Epigenetic upregulation of Schlafen11 renders WNT- and SHH-activated medulloblastomas sensitive to cisplatin

BACKGROUND

Intensive chemotherapeutic regimens with craniospinal irradiation have greatly improved survival in medulloblastoma patients. However, survival markedly differs among molecular subgroups and their biomarkers are unknown. Through unbiased screening, we found Schlafen family member 11 (SLFN11), which is known to improve response to DNA damaging agents in various cancers, to be one of the top prognostic markers in medulloblastomas. Hence, we explored the expression and functions of SLFN11 in medulloblastoma.

METHODS

SLFN11 expression for each subgroup was assessed by immunohistochemistry in 98 medulloblastoma patient samples and by analyzing transcriptomic databases. We genetically or epigenetically modulated SLFN11 expression in medulloblastoma cell lines and determined cytotoxic response to the DNA damaging agents cisplatin and topoisomerase I inhibitor SN-38 in vitro and in vivo.

RESULTS

High SLFN11 expressing cases exhibited significantly longer survival than low expressing cases. SLFN11 was highly expressed in the WNT-activated subgroup and in a proportion of the SHH-activated subgroup. While WNT activation was not a direct cause of the high expression of SLFN11, a specific hypomethylation locus on the SLFN11 promoter was significantly correlated with high SLFN11 expression. Overexpression or deletion of SLFN11 made medulloblastoma cells sensitive and resistant to cisplatin and SN-38, respectively. Pharmacological upregulation of SLFN11 by the brain-penetrant histone deacetylase-inhibitor RG2833 markedly increased sensitivity to cisplatin and SN-38 in SLFN11-negative medulloblastoma cells. Intracranial xenograft studies also showed marked sensitivity to cisplatin by SLFN11-overexpression in medulloblastoma cells.

CONCLUSIONS

High SLFN11 expression is one factor which renders favorable outcomes in WNT-activated and a subset of SHH-activated medulloblastoma possibly through enhancing response to cisplatin.

Application of 7 tesla magnetic resonance imaging for pediatric neurological disorders: Early clinical experience

Ultra-high field magnetic resonance imaging (MRI) has been introduced for use in pediatric developmental neurology. While higher magnetic fields have certain advantages, optimized techniques with specific considerations are required to ensure rational and safe use in children and those with pediatric neurological disorders (PNDs). Here, we summarize our initial experience with clinical translational studies that utilized 7 tesla (T)-MRI in the fields of developmental neurology. T2-reversed images and three-dimensional anisotropy contrast imaging enabled the depiction of targeted pathological brain structures with better spatial resolution. Diffusion imaging and susceptibility-weighted imaging enabled visualization of intracortical, subcortical, and intratumoral microstructures in vivo within highly limited scan times appropriate for patients with PNDs. 7T-MRI appears to have significant potential to enhance the depiction of the structural and functional properties of the brain, particularly those associated with atypical brain development.

Mechanical Thrombectomy for Bihemispheric Infarction Caused by Acute Unilateral Internal Carotid Artery Occlusion in a Patient with Contralateral Chronic Carotid Occlusion: A Case Report

Objective

We report a patient with acute bihemispheric infarction who underwent mechanical thrombectomy.

Case Presentation

A 76-year-old man suddenly developed coma and quadriplegia. Brain MRI and MRA revealed acute bihemispheric infarction due to occlusions of both the internal carotid arteries (ICAs). According to the DSA findings, we considered the left ICA as chronic occlusion and the right as acute. Mechanical thrombectomy for the right ICA occlusion was performed. Total recanalization was achieved using a stent retriever 181 minutes after onset. The left hemisphere was perfused by cross circulation through the anterior communicating artery, but the symptoms did not improve. MRI the day after thrombectomy showed extensive bihemispheric infarction. Recanalization for the bilateral hemispheres was maintained, although the left ICA remained occluded. He died 2 months later due to gastrointestinal bleeding.

Conclusion

Acute bihemispheric infarction due to occlusions of both ICAs is a rare entity. The symptoms are very severe and the therapeutic time window is extremely short because of absent collateral pathways. We should consider pre-existing carotid occlusive disease, determine whether the occlusions are acute or chronic, and perform prompt therapy. Further investigation is warranted to obtain a better outcome.

GLI3 Is Associated With Neuronal Differentiation in SHH-Activated and WNT-Activated Medulloblastoma

Glioma-associated oncogene homolog 3 (GLI3), whose main function is to inhibit GLI1, has been associated with neuronal differentiation in medulloblastoma. However, it is not clear what molecular subtype(s) show increased GLI3 expression. GLI3 levels were assessed by immunohistochemistry in 2 independent cohorts, including a total of 88 cases, and found to be high in both WNT- and SHH-activated medulloblastoma. Analysis of bulk mRNA expression data and single cell RNA sequencing studies confirmed that GLI1 and GLI3 are highly expressed in SHH-activated medulloblastoma, whereas GLI3 but not GLI1 is highly expressed in WNT-activated medulloblastoma. Immunohistochemical analysis has shown that GLI3 is expressed inside the neuronal differentiated nodules of SHH-activated medulloblastoma, whereas GLI1/2 are expressed in desmoplastic areas. In contrast, GLI3 is diffusely expressed in WNT-activated medulloblastoma, whereas GLI1 is suppressed. Our data suggest that GLI3 may be a master regulator of neuronal differentiation and morphology in these subgroups.

Low Detection Rate of H3K27M Mutations in Cerebrospinal Fluid Obtained from Lumbar Puncture in Newly Diagnosed Diffuse Midline Gliomas

Recent studies have suggested the feasibility of detecting H3K27M mutations in the cerebrospinal fluid of diffuse midline glioma (DMG) patients. However, cerebrospinal fluid from patients in these studies were collected mainly during biopsy, ventriculo-peritoneal shunt procedures or postmortem. We assessed circulating tumor DNA (ctDNA) extracted from cerebrospinal fluid (CSF) and plasma in a series of 12 radiographically suspected and/or pathologically confirmed diffuse midline glioma patients and assessed for H3F3A K27M mutation using digital droplet PCR. In 10 patients, CSF was obtained by lumbar puncture at presentation. A definitive detection of H3F3A K27M mutation was achieved in only one case (10%); H3F3A K27M mutation was suspected in three other cases (30%). H3F3A K27M mutation was detected in two patients in CSF obtained by ventricular tap during a ventriculo-peritoneal shunt for obstructive hydrocephalus. Cases in which a definitive assessment was possible (definite H3F3A K27M or definite H3F3A wildtype) tended to be younger (median 7.5 years vs. 40.5 years; p = 0.07) and have a higher concentration of CSF protein (median 123 mg/dL vs. 27.5 mg/dL; p = 0.21) compared to nondefinite cases. Low proliferation and apoptotic rates seemed to be characteristics of DMG unfavorable for liquid biopsy. More advanced lesions with necrosis and evidence of dissemination were unlikely to be candidates for lumbar puncture due to the fear of exacerbating obstructive hydrocephalus. Methods to safely sample CSF and a more sensitive detection of ctDNA are necessary for reliable liquid biopsy of DMG at presentation.

Topoisomerase IIβ immunoreactivity (IR) co-localizes with neuronal marker-IR but not glial fibrillary acidic protein-IR in GLI3-positive medulloblastomas: an immunohistochemical analysis of 124 medulloblastomas from the Japan Children's Cancer Group

We previously reported observing GLI3 in medulloblastomas expressing neuronal markers (NM) and/or glial fibrillary acidic protein (GFAP). Furthermore, patients with medulloblastomas expressing NM or GFAP tended to show favorable or poor prognosis, respectively. In the present study, we focused on the role of topoisomerase IIβ (TOP2β) as a possible regulator for neuronal differentiation in medulloblastomas and examined the pathological roles of GLI3, NM, GFAP, and TOP2β expressions in a larger population. We divided 124 medulloblastomas into three groups (NM-/GFAP-, NM +/GFAP-, and GFAP +) based on their immunoreactivity (IR) against NM and GFAP. The relationship among GLI3, NM, GFAP, and TOP2β was evaluated using fluorescent immunostaining and a publicly available single-cell RNA sequencing dataset. In total, 87, 30, and 7 medulloblastomas were classified as NM-/GFAP-, NM + /GFAP-, and GFAP +, and showed intermediate, good, and poor prognoses, respectively. GLI3-IR was frequently observed in NM +/GFAP-  and GFAP + , and TOP2β-IR was frequently observed only in NM +/GFAP-  medulloblastomas. In fluorescent immunostaining, TOP2β-IR was mostly co-localized with NeuN-IR but not with GFAP-IR. In single-cell RNA sequencing, TOP2β expression was elevated in CMAS/DCX-positive, but not in GFAP-positive, cells. NM-IR and GFAP-IR are important for estimating the prognosis of patients with medulloblastoma; hence they should be assessed in clinical practice.

MBRS-06. Gli3 INDUCES NEURONAL DIFFERENTIATION IN WNT- AND SHH- ACTIVATED MEDULLOBLASTOMA

BACKGROUND

We have previously investigated the expression of Gli3, a downstream target of the Sonic Hedgehog pathway, which main function is to suppress Gli1/2 in medulloblastomas. We found that Gli3 is associated with neuronal and glial differentiation in desmoplastic / nodular (D/N) type medulloblastomas (Miyahara et al., Neuropathology, 2013). In the present study, we investigated the expression of Gli3 in molecular subgroups.

METHOD

Thirty-one medulloblastomas treated at Niigata University between 1982 and 2013 were studied. Molecular classification into 4 subgroups (WNT-activated, SHH-activated, Group 3 and Group 4) using Nanostring and immunohistochemistry was performed. Furthermore, Gli3 and Gli1 expression in molecular subgroups was assessed using public data bases.

RESULTS

Nanostring was considered reliable (confidence > 0.9) in 28 cases. Four cases were classified as WNT-, 5 cases as SHH-activated, 4 cases as Group 3 and 16 cases as Group 4. Gli3 was positive in 7 out of 9 (78%) WNT-/SHH- cases, but positive in only 8 out of 19 (42.1%) non-WNT-/SHH- subgroup cases (p = 0.1145, Fisher’s exact test). R2 database analysis confirmed that Gli3 was significantly elevated in WNT- and SHH-activated medulloblastoma. Gli1 was elevated in SHH-activated cases but suppressed in WNT-activated cases. IHC analysis revealed that Gli3 was elevated inside nodules showing neuronal differentiation in D/N type medulloblastoma. Results of single cell RNA analyses were consistent with those of IHC, Nanostring and R2.

CONCLUSION

These results suggest that Gli3 is elevated inside the nodules of SHH-activated medulloblastoma, whereas in WNT-activated cases, Gli3 diffusely suppresses HH signaling.

MBRS-32. TOPOISOMERASE II β INDUCES NEURONAL, BUT NOT GLIAL, DIFFERENTIATION IN MEDULLOBLASTOMA

BACKGROUND

We previously reported that Gli3, which was a downstream molecule of Sonic Hedgehog signal, induced neuronal and/or glial differentiation in some types of medulloblastoma (desmoplastic/nodular medulloblastoma and medulloblastoma with extensive nodularity), and patients of medulloblastoma with neuronal differentiation showed favorable prognosis, but those with glial differentiation tended to show miserable prognosis (Miyahara H, Neuropathology, 2013). This time, we focused on Topoisomerase II β (Top2β), which was reported to induce neuronal differentiation and inhibit glial differentiation, and examined the expression of Top2β in medulloblastomas with neuronal and glial differentiations.

METHODS

We assessed the expression of Top2β, NeuN, and GFAP using triple fluorescent immunostaining method in medulloblastoma samples with both neuronal and glial differentiations. Furthermore, the expression of Top2β, H3K4me2, and H3K27me3 were also assessed, because Top2βwas positively or negatively regulated by H3K4me2 and H3K27me3, respectively.

RESULTS

Many large nuclei in the nodules, in which differentiated cells were seen, was visualized by Top2β. The Top2β signals were seen in NeuN+ cells but not GFAP+ cells. H3K4me2 signals were visualized in Top2β+ large nuclei, but H3K27me3 and NeuN+ large nuclei were distributed independently.

CONCLUSIONS

These results indicate that Top2β may be a molecule associated with neuronal, but not glial, differentiation of medulloblastoma cells. Drugs targeting histone modification enzymes such as EZH2 inhibitors are possible therapeutic targets as a differentiation-inducing therapy for medulloblastoma.

[Surgical Case of Accidental Infantile Acute Subdural Hematoma Caused by Household Minor Head Trauma:Hyperperfusion during Postoperative Hemispheric Hypodensity, Namely "Big Black Brain"]

We experienced a case of an accidental infantile acute subdural hematoma caused by household minor head trauma(Nakamura type I intracranial hemorrhage)with postoperative hemispheric hypodensity lesion(Big Black Brain)whose pathophysiology was analyzed using perfusion MRI. A ten-month-old boy was admitted to our hospital in a comatose state. His mother revealed that the boy suffered a fall from a sofa bed. A CT scan indicated massive acute subdural hematoma in the left cerebral hemisphere. Emergency craniotomy and hematoma evacuation were performed. On postoperative day 3, CT revealed hemispheric hypodensity, and the boy suffered from status epilepticus. MRI on the following day showed widespread white matter hyperintensity in diffusion-weighted images, and MRA demonstrated dilation of the middle cerebral artery. Perfusion MRI using the dynamic susceptibility contrast method revealed a marked increase in cerebral blood flow in the left hemisphere. These abnormal MRI and MRA findings disappeared on postoperative day 13. Status epilepticus also improved upon administration of multi-antiepileptic drugs. Fundoscopy findings on postoperative day 3 showed small bilateral petechial or brush retinal hemorrhages. However, whole-body examination did not show any problems, and was consistent with the mother's account. Thus, we judged non-abusive head trauma. Although follow-up MRI showed diffuse atrophy of the left cerebral hemisphere, the boy aged well without obvious paresis or verbal developmental delay as judged by a follow-up more than a year later. Based on these results, we speculated that hyperperfusion caused by dilation of the cerebral artery was related to the postoperative hemispheric hypodensity, namely "Big Black Brain".

Overlapping Stents and Coil Embolization of Ruptured Anterior Cerebral Artery Dissecting Aneurysms in the Acute Phase

Objective

To report a case of ruptured anterior cerebral artery dissection treated with stent-assisted coil embolization with overlapping stents.

Case Presentation

A 51-year-old woman developed subarachnoid hemorrhage the day after transient left hemiparesis. Angiography revealed a ruptured anterior cerebral artery dissecting aneurysm. We conducted stent-assisted coil embolization with the overlapping stent technique on the day after the hemorrhage. She recovered steadily without rebleeding. Six months after embolization, no recurrence was found on angiography.

Conclusion

Although an acceptable result was achieved in this case, the safety and efficacy of this procedure are unconfirmed. A larger number of cases should be accumulated.

MGMT Expression Contributes to Temozolomide Resistance in H3K27M-Mutant Diffuse Midline Gliomas

Diffuse midline gliomas (DMGs) show resistance to many chemotherapeutic agents including temozolomide (TMZ). Histone gene mutations in DMGs trigger epigenetic changes including DNA hypomethylation, one of which is a frequent lack of O6-methyl-guanine-DNA methyltransferase (MGMT) promoter methylation, resulting in increased MGMT expression. We established the NGT16 cell line with HIST1H3B K27M and ACVR1 G328E gene mutations from a DMG patient and used this cell line and other DMG cell lines with H3F3A gene mutation (SF7761, SF8628, JHH-DIPG1) to analyze MGMT promoter methylation, MGMT protein expression, and response to TMZ. Three out of 4 DMG cell lines (NGT16, SF8628, and JHH-DIPG1) had unmethylated MGMT promoter, increased MGMT expression, and showed resistance to TMZ treatment. SF7761 cells with H3F3A gene mutation showed MGMT promoter methylation, lacked MGMT expression, and sensitivity to TMZ treatment. NGT16 line showed response to ALK2 inhibitor K02288 treatment in vitro. We confirmed in vitro that MGMT expression contributes to TMZ resistance in DMG cell lines. There is an urgent need to develop new strategies to treat TMZ-resistant DMGs.

A Case of Curative Onyx Embolization for Tentorial dAVF via Low-flow Feeders with Temporary Balloon Occlusion of High-flow Feeders

Objective

For curative Onyx embolization of dural arteriovenous fistulas (dAVF) with multiple feeders, it is essential to select the optimal target artery as well as to control the blood flow at the fistula point. We report a case of tentorial dAVF (TdAVF) treated by Onyx embolization under flow control using balloon catheters.

Case Presentation

A 66-year-old male was admitted to our hospital for treatment of TdAVF detected incidentally by MRI, which revealed a dilated and tortuous vein around the cerebellum. Cerebral angiography demonstrated a TdAVF, fed mainly by bilateral middle meningeal arteries (MMA) and bilateral occipital arteries (OA), with the fistula point at the torcular and venous drainage to the two superior vermian veins (SVVs). Onyx 18 was injected from the low-flow feeder of the MMA under flow control by occluding the high-flow feeder of the OA using balloon catheters, obliterating the arteriovenous shunt.

Conclusion

In treatment of TdAVF involving low- and high-flow feeders, Onyx embolization via the low-flow feeder with temporary balloon occlusion of other high-flow feeders is a useful method. This technique makes it easier for Onyx to penetrate the fistula point.

COT-21 EFFECT OF BEVACIZUMAB FOR PEDIATRIC HIGH GRADE GLIOMA

INTRODUCTION

Bevacizumab (BEV) therapy has been used for pediatric high grade glioma,however the evidence and effectiveness are not understood yet.

METHODS

We report 7 cases (age 2 to 10 years old) of pediatric high grade glioma treated with BEV. One case is thalamic diffuse midline glioma H3K27 mutant (DMGH3K27M),one case is brain stem DMGH3K27M,one case is cerebellar high grade glioma,and 4 cases are diffuse intrinsic pontine glioma (DIPG) diagnosed clinically without biopsy. 5 cases were treated with BEV when diagnosed as recurrence after chemo-radiotherapy. One case was treated for rapid tumor progression during radiotherapy. One case was started on BEV therapy with radiation and concomitant temozolomide therapy.

RESULT

The number of times of BEV was 2 to 13 times (median 7 times). The period of BEV was 1 to 9 months (median 4 months). One case which was treated with BEV at rapid progression during radiation showed good response on imaging and improvement of symptoms. 4 of 5 cases who were treated at recurrence clinically showed mild symptomatic improvement. One case treated with BEV and radiotherapy initially was not evaluated. The adverse effects of BEV included wound complication of tracheostomy and rash.

CONCLUSION

BEV showed good response for rapid progression during radiotherapy,and mild response for recurrence cases. BEV is thought to be an effective therapeutic agent for pediatric HGG at recurrence and rapid tumor progression during radiotherapy.

De Novo Pineal Region Germinoma in the Seventh Decade of Life: A Case Report

Germ cell tumors typically occur in children and adolescents. We here report a rare case of de novo pineal region germinoma in the seventh decade of life. A 62-year-old man presented with double vision. Computerized tomography and magnetic resonance imaging (MRI) identified a heterogeneously enhanced tumor with calcification in the pineal region with ventricular dilatation due to aqueduct stenosis. The tumor had not been observed at all on MRI obtained 2 years previously. The patient underwent endoscopic biopsy and third ventriculostomy for the obstructive hydrocephalus. The tumor was histopathologically diagnosed as a pure germinoma. The patient underwent radiomonotherapy, resulting in his complete remission, which was confirmed by a series of follow-up MRI studies and hematological examinations. Intracranial germinoma should be considered in the differential diagnosis of pineal region tumors regardless of age, even though the tumor was undetectable on the previous neuroimaging.

Detectability of the choroid plexus of the third ventricle with magnetic resonance ventriculography

PURPOSE

To clarify the detectability of the choroid plexus of the third ventricle (ChPl3V) with magnetic resonance ventriculography (MRVn) employing a steady-state free precession (SSFP) sequence in comparison to surgical endoscopic movies as a golden standard, as we encountered some clinical cases of total agenesis of corpus callosum (ACC) where we could not recognize the choroid plexus of the third ventricle and found no previous article addressing this problem.

MATERIALS AND METHODS

This retrospective study included consecutive patients from 2010 to 2016 for whom endoscopic evaluation of the third ventricle was conducted. The anterior portion of the right and left streaks of ChPl3V was evaluated in 8 patients on 16 sites, while the posterior portion of both streaks of ChPl3V was evaluated in 13 patients on 26 sites. Sensitivity of MRVn to visualize ChPl3V with endoscopic movies as the golden standard was calculated.

RESULTS

Sensitivity of MRVn in visualizing the anterior portion of ChPl3V was 0.813, and that for the posterior portion 0.692. The anterior portion of ChPl3V was visualized in all cases where no tumor contacted the foramen of Monro.

CONCLUSION

MRVn visualizes the anterior portion of ChPl3V with significant sensitivity and the posterior portion with lower one.

Polysomnography as an indicator for cervicomedullary decompression to treat foramen magnum stenosis in achondroplasia

OBJECTIVE

Management of cervicomedullary compression due to foramen magnum stenosis in achondroplasia remains controversial, especially for patients with no symptoms or mild symptoms. We examined the effectiveness of polysomnography (PSG) as an indicator for cervicomedullary decompression treatment.

METHODS

We retrospectively reviewed nine achondroplasia cases (mean age 1 year and 9 months) treated from 2008 to 2015. All patients were examined by PSG, magnetic resonance imaging (MRI), and otolaryngeal fibroscopy. We analyzed demographic data, clinical presentation, degree and type of respiratory impairment, severity of foramen magnum stenosis and concomitant cervicomedullary compression, treatment (conservative or surgical), and clinical outcome.

RESULTS

Eight of nine patients presented with no severe symptoms in the daytime. However, MRI revealed four severe, four moderate, and one mild case of cervicomedullary compression, and PSG demonstrated severe sleep apnea in four cases and moderate sleep apnea in five cases. All sleep apnea cases were obstructive or obstructive-dominant. Fibroscopy revealed no upper airway stenosis in six cases and mild stenosis in three cases. Four patients who had severe sleep-related respiratory disturbance on PSG and severe or moderate cervicomedullary compression were treated by cervicomedullary decompression. Three of these patients demonstrated improved sleep respiration soon after surgery, while one required temporary tracheostomy due to bilateral vocal cord paralysis caused by compression during intratracheal intubation.

CONCLUSION

Polysomnography can be a useful indicator for cervicomedullary decompression surgery, especially in cases of seemingly asymptomatic achondroplasia with severe foramen magnum stenosis.

MGMT Expression Contributes to Temozolomide Resistance in H3K27M-Mutant Diffuse Midline Gliomas and MGMT Silencing to Temozolomide Sensitivity in IDH-Mutant Gliomas

Histone H3 mutations are frequently found in diffuse midline gliomas (DMGs), which include diffuse intrinsic pontine gliomas and thalamic gliomas. These tumors have dismal prognoses. Recent evidence suggests that one reason for the poor prognoses is that O⁶-methylguanine-DNA methyltransferase (MGMT) promoter frequently lacks methylation in DMGs. This review compares the epigenetic changes brought about by histone mutations to those by isocitrate dehydrogenase-mutant gliomas, which frequently have methylated MGMT promoters and are known to be sensitive to temozolomide.

[Bilateral Internal Carotid Artery Dissection Caused by Elongated Styloid Processes:A Case Report]

We report a case of bilateral internal carotid artery(ICA)dissection associated with bilateral elongated styloid processes(ESPs). A 46-year-old man presented with transient aphasia and left visual disturbance at a business meeting. He complained of a foreign body sensation in his throat during swallowing for two years. Magnetic resonance imaging(MRI)demonstrated fresh small infarcts in the left corona radiata. Magnetic resonance angiography(MRA)revealed string signs bilaterally in the cervical ICAs. The patient was diagnosed with bilateral idiopathic ICA dissection and was treated with ozagrel and clopidogrel. Three-dimensional computed tomographic angiogram(3DCTA)indicated bilateral ESPs and bilateral ICA stenosis. 3DCTA with the patient's head tilting and neck extension revealed that each ICA was compressed by the ipsilateral ESP. A follow-up MRA showed complete normalization of bilateral ICAs after neck rest and anti-platelet therapy, following which, clopidogrel was stopped. The patient wore a soft cervical collar until the operation, to avoid contact between the ESPs and ICAs due to changes in head position. Bilateral ESP resection was performed to prevent recurrence of cerebral ischemic events caused by ICA dissection. The patient was discharged one week after the surgery without any neurological deficit. There was no recurrence of symptoms during the next eight months after the operation.

Adult Chiari Type 1 Malformation with Holocord Syringomyelia Associated with Sagittal Synostosis

Craniosynostosis associated with Chiari malformation (CM) is usually found in infants with an underdeveloped posterior fossa. We here present a case of adult craniosynostosis, CM, and symptomatic syringomyelia caused by the protrusion of the posterior rim of the foramen magnum without a tight posterior fossa. A 22-year-old woman with an abnormal head shape and forearm hypesthesia was given a diagnosis of sagittal suture synostosis with CM and syringomyelia caused by foramen magnum stenosis. She underwent foramen magnum decompression with a C1 laminectomy without cranial vault expansion or duraplasty. Her symptoms and radiographical findings improved after surgery. In cases of non-operative craniosynostosis with CM, clinicians should be alert to late-onset syringomyelia and choose surgical strategies according to the pathophysiology.

Third Ventricle Germ Cell Tumor Originating from the Infundibulum with Rapidly Expansive Enlargement

We present a pediatric case of a rapidly expanding third ventricle germ cell tumor (GCT). A 14-year-old boy suffered from gradual-onset central diabetes insipidus (DI) and received desmopressin treatment. Magnetic resonance imaging (MRI) showed nonspecific findings of the pituitary-hypothalamic axis. Nine months after the initial DI diagnosis, he developed progressively worsening headache. MRI demonstrated a third ventricle tumor causing noncommunicating hydrocephalus, although an MRI 16 weeks before admission did not show the lesion. We performed gross total resection (GTR) of the tumor in 2 stages: a translamina terminalis approach and an extended transsphenoidal approach. The lesion was histologically diagnosed as immature teratoma with some germinoma. His noncommunicating hydrocephalus resolved after surgery. Through postoperative radiochemotherapy (whole ventricle: 23.4 Gy/13 fractions, tumor bed: 27.0 Gy/15 fractions, and 3 courses of carboplatin-etoposide), he has was in complete remission at the 3-year follow-up and has continued his high school program. This case suggests the following: (1) a mixed GCT originating from the neurohypophysis/infundibulum can show rapidly expansive growth in a child with central DI; (2) GTR and adjuvant radiochemotherapy can result in a good therapeutic outcome in rapidly expanding GCT; and (3) the extended transsphenoidal approach is a complementary approach to transcranial resection of anterior third ventricle GCTs.

Perifocal Inflammatory Reaction with Volume Fluctuation Caused by Diagnostic Radiation-Induced Regression in Germinoma Makes Histological Diagnosis Difficult despite Its Disappearance following Treatment: A Significant Pitfall and Countermeasures to It

We present a pediatric case of neurohypophyseal germinoma with a perifocal inflammatory reaction (PIR) with volume fluctuation caused by diagnostic radiation-induced regression (DRIR). On-target biopsy failed to confirm the histology because PIR hardly contained any germinoma cells. DRIR-related fluctuation of the tumor volume disguised germinoma as inflammation. We analyzed the cerebrospinal fluid (CSF) and detected a high level of placental alkaline phosphatase (PLAP), which demonstrated the neurohypophyseal lesion to be germinoma and brought the patient from successful radiochemotherapy up to complete remission. PIR adjacent to the germinoma (PIRAG) disappeared completely following radiochemotherapy, although it contained almost no germinoma cells. Examination of the CSF-PLAP level can complement the diagnosis of germinoma and will decrease the risk of misdiagnosis. Neurosurgeons should keep in mind PIRAG, DRIR, and the diagnostic value of CSF-PLAP when germinoma is suspected.

Mobile spinal enterogenous cyst resulting in intermittent paraplegia in a child: case report

The authors report the case of a mobile spinal enterogenous cyst in a 2-year-old boy, who was admitted to the hospital several times for intermittent paraplegia. Magnetic resonance imaging and CT revealed an isolated cyst in the lumbar spinal canal. The symptoms were caused by transient myelopathy of the conus medullaris and radiculopathy of the cauda equina due to the changing size and location of the cyst. The cyst was surgically extirpated, after which the symptoms resolved. The histopathological diagnosis was enterogenous cyst. The clinical history of intraspinal enterogenous cyst is usually progressive. Mobility and changes in size are rare pathophysiological findings. The authors speculate that the cyst wall did not adhere to the surrounding structures and had ruptured and quickly reformed. Enterogenous cyst should be considered in the differential diagnosis of spinal intradural cysts in children with radiculomyelopathy.

Long-term outcomes in patients with pineal nongerminomatous malignant germ cell tumors treated by radical resection during initial treatment combined with adjuvant therapy

BACKGROUND

For pineal nongerminomatous malignant germ cell tumors (NGMGCTs), we mainly performed radical tumor resection during initial treatment combined with adjuvant therapy.

METHODS

We retrospectively analyzed 17 patients treated for pineal NGMGCTs between 1986 and 2007 at the University of Niigata.

RESULTS

Twelve patients underwent total or subtotal resection of their tumor via the occipital transtentorial approach. Five patients underwent partial resection, and four of them later underwent total resection by salvage surgery. After surgery, eight patients were treated with combined radiochemotherapy including whole-brain irradiation, two received radiation monotherapy, one had chemotherapy with local irradiation, and six were treated with chemotherapy alone. The median follow-up period for surviving patients was 179 months. The 10-year overall survival and progression-free survival rates for the radiochemotherapy group were both 75.0 % (two patients had a recurrence and died); the rates for other adjuvant therapies were 77.8 % (two died) and 22.2 % (seven had a recurrence), respectively. Radiochemotherapy was significantly associated with an increased rate of progression-free survival compared with the other adjuvant therapies (p = 0.0396).

CONCLUSIONS

For pineal NGMGCTs, initial treatment strategies including gross total resection of the tumor before or after whole-brain irradiation and chemotherapy provided good therapeutic outcomes. Obtaining complete remission of the primary tumor, irrespective of the timing of surgical resection (i.e., before or after adjuvant therapies), or complete response by neoadjuvant radiochemotherapy during an initial treatment appears to be essential for improving therapeutic outcomes of intracranial NGMGCTs.

Limitations of Neuroendoscopic Treatment for Pediatric Hydrocephalus and Considerations from Future Perspectives

Neuroendoscopy has become common in the field of pediatric neurosurgery. As an alternative procedure to cerebrospinal fluid shunt, endoscopic third ventriculostomy has been the routine surgical treatment for obstructive hydrocephalus. However, the indication is still debatable in infantile periods. The predictors of late failure and how to manage are still unknown. Recently, the remarkable results of endoscopic choroid plexus coagulation in combination with third ventriculostomy, reported from experiences in Africa, present puzzling complexity. The current data on the role of neuroendoscopic surgery for pediatric hydrocephalus is reported with discussion of its limitations and future perspectives, in this review.

Successful removal of a huge hypervascular tentorial cavernous angioma after preoperative endovascular embolization

The authors report a rare case of a huge hypervascular tentorial cavernous angioma treated with preoperative endovascular embolization, followed by successful gross-total removal. A 15-year-old girl presented with scintillation, diplopia, and papilledema. Computed tomography and MRI studies revealed a huge irregularly shaped tumor located in the right occipital and suboccipital regions. The tumor, which had both intra- and extradural components, showed marked enhancement and invasion of the overlying occipital bone. Angiography revealed marked tumor stain, with blood supply mainly from a large branch of the left posterior meningeal artery. Therefore, this lesion was diagnosed as a tentorium-based extraaxial tumor. For differential diagnosis, meningioma, hemangiopericytoma, and malignant skull tumor were considered. Tumor feeders were endovascularly embolized with particles of polyvinyl alcohol. On the following day, the tumor was safely gross totally removed with minimum blood loss. Histopathological examination confirmed the diagnosis of cavernous angioma. To date, there have been no reports of tentorium-based cavernous angiomas endovascularly embolized preoperatively. A tentorial cavernous angioma is most likely to show massive intraoperative bleeding. Therefore, preoperative embolization appears to be quite useful for safe maximum resection. Hence, the authors assert that the differential diagnosis of tentorium-based tumors should include tentorial cavernous angioma, for which preoperative endovascular embolization should be considered.

Intraspinal lesions associated with sacrococcygeal dimples

OBJECT.: Sacrococcygeal dimples in the gluteal fold, also known as coccygeal pits, are observed in 2%-4% of newborns. Sacrococcygeal dimples are not generally considered to be associated with a significant risk of intraspinal anomalies and therefore are not thought to require further radiographic evaluation. Accordingly, the precise incidence and nature of intraspinal lesions that may be associated with sacrococcygeal dimples is unclear. This study was conducted to determine the incidence of intraspinal lesions in patients with intergluteal dimples.

METHODS

In this study, the authors used MRI to evaluate 103 children who were seen at the Niigata University Medical and Dental Hospital between 2006 and 2011 because of skin abnormalities in the lumbosacral region. Of these children, 14 were excluded as having a subcutaneous fatty mass, and 5 were excluded because the dimples were above the gluteal fold or did not end at the coccyx. The remaining 84 patients were classified according to whether the bottom of the dimple was visible (shallow) or not (deep). The authors also retrospectively examined other skin abnormalities and coexisting anomalies.

RESULTS

The mean age at the time of MRI evaluation was 11.7 months. Magnetic resonance imaging led to the identification of fibrolipoma of the terminal filum (FTF) in 14 cases (16.7%); 6 of these patients also had a low conus. Classified by depth, there were 58 cases with shallow and 26 with deep dimples. Fibrolipoma of the terminal filum was found in significantly more patients with deep dimples (9 [34.6%]) than in those with shallow dimples (5 [8.6%]). The frequency of other congenital anomalies was significantly higher in patients with FTF-associated dimples (6 [42.9%] of 14) than in those with dimples that were not associated with FTF (9 [12.9%] of 70).

CONCLUSIONS

Fibrolipoma of the terminal filum was identified by MRI in 16.7% of patients with sacrococcygeal dimples. The risk of FTF increased when the dimples were deeply excavated or were accompanied by congenital anomalies. Magnetic resonance imaging should be performed to identify intraspinal lesions when there are high risk factors for intraspinal abnormalities, or when an ultrasound screening suggests intraspinal abnormalities.

Intraspinal lesions associated with sacrococcygeal dimples

OBJECT.: Sacrococcygeal dimples in the gluteal fold, also known as coccygeal pits, are observed in 2%-4% of newborns. Sacrococcygeal dimples are not generally considered to be associated with a significant risk of intraspinal anomalies and therefore are not thought to require further radiographic evaluation. Accordingly, the precise incidence and nature of intraspinal lesions that may be associated with sacrococcygeal dimples is unclear. This study was conducted to determine the incidence of intraspinal lesions in patients with intergluteal dimples.

METHODS

In this study, the authors used MRI to evaluate 103 children who were seen at the Niigata University Medical and Dental Hospital between 2006 and 2011 because of skin abnormalities in the lumbosacral region. Of these children, 14 were excluded as having a subcutaneous fatty mass, and 5 were excluded because the dimples were above the gluteal fold or did not end at the coccyx. The remaining 84 patients were classified according to whether the bottom of the dimple was visible (shallow) or not (deep). The authors also retrospectively examined other skin abnormalities and coexisting anomalies.

RESULTS

The mean age at the time of MRI evaluation was 11.7 months. Magnetic resonance imaging led to the identification of fibrolipoma of the terminal filum (FTF) in 14 cases (16.7%); 6 of these patients also had a low conus. Classified by depth, there were 58 cases with shallow and 26 with deep dimples. Fibrolipoma of the terminal filum was found in significantly more patients with deep dimples (9 [34.6%]) than in those with shallow dimples (5 [8.6%]). The frequency of other congenital anomalies was significantly higher in patients with FTF-associated dimples (6 [42.9%] of 14) than in those with dimples that were not associated with FTF (9 [12.9%] of 70).

CONCLUSIONS

Fibrolipoma of the terminal filum was identified by MRI in 16.7% of patients with sacrococcygeal dimples. The risk of FTF increased when the dimples were deeply excavated or were accompanied by congenital anomalies. Magnetic resonance imaging should be performed to identify intraspinal lesions when there are high risk factors for intraspinal abnormalities, or when an ultrasound screening suggests intraspinal abnormalities.

Neuronal differentiation associated with Gli3 expression predicts favorable outcome for patients with medulloblastoma

Medulloblastoma (MB) is a malignant cerebellar tumor arising in children, and its ontogenesis is regulated by Sonic Hedgehog (Shh) signaling. No data are available regarding the correlation between expression of Gli3, a protein lying downstream of Shh, and neuronal differentiation of MB cells, or the prognostic significance of these features. We re-evaluated the histopathological features of surgical specimens of MB taken from 32 patients, and defined 15 of them as MB with neuronal differentiation (ND), three as MB with both glial and neuronal differentiation (GD), and 14 as differentiation-free (DF) MB. Gli3-immunoreactivity (IR) was evident as a clear circular stain outlining the nuclei of the tumor cells. The difference in the frequency of IR between the ND+GD (94.4%) and DF (0%) groups was significant (P < 0.001). The tumor cells with ND showed IR for both Gli3 and neuronal nuclei. Ultrastructurally, Gli3-IR was observed at the nuclear membrane. The overall survival and event-free survival rates of the patients in the ND group were significantly higher than those in the other groups. The expression profile of Gli3 is of considerable significance, and the association of ND with this feature may be prognostically favorable in patients with MB.

[Radiation-induced intracranial osteosarcoma after radiation for acute lymphocytic leukemia associated with Li-Fraumeni syndrome]

A 28-year-old man presented with osteosarcoma of the occipital bone 16 years after 24 Gy of craniospinal irradiation for acute lymphocytic leukemia. The tumor had both intra- and extra-cranial components. However, the affected skull appeared to be normal on imaging because of permeative infiltration by the tumor. Subtotal resection was achieved and the tumor was verified histologically as an osteosarcoma. The residual tumor soon showed remarkable enlargement and disseminated to the spinal cord. Both of the enlarged and disseminated tumor masses were treated by surgical intervention and chemotherapy. However, the patient deteriorated due to the tumor regrowth and died 11 months after the initial diagnosis. This patient had previously developed a leukemia, a colon cancer, a rectal cancer and a hepatocellular carcinoma. His brother also died of leukemia. The patient had a heterozygous TP53 germ-line mutation of codon 248 in the exon 7. In conclusion, we consider the present tumor to be a rare example of radiation-induced skull osteosarcoma in a member of the cancer-prone family with TP53 germ-line mutation which is associated with Li-Fraumeni syndrome.

Factors affecting functional outcomes in long-term survivors of intracranial germinomas: a 20-year experience in a single institution

OBJECT

Radiation monotherapy-prophylactic craniospinal or whole-brain irradiation paired with a radiation boost to the primary tumor-is the standard treatment for intracranial germinomas at the authors' institution. The authors assessed long-term outcomes of patients with germinoma who underwent therapy and identified factors affecting them.

METHODS

The authors retrospectively analyzed data obtained in 46 patients (35 males and 11 females, age 5-43 years at diagnosis) who had been treated for intracranial germinomas between 1990 and 2009 at the authors' institution. Thirty patients had germinomas in localized regions and 16 in multiple regions. Thirty-eight patients (83%) underwent radiotherapy alone (craniospinal irradiation in 32 and whole-brain irradiation in 6). Seven patients underwent radiochemotherapy and 1 underwent chemotherapy alone. The mean radiation doses for the whole brain, spine, and primary tumor site were 26.9, 26.6, and 49.8 Gy, respectively. The median follow-up period was 125 months.

RESULTS

The 10-year overall and recurrence-free survival rates were 93.3% and 89.3%, respectively. None of the 38 patients who received radiation monotherapy developed a recurrent lesion, whereas 1 of 7 who underwent radiochemotherapy and the 1 patient who underwent chemotherapy had a recurrent lesion. Of the entire population, 26 patients required hormone replacement therapy, 2 had short stature, and 1 developed a radiation-induced meningioma. Seventeen of the 25 childhood- or adolescent-onset patients were 19 years or older at the latest follow-up visit, 15 of whom graduated from senior high school, and only 2 of whom graduated from college. Of 34 patients who were 19 years or older at the latest visit, 4 were students, 18 worked independently, 4 worked in sheltered workplaces, and 8 were unemployed. Of the 34 patients, 4 got married after the initial treatment, 3 of whom had children. There were 8 patients (17%) with low postoperative Karnofsky Performance Scale (KPS) scores that were significantly associated with impaired neurocognitive functions, severe surgical complications, and neurological impairments. In 10 of the 46 patients, KPS scores at the latest visit were lower than their postoperative KPS scores. These decreases in KPS scores were significantly correlated with a delayed decline in neurocognitive functions in childhood-onset patients and a postoperative impairment of neurocognitive functions in patients with adolescent- or adult-onset germinoma.

CONCLUSIONS

No tumor recurrence occurred in germinoma patients treated with the authors' radiation monotherapy, which appears to be effective enough to cure the tumor. Brain damage caused by tumors themselves and surgical complications were found to adversely affect functional outcomes in patients regardless of their age. Although radiotherapy rarely caused late adverse effects in patients with adolescent- or adult-onset, in some childhood-onset lesions, the radiation seems to carry the risk of neurocognitive dysfunctions, which are attributable to late adverse effects. Accordingly, treatments for germinoma patients should be selected according to a patient's age and the extent of the tumor and with particular care to avoid surgical complications.

Endoscopic biopsies of lesions associated with a thickened pituitary stalk

BACKGROUND

Lesions associated with a thickened pituitary stalk (TPS lesions) revealed by magnetic resonance imaging have a diverse pathology. Accordingly, for clinical decision-making, it is necessary to make a diagnosis based on histopathological examination of the TPS lesions. The objectives of this study were to review endoscopic biopsies of TPS lesions and to assess the surgical strategy for treating these lesions.

METHODS

Eleven patients (four males and seven females) aged from 6 to 75 years underwent endoscopic biopsy of a TPS lesion between 2006 and 2011 at University of Niigata. The relationships of the extent of lesions with surgical approaches were retrospectively examined.

RESULTS

Among the 11 patients, a biopsy was performed via an endoscopic transsphenoidal approach for five with intrasellar lesions; via an endoscopic extended transsphenoidal approach for two with localized TPS lesions; and via an endoscopic intraventricular approach for four with the lesion protruding from the infundibulum. Histopathological examinations of all the lesions confirmed diagnoses of germinoma in four patients, hypophysitis in three, Langerhans cell histiocytosis in two, craniopharyngioma in one, and cancer metastasis in one. None of the 11 patients had further deterioration of pituitary function postoperatively.

CONCLUSIONS

Endoscopic biopsy of TPS lesions is a less invasive alternative to open biopsy requiring transcranial surgery. The endoscopic transsphenoidal approach is most suitable for biopsies of TPS lesions associated with intrasellar lesions. Otherwise, the endoscopic intraventricular approach seems reasonable for intraventricular lesions protruding from the infundibulum, and the endoscopic extended transsphenoidal approach appears appropriate for localized TPS lesions.

Occurrence of metachronous pure germinomas long after treatment of a mixed germ cell tumor containing yolk sac tumor and germinoma

The authors report a rare case involving the occurrence of metachronous pure germinomas long after treatment of a mixed germ cell tumor (GCT) categorized as having a poor prognosis. A neurohypophysial germinoma occurred 4 years and 6 months after the initial treatment of a mixed pineal GCT containing a yolk sac tumor and a germinoma. Furthermore, intramedullary germinomas occurred 21 years after the initial treatment of the mixed GCT and 15 years after the second treatment of the neurohypophysial germinoma. The neurohypophysial germinoma was not confirmed histopathologically, but the intramedullary germinoma was histopathologically diagnosed as a pure germinoma. Serum α-fetoprotein levels at the second neurohypophysial and third intramedullary occurrences of the germinomas were less than 10 ng/ml. Therefore, no yolk sac components seemed to be contained in the tumors. The second neurohypophysial and third intramedullary germinomas might be recurrences of the germinoma component of the pineal mixed GCT, which consisted of a yolk sac tumor and a germinoma. However, it seems very unlikely that only the germinoma, categorized in the good prognosis group, would be the only one to recur. Hence, it seems plausible that both the second and the third occurrences of pure germinoma were de novo metachronous GCTs arising after the pineal mixed GCT was cured. The authors' case indicates the possibility of multicentric GCTs in the CNS.

Adult cerebellopontine angle medulloblastoma originating in the pons mimicking focal brainstem tumor

We herein report a rare case of cerebellopontine angle (CPA) medulloblastoma originating in the brainstem that demonstrated a very unusual clinical presentation and radiological appearances. A 25-year-old female was admitted to our hospital with a right hearing disturbance and a right facial palsy. A small non-enhanced lesion having minimal mass effect in the right CPA was identified by using a 1.5-tesla-MR system, whose size remained almost unchanged a year. The 3-tesla MR images revealed that the precise region was in the right side of the tegmentum of the lower pons to the inferior cerebellar peduncle and the flocculus. MR spectroscopic images using a 3-tesla system revealed a high ratio of choline-to-N-acetylaspartate in the region of interest in comparison to the contra-lateral side. Craniotomy and biopsy were performed. The histopathological diagnosis was medulloblastoma. The patient received craniospinal irradiation and chemotherapy, and achieved complete remission by the time of the follow-up MR images. She is now doing well with a full recovery of the right facial palsy. MR spectroscopic imaging is considered to be quite useful for the management of this rare type of brainstem tumor.

Endoscopic fenestration of the third ventricle in the reverse direction

INTRODUCTION

A case of safely treated parasellar cyst by endoscopic fenestration of the third ventricular floor from outside of the ventricle to establish communications between the cyst and the ventricle is reported.

MATERIALS AND METHODS

During the endoscopic procedures, the anterior commissure and the foramina of Monro could be clearly observed using this approach.

CONCLUSION

In treating parasellar cysts with thick walls, endoscopic fenestration of the third ventricular floor in the reverse direction, i.e., from inside of the cyst, should be considered.

A case of congenital supratentorial tumor: atypical teratoid/rhabdoid tumor or primitive neuroectodermal tumor?

Two embryonal CNS tumors, atypical teratoid/rabdoid tumor (AT/RT) and primitive neuroectodermal tumor (PNET), may be confused with each other and misdiagnosed. Here we report an infant with a congenital supratentorial tumor, which was detected by fetal MRI at 37 weeks gestation. On routine histological examination, the tumor was composed mainly of small undifferentiated cells, among which many rhabdoid cells and occasional sickle-shaped embracing cells were observed. No mesenchymal or epithelial areas were evident. Our impression was that the tumor was an atypical example of AT/RT. Immunohistochemically, almost all the tumor cells were strongly positive for vimentin. However, epithelial membrane antigen was notably negative, and most of the tumor cell nuclei were clearly positive for INI1. In addition, many tumor cells were positive for neurofilament protein. There were also occasional small areas containing many tumor cells positive for glial fibrillary acidic protein. Finally, a diagnosis of PNET, with a rhabdoid phenotype and expression of neuronal and glial markers, was made. In the present case, application of INI1 immunostaining was very helpful for distinguishing PNET from AT/RT.

Endoscopic stent placement for treatment of secondary bilateral occlusion of the Monro foramina following endoscopic third ventriculostomy in a patient with aqueductal stenosis

✓ Nontumoral bilateral occlusion of the Monro foramina is a rare clinical condition. Treatment includes shunt placement, endoscopic procedures, or both. The authors describe the case of a 22-year-old woman who had previously undergone placement of a ventriculoperitoneal shunt via a right frontal approach for management of triventricular dilation due to aqueductal stenosis. Six years postoperatively she presented with right-sided slit-ventricle syndrome and stenosis of the right Monro foramen, which was treated with an endoscopic third ventriculostomy and fenestration of the septum pellucidum. Two years later she presented with bilateral lateral ventricular dilation. Inspection of the right lateral ventricle with a fiberscope revealed occlusion of the septum pellucidum fenestration; on observation, the right Monro foramen was covered by thick, tough granulation tissue and the left was occluded by thin membranous tissue. Repeated fenestration of the septum pellucidum and left Monro foraminoplasty were therefore performed by perforating this thin tissue. A stent was then introduced into the third ventricle via the right lateral ventricle, the fenestration in the septum pellucidum, and the left Monro foramen.

The authors note that fiberscopes are in general more maneuverable than rigid endoscopes and conclude that they are particularly useful for the treatment of this type of hydrocephalus.

Megalencephaly and polymicrogyria with polydactyly syndrome

We report the clinical manifestations of a 26-month-old Japanese girl with megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome. She was born to healthy, nonconsanguineous parents at 37 weeks by caesarian section after prenatal ultrasonography suggested hydrocephalus. Macrocephaly and polydactyly of both lower extremities were noted at birth. At 3 months of age, epileptic seizures developed. The patient displayed impaired vision and profound global developmental delay. Magnetic resonance imaging of the brain revealed dilatation of the lateral and third ventricles with cavum septi pellucidi et vergae and generalized polymicrogyria, most prominent in both perisylvian regions and the right frontal region. Despite ventriculomegaly, radionuclide cisternography indicated normal cerebrospinal circulation, suggesting that pathogenesis of the megalencephaly was unrelated to obstructive hydrocephalus. Decreased white matter volume and abnormal signal intensity in the occipital lobes were also noted. Visual disturbance due to white matter abnormality appears to represent a significant characteristic of this syndrome. The genetic background of the syndrome remains unclear.