one. In these patients, the clinical course, radiological findings, and management were retrospectively reviewed. Results Thrombus formation was observed in the posterior cerebral artery, anterior cerebral artery (A2), AChoA, and middle cerebral artery. The timing of thrombus formation was during coil delivery in four cases, and guiding catheter advancement in one. As for thrombus management, for all patients, administrations of heparin and antiplatelet agents were performed. For four patients, urokinase injection into the affected arteries was added after the completion of embolization. Cerebral infarction was postoperatively identified in two patients, but no hemorrhage was noted. Conclusion Administrations of heparin and antiplatelet drugs should be performed appropriately during procedures, and close observation of the arterial condition on angiography is necessary. Once thromboembolism occurs during the endovascular embolization of ruptured cerebral aneurysms, adequate heparinization, and antiplatelet therapy should first be performed.

Superficial Temporal Artery-Middle Cerebral Artery Bypass Using a Thick STA after Endarterectomy: A Rescue Technique

Background and Objective Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is a procedure to reconstruct cerebral blood flow in the MCA territory. In some cases, the STA wall is thickened and the size discrepancy between STA and MCA is apparent. In such a situation, STA-MCA bypass is challenging. We present two patients who underwent STA-MCA bypass using STA in which a thickened intima was removed. We discuss the usefulness of this rescue technique.

Patients and Results A patient with an atherosclerotic MCA occlusion and another with an occluded internal carotid artery are included. Endarterectomy of STA was performed before or during anastomosis, and the intima-resected STA was anastomosed to MCA. In both cases, the STA was thick and hard, and it was difficult to anastomose the STA as it was to the MCA. Patency of the bypass was confirmed by postoperative angiography.

Conclusion Endarterectomy of a thickened STA might be an effective rescue technique in cases with severely atherosclerotic STA in STA-MCA bypass.

Pseudoaneurysm formation due to rupture of intracranial aneurysms: Case series and literature review

Background Intracranial pseudoaneurysm formation due to a ruptured non-traumatic aneurysm is extremely rare. We describe the radiological findings and management of pseudoaneurysms due to ruptured cerebral aneurysms in our case series and previously reported cases. Patients and methods Four additional and 20 reported patients presenting with subarachnoid hemorrhage (SAH) are included. Radiological findings and clinical features of these patients were reviewed. Results In our series, three-dimensional computed tomographic angiography (3D-CTA) and/or angiography showed an irregular- or snowman-shaped cavity extending from the parent artery. The radiological examination additionally revealed delayed filling and retention of contrast medium. These findings were the same as previously reported cases. One patient underwent direct clipping of the true aneurysm. For the other three patients with aneurysms at the basilar and anterior communicating arteries, the true portion of the aneurysm was embolized with platinum coils. During the procedures, care was taken not to insert the coils into the distal pseudoaneurysm portion to prevent rupture. The review of 24 cases revealed that the location of the aneurysms was most frequent in the anterior communicating artery (41.7%), and 86.7% of patients were in a severe stage of SAH (>Grade 3 in WFNS or Hunt & Kosnik grading) implying abundant SAH. Conclusions Pseudoaneurysm formation in SAH after non-traumatic aneurysm rupture is rare. However, in cases with an irregular-shaped aneurysm cavity, pseudoaneurysm formation should be taken into consideration.

Late Seizures after Stroke in Clinical Practice: The Prevalence of Non-convulsive Seizures

Objective The prevalence of the non-convulsive type of late seizure after stroke is unknown. The aim of the present study was to clarify the characteristics of late seizure in clinical practice, mainly focusing on the prevalence of non-convulsive seizure. Methods A total of 178 consecutive patients who were admitted and diagnosed with late seizure after stroke were retrospectively enrolled, and the data of 127 patients for whom the complete seizure was observed by a bystander were analyzed. Clinical information was obtained from the medical records and nursing notes. Results A non-convulsive seizure was observed in 37 patients (29%). A focal seizure and its secondary generalization accounted for 79% of the seizure types. Status epilepticus was observed in 60 patients (47%), including 11 patients (9%) without convulsion. The patients with non-convulsive seizures were significantly younger than those with convulsive seizures, but there were no other significant differences between the two groups with respect to sex, classification or the lesion of stroke. Conclusion There was a high rate of non-convulsive seizures in patients with late seizure after stroke. A non-convulsive seizure may be caused by any type or location of preceding stroke. More attention is needed in the differential diagnosis of neurological deterioration after stroke.

Primary aldosteronism in patients with acute stroke: prevalence and diagnosis during initial hospitalization

Background

Hypertension is the prime risk factor for stroke, and primary aldosteronism (PA) is the most common cause of secondary hypertension. The prevalence of PA in stroke patients has never been reported. The aim of this study was to elucidate the prevalence of PA.

Methods

A total of 427 consecutive patients with acute stroke were prospectively enrolled for this study. The screening tests were performed at the initial visit and a week after admission by measuring plasma aldosterone concentration and plasma renin activity. The rapid adrenocorticotropic hormone (ACTH) test was performed as the confirmatory test when both screening tests were positive. The primary endpoint was a final diagnosis of PA.

Results

The sensitivity of the dual screening system for the diagnosis of PA was 88.2 %, and PA was finally diagnosed in 4.0 % of acute stroke patients and in 4.9 % of stroke patients with a history of hypertension. Patients with PA were less likely to be male and have diabetes, and they had higher blood pressure at the initial visit, lower potassium concentration, and more intracerebral hemorrhage. The rapid ACTH test was performed safely even in acute stroke patients.

Conclusions

The prevalence of PA is not low among acute stroke patients. Efficient screening of PA should be performed particularly for patients with risk factors.

Trial registration

UMIN-CTR; UMIN000011021. Trial registration date: June 23, 2013 (retrospectively registered).

Post-ischaemic hyperperfusion in traumatic middle cerebral artery dissection detected by arterial spin labelling of magnetic resonance imaging

We report a patient with a traumatic middle cerebral artery dissection, which showed hyperperfusion in the territory supplied by the left middle cerebral artery. A 45-year-old man experienced speech disturbance and motor weakness in his right hemibody on the day following mild head trauma. His symptoms worsened on the fourth day. Magnetic resonance imaging showed narrowing in the left M1 portion of the middle cerebral artery. Angiography showed narrowing and dilatation in the left middle cerebral artery trunk. The lesion was diagnosed as a dissection of the middle cerebral artery. Arterial spin labelling of magnetic resonance imaging and single photon emission computed tomography showed increased cerebral blood flow in the left temporal region compared with the right. The patient was treated conservatively and the symptoms gradually improved. The hyperperfusion observed on arterial spin labelling and single photon emission computed tomography gradually improved and disappeared on the 25th day. This is the first reported case of traumatic middle cerebral artery dissection, which showed post-ischaemic hyperperfusion in the territory of the affected artery. To detect hyperperfusion in the brain, arterial spin labelling is a useful technique.

Intraparenchymal hemorrhage from dural metastasis of breast cancer mimicking meningioma

Intraparenchymal hemorrhage from dural metastasis of breast cancer is rare. A 54-year-old woman without a significant medical history showed altered consciousness and left hemiparesis. Radiological examination revealed an extra-axial mass in the right middle fossa with intraparenchymal hemorrhage and another mass invading the skull in the right parietal region. The pre-operative diagnosis was a sphenoid ridge meningioma presenting with intraparenchymal hemorrhage and another meningioma in the convexity. The tumors and hematoma were removed. Pathological findings of the tumors were compatible with adenocarcinoma. Systemic examination revealed breast cancer with metastasis to the spine. Although the radiological findings were similar to those of meningioma, a differential diagnosis of metastatic brain tumor with intraparenchymal hemorrhage should be taken into consideration.

Subarachnoid and intracerebral hemorrhage from intracranial hemangiopericytoma: An uncommon cause of intracranial hemorrhage

BACKGROUND

Hemorrhage from an intracranial tumor is well known but uncommon. In cases of subarachnoid hemorrhage, aneurysm rupture is a main cause.

CASE DESCRIPTION

A 64-year-old woman presented with sudden-onset motor aphasia. Computed tomography revealed subarachnoid hemorrhage, and intracerebral hemorrhage in the left temporal lobe. From the findings of pre-enhancement computed tomography, hemorrhage from a left middle cerebral artery aneurysm was initially suspected. Further radiological examinations demonstrated an enhanced mass with dural attachment in the left temporal region, but no vascular abnormality. Emergency craniotomy was performed, and the tumor and intracerebral hematoma were removed. The hemorrhage from fragile tumor vessels may destroy the tumor tissue and spread into the temporal lobe and subarachnoid space. Pathological examination of the tumor yielded findings consistent with hemangiopericytoma. Post-operatively, the patient was treated to prevent vasospasm.

CONCLUSION

Although an intracranial tumor including hemangiopericytoma uncommonly causes subarachnoid hemorrhage, it should be taken into consideration as a source of intracranial hemorrhage.

Cavernous Sinus Dural Arteriovenous Fistula Patients Presenting With Headache as an Initial Symptom

Cavernous sinus (CS) dural arteriovenous fistula (dAVF) patients presenting with only headache as an initial symptom are not common. Patients with CS-dAVF commonly present with symptoms related to their eyes. In all three patients, headache was the initial symptom. Other symptoms related to the eyes developed 1 - 7 months after headache. In one patient, headache was controlled by sumatriptan succinate, but not diclofenac sodium or loxoprofen sodium. In another patient, headache was controlled by loxoprofen sodium. In the third patient, headache was improved by stellate ganglion block. In all patients, magnetic resonance angiography (MRA) in the early stage of the clinical course showed abnormal blood flow in the CS. However, reflux to the superior ophthalmic vein (SOV) was not detected. As treatment, transarterial and transvenous embolizations were necessary for one patient, and transvenous embolization was performed for another patient with significant blood flow to the SOV and cortical veins. On the other hand, manual compression of the bilateral carotid arteries at the neck resulted in disappearance of the fistula in the third patient. In all patients, the symptoms improved after the disappearance of blood reflux to the CS. The refluxed blood to the CS might cause elevation of the CS pressure and stimulate the trigeminal nerve in the dural membrane, resulting in headache before developing reflux in an anterior direction. CS-dAVF could induce both migraine and common headache. In cases with blood reflux to the CS on magnetic resonance imaging and/or MRA even without eye symptoms, a differential diagnosis of CS-dAVF should be taken into consideration.

Aneurysm at origin of duplicated middle cerebral artery associated with another aneurysm

Background:

A duplicated middle cerebral artery (DMCA) is a rare vessel anomaly. Aneurysms at the origin of DMCA have been reported.

Case Description:

We report 2 cases of aneurysms at the origin of DMCA accompanied by aneurysms at different sites. Each case of ruptured and unruptured aneurysm at the DMCA origin was associated with an unruptured aneurysm at the ipsilateral internal carotid artery and a ruptured one at the ipsilateral MCA, respectively. The aneurysms were clipped successfully in both patients.

Conclusion:

In cases of DMCA aneurysm associated with an aneurysm at another site, either aneurysm has a high risk of rupture. In such a case, radical treatment is necessary.

Pseudoaneurysm Formation in Intracerebral Hematoma due to Ruptured Middle Cerebral Artery Aneurysm

We report the case of a ruptured middle cerebral artery aneurysm that showed pseudoaneurysm formation in an intracerebral hematoma. A 61-year-old man who was taking warfarin complained of dysarthria. Three days later, he was found unconscious, and computed tomography on admission showed subarachnoid hemorrhage and an intracerebral hematoma in the left temporal lobe. Three-dimensional computed tomographic angiography showed an irregular-shaped aneurysm-like cavity extending from the left middle cerebral artery into the hematoma. Intraoperative observation revealed that the aneurysm itself was small and the lesion observed on computed tomography was a pseudoaneurysm that had formed in the hematoma. Pathologic examination of the aneurysm demonstrated that there was a thrombus at its tip. In this report, radiologic characteristics of three-dimensional computed tomographic angiography and etiology of a pseudoaneurysm in an intracerebral hematoma due to aneurysm rupture are discussed.

Accessory middle cerebral artery associated with an unruptured aneurysm at its origin

BACKGROUND

An aneurysm originating from the junction of the A1 segment of the anterior cerebral artery and accessory middle cerebral artery (Acc-MCA) is markedly rare. We report a rare case of an Acc-MCA aneurysm, and discuss the clinical course and management of this rare condition.

CASE DESCRIPTION

A 64-year-old man with a past history of cerebral infarction was revealed to have a left Acc-MCA and an aneurysm at its origin. The aneurysm was clipped via a transsylvian approach. Due to its location and projectile direction, the neck of the aneurysm was left partially unclipped.

CONCLUSION

Although an Acc-MCA aneurysm is very rare, it has a potential risk of rupture. Therefore, radical treatment is necessary for such aneurysms.

High-resolution magnetic resonance imaging findings of basilar artery plaque in a patient with branch atheromatous disease: a case report

Introduction

Intracranial branch atheromatous disease is a type of ischemic stroke that is caused by narrowing or occlusion of the orifice of the penetrating artery by atheromatous plaque. Pontine branch atheromatous disease is usually diagnosed using indirect findings such as the extension of a lesion to the basal surface of the pons because of the difficulty of demonstrating plaque in the basilar artery.

Case presentation

A 72-year-old Japanese man developed sudden dysarthria and left hemiparesis, and his symptoms deteriorated thereafter. Brain magnetic resonance imaging revealed an acute infarction in the territory of the right paramedian pontine artery extending to the basal surface. Non-contrast-enhanced three-dimensional fast spin-echo T1 imaging with variable flip angles and three-dimensional fast imaging with steady-state acquisition revealed a plaque in the dorsal wall of the basilar artery that spread to the origin of the paramedian pontine artery that branched toward the infarction. Although antithrombotic agents were started, the left hemiparesis got worse and became flaccid on the following day.

Conclusions

This is the first report to confirm the pathological basis of branch atheromatous disease by three-dimensional images using the new modalities of 3-Tesla magnetic resonance imaging. The use of these techniques will foster better understanding of the clinicopathological mechanisms of branch atheromatous disease.

A chronic intracerebral fluid hematoma

Intracerebral hematoma usually resolves and a chronic fluid hematoma is rare. We describe a rare case of intracerebral fluid hematoma. This report describes a case of intracerebral fluid hematoma mimicking a brain tumor and discusses the characteristics of this condition. A 70-year-old woman had a six-month history of memory disturbance. Computed tomography scan showed a low-density lesion with a partial high-density area in the right frontal lobe. MRI revealed a lesion of the main cystic portion showing high intensity on both T1 and T2 weighted images with a low-intensity solid portion in the anteromedial side. The lesion was adjacent to the lateral ventricle. Craniotomy was carried out and the lesion was removed. Pathological examination of the solid portion revealed that the diagnosis was reactive changes due to intracerebral hemorrhage. In our case, there was a possibility that the hematoma was diluted with cerebrospinal fluid, and coagulation might have been prevented.

Cerebellar hemorrhage after embolization of ruptured vertebral dissecting aneurysm proximal to PICA including parent artery

BACKGROUND

Some complications related to vertebral artery occlusion by endovascular technique have been reported. However, cerebellar hemorrhage after vertebral artery occlusion in subacute phase is rare. In this report, we describe a patient who showed cerebellar hemorrhage during hypertensive therapy for vasospasm after embolization of a vertebral dissecting aneurysm.

CASE DESCRIPTION

A 56-year-old female with a ruptured vertebral dissecting aneurysm proximal to the posterior inferior cerebellar artery developed cerebellar hemorrhage 15 days after embolization of the vertebral artery, including the dissected site. In this patient, the preserved posterior inferior cerebellar artery fed by retrograde blood flow might have been hemodynamically stressed during hypertensive and antiplatelet therapies for subarachnoid hemorrhage, resulting in cerebellar hemorrhage.

CONCLUSION

Although cerebellar hemorrhage is not prone to occur in the nonacute stage of embolization of the vertebral artery, it should be taken into consideration that cerebellar hemorrhage may occur during hypertensive treatment.

Giant subependymoma developed in a patient with aniridia: analyses of PAX6 and tumor-relevant genes

We observed an unusually large subependymoma in a female patient with congenital aniridia. To analyze the genetic mechanisms of tumorigenesis, we first examined the paired box 6 (PAX6) gene using both tumor tissue and peripheral lymphocytes. Tumor suppressor activity has been proposed for PAX6 in gliomas, in addition to its well‐known role in the eye development. Using genomic quantitative PCR and loss of heterozygosity analysis, we identified hemizygous deletions in the 5′‐region of PAX6. In lymphocytes, the deletion within PAX6 spanned from between exons 6 and 7 to the 5′‐upstream region of the gene, but did not reach the upstream gene, RNC1, which is reported to be associated with tumors. The subependymoma had an additional de novo deletion spanning from the intron 4 to intron 6 of PAX6, although we could not completely determine whether these two deletions are on the same chromosome or not. We also examined other potentially relevant tumor suppressor genes: PTEN, TP53 and SOX2. However, we detected no exonic mutations or deletions in these genes. Collectively, we speculate that the defect in PAX6 may have contributed to the extremely large size of the subependymoma, due to a loss of tumor suppressor activity in glial cell lineage.

NKX2.2 suppresses self-renewal of glioma-initiating cells

Glioblastoma (GBM) is the most aggressive and destructive form of brain cancer. Animal models that can unravel the mechanisms underlying its progression are needed to develop rational and effective molecular therapeutic approaches. In this study, we report the development of mouse models for spontaneous gliomas representing distinct progressive stages of disease that are governed by defined genetic alterations. Neural stem/progenitor cell (NPC)-specific constitutive Ras activation in vivo plus p53 deficiency led to development of primarily anaplastic astrocytoma (grade III), whereas combined loss of p53 plus p16(Ink4a)/p19(Arf) led to development of GBM (grade IV) at 100% penetrance within 6 weeks. These glioma models showed enhanced stem cell properties (stemness) accompanied by malignant progression. Notably, we determined that, in our models and in human specimens, downregulation of the homeodomain transcription factor NKX2.2, which is essential for oligodendroglial differentiation, was correlated with increased tumor malignancy. NKX2.2 overexpression by GBM-derived glioma-initiating cells (GIC) induced oligodendroglial differentiation and suppressed self-renewal capacity. By contrast, Nkx2.2 downregulation in mouse NPCs accelerated GBM formation. Importantly, the inhibitory effects of NXK2.2 on GIC self-renewal were conserved in human cells. Thus, our mouse models offer pathobiologically significant advantages to investigate the nature of brain tumors, with improved opportunities to develop novel mechanism-based therapeutic approaches.

Recurrent intracranial esthesioneuroblastoma outside the initial field of radiation with progressive dural and intra-orbital invasion

A 55-year-old man presented with esthesioneuroblastoma in the right paranasal sinuses and orbita, extending into the right anterior and middle cranial fossa. He received a partial resection of tumour and post-operative radiotherapy, which was set with a central focus on the right orbit. Five years later, he came to our hospital with a complaint of left exophthalmos. Neuro-imaging revealed that the tumour recurred on the opposite side of the primary lesion, which was out side the irradiated field, with progressive invasion of the left temporal dura. The residual tumour in the irradiated field had reduced in size. He received gross total resection and post-operative radiotherapy. We would like to emphasize that radiotherapy is an important adjuvant therapy for esthesioneuroblastoma, and that the field setting for radiation therapy is extremely important.